add assimp submodule

62 files changed, 15356 insertions, 0 deletions

diff --git a/src/mesh/assimp-master/code/PostProcessing/ArmaturePopulate.cpp b/src/mesh/assimp-master/code/PostProcessing/ArmaturePopulate.cpp
new file mode 100644
index 0000000..3fc1e12
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/ArmaturePopulate.cpp
@@ -0,0 +1,263 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+----------------------------------------------------------------------
+*/
+#include "ArmaturePopulate.h"
+
+#include <assimp/BaseImporter.h>
+#include <assimp/DefaultLogger.hpp>
+#include <assimp/postprocess.h>
+#include <assimp/scene.h>
+#include <iostream>
+
+namespace Assimp {
+
+/// The default class constructor.
+ArmaturePopulate::ArmaturePopulate() :
+        BaseProcess() {
+    // do nothing
+}
+
+/// The class destructor.
+ArmaturePopulate::~ArmaturePopulate() {
+    // do nothing
+}
+
+bool ArmaturePopulate::IsActive(unsigned int pFlags) const {
+    return (pFlags & aiProcess_PopulateArmatureData) != 0;
+}
+
+void ArmaturePopulate::SetupProperties(const Importer *) {
+    // do nothing
+}
+
+void ArmaturePopulate::Execute(aiScene *out) {
+
+    // Now convert all bone positions to the correct mOffsetMatrix
+    std::vector<aiBone *> bones;
+    std::vector<aiNode *> nodes;
+    std::map<aiBone *, aiNode *> bone_stack;
+    BuildBoneList(out->mRootNode, out->mRootNode, out, bones);
+    BuildNodeList(out->mRootNode, nodes);
+
+    BuildBoneStack(out->mRootNode, out->mRootNode, out, bones, bone_stack, nodes);
+
+    ASSIMP_LOG_DEBUG("Bone stack size: ", bone_stack.size());
+
+    for (std::pair<aiBone *, aiNode *> kvp : bone_stack) {
+        aiBone *bone = kvp.first;
+        aiNode *bone_node = kvp.second;
+        ASSIMP_LOG_VERBOSE_DEBUG("active node lookup: ", bone->mName.C_Str());
+        // lcl transform grab - done in generate_nodes :)
+
+        // bone->mOffsetMatrix = bone_node->mTransformation;
+        aiNode *armature = GetArmatureRoot(bone_node, bones);
+
+        ai_assert(armature);
+
+        // set up bone armature id
+        bone->mArmature = armature;
+
+        // set this bone node to be referenced properly
+        ai_assert(bone_node);
+        bone->mNode = bone_node;
+    }
+}
+
+
+// Reprocess all nodes to calculate bone transforms properly based on the REAL
+// mOffsetMatrix not the local.
+// Before this would use mesh transforms which is wrong for bone transforms
+// Before this would work for simple character skeletons but not complex meshes
+// with multiple origins
+// Source: sketch fab log cutter fbx
+void ArmaturePopulate::BuildBoneList(aiNode *current_node,
+                                     const aiNode *root_node,
+                                     const aiScene *scene,
+                                     std::vector<aiBone *> &bones) {
+    ai_assert(scene);
+    for (unsigned int nodeId = 0; nodeId < current_node->mNumChildren; ++nodeId) {
+        aiNode *child = current_node->mChildren[nodeId];
+        ai_assert(child);
+
+        // check for bones
+        for (unsigned int meshId = 0; meshId < child->mNumMeshes; ++meshId) {
+            ai_assert(child->mMeshes);
+            unsigned int mesh_index = child->mMeshes[meshId];
+            aiMesh *mesh = scene->mMeshes[mesh_index];
+            ai_assert(mesh);
+
+            for (unsigned int boneId = 0; boneId < mesh->mNumBones; ++boneId) {
+                aiBone *bone = mesh->mBones[boneId];
+                ai_assert(nullptr != bone);
+
+                // duplicate mehes exist with the same bones sometimes :)
+                // so this must be detected
+                if (std::find(bones.begin(), bones.end(), bone) == bones.end()) {
+                    // add the element once
+                    bones.emplace_back(bone);
+                }
+            }
+
+            // find mesh and get bones
+            // then do recursive lookup for bones in root node hierarchy
+        }
+
+        BuildBoneList(child, root_node, scene, bones);
+    }
+}
+
+// Prepare flat node list which can be used for non recursive lookups later
+void ArmaturePopulate::BuildNodeList(const aiNode *current_node,
+                                     std::vector<aiNode *> &nodes) {
+    ai_assert(nullptr != current_node);
+
+    for (unsigned int nodeId = 0; nodeId < current_node->mNumChildren; ++nodeId) {
+        aiNode *child = current_node->mChildren[nodeId];
+        ai_assert(child);
+
+        if (child->mNumMeshes == 0) {
+            nodes.emplace_back(child);
+        }
+
+        BuildNodeList(child, nodes);
+  }
+}
+
+// A bone stack allows us to have multiple armatures, with the same bone names
+// A bone stack allows us also to retrieve bones true transform even with
+// duplicate names :)
+void ArmaturePopulate::BuildBoneStack(aiNode *,
+                                      const aiNode *root_node,
+                                      const aiScene*,
+                                      const std::vector<aiBone *> &bones,
+                                      std::map<aiBone *, aiNode *> &bone_stack,
+                                  std::vector<aiNode *> &node_stack) {
+    if (node_stack.empty()) {
+        return;
+    }
+    ai_assert(nullptr != root_node);
+
+    for (aiBone *bone : bones) {
+        ai_assert(bone);
+        aiNode *node = GetNodeFromStack(bone->mName, node_stack);
+        if (node == nullptr) {
+            node_stack.clear();
+            BuildNodeList(root_node, node_stack);
+            ASSIMP_LOG_VERBOSE_DEBUG("Resetting bone stack: nullptr element ", bone->mName.C_Str());
+
+            node = GetNodeFromStack(bone->mName, node_stack);
+
+            if (nullptr == node) {
+                ASSIMP_LOG_ERROR("serious import issue node for bone was not detected");
+                continue;
+            }
+        }
+
+        ASSIMP_LOG_VERBOSE_DEBUG("Successfully added bone[", bone->mName.C_Str(), "] to stack and bone node is: ", node->mName.C_Str());
+
+        bone_stack.insert(std::pair<aiBone *, aiNode *>(bone, node));
+    }
+}
+
+// Returns the armature root node
+// This is required to be detected for a bone initially, it will recurse up
+// until it cannot find another bone and return the node No known failure
+// points. (yet)
+aiNode *ArmaturePopulate::GetArmatureRoot(aiNode *bone_node,
+                                          std::vector<aiBone *> &bone_list) {
+    while (nullptr != bone_node) {
+        if (!IsBoneNode(bone_node->mName, bone_list)) {
+            ASSIMP_LOG_VERBOSE_DEBUG("GetArmatureRoot() Found valid armature: ", bone_node->mName.C_Str());
+            return bone_node;
+        }
+
+        bone_node = bone_node->mParent;
+    }
+
+    ASSIMP_LOG_ERROR("GetArmatureRoot() can't find armature!");
+
+    return nullptr;
+}
+
+// Simple IsBoneNode check if this could be a bone
+bool ArmaturePopulate::IsBoneNode(const aiString &bone_name,
+                                  std::vector<aiBone *> &bones) {
+    for (aiBone *bone : bones) {
+        if (bone->mName == bone_name) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+// Pop this node by name from the stack if found
+// Used in multiple armature situations with duplicate node / bone names
+// Known flaw: cannot have nodes with bone names, will be fixed in later release
+// (serious to be fixed) Known flaw: nodes which have more than one bone could
+// be prematurely dropped from stack
+aiNode *ArmaturePopulate::GetNodeFromStack(const aiString &node_name,
+                                           std::vector<aiNode *> &nodes) {
+    std::vector<aiNode *>::iterator iter;
+    aiNode *found = nullptr;
+    for (iter = nodes.begin(); iter < nodes.end(); ++iter) {
+        aiNode *element = *iter;
+        ai_assert(nullptr != element);
+        // node valid and node name matches
+        if (element->mName == node_name) {
+            found = element;
+            break;
+        }
+    }
+
+    if (found != nullptr) {
+        ASSIMP_LOG_INFO("Removed node from stack: ", found->mName.C_Str());
+        // now pop the element from the node list
+        nodes.erase(iter);
+
+        return found;
+    }
+
+    // unique names can cause this problem
+    ASSIMP_LOG_ERROR("[Serious] GetNodeFromStack() can't find node from stack!");
+
+    return nullptr;
+}
+
+} // Namespace Assimp
diff --git a/src/mesh/assimp-master/code/PostProcessing/ArmaturePopulate.h b/src/mesh/assimp-master/code/PostProcessing/ArmaturePopulate.h
new file mode 100644
index 0000000..530932f
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/ArmaturePopulate.h
@@ -0,0 +1,112 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+#ifndef ARMATURE_POPULATE_H_
+#define ARMATURE_POPULATE_H_
+
+#include "Common/BaseProcess.h"
+#include <assimp/BaseImporter.h>
+#include <vector>
+#include <map>
+
+
+struct aiNode;
+struct aiBone;
+
+namespace Assimp {
+
+// ---------------------------------------------------------------------------
+/** Armature Populate: This is a post process designed
+ * To save you time when importing models into your game engines
+ * This was originally designed only for fbx but will work with other formats
+ * it is intended to auto populate aiBone data with armature and the aiNode
+ * This is very useful when dealing with skinned meshes
+ * or when dealing with many different skeletons
+ * It's off by default but recommend that you try it and use it
+ * It should reduce down any glue code you have in your
+ * importers
+ * You can contact RevoluPowered <gordon@gordonite.tech>
+ * For more info about this
+*/
+class ASSIMP_API ArmaturePopulate : public BaseProcess {
+public:
+    /// The default class constructor.
+    ArmaturePopulate();
+
+    /// The class destructor.
+    virtual ~ArmaturePopulate();
+
+    /// Overwritten, @see BaseProcess
+    virtual bool IsActive( unsigned int pFlags ) const;
+
+    /// Overwritten, @see BaseProcess
+    virtual void SetupProperties( const Importer* pImp );
+
+    /// Overwritten, @see BaseProcess
+    virtual void Execute( aiScene* pScene );
+
+    static aiNode *GetArmatureRoot(aiNode *bone_node,
+                                      std::vector<aiBone *> &bone_list);
+
+    static bool IsBoneNode(const aiString &bone_name,
+                              std::vector<aiBone *> &bones);
+
+    static aiNode *GetNodeFromStack(const aiString &node_name,
+                                       std::vector<aiNode *> &nodes);
+
+    static void BuildNodeList(const aiNode *current_node,
+                                 std::vector<aiNode *> &nodes);
+
+    static void BuildBoneList(aiNode *current_node, const aiNode *root_node,
+                                 const aiScene *scene,
+                                 std::vector<aiBone *> &bones);
+
+    static void BuildBoneStack(aiNode *current_node, const aiNode *root_node,
+                                  const aiScene *scene,
+                                  const std::vector<aiBone *> &bones,
+                                  std::map<aiBone *, aiNode *> &bone_stack,
+                                  std::vector<aiNode *> &node_stack);
+};
+
+} // Namespace Assimp
+
+
+#endif // SCALE_PROCESS_H_
diff --git a/src/mesh/assimp-master/code/PostProcessing/CalcTangentsProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/CalcTangentsProcess.cpp
new file mode 100644
index 0000000..b8847e4
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/CalcTangentsProcess.cpp
@@ -0,0 +1,303 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file Implementation of the post processing step to calculate
+ *  tangents and bitangents for all imported meshes
+ */
+
+// internal headers
+#include "CalcTangentsProcess.h"
+#include "ProcessHelper.h"
+#include <assimp/TinyFormatter.h>
+#include <assimp/qnan.h>
+
+using namespace Assimp;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+CalcTangentsProcess::CalcTangentsProcess() :
+        configMaxAngle(float(AI_DEG_TO_RAD(45.f))), configSourceUV(0) {
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+CalcTangentsProcess::~CalcTangentsProcess() {
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool CalcTangentsProcess::IsActive(unsigned int pFlags) const {
+    return (pFlags & aiProcess_CalcTangentSpace) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void CalcTangentsProcess::SetupProperties(const Importer *pImp) {
+    ai_assert(nullptr != pImp);
+
+    // get the current value of the property
+    configMaxAngle = pImp->GetPropertyFloat(AI_CONFIG_PP_CT_MAX_SMOOTHING_ANGLE, 45.f);
+    configMaxAngle = std::max(std::min(configMaxAngle, 45.0f), 0.0f);
+    configMaxAngle = AI_DEG_TO_RAD(configMaxAngle);
+
+    configSourceUV = pImp->GetPropertyInteger(AI_CONFIG_PP_CT_TEXTURE_CHANNEL_INDEX, 0);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void CalcTangentsProcess::Execute(aiScene *pScene) {
+    ai_assert(nullptr != pScene);
+
+    ASSIMP_LOG_DEBUG("CalcTangentsProcess begin");
+
+    bool bHas = false;
+    for (unsigned int a = 0; a < pScene->mNumMeshes; a++) {
+        if (ProcessMesh(pScene->mMeshes[a], a)) bHas = true;
+    }
+
+    if (bHas) {
+        ASSIMP_LOG_INFO("CalcTangentsProcess finished. Tangents have been calculated");
+    } else {
+        ASSIMP_LOG_DEBUG("CalcTangentsProcess finished");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Calculates tangents and bi-tangents for the given mesh
+bool CalcTangentsProcess::ProcessMesh(aiMesh *pMesh, unsigned int meshIndex) {
+    // we assume that the mesh is still in the verbose vertex format where each face has its own set
+    // of vertices and no vertices are shared between faces. Sadly I don't know any quick test to
+    // assert() it here.
+    // assert( must be verbose, dammit);
+
+    if (pMesh->mTangents) // this implies that mBitangents is also there
+        return false;
+
+    // If the mesh consists of lines and/or points but not of
+    // triangles or higher-order polygons the normal vectors
+    // are undefined.
+    if (!(pMesh->mPrimitiveTypes & (aiPrimitiveType_TRIANGLE | aiPrimitiveType_POLYGON))) {
+        ASSIMP_LOG_INFO("Tangents are undefined for line and point meshes");
+        return false;
+    }
+
+    // what we can check, though, is if the mesh has normals and texture coordinates. That's a requirement
+    if (pMesh->mNormals == nullptr) {
+        ASSIMP_LOG_ERROR("Failed to compute tangents; need normals");
+        return false;
+    }
+    if (configSourceUV >= AI_MAX_NUMBER_OF_TEXTURECOORDS || !pMesh->mTextureCoords[configSourceUV]) {
+        ASSIMP_LOG_ERROR("Failed to compute tangents; need UV data in channel", configSourceUV);
+        return false;
+    }
+
+    const float angleEpsilon = 0.9999f;
+
+    std::vector<bool> vertexDone(pMesh->mNumVertices, false);
+    const float qnan = get_qnan();
+
+    // create space for the tangents and bitangents
+    pMesh->mTangents = new aiVector3D[pMesh->mNumVertices];
+    pMesh->mBitangents = new aiVector3D[pMesh->mNumVertices];
+
+    const aiVector3D *meshPos = pMesh->mVertices;
+    const aiVector3D *meshNorm = pMesh->mNormals;
+    const aiVector3D *meshTex = pMesh->mTextureCoords[configSourceUV];
+    aiVector3D *meshTang = pMesh->mTangents;
+    aiVector3D *meshBitang = pMesh->mBitangents;
+
+    // calculate the tangent and bitangent for every face
+    for (unsigned int a = 0; a < pMesh->mNumFaces; a++) {
+        const aiFace &face = pMesh->mFaces[a];
+        if (face.mNumIndices < 3) {
+            // There are less than three indices, thus the tangent vector
+            // is not defined. We are finished with these vertices now,
+            // their tangent vectors are set to qnan.
+            for (unsigned int i = 0; i < face.mNumIndices; ++i) {
+                unsigned int idx = face.mIndices[i];
+                vertexDone[idx] = true;
+                meshTang[idx] = aiVector3D(qnan);
+                meshBitang[idx] = aiVector3D(qnan);
+            }
+
+            continue;
+        }
+
+        // triangle or polygon... we always use only the first three indices. A polygon
+        // is supposed to be planar anyways....
+        // FIXME: (thom) create correct calculation for multi-vertex polygons maybe?
+        const unsigned int p0 = face.mIndices[0], p1 = face.mIndices[1], p2 = face.mIndices[2];
+
+        // position differences p1->p2 and p1->p3
+        aiVector3D v = meshPos[p1] - meshPos[p0], w = meshPos[p2] - meshPos[p0];
+
+        // texture offset p1->p2 and p1->p3
+        float sx = meshTex[p1].x - meshTex[p0].x, sy = meshTex[p1].y - meshTex[p0].y;
+        float tx = meshTex[p2].x - meshTex[p0].x, ty = meshTex[p2].y - meshTex[p0].y;
+        float dirCorrection = (tx * sy - ty * sx) < 0.0f ? -1.0f : 1.0f;
+        // when t1, t2, t3 in same position in UV space, just use default UV direction.
+        if (sx * ty == sy * tx) {
+            sx = 0.0;
+            sy = 1.0;
+            tx = 1.0;
+            ty = 0.0;
+        }
+
+        // tangent points in the direction where to positive X axis of the texture coord's would point in model space
+        // bitangent's points along the positive Y axis of the texture coord's, respectively
+        aiVector3D tangent, bitangent;
+        tangent.x = (w.x * sy - v.x * ty) * dirCorrection;
+        tangent.y = (w.y * sy - v.y * ty) * dirCorrection;
+        tangent.z = (w.z * sy - v.z * ty) * dirCorrection;
+        bitangent.x = (- w.x * sx + v.x * tx) * dirCorrection;
+        bitangent.y = (- w.y * sx + v.y * tx) * dirCorrection;
+        bitangent.z = (- w.z * sx + v.z * tx) * dirCorrection;
+
+        // store for every vertex of that face
+        for (unsigned int b = 0; b < face.mNumIndices; ++b) {
+            unsigned int p = face.mIndices[b];
+
+            // project tangent and bitangent into the plane formed by the vertex' normal
+            aiVector3D localTangent = tangent - meshNorm[p] * (tangent * meshNorm[p]);
+            aiVector3D localBitangent = bitangent - meshNorm[p] * (bitangent * meshNorm[p]) - localTangent * (bitangent * localTangent);
+            localTangent.NormalizeSafe();
+            localBitangent.NormalizeSafe();
+
+            // reconstruct tangent/bitangent according to normal and bitangent/tangent when it's infinite or NaN.
+            bool invalid_tangent = is_special_float(localTangent.x) || is_special_float(localTangent.y) || is_special_float(localTangent.z);
+            bool invalid_bitangent = is_special_float(localBitangent.x) || is_special_float(localBitangent.y) || is_special_float(localBitangent.z);
+            if (invalid_tangent != invalid_bitangent) {
+                if (invalid_tangent) {
+                    localTangent = meshNorm[p] ^ localBitangent;
+                    localTangent.NormalizeSafe();
+                } else {
+                    localBitangent = localTangent ^ meshNorm[p];
+                    localBitangent.NormalizeSafe();
+                }
+            }
+
+            // and write it into the mesh.
+            meshTang[p] = localTangent;
+            meshBitang[p] = localBitangent;
+        }
+    }
+
+    // create a helper to quickly find locally close vertices among the vertex array
+    // FIX: check whether we can reuse the SpatialSort of a previous step
+    SpatialSort *vertexFinder = nullptr;
+    SpatialSort _vertexFinder;
+    float posEpsilon = 10e-6f;
+    if (shared) {
+        std::vector<std::pair<SpatialSort, float>> *avf;
+        shared->GetProperty(AI_SPP_SPATIAL_SORT, avf);
+        if (avf) {
+            std::pair<SpatialSort, float> &blubb = avf->operator[](meshIndex);
+            vertexFinder = &blubb.first;
+            posEpsilon = blubb.second;
+            ;
+        }
+    }
+    if (!vertexFinder) {
+        _vertexFinder.Fill(pMesh->mVertices, pMesh->mNumVertices, sizeof(aiVector3D));
+        vertexFinder = &_vertexFinder;
+        posEpsilon = ComputePositionEpsilon(pMesh);
+    }
+    std::vector<unsigned int> verticesFound;
+
+    const float fLimit = std::cos(configMaxAngle);
+    std::vector<unsigned int> closeVertices;
+
+    // in the second pass we now smooth out all tangents and bitangents at the same local position
+    // if they are not too far off.
+    for (unsigned int a = 0; a < pMesh->mNumVertices; a++) {
+        if (vertexDone[a])
+            continue;
+
+        const aiVector3D &origPos = pMesh->mVertices[a];
+        const aiVector3D &origNorm = pMesh->mNormals[a];
+        const aiVector3D &origTang = pMesh->mTangents[a];
+        const aiVector3D &origBitang = pMesh->mBitangents[a];
+        closeVertices.resize(0);
+
+        // find all vertices close to that position
+        vertexFinder->FindPositions(origPos, posEpsilon, verticesFound);
+
+        closeVertices.reserve(verticesFound.size() + 5);
+        closeVertices.push_back(a);
+
+        // look among them for other vertices sharing the same normal and a close-enough tangent/bitangent
+        for (unsigned int b = 0; b < verticesFound.size(); b++) {
+            unsigned int idx = verticesFound[b];
+            if (vertexDone[idx])
+                continue;
+            if (meshNorm[idx] * origNorm < angleEpsilon)
+                continue;
+            if (meshTang[idx] * origTang < fLimit)
+                continue;
+            if (meshBitang[idx] * origBitang < fLimit)
+                continue;
+
+            // it's similar enough -> add it to the smoothing group
+            closeVertices.push_back(idx);
+            vertexDone[idx] = true;
+        }
+
+        // smooth the tangents and bitangents of all vertices that were found to be close enough
+        aiVector3D smoothTangent(0, 0, 0), smoothBitangent(0, 0, 0);
+        for (unsigned int b = 0; b < closeVertices.size(); ++b) {
+            smoothTangent += meshTang[closeVertices[b]];
+            smoothBitangent += meshBitang[closeVertices[b]];
+        }
+        smoothTangent.Normalize();
+        smoothBitangent.Normalize();
+
+        // and write it back into all affected tangents
+        for (unsigned int b = 0; b < closeVertices.size(); ++b) {
+            meshTang[closeVertices[b]] = smoothTangent;
+            meshBitang[closeVertices[b]] = smoothBitangent;
+        }
+    }
+    return true;
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/CalcTangentsProcess.h b/src/mesh/assimp-master/code/PostProcessing/CalcTangentsProcess.h
new file mode 100644
index 0000000..018789b
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/CalcTangentsProcess.h
@@ -0,0 +1,117 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+
+/** @file Defines a post processing step to calculate tangents and
+    bi-tangents on all imported meshes.*/
+#ifndef AI_CALCTANGENTSPROCESS_H_INC
+#define AI_CALCTANGENTSPROCESS_H_INC
+
+#include "Common/BaseProcess.h"
+
+struct aiMesh;
+
+namespace Assimp
+{
+
+// ---------------------------------------------------------------------------
+/** The CalcTangentsProcess calculates the tangent and bitangent for any vertex
+ * of all meshes. It is expected to be run before the JoinVerticesProcess runs
+ * because the joining of vertices also considers tangents and bitangents for
+ * uniqueness.
+ */
+class ASSIMP_API_WINONLY CalcTangentsProcess : public BaseProcess
+{
+public:
+
+    CalcTangentsProcess();
+    ~CalcTangentsProcess();
+
+public:
+    // -------------------------------------------------------------------
+    /** Returns whether the processing step is present in the given flag.
+    * @param pFlags The processing flags the importer was called with.
+    *   A bitwise combination of #aiPostProcessSteps.
+    * @return true if the process is present in this flag fields,
+    *   false if not.
+    */
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    /** Called prior to ExecuteOnScene().
+    * The function is a request to the process to update its configuration
+    * basing on the Importer's configuration property list.
+    */
+    void SetupProperties(const Importer* pImp);
+
+
+    // setter for configMaxAngle
+    inline void SetMaxSmoothAngle(float f)
+    {
+        configMaxAngle =f;
+    }
+
+protected:
+
+    // -------------------------------------------------------------------
+    /** Calculates tangents and bitangents for a specific mesh.
+    * @param pMesh The mesh to process.
+    * @param meshIndex Index of the mesh
+    */
+    bool ProcessMesh( aiMesh* pMesh, unsigned int meshIndex);
+
+    // -------------------------------------------------------------------
+    /** Executes the post processing step on the given imported data.
+    * @param pScene The imported data to work at.
+    */
+    void Execute( aiScene* pScene);
+
+private:
+
+    /** Configuration option: maximum smoothing angle, in radians*/
+    float configMaxAngle;
+    unsigned int configSourceUV;
+};
+
+} // end of namespace Assimp
+
+#endif // AI_CALCTANGENTSPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/ComputeUVMappingProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/ComputeUVMappingProcess.cpp
new file mode 100644
index 0000000..c7456cc
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/ComputeUVMappingProcess.cpp
@@ -0,0 +1,506 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file GenUVCoords step */
+
+
+#include "ComputeUVMappingProcess.h"
+#include "ProcessHelper.h"
+#include <assimp/Exceptional.h>
+
+using namespace Assimp;
+
+namespace {
+
+    const static aiVector3D base_axis_y(0.0,1.0,0.0);
+    const static aiVector3D base_axis_x(1.0,0.0,0.0);
+    const static aiVector3D base_axis_z(0.0,0.0,1.0);
+    const static ai_real angle_epsilon = ai_real( 0.95 );
+}
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+ComputeUVMappingProcess::ComputeUVMappingProcess()
+{
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+ComputeUVMappingProcess::~ComputeUVMappingProcess()
+{
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool ComputeUVMappingProcess::IsActive( unsigned int pFlags) const
+{
+    return  (pFlags & aiProcess_GenUVCoords) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Check whether a ray intersects a plane and find the intersection point
+inline bool PlaneIntersect(const aiRay& ray, const aiVector3D& planePos,
+    const aiVector3D& planeNormal, aiVector3D& pos)
+{
+    const ai_real b = planeNormal * (planePos - ray.pos);
+    ai_real h = ray.dir * planeNormal;
+    if ((h < 10e-5 && h > -10e-5) || (h = b/h) < 0)
+        return false;
+
+    pos = ray.pos + (ray.dir * h);
+    return true;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Find the first empty UV channel in a mesh
+inline unsigned int FindEmptyUVChannel (aiMesh* mesh)
+{
+    for (unsigned int m = 0; m < AI_MAX_NUMBER_OF_TEXTURECOORDS;++m)
+        if (!mesh->mTextureCoords[m])return m;
+
+    ASSIMP_LOG_ERROR("Unable to compute UV coordinates, no free UV slot found");
+    return UINT_MAX;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Try to remove UV seams
+void RemoveUVSeams (aiMesh* mesh, aiVector3D* out)
+{
+    // TODO: just a very rough algorithm. I think it could be done
+    // much easier, but I don't know how and am currently too tired to
+    // to think about a better solution.
+
+    const static ai_real LOWER_LIMIT = ai_real( 0.1 );
+    const static ai_real UPPER_LIMIT = ai_real( 0.9 );
+
+    const static ai_real LOWER_EPSILON = ai_real( 10e-3 );
+    const static ai_real UPPER_EPSILON = ai_real( 1.0-10e-3 );
+
+    for (unsigned int fidx = 0; fidx < mesh->mNumFaces;++fidx)
+    {
+        const aiFace& face = mesh->mFaces[fidx];
+        if (face.mNumIndices < 3) continue; // triangles and polygons only, please
+
+        unsigned int smallV = face.mNumIndices, large = smallV;
+        bool zero = false, one = false, round_to_zero = false;
+
+        // Check whether this face lies on a UV seam. We can just guess,
+        // but the assumption that a face with at least one very small
+        // on the one side and one very large U coord on the other side
+        // lies on a UV seam should work for most cases.
+        for (unsigned int n = 0; n < face.mNumIndices;++n)
+        {
+            if (out[face.mIndices[n]].x < LOWER_LIMIT)
+            {
+                smallV = n;
+
+                // If we have a U value very close to 0 we can't
+                // round the others to 0, too.
+                if (out[face.mIndices[n]].x <= LOWER_EPSILON)
+                    zero = true;
+                else round_to_zero = true;
+            }
+            if (out[face.mIndices[n]].x > UPPER_LIMIT)
+            {
+                large = n;
+
+                // If we have a U value very close to 1 we can't
+                // round the others to 1, too.
+                if (out[face.mIndices[n]].x >= UPPER_EPSILON)
+                    one = true;
+            }
+        }
+        if (smallV != face.mNumIndices && large != face.mNumIndices)
+        {
+            for (unsigned int n = 0; n < face.mNumIndices;++n)
+            {
+                // If the u value is over the upper limit and no other u
+                // value of that face is 0, round it to 0
+                if (out[face.mIndices[n]].x > UPPER_LIMIT && !zero)
+                    out[face.mIndices[n]].x = 0.0;
+
+                // If the u value is below the lower limit and no other u
+                // value of that face is 1, round it to 1
+                else if (out[face.mIndices[n]].x < LOWER_LIMIT && !one)
+                    out[face.mIndices[n]].x = 1.0;
+
+                // The face contains both 0 and 1 as UV coords. This can occur
+                // for faces which have an edge that lies directly on the seam.
+                // Due to numerical inaccuracies one U coord becomes 0, the
+                // other 1. But we do still have a third UV coord to determine
+                // to which side we must round to.
+                else if (one && zero)
+                {
+                    if (round_to_zero && out[face.mIndices[n]].x >=  UPPER_EPSILON)
+                        out[face.mIndices[n]].x = 0.0;
+                    else if (!round_to_zero && out[face.mIndices[n]].x <= LOWER_EPSILON)
+                        out[face.mIndices[n]].x = 1.0;
+                }
+            }
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+void ComputeUVMappingProcess::ComputeSphereMapping(aiMesh* mesh,const aiVector3D& axis, aiVector3D* out)
+{
+    aiVector3D center, min, max;
+    FindMeshCenter(mesh, center, min, max);
+
+    // If the axis is one of x,y,z run a faster code path. It's worth the extra effort ...
+    // currently the mapping axis will always be one of x,y,z, except if the
+    // PretransformVertices step is used (it transforms the meshes into worldspace,
+    // thus changing the mapping axis)
+    if (axis * base_axis_x >= angle_epsilon)    {
+
+        // For each point get a normalized projection vector in the sphere,
+        // get its longitude and latitude and map them to their respective
+        // UV axes. Problems occur around the poles ... unsolvable.
+        //
+        // The spherical coordinate system looks like this:
+        // x = cos(lon)*cos(lat)
+        // y = sin(lon)*cos(lat)
+        // z = sin(lat)
+        //
+        // Thus we can derive:
+        // lat  = arcsin (z)
+        // lon  = arctan (y/x)
+        for (unsigned int pnt = 0; pnt < mesh->mNumVertices;++pnt)  {
+            const aiVector3D diff = (mesh->mVertices[pnt]-center).Normalize();
+            out[pnt] = aiVector3D((std::atan2(diff.z, diff.y) + AI_MATH_PI_F ) / AI_MATH_TWO_PI_F,
+                (std::asin  (diff.x) + AI_MATH_HALF_PI_F) / AI_MATH_PI_F, 0.0);
+        }
+    }
+    else if (axis * base_axis_y >= angle_epsilon)   {
+        // ... just the same again
+        for (unsigned int pnt = 0; pnt < mesh->mNumVertices;++pnt)  {
+            const aiVector3D diff = (mesh->mVertices[pnt]-center).Normalize();
+            out[pnt] = aiVector3D((std::atan2(diff.x, diff.z) + AI_MATH_PI_F ) / AI_MATH_TWO_PI_F,
+                (std::asin  (diff.y) + AI_MATH_HALF_PI_F) / AI_MATH_PI_F, 0.0);
+        }
+    }
+    else if (axis * base_axis_z >= angle_epsilon)   {
+        // ... just the same again
+        for (unsigned int pnt = 0; pnt < mesh->mNumVertices;++pnt)  {
+            const aiVector3D diff = (mesh->mVertices[pnt]-center).Normalize();
+            out[pnt] = aiVector3D((std::atan2(diff.y, diff.x) + AI_MATH_PI_F ) / AI_MATH_TWO_PI_F,
+                (std::asin  (diff.z) + AI_MATH_HALF_PI_F) / AI_MATH_PI_F, 0.0);
+        }
+    }
+    // slower code path in case the mapping axis is not one of the coordinate system axes
+    else    {
+        aiMatrix4x4 mTrafo;
+        aiMatrix4x4::FromToMatrix(axis,base_axis_y,mTrafo);
+
+        // again the same, except we're applying a transformation now
+        for (unsigned int pnt = 0; pnt < mesh->mNumVertices;++pnt)  {
+            const aiVector3D diff = ((mTrafo*mesh->mVertices[pnt])-center).Normalize();
+            out[pnt] = aiVector3D((std::atan2(diff.y, diff.x) + AI_MATH_PI_F ) / AI_MATH_TWO_PI_F,
+                (std::asin(diff.z) + AI_MATH_HALF_PI_F) / AI_MATH_PI_F, 0.0);
+        }
+    }
+
+
+    // Now find and remove UV seams. A seam occurs if a face has a tcoord
+    // close to zero on the one side, and a tcoord close to one on the
+    // other side.
+    RemoveUVSeams(mesh,out);
+}
+
+// ------------------------------------------------------------------------------------------------
+void ComputeUVMappingProcess::ComputeCylinderMapping(aiMesh* mesh,const aiVector3D& axis, aiVector3D* out)
+{
+    aiVector3D center, min, max;
+
+    // If the axis is one of x,y,z run a faster code path. It's worth the extra effort ...
+    // currently the mapping axis will always be one of x,y,z, except if the
+    // PretransformVertices step is used (it transforms the meshes into worldspace,
+    // thus changing the mapping axis)
+    if (axis * base_axis_x >= angle_epsilon)    {
+        FindMeshCenter(mesh, center, min, max);
+        const ai_real diff = max.x - min.x;
+
+        // If the main axis is 'z', the z coordinate of a point 'p' is mapped
+        // directly to the texture V axis. The other axis is derived from
+        // the angle between ( p.x - c.x, p.y - c.y ) and (1,0), where
+        // 'c' is the center point of the mesh.
+        for (unsigned int pnt = 0; pnt < mesh->mNumVertices;++pnt)  {
+            const aiVector3D& pos = mesh->mVertices[pnt];
+            aiVector3D& uv  = out[pnt];
+
+            uv.y = (pos.x - min.x) / diff;
+            uv.x = (std::atan2( pos.z - center.z, pos.y - center.y) +(ai_real)AI_MATH_PI ) / (ai_real)AI_MATH_TWO_PI;
+        }
+    }
+    else if (axis * base_axis_y >= angle_epsilon)   {
+        FindMeshCenter(mesh, center, min, max);
+        const ai_real diff = max.y - min.y;
+
+        // just the same ...
+        for (unsigned int pnt = 0; pnt < mesh->mNumVertices;++pnt)  {
+            const aiVector3D& pos = mesh->mVertices[pnt];
+            aiVector3D& uv  = out[pnt];
+
+            uv.y = (pos.y - min.y) / diff;
+            uv.x = (std::atan2( pos.x - center.x, pos.z - center.z) +(ai_real)AI_MATH_PI ) / (ai_real)AI_MATH_TWO_PI;
+        }
+    }
+    else if (axis * base_axis_z >= angle_epsilon)   {
+        FindMeshCenter(mesh, center, min, max);
+        const ai_real diff = max.z - min.z;
+
+        // just the same ...
+        for (unsigned int pnt = 0; pnt < mesh->mNumVertices;++pnt)  {
+            const aiVector3D& pos = mesh->mVertices[pnt];
+            aiVector3D& uv  = out[pnt];
+
+            uv.y = (pos.z - min.z) / diff;
+            uv.x = (std::atan2( pos.y - center.y, pos.x - center.x) +(ai_real)AI_MATH_PI ) / (ai_real)AI_MATH_TWO_PI;
+        }
+    }
+    // slower code path in case the mapping axis is not one of the coordinate system axes
+    else {
+        aiMatrix4x4 mTrafo;
+        aiMatrix4x4::FromToMatrix(axis,base_axis_y,mTrafo);
+        FindMeshCenterTransformed(mesh, center, min, max,mTrafo);
+        const ai_real diff = max.y - min.y;
+
+        // again the same, except we're applying a transformation now
+        for (unsigned int pnt = 0; pnt < mesh->mNumVertices;++pnt){
+            const aiVector3D pos = mTrafo* mesh->mVertices[pnt];
+            aiVector3D& uv  = out[pnt];
+
+            uv.y = (pos.y - min.y) / diff;
+            uv.x = (std::atan2( pos.x - center.x, pos.z - center.z) +(ai_real)AI_MATH_PI ) / (ai_real)AI_MATH_TWO_PI;
+        }
+    }
+
+    // Now find and remove UV seams. A seam occurs if a face has a tcoord
+    // close to zero on the one side, and a tcoord close to one on the
+    // other side.
+    RemoveUVSeams(mesh,out);
+}
+
+// ------------------------------------------------------------------------------------------------
+void ComputeUVMappingProcess::ComputePlaneMapping(aiMesh* mesh,const aiVector3D& axis, aiVector3D* out)
+{
+    ai_real diffu,diffv;
+    aiVector3D center, min, max;
+
+    // If the axis is one of x,y,z run a faster code path. It's worth the extra effort ...
+    // currently the mapping axis will always be one of x,y,z, except if the
+    // PretransformVertices step is used (it transforms the meshes into worldspace,
+    // thus changing the mapping axis)
+    if (axis * base_axis_x >= angle_epsilon)    {
+        FindMeshCenter(mesh, center, min, max);
+        diffu = max.z - min.z;
+        diffv = max.y - min.y;
+
+        for (unsigned int pnt = 0; pnt < mesh->mNumVertices;++pnt)  {
+            const aiVector3D& pos = mesh->mVertices[pnt];
+            out[pnt].Set((pos.z - min.z) / diffu,(pos.y - min.y) / diffv,0.0);
+        }
+    }
+    else if (axis * base_axis_y >= angle_epsilon)   {
+        FindMeshCenter(mesh, center, min, max);
+        diffu = max.x - min.x;
+        diffv = max.z - min.z;
+
+        for (unsigned int pnt = 0; pnt < mesh->mNumVertices;++pnt)  {
+            const aiVector3D& pos = mesh->mVertices[pnt];
+            out[pnt].Set((pos.x - min.x) / diffu,(pos.z - min.z) / diffv,0.0);
+        }
+    }
+    else if (axis * base_axis_z >= angle_epsilon)   {
+        FindMeshCenter(mesh, center, min, max);
+        diffu = max.x - min.x;
+        diffv = max.y - min.y;
+
+        for (unsigned int pnt = 0; pnt < mesh->mNumVertices;++pnt)  {
+            const aiVector3D& pos = mesh->mVertices[pnt];
+            out[pnt].Set((pos.x - min.x) / diffu,(pos.y - min.y) / diffv,0.0);
+        }
+    }
+    // slower code path in case the mapping axis is not one of the coordinate system axes
+    else
+    {
+        aiMatrix4x4 mTrafo;
+        aiMatrix4x4::FromToMatrix(axis,base_axis_y,mTrafo);
+        FindMeshCenterTransformed(mesh, center, min, max,mTrafo);
+        diffu = max.x - min.x;
+        diffv = max.z - min.z;
+
+        // again the same, except we're applying a transformation now
+        for (unsigned int pnt = 0; pnt < mesh->mNumVertices;++pnt)  {
+            const aiVector3D pos = mTrafo * mesh->mVertices[pnt];
+            out[pnt].Set((pos.x - min.x) / diffu,(pos.z - min.z) / diffv,0.0);
+        }
+    }
+
+    // shouldn't be necessary to remove UV seams ...
+}
+
+// ------------------------------------------------------------------------------------------------
+void ComputeUVMappingProcess::ComputeBoxMapping( aiMesh*, aiVector3D* )
+{
+    ASSIMP_LOG_ERROR("Mapping type currently not implemented");
+}
+
+// ------------------------------------------------------------------------------------------------
+void ComputeUVMappingProcess::Execute( aiScene* pScene)
+{
+    ASSIMP_LOG_DEBUG("GenUVCoordsProcess begin");
+    char buffer[1024];
+
+    if (pScene->mFlags & AI_SCENE_FLAGS_NON_VERBOSE_FORMAT)
+        throw DeadlyImportError("Post-processing order mismatch: expecting pseudo-indexed (\"verbose\") vertices here");
+
+    std::list<MappingInfo> mappingStack;
+
+    /*  Iterate through all materials and search for non-UV mapped textures
+     */
+    for (unsigned int i = 0; i < pScene->mNumMaterials;++i)
+    {
+        mappingStack.clear();
+        aiMaterial* mat = pScene->mMaterials[i];
+        for (unsigned int a = 0; a < mat->mNumProperties;++a)
+        {
+            aiMaterialProperty* prop = mat->mProperties[a];
+            if (!::strcmp( prop->mKey.data, "$tex.mapping"))
+            {
+                aiTextureMapping& mapping = *((aiTextureMapping*)prop->mData);
+                if (aiTextureMapping_UV != mapping)
+                {
+                    if (!DefaultLogger::isNullLogger())
+                    {
+                        ai_snprintf(buffer, 1024, "Found non-UV mapped texture (%s,%u). Mapping type: %s",
+                            TextureTypeToString((aiTextureType)prop->mSemantic),prop->mIndex,
+                            MappingTypeToString(mapping));
+
+                        ASSIMP_LOG_INFO(buffer);
+                    }
+
+                    if (aiTextureMapping_OTHER == mapping)
+                        continue;
+
+                    MappingInfo info (mapping);
+
+                    // Get further properties - currently only the major axis
+                    for (unsigned int a2 = 0; a2 < mat->mNumProperties;++a2)
+                    {
+                        aiMaterialProperty* prop2 = mat->mProperties[a2];
+                        if (prop2->mSemantic != prop->mSemantic || prop2->mIndex != prop->mIndex)
+                            continue;
+
+                        if ( !::strcmp( prop2->mKey.data, "$tex.mapaxis"))  {
+                            info.axis = *((aiVector3D*)prop2->mData);
+                            break;
+                        }
+                    }
+
+                    unsigned int idx( 99999999 );
+
+                    // Check whether we have this mapping mode already
+                    std::list<MappingInfo>::iterator it = std::find (mappingStack.begin(),mappingStack.end(), info);
+                    if (mappingStack.end() != it)
+                    {
+                        idx = (*it).uv;
+                    }
+                    else
+                    {
+                        /*  We have found a non-UV mapped texture. Now
+                        *   we need to find all meshes using this material
+                        *   that we can compute UV channels for them.
+                        */
+                        for (unsigned int m = 0; m < pScene->mNumMeshes;++m)
+                        {
+                            aiMesh* mesh = pScene->mMeshes[m];
+                            unsigned int outIdx = 0;
+                            if ( mesh->mMaterialIndex != i || ( outIdx = FindEmptyUVChannel(mesh) ) == UINT_MAX ||
+                                !mesh->mNumVertices)
+                            {
+                                continue;
+                            }
+
+                            // Allocate output storage
+                            aiVector3D* p = mesh->mTextureCoords[outIdx] = new aiVector3D[mesh->mNumVertices];
+
+                            switch (mapping)
+                            {
+                            case aiTextureMapping_SPHERE:
+                                ComputeSphereMapping(mesh,info.axis,p);
+                                break;
+                            case aiTextureMapping_CYLINDER:
+                                ComputeCylinderMapping(mesh,info.axis,p);
+                                break;
+                            case aiTextureMapping_PLANE:
+                                ComputePlaneMapping(mesh,info.axis,p);
+                                break;
+                            case aiTextureMapping_BOX:
+                                ComputeBoxMapping(mesh,p);
+                                break;
+                            default:
+                                ai_assert(false);
+                            }
+                            if (m && idx != outIdx)
+                            {
+                                ASSIMP_LOG_WARN("UV index mismatch. Not all meshes assigned to "
+                                    "this material have equal numbers of UV channels. The UV index stored in  "
+                                    "the material structure does therefore not apply for all meshes. ");
+                            }
+                            idx = outIdx;
+                        }
+                        info.uv = idx;
+                        mappingStack.push_back(info);
+                    }
+
+                    // Update the material property list
+                    mapping = aiTextureMapping_UV;
+                    ((aiMaterial*)mat)->AddProperty(&idx,1,AI_MATKEY_UVWSRC(prop->mSemantic,prop->mIndex));
+                }
+            }
+        }
+    }
+    ASSIMP_LOG_DEBUG("GenUVCoordsProcess finished");
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/ComputeUVMappingProcess.h b/src/mesh/assimp-master/code/PostProcessing/ComputeUVMappingProcess.h
new file mode 100644
index 0000000..74744be
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/ComputeUVMappingProcess.h
@@ -0,0 +1,149 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file Defines a post processing step to compute UV coordinates
+  from abstract mappings, such as box or spherical*/
+#ifndef AI_COMPUTEUVMAPPING_H_INC
+#define AI_COMPUTEUVMAPPING_H_INC
+
+#include "Common/BaseProcess.h"
+
+#include <assimp/mesh.h>
+#include <assimp/material.h>
+#include <assimp/types.h>
+
+class ComputeUVMappingTest;
+
+namespace Assimp {
+
+// ---------------------------------------------------------------------------
+/** ComputeUVMappingProcess - converts special mappings, such as spherical,
+ *  cylindrical or boxed to proper UV coordinates for rendering.
+*/
+class ComputeUVMappingProcess : public BaseProcess
+{
+public:
+    ComputeUVMappingProcess();
+    ~ComputeUVMappingProcess();
+
+public:
+
+    // -------------------------------------------------------------------
+    /** Returns whether the processing step is present in the given flag field.
+    * @param pFlags The processing flags the importer was called with. A bitwise
+    *   combination of #aiPostProcessSteps.
+    * @return true if the process is present in this flag fields, false if not.
+    */
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    /** Executes the post processing step on the given imported data.
+    * At the moment a process is not supposed to fail.
+    * @param pScene The imported data to work at.
+    */
+    void Execute( aiScene* pScene);
+
+protected:
+
+    // -------------------------------------------------------------------
+    /** Computes spherical UV coordinates for a mesh
+     *
+     *  @param mesh Mesh to be processed
+     *  @param axis Main axis
+     *  @param out Receives output UV coordinates
+    */
+    void ComputeSphereMapping(aiMesh* mesh,const aiVector3D& axis,
+        aiVector3D* out);
+
+    // -------------------------------------------------------------------
+    /** Computes cylindrical UV coordinates for a mesh
+     *
+     *  @param mesh Mesh to be processed
+     *  @param axis Main axis
+     *  @param out Receives output UV coordinates
+    */
+    void ComputeCylinderMapping(aiMesh* mesh,const aiVector3D& axis,
+        aiVector3D* out);
+
+    // -------------------------------------------------------------------
+    /** Computes planar UV coordinates for a mesh
+     *
+     *  @param mesh Mesh to be processed
+     *  @param axis Main axis
+     *  @param out Receives output UV coordinates
+    */
+    void ComputePlaneMapping(aiMesh* mesh,const aiVector3D& axis,
+        aiVector3D* out);
+
+    // -------------------------------------------------------------------
+    /** Computes cubic UV coordinates for a mesh
+     *
+     *  @param mesh Mesh to be processed
+     *  @param out Receives output UV coordinates
+    */
+    void ComputeBoxMapping(aiMesh* mesh, aiVector3D* out);
+
+private:
+
+    // temporary structure to describe a mapping
+    struct MappingInfo
+    {
+        explicit MappingInfo(aiTextureMapping _type)
+            : type  (_type)
+            , axis  (0.f,1.f,0.f)
+            , uv    (0u)
+        {}
+
+        aiTextureMapping type;
+        aiVector3D axis;
+        unsigned int uv;
+
+        bool operator== (const MappingInfo& other)
+        {
+            return type == other.type && axis == other.axis;
+        }
+    };
+};
+
+} // end of namespace Assimp
+
+#endif // AI_COMPUTEUVMAPPING_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/ConvertToLHProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/ConvertToLHProcess.cpp
new file mode 100644
index 0000000..4ded0fc
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/ConvertToLHProcess.cpp
@@ -0,0 +1,384 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file  MakeLeftHandedProcess.cpp
+ *  @brief Implementation of the post processing step to convert all
+ *  imported data to a left-handed coordinate system.
+ *
+ *  Face order & UV flip are also implemented here, for the sake of a
+ *  better location.
+ */
+
+#include "ConvertToLHProcess.h"
+#include <assimp/postprocess.h>
+#include <assimp/scene.h>
+#include <assimp/DefaultLogger.hpp>
+
+using namespace Assimp;
+
+#ifndef ASSIMP_BUILD_NO_MAKELEFTHANDED_PROCESS
+
+namespace {
+
+template <typename aiMeshType>
+void flipUVs(aiMeshType *pMesh) {
+    if (pMesh == nullptr) {
+        return;
+    }
+    // mirror texture y coordinate
+    for (unsigned int tcIdx = 0; tcIdx < AI_MAX_NUMBER_OF_TEXTURECOORDS; tcIdx++) {
+        if (!pMesh->HasTextureCoords(tcIdx)) {
+            break;
+        }
+
+        for (unsigned int vIdx = 0; vIdx < pMesh->mNumVertices; vIdx++) {
+            pMesh->mTextureCoords[tcIdx][vIdx].y = 1.0f - pMesh->mTextureCoords[tcIdx][vIdx].y;
+        }
+    }
+}
+
+} // namespace
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+MakeLeftHandedProcess::MakeLeftHandedProcess() :
+        BaseProcess() {
+    // empty
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+MakeLeftHandedProcess::~MakeLeftHandedProcess() {
+    // empty
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool MakeLeftHandedProcess::IsActive(unsigned int pFlags) const {
+    return 0 != (pFlags & aiProcess_MakeLeftHanded);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void MakeLeftHandedProcess::Execute(aiScene *pScene) {
+    // Check for an existent root node to proceed
+    ai_assert(pScene->mRootNode != nullptr);
+    ASSIMP_LOG_DEBUG("MakeLeftHandedProcess begin");
+
+    // recursively convert all the nodes
+    ProcessNode(pScene->mRootNode, aiMatrix4x4());
+
+    // process the meshes accordingly
+    for (unsigned int a = 0; a < pScene->mNumMeshes; ++a) {
+        ProcessMesh(pScene->mMeshes[a]);
+    }
+
+    // process the materials accordingly
+    for (unsigned int a = 0; a < pScene->mNumMaterials; ++a) {
+        ProcessMaterial(pScene->mMaterials[a]);
+    }
+
+    // transform all animation channels as well
+    for (unsigned int a = 0; a < pScene->mNumAnimations; a++) {
+        aiAnimation *anim = pScene->mAnimations[a];
+        for (unsigned int b = 0; b < anim->mNumChannels; b++) {
+            aiNodeAnim *nodeAnim = anim->mChannels[b];
+            ProcessAnimation(nodeAnim);
+        }
+    }
+    ASSIMP_LOG_DEBUG("MakeLeftHandedProcess finished");
+}
+
+// ------------------------------------------------------------------------------------------------
+// Recursively converts a node, all of its children and all of its meshes
+void MakeLeftHandedProcess::ProcessNode(aiNode *pNode, const aiMatrix4x4 &pParentGlobalRotation) {
+    // mirror all base vectors at the local Z axis
+    pNode->mTransformation.c1 = -pNode->mTransformation.c1;
+    pNode->mTransformation.c2 = -pNode->mTransformation.c2;
+    pNode->mTransformation.c3 = -pNode->mTransformation.c3;
+    pNode->mTransformation.c4 = -pNode->mTransformation.c4;
+
+    // now invert the Z axis again to keep the matrix determinant positive.
+    // The local meshes will be inverted accordingly so that the result should look just fine again.
+    pNode->mTransformation.a3 = -pNode->mTransformation.a3;
+    pNode->mTransformation.b3 = -pNode->mTransformation.b3;
+    pNode->mTransformation.c3 = -pNode->mTransformation.c3;
+    pNode->mTransformation.d3 = -pNode->mTransformation.d3; // useless, but anyways...
+
+    // continue for all children
+    for (size_t a = 0; a < pNode->mNumChildren; ++a) {
+        ProcessNode(pNode->mChildren[a], pParentGlobalRotation * pNode->mTransformation);
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Converts a single mesh to left handed coordinates.
+void MakeLeftHandedProcess::ProcessMesh(aiMesh *pMesh) {
+    if (nullptr == pMesh) {
+        ASSIMP_LOG_ERROR("Nullptr to mesh found.");
+        return;
+    }
+    // mirror positions, normals and stuff along the Z axis
+    for (size_t a = 0; a < pMesh->mNumVertices; ++a) {
+        pMesh->mVertices[a].z *= -1.0f;
+        if (pMesh->HasNormals()) {
+            pMesh->mNormals[a].z *= -1.0f;
+        }
+        if (pMesh->HasTangentsAndBitangents()) {
+            pMesh->mTangents[a].z *= -1.0f;
+            pMesh->mBitangents[a].z *= -1.0f;
+        }
+    }
+
+    // mirror anim meshes positions, normals and stuff along the Z axis
+    for (size_t m = 0; m < pMesh->mNumAnimMeshes; ++m) {
+        for (size_t a = 0; a < pMesh->mAnimMeshes[m]->mNumVertices; ++a) {
+            pMesh->mAnimMeshes[m]->mVertices[a].z *= -1.0f;
+            if (pMesh->mAnimMeshes[m]->HasNormals()) {
+                pMesh->mAnimMeshes[m]->mNormals[a].z *= -1.0f;
+            }
+            if (pMesh->mAnimMeshes[m]->HasTangentsAndBitangents()) {
+                pMesh->mAnimMeshes[m]->mTangents[a].z *= -1.0f;
+                pMesh->mAnimMeshes[m]->mBitangents[a].z *= -1.0f;
+            }
+        }
+    }
+
+    // mirror offset matrices of all bones
+    for (size_t a = 0; a < pMesh->mNumBones; ++a) {
+        aiBone *bone = pMesh->mBones[a];
+        bone->mOffsetMatrix.a3 = -bone->mOffsetMatrix.a3;
+        bone->mOffsetMatrix.b3 = -bone->mOffsetMatrix.b3;
+        bone->mOffsetMatrix.d3 = -bone->mOffsetMatrix.d3;
+        bone->mOffsetMatrix.c1 = -bone->mOffsetMatrix.c1;
+        bone->mOffsetMatrix.c2 = -bone->mOffsetMatrix.c2;
+        bone->mOffsetMatrix.c4 = -bone->mOffsetMatrix.c4;
+    }
+
+    // mirror bitangents as well as they're derived from the texture coords
+    if (pMesh->HasTangentsAndBitangents()) {
+        for (unsigned int a = 0; a < pMesh->mNumVertices; a++)
+            pMesh->mBitangents[a] *= -1.0f;
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Converts a single material to left handed coordinates.
+void MakeLeftHandedProcess::ProcessMaterial(aiMaterial *_mat) {
+    if (nullptr == _mat) {
+        ASSIMP_LOG_ERROR("Nullptr to aiMaterial found.");
+        return;
+    }
+
+    aiMaterial *mat = (aiMaterial *)_mat;
+    for (unsigned int a = 0; a < mat->mNumProperties; ++a) {
+        aiMaterialProperty *prop = mat->mProperties[a];
+
+        // Mapping axis for UV mappings?
+        if (!::strcmp(prop->mKey.data, "$tex.mapaxis")) {
+            ai_assert(prop->mDataLength >= sizeof(aiVector3D)); // something is wrong with the validation if we end up here
+            aiVector3D *pff = (aiVector3D *)prop->mData;
+            pff->z *= -1.f;
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Converts the given animation to LH coordinates.
+void MakeLeftHandedProcess::ProcessAnimation(aiNodeAnim *pAnim) {
+    // position keys
+    for (unsigned int a = 0; a < pAnim->mNumPositionKeys; a++)
+        pAnim->mPositionKeys[a].mValue.z *= -1.0f;
+
+    // rotation keys
+    for (unsigned int a = 0; a < pAnim->mNumRotationKeys; a++) {
+        /* That's the safe version, but the float errors add up. So we try the short version instead
+        aiMatrix3x3 rotmat = pAnim->mRotationKeys[a].mValue.GetMatrix();
+        rotmat.a3 = -rotmat.a3; rotmat.b3 = -rotmat.b3;
+        rotmat.c1 = -rotmat.c1; rotmat.c2 = -rotmat.c2;
+        aiQuaternion rotquat( rotmat);
+        pAnim->mRotationKeys[a].mValue = rotquat;
+        */
+        pAnim->mRotationKeys[a].mValue.x *= -1.0f;
+        pAnim->mRotationKeys[a].mValue.y *= -1.0f;
+    }
+}
+
+#endif // !!  ASSIMP_BUILD_NO_MAKELEFTHANDED_PROCESS
+#ifndef ASSIMP_BUILD_NO_FLIPUVS_PROCESS
+// # FlipUVsProcess
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+FlipUVsProcess::FlipUVsProcess() {}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+FlipUVsProcess::~FlipUVsProcess() {}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool FlipUVsProcess::IsActive(unsigned int pFlags) const {
+    return 0 != (pFlags & aiProcess_FlipUVs);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void FlipUVsProcess::Execute(aiScene *pScene) {
+    ASSIMP_LOG_DEBUG("FlipUVsProcess begin");
+    for (unsigned int i = 0; i < pScene->mNumMeshes; ++i)
+        ProcessMesh(pScene->mMeshes[i]);
+
+    for (unsigned int i = 0; i < pScene->mNumMaterials; ++i)
+        ProcessMaterial(pScene->mMaterials[i]);
+    ASSIMP_LOG_DEBUG("FlipUVsProcess finished");
+}
+
+// ------------------------------------------------------------------------------------------------
+// Converts a single material
+void FlipUVsProcess::ProcessMaterial(aiMaterial *_mat) {
+    aiMaterial *mat = (aiMaterial *)_mat;
+    for (unsigned int a = 0; a < mat->mNumProperties; ++a) {
+        aiMaterialProperty *prop = mat->mProperties[a];
+        if (!prop) {
+            ASSIMP_LOG_VERBOSE_DEBUG("Property is null");
+            continue;
+        }
+
+        // UV transformation key?
+        if (!::strcmp(prop->mKey.data, "$tex.uvtrafo")) {
+            ai_assert(prop->mDataLength >= sizeof(aiUVTransform)); // something is wrong with the validation if we end up here
+            aiUVTransform *uv = (aiUVTransform *)prop->mData;
+
+            // just flip it, that's everything
+            uv->mTranslation.y *= -1.f;
+            uv->mRotation *= -1.f;
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Converts a single mesh
+void FlipUVsProcess::ProcessMesh(aiMesh *pMesh) {
+    flipUVs(pMesh);
+    for (unsigned int idx = 0; idx < pMesh->mNumAnimMeshes; idx++) {
+        flipUVs(pMesh->mAnimMeshes[idx]);
+    }
+}
+
+#endif // !ASSIMP_BUILD_NO_FLIPUVS_PROCESS
+#ifndef ASSIMP_BUILD_NO_FLIPWINDING_PROCESS
+// # FlipWindingOrderProcess
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+FlipWindingOrderProcess::FlipWindingOrderProcess() {}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+FlipWindingOrderProcess::~FlipWindingOrderProcess() {}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool FlipWindingOrderProcess::IsActive(unsigned int pFlags) const {
+    return 0 != (pFlags & aiProcess_FlipWindingOrder);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void FlipWindingOrderProcess::Execute(aiScene *pScene) {
+    ASSIMP_LOG_DEBUG("FlipWindingOrderProcess begin");
+    for (unsigned int i = 0; i < pScene->mNumMeshes; ++i)
+        ProcessMesh(pScene->mMeshes[i]);
+    ASSIMP_LOG_DEBUG("FlipWindingOrderProcess finished");
+}
+
+// ------------------------------------------------------------------------------------------------
+// Converts a single mesh
+void FlipWindingOrderProcess::ProcessMesh(aiMesh *pMesh) {
+    // invert the order of all faces in this mesh
+    for (unsigned int a = 0; a < pMesh->mNumFaces; a++) {
+        aiFace &face = pMesh->mFaces[a];
+        for (unsigned int b = 0; b < face.mNumIndices / 2; b++) {
+            std::swap(face.mIndices[b], face.mIndices[face.mNumIndices - 1 - b]);
+        }
+    }
+
+    // invert the order of all components in this mesh anim meshes
+    for (unsigned int m = 0; m < pMesh->mNumAnimMeshes; m++) {
+        aiAnimMesh *animMesh = pMesh->mAnimMeshes[m];
+        unsigned int numVertices = animMesh->mNumVertices;
+        if (animMesh->HasPositions()) {
+            for (unsigned int a = 0; a < numVertices; a++) {
+                std::swap(animMesh->mVertices[a], animMesh->mVertices[numVertices - 1 - a]);
+            }
+        }
+        if (animMesh->HasNormals()) {
+            for (unsigned int a = 0; a < numVertices; a++) {
+                std::swap(animMesh->mNormals[a], animMesh->mNormals[numVertices - 1 - a]);
+            }
+        }
+        for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; i++) {
+            if (animMesh->HasTextureCoords(i)) {
+                for (unsigned int a = 0; a < numVertices; a++) {
+                    std::swap(animMesh->mTextureCoords[i][a], animMesh->mTextureCoords[i][numVertices - 1 - a]);
+                }
+            }
+        }
+        if (animMesh->HasTangentsAndBitangents()) {
+            for (unsigned int a = 0; a < numVertices; a++) {
+                std::swap(animMesh->mTangents[a], animMesh->mTangents[numVertices - 1 - a]);
+                std::swap(animMesh->mBitangents[a], animMesh->mBitangents[numVertices - 1 - a]);
+            }
+        }
+        for (unsigned int v = 0; v < AI_MAX_NUMBER_OF_COLOR_SETS; v++) {
+            if (animMesh->HasVertexColors(v)) {
+                for (unsigned int a = 0; a < numVertices; a++) {
+                    std::swap(animMesh->mColors[v][a], animMesh->mColors[v][numVertices - 1 - a]);
+                }
+            }
+        }
+    }
+}
+
+#endif // !! ASSIMP_BUILD_NO_FLIPWINDING_PROCESS
diff --git a/src/mesh/assimp-master/code/PostProcessing/ConvertToLHProcess.h b/src/mesh/assimp-master/code/PostProcessing/ConvertToLHProcess.h
new file mode 100644
index 0000000..474056c
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/ConvertToLHProcess.h
@@ -0,0 +1,172 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file  MakeLeftHandedProcess.h
+ *  @brief Defines a bunch of post-processing steps to handle
+ *    coordinate system conversions.
+ *
+ *  - LH to RH
+ *  - UV origin upper-left to lower-left
+ *  - face order cw to ccw
+ */
+#ifndef AI_CONVERTTOLHPROCESS_H_INC
+#define AI_CONVERTTOLHPROCESS_H_INC
+
+#include <assimp/types.h>
+
+#include "Common/BaseProcess.h"
+
+struct aiMesh;
+struct aiNodeAnim;
+struct aiNode;
+struct aiMaterial;
+
+namespace Assimp    {
+
+// -----------------------------------------------------------------------------------
+/** @brief The MakeLeftHandedProcess converts all imported data to a left-handed
+ *   coordinate system.
+ *
+ * This implies a mirroring of the Z axis of the coordinate system. But to keep
+ * transformation matrices free from reflections we shift the reflection to other
+ * places. We mirror the meshes and adapt the rotations.
+ *
+ * @note RH-LH and LH-RH is the same, so this class can be used for both
+ */
+class MakeLeftHandedProcess : public BaseProcess
+{
+
+
+public:
+    MakeLeftHandedProcess();
+    ~MakeLeftHandedProcess();
+
+    // -------------------------------------------------------------------
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    void Execute( aiScene* pScene);
+
+protected:
+
+    // -------------------------------------------------------------------
+    /** Recursively converts a node and all of its children
+     */
+    void ProcessNode( aiNode* pNode, const aiMatrix4x4& pParentGlobalRotation);
+
+    // -------------------------------------------------------------------
+    /** Converts a single mesh to left handed coordinates.
+     * This means that positions, normals and tangents are mirrored at
+     * the local Z axis and the order of all faces are inverted.
+     * @param pMesh The mesh to convert.
+     */
+    void ProcessMesh( aiMesh* pMesh);
+
+    // -------------------------------------------------------------------
+    /** Converts a single material to left-handed coordinates
+     * @param pMat Material to convert
+     */
+    void ProcessMaterial( aiMaterial* pMat);
+
+    // -------------------------------------------------------------------
+    /** Converts the given animation to LH coordinates.
+     * The rotation and translation keys are transformed, the scale keys
+     * work in local space and can therefore be left untouched.
+     * @param pAnim The bone animation to transform
+     */
+    void ProcessAnimation( aiNodeAnim* pAnim);
+};
+
+
+// ---------------------------------------------------------------------------
+/** Postprocessing step to flip the face order of the imported data
+ */
+class FlipWindingOrderProcess : public BaseProcess
+{
+    friend class Importer;
+
+public:
+    /** Constructor to be privately used by Importer */
+    FlipWindingOrderProcess();
+
+    /** Destructor, private as well */
+    ~FlipWindingOrderProcess();
+
+    // -------------------------------------------------------------------
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    void Execute( aiScene* pScene);
+
+public:
+    /** Some other types of post-processing require winding order flips */
+    static void ProcessMesh( aiMesh* pMesh);
+};
+
+// ---------------------------------------------------------------------------
+/** Postprocessing step to flip the UV coordinate system of the import data
+ */
+class FlipUVsProcess : public BaseProcess
+{
+    friend class Importer;
+
+public:
+    /** Constructor to be privately used by Importer */
+    FlipUVsProcess();
+
+    /** Destructor, private as well */
+    ~FlipUVsProcess();
+
+    // -------------------------------------------------------------------
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    void Execute( aiScene* pScene);
+
+protected:
+    void ProcessMesh( aiMesh* pMesh);
+    void ProcessMaterial( aiMaterial* mat);
+};
+
+} // end of namespace Assimp
+
+#endif // AI_CONVERTTOLHPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/DeboneProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/DeboneProcess.cpp
new file mode 100644
index 0000000..e8cfb16
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/DeboneProcess.cpp
@@ -0,0 +1,466 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/// @file DeboneProcess.cpp
+/** Implementation of the DeboneProcess post processing step */
+
+
+
+// internal headers of the post-processing framework
+#include "ProcessHelper.h"
+#include "DeboneProcess.h"
+#include <stdio.h>
+
+
+using namespace Assimp;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+DeboneProcess::DeboneProcess()
+{
+    mNumBones = 0;
+    mNumBonesCanDoWithout = 0;
+
+    mThreshold = AI_DEBONE_THRESHOLD;
+    mAllOrNone = false;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+DeboneProcess::~DeboneProcess()
+{
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool DeboneProcess::IsActive( unsigned int pFlags) const
+{
+    return (pFlags & aiProcess_Debone) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void DeboneProcess::SetupProperties(const Importer* pImp)
+{
+    // get the current value of the property
+    mAllOrNone = pImp->GetPropertyInteger(AI_CONFIG_PP_DB_ALL_OR_NONE,0)?true:false;
+    mThreshold = pImp->GetPropertyFloat(AI_CONFIG_PP_DB_THRESHOLD,AI_DEBONE_THRESHOLD);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void DeboneProcess::Execute( aiScene* pScene)
+{
+    ASSIMP_LOG_DEBUG("DeboneProcess begin");
+
+    if(!pScene->mNumMeshes) {
+        return;
+    }
+
+    std::vector<bool> splitList(pScene->mNumMeshes);
+    for( unsigned int a = 0; a < pScene->mNumMeshes; a++) {
+        splitList[a] = ConsiderMesh( pScene->mMeshes[a] );
+    }
+
+    int numSplits = 0;
+
+    if(!!mNumBonesCanDoWithout && (!mAllOrNone||mNumBonesCanDoWithout==mNumBones))  {
+        for(unsigned int a = 0; a < pScene->mNumMeshes; a++)    {
+            if(splitList[a]) {
+                numSplits++;
+            }
+        }
+    }
+
+    if(numSplits)   {
+        // we need to do something. Let's go.
+        //mSubMeshIndices.clear();                  // really needed?
+        mSubMeshIndices.resize(pScene->mNumMeshes); // because we're doing it here anyway
+
+        // build a new array of meshes for the scene
+        std::vector<aiMesh*> meshes;
+
+        for(unsigned int a=0;a<pScene->mNumMeshes;a++)
+        {
+            aiMesh* srcMesh = pScene->mMeshes[a];
+
+            std::vector<std::pair<aiMesh*,const aiBone*> > newMeshes;
+
+            if(splitList[a]) {
+                SplitMesh(srcMesh,newMeshes);
+            }
+
+            // mesh was split
+            if(!newMeshes.empty())  {
+                unsigned int out = 0, in = srcMesh->mNumBones;
+
+                // store new meshes and indices of the new meshes
+                for(unsigned int b=0;b<newMeshes.size();b++)    {
+                    const aiString *find = newMeshes[b].second?&newMeshes[b].second->mName:0;
+
+                    aiNode *theNode = find?pScene->mRootNode->FindNode(*find):0;
+                    std::pair<unsigned int,aiNode*> push_pair(static_cast<unsigned int>(meshes.size()),theNode);
+
+                    mSubMeshIndices[a].push_back(push_pair);
+                    meshes.push_back(newMeshes[b].first);
+
+                    out+=newMeshes[b].first->mNumBones;
+                }
+
+                if(!DefaultLogger::isNullLogger()) {
+                    ASSIMP_LOG_INFO("Removed %u bones. Input bones:", in - out, ". Output bones: ", out);
+                }
+
+                // and destroy the source mesh. It should be completely contained inside the new submeshes
+                delete srcMesh;
+            }
+            else    {
+                // Mesh is kept unchanged - store it's new place in the mesh array
+                mSubMeshIndices[a].push_back(std::pair<unsigned int,aiNode*>(static_cast<unsigned int>(meshes.size()),(aiNode*)0));
+                meshes.push_back(srcMesh);
+            }
+        }
+
+        // rebuild the scene's mesh array
+        pScene->mNumMeshes = static_cast<unsigned int>(meshes.size());
+        delete [] pScene->mMeshes;
+        pScene->mMeshes = new aiMesh*[pScene->mNumMeshes];
+        std::copy( meshes.begin(), meshes.end(), pScene->mMeshes);
+
+        // recurse through all nodes and translate the node's mesh indices to fit the new mesh array
+        UpdateNode( pScene->mRootNode);
+    }
+
+    ASSIMP_LOG_DEBUG("DeboneProcess end");
+}
+
+// ------------------------------------------------------------------------------------------------
+// Counts bones total/removable in a given mesh.
+bool DeboneProcess::ConsiderMesh(const aiMesh* pMesh)
+{
+    if(!pMesh->HasBones()) {
+        return false;
+    }
+
+    bool split = false;
+
+    //interstitial faces not permitted
+    bool isInterstitialRequired = false;
+
+    std::vector<bool> isBoneNecessary(pMesh->mNumBones,false);
+    std::vector<unsigned int> vertexBones(pMesh->mNumVertices,UINT_MAX);
+
+    const unsigned int cUnowned = UINT_MAX;
+    const unsigned int cCoowned = UINT_MAX-1;
+
+    for(unsigned int i=0;i<pMesh->mNumBones;i++)    {
+        for(unsigned int j=0;j<pMesh->mBones[i]->mNumWeights;j++)   {
+            float w = pMesh->mBones[i]->mWeights[j].mWeight;
+
+            if(w==0.0f) {
+                continue;
+            }
+
+            unsigned int vid = pMesh->mBones[i]->mWeights[j].mVertexId;
+            if(w>=mThreshold)   {
+
+                if(vertexBones[vid]!=cUnowned)  {
+                    if(vertexBones[vid]==i) //double entry
+                    {
+                        ASSIMP_LOG_WARN("Encountered double entry in bone weights");
+                    }
+                    else //TODO: track attraction in order to break tie
+                    {
+                        vertexBones[vid] = cCoowned;
+                    }
+                }
+                else vertexBones[vid] = i;
+            }
+
+            if(!isBoneNecessary[i]) {
+                isBoneNecessary[i] = w<mThreshold;
+            }
+        }
+
+        if(!isBoneNecessary[i])  {
+            isInterstitialRequired = true;
+        }
+    }
+
+    if(isInterstitialRequired) {
+        for(unsigned int i=0;i<pMesh->mNumFaces;i++) {
+            unsigned int v = vertexBones[pMesh->mFaces[i].mIndices[0]];
+
+            for(unsigned int j=1;j<pMesh->mFaces[i].mNumIndices;j++) {
+                unsigned int w = vertexBones[pMesh->mFaces[i].mIndices[j]];
+
+                if(v!=w)    {
+                    if(v<pMesh->mNumBones) isBoneNecessary[v] = true;
+                    if(w<pMesh->mNumBones) isBoneNecessary[w] = true;
+                }
+            }
+        }
+    }
+
+    for(unsigned int i=0;i<pMesh->mNumBones;i++)    {
+        if(!isBoneNecessary[i]) {
+            mNumBonesCanDoWithout++;
+            split = true;
+        }
+
+        mNumBones++;
+    }
+    return split;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Splits the given mesh by bone count.
+void DeboneProcess::SplitMesh( const aiMesh* pMesh, std::vector< std::pair< aiMesh*,const aiBone* > >& poNewMeshes) const
+{
+    // same deal here as ConsiderMesh basically
+
+    std::vector<bool> isBoneNecessary(pMesh->mNumBones,false);
+    std::vector<unsigned int> vertexBones(pMesh->mNumVertices,UINT_MAX);
+
+    const unsigned int cUnowned = UINT_MAX;
+    const unsigned int cCoowned = UINT_MAX-1;
+
+    for(unsigned int i=0;i<pMesh->mNumBones;i++)    {
+        for(unsigned int j=0;j<pMesh->mBones[i]->mNumWeights;j++)   {
+            float w = pMesh->mBones[i]->mWeights[j].mWeight;
+
+            if(w==0.0f) {
+                continue;
+            }
+
+            unsigned int vid = pMesh->mBones[i]->mWeights[j].mVertexId;
+
+            if(w>=mThreshold) {
+                if(vertexBones[vid]!=cUnowned)  {
+                    if(vertexBones[vid]==i) //double entry
+                    {
+                        ASSIMP_LOG_WARN("Encountered double entry in bone weights");
+                    }
+                    else //TODO: track attraction in order to break tie
+                    {
+                        vertexBones[vid] = cCoowned;
+                    }
+                }
+                else vertexBones[vid] = i;
+            }
+
+            if(!isBoneNecessary[i]) {
+                isBoneNecessary[i] = w<mThreshold;
+            }
+        }
+    }
+
+    unsigned int nFacesUnowned = 0;
+
+    std::vector<unsigned int> faceBones(pMesh->mNumFaces,UINT_MAX);
+    std::vector<unsigned int> facesPerBone(pMesh->mNumBones,0);
+
+    for(unsigned int i=0;i<pMesh->mNumFaces;i++) {
+        unsigned int nInterstitial = 1;
+
+        unsigned int v = vertexBones[pMesh->mFaces[i].mIndices[0]];
+
+        for(unsigned int j=1;j<pMesh->mFaces[i].mNumIndices;j++) {
+            unsigned int w = vertexBones[pMesh->mFaces[i].mIndices[j]];
+
+            if(v!=w)    {
+                if(v<pMesh->mNumBones) isBoneNecessary[v] = true;
+                if(w<pMesh->mNumBones) isBoneNecessary[w] = true;
+            }
+            else nInterstitial++;
+        }
+
+        if(v<pMesh->mNumBones &&nInterstitial==pMesh->mFaces[i].mNumIndices)    {
+            faceBones[i] = v; //primitive belongs to bone #v
+            facesPerBone[v]++;
+        }
+        else nFacesUnowned++;
+    }
+
+    // invalidate any "cojoined" faces
+    for(unsigned int i=0;i<pMesh->mNumFaces;i++) {
+        if(faceBones[i]<pMesh->mNumBones&&isBoneNecessary[faceBones[i]])
+        {
+            ai_assert(facesPerBone[faceBones[i]]>0);
+            facesPerBone[faceBones[i]]--;
+
+            nFacesUnowned++;
+            faceBones[i] = cUnowned;
+        }
+    }
+
+    if(nFacesUnowned) {
+        std::vector<unsigned int> subFaces;
+
+        for(unsigned int i=0;i<pMesh->mNumFaces;i++)    {
+            if(faceBones[i]==cUnowned) {
+                subFaces.push_back(i);
+            }
+        }
+
+        aiMesh *baseMesh = MakeSubmesh(pMesh,subFaces,0);
+        std::pair<aiMesh*,const aiBone*> push_pair(baseMesh,(const aiBone*)0);
+
+        poNewMeshes.push_back(push_pair);
+    }
+
+    for(unsigned int i=0;i<pMesh->mNumBones;i++) {
+
+        if(!isBoneNecessary[i]&&facesPerBone[i]>0)  {
+            std::vector<unsigned int> subFaces;
+
+            for(unsigned int j=0;j<pMesh->mNumFaces;j++)    {
+                if(faceBones[j]==i) {
+                    subFaces.push_back(j);
+                }
+            }
+
+            unsigned int f = AI_SUBMESH_FLAGS_SANS_BONES;
+            aiMesh *subMesh =MakeSubmesh(pMesh,subFaces,f);
+
+            //Lifted from PretransformVertices.cpp
+            ApplyTransform(subMesh,pMesh->mBones[i]->mOffsetMatrix);
+            std::pair<aiMesh*,const aiBone*> push_pair(subMesh,pMesh->mBones[i]);
+
+            poNewMeshes.push_back(push_pair);
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Recursively updates the node's mesh list to account for the changed mesh list
+void DeboneProcess::UpdateNode(aiNode* pNode) const
+{
+    // rebuild the node's mesh index list
+
+    std::vector<unsigned int> newMeshList;
+
+    // this will require two passes
+
+    unsigned int m = static_cast<unsigned int>(pNode->mNumMeshes), n = static_cast<unsigned int>(mSubMeshIndices.size());
+
+    // first pass, look for meshes which have not moved
+
+    for(unsigned int a=0;a<m;a++)   {
+
+        unsigned int srcIndex = pNode->mMeshes[a];
+        const std::vector< std::pair< unsigned int,aiNode* > > &subMeshes = mSubMeshIndices[srcIndex];
+        unsigned int nSubmeshes = static_cast<unsigned int>(subMeshes.size());
+
+        for(unsigned int b=0;b<nSubmeshes;b++) {
+            if(!subMeshes[b].second) {
+                newMeshList.push_back(subMeshes[b].first);
+            }
+        }
+    }
+
+    // second pass, collect deboned meshes
+
+    for(unsigned int a=0;a<n;a++)
+    {
+        const std::vector< std::pair< unsigned int,aiNode* > > &subMeshes = mSubMeshIndices[a];
+        unsigned int nSubmeshes = static_cast<unsigned int>(subMeshes.size());
+
+        for(unsigned int b=0;b<nSubmeshes;b++) {
+            if(subMeshes[b].second == pNode)    {
+                newMeshList.push_back(subMeshes[b].first);
+            }
+        }
+    }
+
+    if( pNode->mNumMeshes > 0 ) {
+        delete[] pNode->mMeshes;
+        pNode->mMeshes = nullptr;
+    }
+
+    pNode->mNumMeshes = static_cast<unsigned int>(newMeshList.size());
+
+    if(pNode->mNumMeshes)   {
+        pNode->mMeshes = new unsigned int[pNode->mNumMeshes];
+        std::copy( newMeshList.begin(), newMeshList.end(), pNode->mMeshes);
+    }
+
+    // do that also recursively for all children
+    for( unsigned int a = 0; a < pNode->mNumChildren; ++a ) {
+        UpdateNode( pNode->mChildren[a]);
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Apply the node transformation to a mesh
+void DeboneProcess::ApplyTransform(aiMesh* mesh, const aiMatrix4x4& mat)const
+{
+    // Check whether we need to transform the coordinates at all
+    if (!mat.IsIdentity()) {
+
+        if (mesh->HasPositions()) {
+            for (unsigned int i = 0; i < mesh->mNumVertices; ++i) {
+                mesh->mVertices[i] = mat * mesh->mVertices[i];
+            }
+        }
+        if (mesh->HasNormals() || mesh->HasTangentsAndBitangents()) {
+            aiMatrix4x4 mWorldIT = mat;
+            mWorldIT.Inverse().Transpose();
+
+            // TODO: implement Inverse() for aiMatrix3x3
+            aiMatrix3x3 m = aiMatrix3x3(mWorldIT);
+
+            if (mesh->HasNormals()) {
+                for (unsigned int i = 0; i < mesh->mNumVertices; ++i) {
+                    mesh->mNormals[i] = (m * mesh->mNormals[i]).Normalize();
+                }
+            }
+            if (mesh->HasTangentsAndBitangents()) {
+                for (unsigned int i = 0; i < mesh->mNumVertices; ++i) {
+                    mesh->mTangents[i]   = (m * mesh->mTangents[i]).Normalize();
+                    mesh->mBitangents[i] = (m * mesh->mBitangents[i]).Normalize();
+                }
+            }
+        }
+    }
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/DeboneProcess.h b/src/mesh/assimp-master/code/PostProcessing/DeboneProcess.h
new file mode 100644
index 0000000..cb072b7
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/DeboneProcess.h
@@ -0,0 +1,131 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** Defines a post processing step to limit the number of bones affecting a single vertex. */
+#ifndef AI_DEBONEPROCESS_H_INC
+#define AI_DEBONEPROCESS_H_INC
+
+#include "Common/BaseProcess.h"
+
+#include <assimp/mesh.h>
+#include <assimp/scene.h>
+
+#include <vector>
+#include <utility>
+
+#// Forward declarations
+class DeboneTest;
+
+namespace Assimp {
+
+#if (!defined AI_DEBONE_THRESHOLD)
+#   define AI_DEBONE_THRESHOLD  1.0f
+#endif // !! AI_DEBONE_THRESHOLD
+
+// ---------------------------------------------------------------------------
+/** This post processing step removes bones nearly losslessly or according to
+* a configured threshold. In order to remove the bone, the primitives affected by
+* the bone are split from the mesh. The split off (new) mesh is boneless. At any
+* point in time, bones without affect upon a given mesh are to be removed.
+*/
+class DeboneProcess : public BaseProcess {
+public:
+    DeboneProcess();
+    ~DeboneProcess();
+
+    // -------------------------------------------------------------------
+    /** Returns whether the processing step is present in the given flag.
+    * @param pFlags The processing flags the importer was called with.
+    *   A bitwise combination of #aiPostProcessSteps.
+    * @return true if the process is present in this flag fields,
+    *   false if not.
+    */
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    /** Called prior to ExecuteOnScene().
+    * The function is a request to the process to update its configuration
+    * basing on the Importer's configuration property list.
+    */
+    void SetupProperties(const Importer* pImp);
+
+protected:
+    // -------------------------------------------------------------------
+    /** Executes the post processing step on the given imported data.
+    * At the moment a process is not supposed to fail.
+    * @param pScene The imported data to work at.
+    */
+    void Execute( aiScene* pScene);
+
+    // -------------------------------------------------------------------
+    /** Counts bones total/removable in a given mesh.
+    * @param pMesh The mesh to process.
+    */
+    bool ConsiderMesh( const aiMesh* pMesh);
+
+    /// Splits the given mesh by bone count.
+    /// @param pMesh the Mesh to split. Is not changed at all, but might be superfluous in case it was split.
+    /// @param poNewMeshes Array of submeshes created in the process. Empty if splitting was not necessary.
+    void SplitMesh(const aiMesh* pMesh, std::vector< std::pair< aiMesh*,const aiBone* > >& poNewMeshes) const;
+
+    /// Recursively updates the node's mesh list to account for the changed mesh list
+    void UpdateNode(aiNode* pNode) const;
+
+    // -------------------------------------------------------------------
+    // Apply transformation to a mesh
+    void ApplyTransform(aiMesh* mesh, const aiMatrix4x4& mat)const;
+
+public:
+    /** Number of bones present in the scene. */
+    unsigned int mNumBones;
+    unsigned int mNumBonesCanDoWithout;
+
+    float mThreshold;
+    bool mAllOrNone;
+
+    /// Per mesh index: Array of indices of the new submeshes.
+    std::vector< std::vector< std::pair< unsigned int,aiNode* > > > mSubMeshIndices;
+};
+
+} // end of namespace Assimp
+
+#endif // AI_DEBONEPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/DropFaceNormalsProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/DropFaceNormalsProcess.cpp
new file mode 100644
index 0000000..0cf17f9
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/DropFaceNormalsProcess.cpp
@@ -0,0 +1,111 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file Implementation of the post processing step to drop face
+* normals for all imported faces.
+*/
+
+
+#include "DropFaceNormalsProcess.h"
+#include <assimp/postprocess.h>
+#include <assimp/scene.h>
+#include <assimp/DefaultLogger.hpp>
+#include <assimp/Exceptional.h>
+
+using namespace Assimp;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+DropFaceNormalsProcess::DropFaceNormalsProcess()
+{
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+DropFaceNormalsProcess::~DropFaceNormalsProcess()
+{
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool DropFaceNormalsProcess::IsActive( unsigned int pFlags) const {
+    return  (pFlags & aiProcess_DropNormals) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void DropFaceNormalsProcess::Execute( aiScene* pScene) {
+    ASSIMP_LOG_DEBUG("DropFaceNormalsProcess begin");
+
+    if (pScene->mFlags & AI_SCENE_FLAGS_NON_VERBOSE_FORMAT) {
+        throw DeadlyImportError("Post-processing order mismatch: expecting pseudo-indexed (\"verbose\") vertices here");
+    }
+
+    bool bHas = false;
+    for( unsigned int a = 0; a < pScene->mNumMeshes; a++) {
+        bHas |= this->DropMeshFaceNormals( pScene->mMeshes[a]);
+    }
+    if (bHas)   {
+        ASSIMP_LOG_INFO("DropFaceNormalsProcess finished. "
+            "Face normals have been removed");
+    } else {
+        ASSIMP_LOG_DEBUG("DropFaceNormalsProcess finished. "
+            "No normals were present");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+bool DropFaceNormalsProcess::DropMeshFaceNormals (aiMesh* mesh) {
+    ai_assert(nullptr != mesh);
+
+    if (nullptr == mesh->mNormals) {
+        return false;
+    }
+
+    delete[] mesh->mNormals;
+    mesh->mNormals = nullptr;
+    return true;
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/DropFaceNormalsProcess.h b/src/mesh/assimp-master/code/PostProcessing/DropFaceNormalsProcess.h
new file mode 100644
index 0000000..50abdc7
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/DropFaceNormalsProcess.h
@@ -0,0 +1,83 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file Defines a post processing step to compute face normals for all loaded faces*/
+#ifndef AI_DROPFACENORMALPROCESS_H_INC
+#define AI_DROPFACENORMALPROCESS_H_INC
+
+#include "Common/BaseProcess.h"
+
+#include <assimp/mesh.h>
+
+namespace Assimp {
+
+// ---------------------------------------------------------------------------
+/** The DropFaceNormalsProcess computes face normals for all faces of all meshes
+*/
+class ASSIMP_API_WINONLY DropFaceNormalsProcess : public BaseProcess {
+public:
+    DropFaceNormalsProcess();
+    ~DropFaceNormalsProcess();
+
+    // -------------------------------------------------------------------
+    /** Returns whether the processing step is present in the given flag field.
+    * @param pFlags The processing flags the importer was called with. A bitwise
+    *   combination of #aiPostProcessSteps.
+    * @return true if the process is present in this flag fields, false if not.
+    */
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    /** Executes the post processing step on the given imported data.
+    * At the moment a process is not supposed to fail.
+    * @param pScene The imported data to work at.
+    */
+    void Execute( aiScene* pScene);
+
+
+private:
+    bool DropMeshFaceNormals(aiMesh* pcMesh);
+};
+
+} // end of namespace Assimp
+
+#endif // !!AI_DROPFACENORMALPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/EmbedTexturesProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/EmbedTexturesProcess.cpp
new file mode 100644
index 0000000..2f80c90
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/EmbedTexturesProcess.cpp
@@ -0,0 +1,161 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+#include "EmbedTexturesProcess.h"
+#include <assimp/IOStream.hpp>
+#include <assimp/IOSystem.hpp>
+#include <assimp/ParsingUtils.h>
+#include "ProcessHelper.h"
+
+#include <fstream>
+
+using namespace Assimp;
+
+EmbedTexturesProcess::EmbedTexturesProcess() :
+        BaseProcess() {
+    // empty
+}
+
+EmbedTexturesProcess::~EmbedTexturesProcess() {
+    // empty
+}
+
+bool EmbedTexturesProcess::IsActive(unsigned int pFlags) const {
+    return (pFlags & aiProcess_EmbedTextures) != 0;
+}
+
+void EmbedTexturesProcess::SetupProperties(const Importer* pImp) {
+    mRootPath = pImp->GetPropertyString("sourceFilePath");
+    mRootPath = mRootPath.substr(0, mRootPath.find_last_of("\\/") + 1u);
+    mIOHandler = pImp->GetIOHandler();
+}
+
+void EmbedTexturesProcess::Execute(aiScene* pScene) {
+    if (pScene == nullptr || pScene->mRootNode == nullptr || mIOHandler == nullptr){
+        return;
+    }
+
+    aiString path;
+    uint32_t embeddedTexturesCount = 0u;
+    for (auto matId = 0u; matId < pScene->mNumMaterials; ++matId) {
+        auto material = pScene->mMaterials[matId];
+
+        for (auto ttId = 1u; ttId < AI_TEXTURE_TYPE_MAX; ++ttId) {
+            auto tt = static_cast<aiTextureType>(ttId);
+            auto texturesCount = material->GetTextureCount(tt);
+
+            for (auto texId = 0u; texId < texturesCount; ++texId) {
+                material->GetTexture(tt, texId, &path);
+                if (path.data[0] == '*') continue; // Already embedded
+
+                // Indeed embed
+                if (addTexture(pScene, path.data)) {
+                    auto embeddedTextureId = pScene->mNumTextures - 1u;
+                    path.length = ::ai_snprintf(path.data, 1024, "*%u", embeddedTextureId);
+                    material->AddProperty(&path, AI_MATKEY_TEXTURE(tt, texId));
+                    embeddedTexturesCount++;
+                }
+            }
+        }
+    }
+
+    ASSIMP_LOG_INFO("EmbedTexturesProcess finished. Embedded ", embeddedTexturesCount, " textures." );
+}
+
+bool EmbedTexturesProcess::addTexture(aiScene *pScene, const std::string &path) const {
+    std::streampos imageSize = 0;
+    std::string    imagePath = path;
+
+    // Test path directly
+    if (!mIOHandler->Exists(imagePath)) {
+        ASSIMP_LOG_WARN("EmbedTexturesProcess: Cannot find image: ", imagePath, ". Will try to find it in root folder.");
+
+        // Test path in root path
+        imagePath = mRootPath + path;
+        if (!mIOHandler->Exists(imagePath)) {
+            // Test path basename in root path
+            imagePath = mRootPath + path.substr(path.find_last_of("\\/") + 1u);
+            if (!mIOHandler->Exists(imagePath)) {
+                ASSIMP_LOG_ERROR("EmbedTexturesProcess: Unable to embed texture: ", path, ".");
+                return false;
+            }
+        }
+    }
+    IOStream* pFile = mIOHandler->Open(imagePath);
+    if (pFile == nullptr) {
+        ASSIMP_LOG_ERROR("EmbedTexturesProcess: Unable to embed texture: ", path, ".");
+        return false;
+    }
+    imageSize = pFile->FileSize();
+
+    aiTexel* imageContent = new aiTexel[ 1ul + static_cast<unsigned long>( imageSize ) / sizeof(aiTexel)];
+    pFile->Seek(0, aiOrigin_SET);
+    pFile->Read(reinterpret_cast<char*>(imageContent), imageSize, 1);
+    mIOHandler->Close(pFile);
+
+    // Enlarging the textures table
+    unsigned int textureId = pScene->mNumTextures++;
+    auto oldTextures = pScene->mTextures;
+    pScene->mTextures = new aiTexture*[pScene->mNumTextures];
+    ::memmove(pScene->mTextures, oldTextures, sizeof(aiTexture*) * (pScene->mNumTextures - 1u));
+    delete [] oldTextures;
+
+    // Add the new texture
+    auto pTexture = new aiTexture;
+    pTexture->mHeight = 0; // Means that this is still compressed
+    pTexture->mWidth = static_cast<uint32_t>(imageSize);
+    pTexture->pcData = imageContent;
+
+    auto extension = path.substr(path.find_last_of('.') + 1u);
+    extension = ai_tolower(extension);
+    if (extension == "jpeg") {
+        extension = "jpg";
+    }
+
+    size_t len = extension.size();
+    if (len > HINTMAXTEXTURELEN -1 ) {
+        len = HINTMAXTEXTURELEN - 1;
+    }
+    ::strncpy(pTexture->achFormatHint, extension.c_str(), len);
+    pScene->mTextures[textureId] = pTexture;
+
+    return true;
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/EmbedTexturesProcess.h b/src/mesh/assimp-master/code/PostProcessing/EmbedTexturesProcess.h
new file mode 100644
index 0000000..c3e6361
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/EmbedTexturesProcess.h
@@ -0,0 +1,88 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+#pragma once
+
+#include "Common/BaseProcess.h"
+
+#include <string>
+
+struct aiNode;
+
+class IOSystem;
+
+namespace Assimp {
+
+/**
+ *  Force embedding of textures (using the path = "*1" convention).
+ *  If a texture's file does not exist at the specified path
+ *  (due, for instance, to an absolute path generated on another system),
+ *  it will check if a file with the same name exists at the root folder
+ *  of the imported model. And if so, it uses that.
+ */
+class ASSIMP_API EmbedTexturesProcess : public BaseProcess {
+public:
+    /// The default class constructor.
+    EmbedTexturesProcess();
+
+    /// The class destructor.
+    virtual ~EmbedTexturesProcess();
+
+    /// Overwritten, @see BaseProcess
+    virtual bool IsActive(unsigned int pFlags) const;
+
+    /// Overwritten, @see BaseProcess
+    virtual void SetupProperties(const Importer* pImp);
+
+    /// Overwritten, @see BaseProcess
+    virtual void Execute(aiScene* pScene);
+
+private:
+    // Resolve the path and add the file content to the scene as a texture.
+    bool addTexture(aiScene *pScene, const std::string &path) const;
+
+private:
+    std::string mRootPath;
+    IOSystem* mIOHandler = nullptr;
+};
+
+} // namespace Assimp
diff --git a/src/mesh/assimp-master/code/PostProcessing/FindDegenerates.cpp b/src/mesh/assimp-master/code/PostProcessing/FindDegenerates.cpp
new file mode 100644
index 0000000..0bbf421
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/FindDegenerates.cpp
@@ -0,0 +1,297 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file  FindDegenerates.cpp
+ *  @brief Implementation of the FindDegenerates post-process step.
+*/
+
+#include "ProcessHelper.h"
+#include "FindDegenerates.h"
+
+#include <assimp/Exceptional.h>
+
+#include <unordered_map>
+
+using namespace Assimp;
+
+// Correct node indices to meshes and remove references to deleted mesh
+static void updateSceneGraph(aiNode* pNode, const std::unordered_map<unsigned int, unsigned int>& meshMap);
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+FindDegeneratesProcess::FindDegeneratesProcess() :
+        mConfigRemoveDegenerates( false ),
+        mConfigCheckAreaOfTriangle( false ){
+    // empty
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+FindDegeneratesProcess::~FindDegeneratesProcess() {
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool FindDegeneratesProcess::IsActive( unsigned int pFlags) const {
+    return 0 != (pFlags & aiProcess_FindDegenerates);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Setup import configuration
+void FindDegeneratesProcess::SetupProperties(const Importer* pImp) {
+    // Get the current value of AI_CONFIG_PP_FD_REMOVE
+    mConfigRemoveDegenerates = (0 != pImp->GetPropertyInteger(AI_CONFIG_PP_FD_REMOVE,0));
+    mConfigCheckAreaOfTriangle = ( 0 != pImp->GetPropertyInteger(AI_CONFIG_PP_FD_CHECKAREA) );
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void FindDegeneratesProcess::Execute( aiScene* pScene) {
+    ASSIMP_LOG_DEBUG("FindDegeneratesProcess begin");
+    if ( nullptr == pScene) {
+        return;
+    }
+
+    std::unordered_map<unsigned int, unsigned int> meshMap;
+    meshMap.reserve(pScene->mNumMeshes);
+
+    const unsigned int originalNumMeshes = pScene->mNumMeshes;
+    unsigned int targetIndex = 0;
+    for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
+        // Do not process point cloud, ExecuteOnMesh works only with faces data
+        if ((pScene->mMeshes[i]->mPrimitiveTypes != aiPrimitiveType::aiPrimitiveType_POINT) && ExecuteOnMesh(pScene->mMeshes[i])) {
+            delete pScene->mMeshes[i];
+            // Not strictly required, but clean:
+            pScene->mMeshes[i] = nullptr;
+        } else {
+            meshMap[i] = targetIndex;
+            pScene->mMeshes[targetIndex] = pScene->mMeshes[i];
+            ++targetIndex;
+        }
+    }
+    pScene->mNumMeshes = targetIndex;
+
+    if (meshMap.size() < originalNumMeshes) {
+        updateSceneGraph(pScene->mRootNode, meshMap);
+    }
+
+    ASSIMP_LOG_DEBUG("FindDegeneratesProcess finished");
+}
+
+static void updateSceneGraph(aiNode* pNode, const std::unordered_map<unsigned int, unsigned int>& meshMap) {
+    unsigned int targetIndex = 0;
+    for (unsigned i = 0; i < pNode->mNumMeshes; ++i) {
+        const unsigned int sourceMeshIndex = pNode->mMeshes[i];
+        auto it = meshMap.find(sourceMeshIndex);
+        if (it != meshMap.end()) {
+            pNode->mMeshes[targetIndex] = it->second;
+            ++targetIndex;
+        }
+    }
+    pNode->mNumMeshes = targetIndex;
+    //recurse to all children
+    for (unsigned i = 0; i < pNode->mNumChildren; ++i) {
+        updateSceneGraph(pNode->mChildren[i], meshMap);
+    }
+}
+
+static ai_real heron( ai_real a, ai_real b, ai_real c ) {
+    ai_real s = (a + b + c) / 2;
+    ai_real area = pow((s * ( s - a ) * ( s - b ) * ( s - c ) ), (ai_real)0.5 );
+    return area;
+}
+
+static ai_real distance3D( const aiVector3D &vA, aiVector3D &vB ) {
+    const ai_real lx = ( vB.x - vA.x );
+    const ai_real ly = ( vB.y - vA.y );
+    const ai_real lz = ( vB.z - vA.z );
+    ai_real a = lx*lx + ly*ly + lz*lz;
+    ai_real d = pow( a, (ai_real)0.5 );
+
+    return d;
+}
+
+static ai_real calculateAreaOfTriangle( const aiFace& face, aiMesh* mesh ) {
+    ai_real area = 0;
+
+    aiVector3D vA( mesh->mVertices[ face.mIndices[ 0 ] ] );
+    aiVector3D vB( mesh->mVertices[ face.mIndices[ 1 ] ] );
+    aiVector3D vC( mesh->mVertices[ face.mIndices[ 2 ] ] );
+
+    ai_real a( distance3D( vA, vB ) );
+    ai_real b( distance3D( vB, vC ) );
+    ai_real c( distance3D( vC, vA ) );
+    area = heron( a, b, c );
+
+    return area;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported mesh
+bool FindDegeneratesProcess::ExecuteOnMesh( aiMesh* mesh) {
+    mesh->mPrimitiveTypes = 0;
+
+    std::vector<bool> remove_me;
+    if (mConfigRemoveDegenerates) {
+        remove_me.resize( mesh->mNumFaces, false );
+    }
+
+    unsigned int deg = 0, limit;
+    for ( unsigned int a = 0; a < mesh->mNumFaces; ++a ) {
+        aiFace& face = mesh->mFaces[a];
+        bool first = true;
+
+        // check whether the face contains degenerated entries
+        for (unsigned int i = 0; i < face.mNumIndices; ++i) {
+            // Polygons with more than 4 points are allowed to have double points, that is
+            // simulating polygons with holes just with concave polygons. However,
+            // double points may not come directly after another.
+            limit = face.mNumIndices;
+            if (face.mNumIndices > 4) {
+                limit = std::min( limit, i+2 );
+            }
+
+            for (unsigned int t = i+1; t < limit; ++t) {
+                if (mesh->mVertices[face.mIndices[ i ] ] == mesh->mVertices[ face.mIndices[ t ] ]) {
+                    // we have found a matching vertex position
+                    // remove the corresponding index from the array
+                    --face.mNumIndices;
+                    --limit;
+                    for (unsigned int m = t; m < face.mNumIndices; ++m) {
+                        face.mIndices[ m ] = face.mIndices[ m+1 ];
+                    }
+                    --t;
+
+                    // NOTE: we set the removed vertex index to an unique value
+                    // to make sure the developer gets notified when his
+                    // application attempts to access this data.
+                    face.mIndices[ face.mNumIndices ] = 0xdeadbeef;
+
+                    if(first) {
+                        ++deg;
+                        first = false;
+                    }
+
+                    if ( mConfigRemoveDegenerates ) {
+                        remove_me[ a ] = true;
+                        goto evil_jump_outside; // hrhrhrh ... yeah, this rocks baby!
+                    }
+                }
+            }
+
+            if ( mConfigCheckAreaOfTriangle ) {
+                if ( face.mNumIndices == 3 ) {
+                    ai_real area = calculateAreaOfTriangle( face, mesh );
+                    if (area < ai_epsilon) {
+                        if ( mConfigRemoveDegenerates ) {
+                            remove_me[ a ] = true;
+                            ++deg;
+                            goto evil_jump_outside;
+                        }
+
+                        // todo: check for index which is corrupt.
+                    }
+                }
+            }
+        }
+
+        // We need to update the primitive flags array of the mesh.
+        switch (face.mNumIndices)
+        {
+        case 1u:
+            mesh->mPrimitiveTypes |= aiPrimitiveType_POINT;
+            break;
+        case 2u:
+            mesh->mPrimitiveTypes |= aiPrimitiveType_LINE;
+            break;
+        case 3u:
+            mesh->mPrimitiveTypes |= aiPrimitiveType_TRIANGLE;
+            break;
+        default:
+            mesh->mPrimitiveTypes |= aiPrimitiveType_POLYGON;
+            break;
+        };
+evil_jump_outside:
+        continue;
+    }
+
+    // If AI_CONFIG_PP_FD_REMOVE is true, remove degenerated faces from the import
+    if (mConfigRemoveDegenerates && deg) {
+        unsigned int n = 0;
+        for (unsigned int a = 0; a < mesh->mNumFaces; ++a)
+        {
+            aiFace& face_src = mesh->mFaces[a];
+            if (!remove_me[a]) {
+                aiFace& face_dest = mesh->mFaces[n++];
+
+                // Do a manual copy, keep the index array
+                face_dest.mNumIndices = face_src.mNumIndices;
+                face_dest.mIndices    = face_src.mIndices;
+
+                if (&face_src != &face_dest) {
+                    // clear source
+                    face_src.mNumIndices = 0;
+                    face_src.mIndices = nullptr;
+                }
+            }
+            else {
+                // Otherwise delete it if we don't need this face
+                delete[] face_src.mIndices;
+                face_src.mIndices = nullptr;
+                face_src.mNumIndices = 0;
+            }
+        }
+        // Just leave the rest of the array unreferenced, we don't care for now
+        mesh->mNumFaces = n;
+        if (!mesh->mNumFaces) {
+            //The whole mesh consists of degenerated faces
+            //signal upward, that this mesh should be deleted.
+            ASSIMP_LOG_VERBOSE_DEBUG("FindDegeneratesProcess removed a mesh full of degenerated primitives");
+            return true;
+        }
+    }
+
+    if (deg && !DefaultLogger::isNullLogger()) {
+        ASSIMP_LOG_WARN( "Found ", deg, " degenerated primitives");
+    }
+    return false;
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/FindDegenerates.h b/src/mesh/assimp-master/code/PostProcessing/FindDegenerates.h
new file mode 100644
index 0000000..6fe1e92
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/FindDegenerates.h
@@ -0,0 +1,130 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file Defines a post processing step to search all meshes for
+  degenerated faces */
+#ifndef AI_FINDDEGENERATESPROCESS_H_INC
+#define AI_FINDDEGENERATESPROCESS_H_INC
+
+#include "Common/BaseProcess.h"
+
+#include <assimp/mesh.h>
+
+class FindDegeneratesProcessTest;
+namespace Assimp    {
+
+
+// ---------------------------------------------------------------------------
+/** FindDegeneratesProcess: Searches a mesh for degenerated triangles.
+*/
+class ASSIMP_API FindDegeneratesProcess : public BaseProcess {
+public:
+    FindDegeneratesProcess();
+    ~FindDegeneratesProcess();
+
+    // -------------------------------------------------------------------
+    // Check whether step is active
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    // Execute step on a given scene
+    void Execute( aiScene* pScene);
+
+    // -------------------------------------------------------------------
+    // Setup import settings
+    void SetupProperties(const Importer* pImp);
+
+    // -------------------------------------------------------------------
+    // Execute step on a given mesh
+    ///@returns true if the current mesh should be deleted, false otherwise
+    bool ExecuteOnMesh( aiMesh* mesh);
+
+    // -------------------------------------------------------------------
+    /// @brief Enable the instant removal of degenerated primitives
+    /// @param enabled  true for enabled.
+    void EnableInstantRemoval(bool enabled);
+
+    // -------------------------------------------------------------------
+    /// @brief Check whether instant removal is currently enabled
+    /// @return The instant removal state.
+    bool IsInstantRemoval() const;
+
+    // -------------------------------------------------------------------
+    /// @brief Enable the area check for triangles.
+    /// @param enabled  true for enabled.
+    void EnableAreaCheck( bool enabled );
+
+    // -------------------------------------------------------------------
+    /// @brief Check whether the area check is enabled.
+    /// @return The area check state.
+    bool isAreaCheckEnabled() const;
+
+private:
+    //! Configuration option: remove degenerates faces immediately
+    bool mConfigRemoveDegenerates;
+    //! Configuration option: check for area
+    bool mConfigCheckAreaOfTriangle;
+};
+
+inline
+void FindDegeneratesProcess::EnableInstantRemoval(bool enabled) {
+    mConfigRemoveDegenerates = enabled;
+}
+
+inline
+bool FindDegeneratesProcess::IsInstantRemoval() const {
+    return mConfigRemoveDegenerates;
+}
+
+inline
+void FindDegeneratesProcess::EnableAreaCheck( bool enabled ) {
+    mConfigCheckAreaOfTriangle = enabled;
+}
+
+inline
+bool FindDegeneratesProcess::isAreaCheckEnabled() const {
+    return mConfigCheckAreaOfTriangle;
+}
+
+} // Namespace Assimp
+
+#endif // !! AI_FINDDEGENERATESPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/FindInstancesProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/FindInstancesProcess.cpp
new file mode 100644
index 0000000..7f8c93f
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/FindInstancesProcess.cpp
@@ -0,0 +1,277 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file  FindInstancesProcess.cpp
+ *  @brief Implementation of the aiProcess_FindInstances postprocessing step
+*/
+
+
+#include "FindInstancesProcess.h"
+#include <memory>
+#include <stdio.h>
+
+using namespace Assimp;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+FindInstancesProcess::FindInstancesProcess()
+:   configSpeedFlag (false)
+{}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+FindInstancesProcess::~FindInstancesProcess()
+{}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool FindInstancesProcess::IsActive( unsigned int pFlags) const
+{
+    // FindInstances makes absolutely no sense together with PreTransformVertices
+    // fixme: spawn error message somewhere else?
+    return 0 != (pFlags & aiProcess_FindInstances) && 0 == (pFlags & aiProcess_PreTransformVertices);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Setup properties for the step
+void FindInstancesProcess::SetupProperties(const Importer* pImp)
+{
+    // AI_CONFIG_FAVOUR_SPEED
+    configSpeedFlag = (0 != pImp->GetPropertyInteger(AI_CONFIG_FAVOUR_SPEED,0));
+}
+
+// ------------------------------------------------------------------------------------------------
+// Compare the bones of two meshes
+bool CompareBones(const aiMesh* orig, const aiMesh* inst)
+{
+    for (unsigned int i = 0; i < orig->mNumBones;++i) {
+        aiBone* aha = orig->mBones[i];
+        aiBone* oha = inst->mBones[i];
+
+        if (aha->mNumWeights   != oha->mNumWeights   ||
+            aha->mOffsetMatrix != oha->mOffsetMatrix) {
+            return false;
+        }
+
+        // compare weight per weight ---
+        for (unsigned int n = 0; n < aha->mNumWeights;++n) {
+            if  (aha->mWeights[n].mVertexId != oha->mWeights[n].mVertexId ||
+                (aha->mWeights[n].mWeight - oha->mWeights[n].mWeight) < 10e-3f) {
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Update mesh indices in the node graph
+void UpdateMeshIndices(aiNode* node, unsigned int* lookup)
+{
+    for (unsigned int n = 0; n < node->mNumMeshes;++n)
+        node->mMeshes[n] = lookup[node->mMeshes[n]];
+
+    for (unsigned int n = 0; n < node->mNumChildren;++n)
+        UpdateMeshIndices(node->mChildren[n],lookup);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void FindInstancesProcess::Execute( aiScene* pScene)
+{
+    ASSIMP_LOG_DEBUG("FindInstancesProcess begin");
+    if (pScene->mNumMeshes) {
+
+        // use a pseudo hash for all meshes in the scene to quickly find
+        // the ones which are possibly equal. This step is executed early
+        // in the pipeline, so we could, depending on the file format,
+        // have several thousand small meshes. That's too much for a brute
+        // everyone-against-everyone check involving up to 10 comparisons
+        // each.
+        std::unique_ptr<uint64_t[]> hashes (new uint64_t[pScene->mNumMeshes]);
+        std::unique_ptr<unsigned int[]> remapping (new unsigned int[pScene->mNumMeshes]);
+
+        unsigned int numMeshesOut = 0;
+        for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
+
+            aiMesh* inst = pScene->mMeshes[i];
+            hashes[i] = GetMeshHash(inst);
+
+            // Find an appropriate epsilon
+            // to compare position differences against
+            float epsilon = ComputePositionEpsilon(inst);
+            epsilon *= epsilon;
+
+            for (int a = i-1; a >= 0; --a) {
+                if (hashes[i] == hashes[a])
+                {
+                    aiMesh* orig = pScene->mMeshes[a];
+                    if (!orig)
+                        continue;
+
+                    // check for hash collision .. we needn't check
+                    // the vertex format, it *must* match due to the
+                    // (brilliant) construction of the hash
+                    if (orig->mNumBones       != inst->mNumBones      ||
+                        orig->mNumFaces       != inst->mNumFaces      ||
+                        orig->mNumVertices    != inst->mNumVertices   ||
+                        orig->mMaterialIndex  != inst->mMaterialIndex ||
+                        orig->mPrimitiveTypes != inst->mPrimitiveTypes)
+                        continue;
+
+                    // up to now the meshes are equal. Now compare vertex positions, normals,
+                    // tangents and bitangents using this epsilon.
+                    if (orig->HasPositions()) {
+                        if(!CompareArrays(orig->mVertices,inst->mVertices,orig->mNumVertices,epsilon))
+                            continue;
+                    }
+                    if (orig->HasNormals()) {
+                        if(!CompareArrays(orig->mNormals,inst->mNormals,orig->mNumVertices,epsilon))
+                            continue;
+                    }
+                    if (orig->HasTangentsAndBitangents()) {
+                        if (!CompareArrays(orig->mTangents,inst->mTangents,orig->mNumVertices,epsilon) ||
+                            !CompareArrays(orig->mBitangents,inst->mBitangents,orig->mNumVertices,epsilon))
+                            continue;
+                    }
+
+                    // use a constant epsilon for colors and UV coordinates
+                    static const float uvEpsilon = 10e-4f;
+                    {
+                        unsigned int j, end = orig->GetNumUVChannels();
+                        for(j = 0; j < end; ++j) {
+                            if (!orig->mTextureCoords[j]) {
+                                continue;
+                            }
+                            if(!CompareArrays(orig->mTextureCoords[j],inst->mTextureCoords[j],orig->mNumVertices,uvEpsilon)) {
+                                break;
+                            }
+                        }
+                        if (j != end) {
+                            continue;
+                        }
+                    }
+                    {
+                        unsigned int j, end = orig->GetNumColorChannels();
+                        for(j = 0; j < end; ++j) {
+                            if (!orig->mColors[j]) {
+                                continue;
+                            }
+                            if(!CompareArrays(orig->mColors[j],inst->mColors[j],orig->mNumVertices,uvEpsilon)) {
+                                break;
+                            }
+                        }
+                        if (j != end) {
+                            continue;
+                        }
+                    }
+
+                    // These two checks are actually quite expensive and almost *never* required.
+                    // Almost. That's why they're still here. But there's no reason to do them
+                    // in speed-targeted imports.
+                    if (!configSpeedFlag) {
+
+                        // It seems to be strange, but we really need to check whether the
+                        // bones are identical too. Although it's extremely unprobable
+                        // that they're not if control reaches here, we need to deal
+                        // with unprobable cases, too. It could still be that there are
+                        // equal shapes which are deformed differently.
+                        if (!CompareBones(orig,inst))
+                            continue;
+
+                        // For completeness ... compare even the index buffers for equality
+                        // face order & winding order doesn't care. Input data is in verbose format.
+                        std::unique_ptr<unsigned int[]> ftbl_orig(new unsigned int[orig->mNumVertices]);
+                        std::unique_ptr<unsigned int[]> ftbl_inst(new unsigned int[orig->mNumVertices]);
+
+                        for (unsigned int tt = 0; tt < orig->mNumFaces;++tt) {
+                            aiFace& f = orig->mFaces[tt];
+                            for (unsigned int nn = 0; nn < f.mNumIndices;++nn)
+                                ftbl_orig[f.mIndices[nn]] = tt;
+
+                            aiFace& f2 = inst->mFaces[tt];
+                            for (unsigned int nn = 0; nn < f2.mNumIndices;++nn)
+                                ftbl_inst[f2.mIndices[nn]] = tt;
+                        }
+                        if (0 != ::memcmp(ftbl_inst.get(),ftbl_orig.get(),orig->mNumVertices*sizeof(unsigned int)))
+                            continue;
+                    }
+
+                    // We're still here. Or in other words: 'inst' is an instance of 'orig'.
+                    // Place a marker in our list that we can easily update mesh indices.
+                    remapping[i] = remapping[a];
+
+                    // Delete the instanced mesh, we don't need it anymore
+                    delete inst;
+                    pScene->mMeshes[i] = nullptr;
+                    break;
+                }
+            }
+
+            // If we didn't find a match for the current mesh: keep it
+            if (pScene->mMeshes[i]) {
+                remapping[i] = numMeshesOut++;
+            }
+        }
+        ai_assert(0 != numMeshesOut);
+        if (numMeshesOut != pScene->mNumMeshes) {
+
+            // Collapse the meshes array by removing all nullptr entries
+            for (unsigned int real = 0, i = 0; real < numMeshesOut; ++i) {
+                if (pScene->mMeshes[i])
+                    pScene->mMeshes[real++] = pScene->mMeshes[i];
+            }
+
+            // And update the node graph with our nice lookup table
+            UpdateMeshIndices(pScene->mRootNode,remapping.get());
+
+            // write to log
+            if (!DefaultLogger::isNullLogger()) {
+                ASSIMP_LOG_INFO( "FindInstancesProcess finished. Found ", (pScene->mNumMeshes - numMeshesOut), " instances" );
+            }
+            pScene->mNumMeshes = numMeshesOut;
+        } else {
+            ASSIMP_LOG_DEBUG("FindInstancesProcess finished. No instanced meshes found");
+        }
+    }
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/FindInstancesProcess.h b/src/mesh/assimp-master/code/PostProcessing/FindInstancesProcess.h
new file mode 100644
index 0000000..b501d88
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/FindInstancesProcess.h
@@ -0,0 +1,137 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file  FindInstancesProcess.h
+ *  @brief Declares the aiProcess_FindInstances post-process step
+ */
+#ifndef AI_FINDINSTANCES_H_INC
+#define AI_FINDINSTANCES_H_INC
+
+#include "Common/BaseProcess.h"
+#include "PostProcessing/ProcessHelper.h"
+
+class FindInstancesProcessTest;
+namespace Assimp    {
+
+// -------------------------------------------------------------------------------
+/** @brief Get a pseudo(!)-hash representing a mesh.
+ *
+ *  The hash is built from number of vertices, faces, primitive types,
+ *  .... but *not* from the real mesh data. The funcction is not a perfect hash.
+ *  @param in Input mesh
+ *  @return Hash.
+ */
+inline
+uint64_t GetMeshHash(aiMesh* in) {
+    ai_assert(nullptr != in);
+
+    // ... get an unique value representing the vertex format of the mesh
+    const unsigned int fhash = GetMeshVFormatUnique(in);
+
+    // and bake it with number of vertices/faces/bones/matidx/ptypes
+    return ((uint64_t)fhash << 32u) | ((
+        (in->mNumBones << 16u) ^  (in->mNumVertices)       ^
+        (in->mNumFaces<<4u)    ^  (in->mMaterialIndex<<15) ^
+        (in->mPrimitiveTypes<<28)) & 0xffffffff );
+}
+
+// -------------------------------------------------------------------------------
+/** @brief Perform a component-wise comparison of two arrays
+ *
+ *  @param first First array
+ *  @param second Second array
+ *  @param size Size of both arrays
+ *  @param e Epsilon
+ *  @return true if the arrays are identical
+ */
+inline
+bool CompareArrays(const aiVector3D* first, const aiVector3D* second,
+        unsigned int size, float e) {
+    for (const aiVector3D* end = first+size; first != end; ++first,++second) {
+        if ( (*first - *second).SquareLength() >= e)
+            return false;
+    }
+    return true;
+}
+
+// and the same for colors ...
+inline bool CompareArrays(const aiColor4D* first, const aiColor4D* second,
+    unsigned int size, float e)
+{
+    for (const aiColor4D* end = first+size; first != end; ++first,++second) {
+        if ( GetColorDifference(*first,*second) >= e)
+            return false;
+    }
+    return true;
+}
+
+// ---------------------------------------------------------------------------
+/** @brief A post-processing steps to search for instanced meshes
+*/
+class FindInstancesProcess : public BaseProcess
+{
+public:
+
+    FindInstancesProcess();
+    ~FindInstancesProcess();
+
+public:
+    // -------------------------------------------------------------------
+    // Check whether step is active in given flags combination
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    // Execute step on a given scene
+    void Execute( aiScene* pScene);
+
+    // -------------------------------------------------------------------
+    // Setup properties prior to executing the process
+    void SetupProperties(const Importer* pImp);
+
+private:
+
+    bool configSpeedFlag;
+
+}; // ! end class FindInstancesProcess
+}  // ! end namespace Assimp
+
+#endif // !! AI_FINDINSTANCES_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/FindInvalidDataProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/FindInvalidDataProcess.cpp
new file mode 100644
index 0000000..b42cbe9
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/FindInvalidDataProcess.cpp
@@ -0,0 +1,409 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file Defines a post processing step to search an importer's output
+    for data that is obviously invalid  */
+
+#ifndef ASSIMP_BUILD_NO_FINDINVALIDDATA_PROCESS
+
+// internal headers
+#include "FindInvalidDataProcess.h"
+#include "ProcessHelper.h"
+
+#include <assimp/Exceptional.h>
+#include <assimp/qnan.h>
+
+using namespace Assimp;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+FindInvalidDataProcess::FindInvalidDataProcess() :
+        configEpsilon(0.0), mIgnoreTexCoods(false) {
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+FindInvalidDataProcess::~FindInvalidDataProcess() {
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool FindInvalidDataProcess::IsActive(unsigned int pFlags) const {
+    return 0 != (pFlags & aiProcess_FindInvalidData);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Setup import configuration
+void FindInvalidDataProcess::SetupProperties(const Importer *pImp) {
+    // Get the current value of AI_CONFIG_PP_FID_ANIM_ACCURACY
+    configEpsilon = (0 != pImp->GetPropertyFloat(AI_CONFIG_PP_FID_ANIM_ACCURACY, 0.f));
+    mIgnoreTexCoods = pImp->GetPropertyBool(AI_CONFIG_PP_FID_IGNORE_TEXTURECOORDS, false);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Update mesh references in the node graph
+void UpdateMeshReferences(aiNode *node, const std::vector<unsigned int> &meshMapping) {
+    if (node->mNumMeshes) {
+        unsigned int out = 0;
+        for (unsigned int a = 0; a < node->mNumMeshes; ++a) {
+
+            unsigned int ref = node->mMeshes[a];
+            if (UINT_MAX != (ref = meshMapping[ref])) {
+                node->mMeshes[out++] = ref;
+            }
+        }
+        // just let the members that are unused, that's much cheaper
+        // than a full array realloc'n'copy party ...
+        node->mNumMeshes = out;
+        if (0 == out) {
+            delete[] node->mMeshes;
+            node->mMeshes = nullptr;
+        }
+    }
+    // recursively update all children
+    for (unsigned int i = 0; i < node->mNumChildren; ++i) {
+        UpdateMeshReferences(node->mChildren[i], meshMapping);
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void FindInvalidDataProcess::Execute(aiScene *pScene) {
+    ASSIMP_LOG_DEBUG("FindInvalidDataProcess begin");
+
+    bool out = false;
+    std::vector<unsigned int> meshMapping(pScene->mNumMeshes);
+    unsigned int real = 0;
+
+    // Process meshes
+    for (unsigned int a = 0; a < pScene->mNumMeshes; a++) {
+        int result = ProcessMesh(pScene->mMeshes[a]);
+        if (0 == result) {
+            out = true;
+        }
+        if (2 == result) {
+            // remove this mesh
+            delete pScene->mMeshes[a];
+            pScene->mMeshes[a] = nullptr;
+
+            meshMapping[a] = UINT_MAX;
+            out = true;
+            continue;
+        }
+
+        pScene->mMeshes[real] = pScene->mMeshes[a];
+        meshMapping[a] = real++;
+    }
+
+    // Process animations
+    for (unsigned int animIdx = 0; animIdx < pScene->mNumAnimations; ++animIdx) {
+        ProcessAnimation(pScene->mAnimations[animIdx]);
+    }
+
+    if (out) {
+        if (real != pScene->mNumMeshes) {
+            if (!real) {
+                throw DeadlyImportError("No meshes remaining");
+            }
+
+            // we need to remove some meshes.
+            // therefore we'll also need to remove all references
+            // to them from the scenegraph
+            UpdateMeshReferences(pScene->mRootNode, meshMapping);
+            pScene->mNumMeshes = real;
+        }
+
+        ASSIMP_LOG_INFO("FindInvalidDataProcess finished. Found issues ...");
+    } else {
+        ASSIMP_LOG_DEBUG("FindInvalidDataProcess finished. Everything seems to be OK.");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+template <typename T>
+inline const char *ValidateArrayContents(const T * /*arr*/, unsigned int /*size*/,
+        const std::vector<bool> & /*dirtyMask*/, bool /*mayBeIdentical = false*/, bool /*mayBeZero = true*/) {
+    return nullptr;
+}
+
+// ------------------------------------------------------------------------------------------------
+template <>
+inline const char *ValidateArrayContents<aiVector3D>(const aiVector3D *arr, unsigned int size,
+        const std::vector<bool> &dirtyMask, bool mayBeIdentical, bool mayBeZero) {
+    bool b = false;
+    unsigned int cnt = 0;
+    for (unsigned int i = 0; i < size; ++i) {
+
+        if (dirtyMask.size() && dirtyMask[i]) {
+            continue;
+        }
+        ++cnt;
+
+        const aiVector3D &v = arr[i];
+        if (is_special_float(v.x) || is_special_float(v.y) || is_special_float(v.z)) {
+            return "INF/NAN was found in a vector component";
+        }
+        if (!mayBeZero && !v.x && !v.y && !v.z) {
+            return "Found zero-length vector";
+        }
+        if (i && v != arr[i - 1]) b = true;
+    }
+    if (cnt > 1 && !b && !mayBeIdentical) {
+        return "All vectors are identical";
+    }
+    return nullptr;
+}
+
+// ------------------------------------------------------------------------------------------------
+template <typename T>
+inline bool ProcessArray(T *&in, unsigned int num, const char *name,
+        const std::vector<bool> &dirtyMask, bool mayBeIdentical = false, bool mayBeZero = true) {
+    const char *err = ValidateArrayContents(in, num, dirtyMask, mayBeIdentical, mayBeZero);
+    if (err) {
+        ASSIMP_LOG_ERROR("FindInvalidDataProcess fails on mesh ", name, ": ", err);
+        delete[] in;
+        in = nullptr;
+        return true;
+    }
+    return false;
+}
+
+// ------------------------------------------------------------------------------------------------
+template <typename T>
+AI_FORCE_INLINE bool EpsilonCompare(const T &n, const T &s, ai_real epsilon);
+
+// ------------------------------------------------------------------------------------------------
+AI_FORCE_INLINE bool EpsilonCompare(ai_real n, ai_real s, ai_real epsilon) {
+    return std::fabs(n - s) > epsilon;
+}
+
+// ------------------------------------------------------------------------------------------------
+template <>
+bool EpsilonCompare<aiVectorKey>(const aiVectorKey &n, const aiVectorKey &s, ai_real epsilon) {
+    return EpsilonCompare(n.mValue.x, s.mValue.x, epsilon) &&
+           EpsilonCompare(n.mValue.y, s.mValue.y, epsilon) &&
+           EpsilonCompare(n.mValue.z, s.mValue.z, epsilon);
+}
+
+// ------------------------------------------------------------------------------------------------
+template <>
+bool EpsilonCompare<aiQuatKey>(const aiQuatKey &n, const aiQuatKey &s, ai_real epsilon) {
+    return EpsilonCompare(n.mValue.x, s.mValue.x, epsilon) &&
+           EpsilonCompare(n.mValue.y, s.mValue.y, epsilon) &&
+           EpsilonCompare(n.mValue.z, s.mValue.z, epsilon) &&
+           EpsilonCompare(n.mValue.w, s.mValue.w, epsilon);
+}
+
+// ------------------------------------------------------------------------------------------------
+template <typename T>
+inline bool AllIdentical(T *in, unsigned int num, ai_real epsilon) {
+    if (num <= 1) {
+        return true;
+    }
+
+    if (fabs(epsilon) > 0.f) {
+        for (unsigned int i = 0; i < num - 1; ++i) {
+            if (!EpsilonCompare(in[i], in[i + 1], epsilon)) {
+                return false;
+            }
+        }
+    } else {
+        for (unsigned int i = 0; i < num - 1; ++i) {
+            if (in[i] != in[i + 1]) {
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Search an animation for invalid content
+void FindInvalidDataProcess::ProcessAnimation(aiAnimation *anim) {
+    // Process all animation channels
+    for (unsigned int a = 0; a < anim->mNumChannels; ++a) {
+        ProcessAnimationChannel(anim->mChannels[a]);
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+void FindInvalidDataProcess::ProcessAnimationChannel(aiNodeAnim *anim) {
+    ai_assert(nullptr != anim);
+    if (anim->mNumPositionKeys == 0 && anim->mNumRotationKeys == 0 && anim->mNumScalingKeys == 0) {
+        ai_assert_entry();
+        return;
+    }
+
+    // Check whether all values in a tracks are identical - in this case
+    // we can remove al keys except one.
+    // POSITIONS
+    int i = 0;
+    if (anim->mNumPositionKeys > 1 && AllIdentical(anim->mPositionKeys, anim->mNumPositionKeys, configEpsilon)) {
+        aiVectorKey v = anim->mPositionKeys[0];
+
+        // Reallocate ... we need just ONE element, it makes no sense to reuse the array
+        delete[] anim->mPositionKeys;
+        anim->mPositionKeys = new aiVectorKey[anim->mNumPositionKeys = 1];
+        anim->mPositionKeys[0] = v;
+        i = 1;
+    }
+
+    // ROTATIONS
+    if (anim->mNumRotationKeys > 1 && AllIdentical(anim->mRotationKeys, anim->mNumRotationKeys, configEpsilon)) {
+        aiQuatKey v = anim->mRotationKeys[0];
+
+        // Reallocate ... we need just ONE element, it makes no sense to reuse the array
+        delete[] anim->mRotationKeys;
+        anim->mRotationKeys = new aiQuatKey[anim->mNumRotationKeys = 1];
+        anim->mRotationKeys[0] = v;
+        i = 1;
+    }
+
+    // SCALINGS
+    if (anim->mNumScalingKeys > 1 && AllIdentical(anim->mScalingKeys, anim->mNumScalingKeys, configEpsilon)) {
+        aiVectorKey v = anim->mScalingKeys[0];
+
+        // Reallocate ... we need just ONE element, it makes no sense to reuse the array
+        delete[] anim->mScalingKeys;
+        anim->mScalingKeys = new aiVectorKey[anim->mNumScalingKeys = 1];
+        anim->mScalingKeys[0] = v;
+        i = 1;
+    }
+    if (1 == i) {
+        ASSIMP_LOG_WARN("Simplified dummy tracks with just one key");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Search a mesh for invalid contents
+int FindInvalidDataProcess::ProcessMesh(aiMesh *pMesh) {
+    bool ret = false;
+    std::vector<bool> dirtyMask(pMesh->mNumVertices, pMesh->mNumFaces != 0);
+
+    // Ignore elements that are not referenced by vertices.
+    // (they are, for example, caused by the FindDegenerates step)
+    for (unsigned int m = 0; m < pMesh->mNumFaces; ++m) {
+        const aiFace &f = pMesh->mFaces[m];
+
+        for (unsigned int i = 0; i < f.mNumIndices; ++i) {
+            dirtyMask[f.mIndices[i]] = false;
+        }
+    }
+
+    // Process vertex positions
+    if (pMesh->mVertices && ProcessArray(pMesh->mVertices, pMesh->mNumVertices, "positions", dirtyMask)) {
+        ASSIMP_LOG_ERROR("Deleting mesh: Unable to continue without vertex positions");
+
+        return 2;
+    }
+
+    // process texture coordinates
+    if (!mIgnoreTexCoods) {
+        for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS && pMesh->mTextureCoords[i]; ++i) {
+            if (ProcessArray(pMesh->mTextureCoords[i], pMesh->mNumVertices, "uvcoords", dirtyMask)) {
+                pMesh->mNumUVComponents[i] = 0;
+
+                // delete all subsequent texture coordinate sets.
+                for (unsigned int a = i + 1; a < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++a) {
+                    delete[] pMesh->mTextureCoords[a];
+                    pMesh->mTextureCoords[a] = nullptr;
+                    pMesh->mNumUVComponents[a] = 0;
+                }
+
+                ret = true;
+            }
+        }
+    }
+
+    // -- we don't validate vertex colors, it's difficult to say whether
+    // they are invalid or not.
+
+    // Normals and tangents are undefined for point and line faces.
+    if (pMesh->mNormals || pMesh->mTangents) {
+
+        if (aiPrimitiveType_POINT & pMesh->mPrimitiveTypes ||
+                aiPrimitiveType_LINE & pMesh->mPrimitiveTypes) {
+            if (aiPrimitiveType_TRIANGLE & pMesh->mPrimitiveTypes ||
+                    aiPrimitiveType_POLYGON & pMesh->mPrimitiveTypes) {
+                // We need to update the lookup-table
+                for (unsigned int m = 0; m < pMesh->mNumFaces; ++m) {
+                    const aiFace &f = pMesh->mFaces[m];
+
+                    if (f.mNumIndices < 3) {
+                        dirtyMask[f.mIndices[0]] = true;
+                        if (f.mNumIndices == 2) {
+                            dirtyMask[f.mIndices[1]] = true;
+                        }
+                    }
+                }
+            }
+            // Normals, tangents and bitangents are undefined for
+            // the whole mesh (and should not even be there)
+            else {
+                return ret;
+            }
+        }
+
+        // Process mesh normals
+        if (pMesh->mNormals && ProcessArray(pMesh->mNormals, pMesh->mNumVertices,
+                                       "normals", dirtyMask, true, false))
+            ret = true;
+
+        // Process mesh tangents
+        if (pMesh->mTangents && ProcessArray(pMesh->mTangents, pMesh->mNumVertices, "tangents", dirtyMask)) {
+            delete[] pMesh->mBitangents;
+            pMesh->mBitangents = nullptr;
+            ret = true;
+        }
+
+        // Process mesh bitangents
+        if (pMesh->mBitangents && ProcessArray(pMesh->mBitangents, pMesh->mNumVertices, "bitangents", dirtyMask)) {
+            delete[] pMesh->mTangents;
+            pMesh->mTangents = nullptr;
+            ret = true;
+        }
+    }
+    return ret ? 1 : 0;
+}
+
+#endif // !! ASSIMP_BUILD_NO_FINDINVALIDDATA_PROCESS
diff --git a/src/mesh/assimp-master/code/PostProcessing/FindInvalidDataProcess.h b/src/mesh/assimp-master/code/PostProcessing/FindInvalidDataProcess.h
new file mode 100644
index 0000000..5ea895c
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/FindInvalidDataProcess.h
@@ -0,0 +1,105 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file Defines a post processing step to search an importer's output
+ *   for data that is obviously invalid
+ */
+#ifndef AI_FINDINVALIDDATA_H_INC
+#define AI_FINDINVALIDDATA_H_INC
+
+#include "Common/BaseProcess.h"
+
+#include <assimp/anim.h>
+#include <assimp/types.h>
+
+struct aiMesh;
+
+class FindInvalidDataProcessTest;
+
+namespace Assimp {
+
+// ---------------------------------------------------------------------------
+/** The FindInvalidData post-processing step. It searches the mesh data
+ *  for parts that are obviously invalid and removes them.
+ *
+ *  Originally this was a workaround for some models written by Blender
+ *  which have zero normal vectors. */
+class ASSIMP_API FindInvalidDataProcess : public BaseProcess {
+public:
+    FindInvalidDataProcess();
+    ~FindInvalidDataProcess();
+
+    // -------------------------------------------------------------------
+    //
+    bool IsActive(unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    // Setup import settings
+    void SetupProperties(const Importer *pImp);
+
+    // -------------------------------------------------------------------
+    // Run the step
+    void Execute(aiScene *pScene);
+
+    // -------------------------------------------------------------------
+    /** Executes the post-processing step on the given mesh
+     * @param pMesh The mesh to process.
+     * @return 0 - nothing, 1 - removed sth, 2 - please delete me  */
+    int ProcessMesh(aiMesh *pMesh);
+
+    // -------------------------------------------------------------------
+    /** Executes the post-processing step on the given animation
+     * @param anim The animation to process.  */
+    void ProcessAnimation(aiAnimation *anim);
+
+    // -------------------------------------------------------------------
+    /** Executes the post-processing step on the given anim channel
+     * @param anim The animation channel to process.*/
+    void ProcessAnimationChannel(aiNodeAnim *anim);
+
+private:
+    ai_real configEpsilon;
+    bool mIgnoreTexCoods;
+};
+
+} // end of namespace Assimp
+
+#endif // AI_AI_FINDINVALIDDATA_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/FixNormalsStep.cpp b/src/mesh/assimp-master/code/PostProcessing/FixNormalsStep.cpp
new file mode 100644
index 0000000..be01042
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/FixNormalsStep.cpp
@@ -0,0 +1,184 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file Implementation of the post processing step to invert
+ * all normals in meshes with infacing normals.
+ */
+
+// internal headers
+#include "FixNormalsStep.h"
+#include <assimp/StringUtils.h>
+#include <assimp/DefaultLogger.hpp>
+#include <assimp/postprocess.h>
+#include <assimp/scene.h>
+#include <stdio.h>
+
+
+using namespace Assimp;
+
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+FixInfacingNormalsProcess::FixInfacingNormalsProcess()
+{
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+FixInfacingNormalsProcess::~FixInfacingNormalsProcess()
+{
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool FixInfacingNormalsProcess::IsActive( unsigned int pFlags) const
+{
+    return (pFlags & aiProcess_FixInfacingNormals) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void FixInfacingNormalsProcess::Execute( aiScene* pScene)
+{
+    ASSIMP_LOG_DEBUG("FixInfacingNormalsProcess begin");
+
+    bool bHas( false );
+    for (unsigned int a = 0; a < pScene->mNumMeshes; ++a) {
+        if (ProcessMesh(pScene->mMeshes[a], a)) {
+            bHas = true;
+        }
+    }
+
+    if (bHas) {
+        ASSIMP_LOG_DEBUG("FixInfacingNormalsProcess finished. Found issues.");
+    } else {
+        ASSIMP_LOG_DEBUG("FixInfacingNormalsProcess finished. No changes to the scene.");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Apply the step to the mesh
+bool FixInfacingNormalsProcess::ProcessMesh( aiMesh* pcMesh, unsigned int index)
+{
+    ai_assert(nullptr != pcMesh);
+
+    // Nothing to do if there are no model normals
+    if (!pcMesh->HasNormals()) {
+        return false;
+    }
+
+    // Compute the bounding box of both the model vertices + normals and
+    // the unmodified model vertices. Then check whether the first BB
+    // is smaller than the second. In this case we can assume that the
+    // normals need to be flipped, although there are a few special cases ..
+    // convex, concave, planar models ...
+
+    aiVector3D vMin0 (1e10f,1e10f,1e10f);
+    aiVector3D vMin1 (1e10f,1e10f,1e10f);
+    aiVector3D vMax0 (-1e10f,-1e10f,-1e10f);
+    aiVector3D vMax1 (-1e10f,-1e10f,-1e10f);
+
+    for (unsigned int i = 0; i < pcMesh->mNumVertices;++i)
+    {
+        vMin1.x = std::min(vMin1.x,pcMesh->mVertices[i].x);
+        vMin1.y = std::min(vMin1.y,pcMesh->mVertices[i].y);
+        vMin1.z = std::min(vMin1.z,pcMesh->mVertices[i].z);
+
+        vMax1.x = std::max(vMax1.x,pcMesh->mVertices[i].x);
+        vMax1.y = std::max(vMax1.y,pcMesh->mVertices[i].y);
+        vMax1.z = std::max(vMax1.z,pcMesh->mVertices[i].z);
+
+        const aiVector3D vWithNormal = pcMesh->mVertices[i] + pcMesh->mNormals[i];
+
+        vMin0.x = std::min(vMin0.x,vWithNormal.x);
+        vMin0.y = std::min(vMin0.y,vWithNormal.y);
+        vMin0.z = std::min(vMin0.z,vWithNormal.z);
+
+        vMax0.x = std::max(vMax0.x,vWithNormal.x);
+        vMax0.y = std::max(vMax0.y,vWithNormal.y);
+        vMax0.z = std::max(vMax0.z,vWithNormal.z);
+    }
+
+    const float fDelta0_x = (vMax0.x - vMin0.x);
+    const float fDelta0_y = (vMax0.y - vMin0.y);
+    const float fDelta0_z = (vMax0.z - vMin0.z);
+
+    const float fDelta1_x = (vMax1.x - vMin1.x);
+    const float fDelta1_y = (vMax1.y - vMin1.y);
+    const float fDelta1_z = (vMax1.z - vMin1.z);
+
+    // Check whether the boxes are overlapping
+    if ((fDelta0_x > 0.0f) != (fDelta1_x > 0.0f))return false;
+    if ((fDelta0_y > 0.0f) != (fDelta1_y > 0.0f))return false;
+    if ((fDelta0_z > 0.0f) != (fDelta1_z > 0.0f))return false;
+
+    // Check whether this is a planar surface
+    const float fDelta1_yz = fDelta1_y * fDelta1_z;
+
+    if (fDelta1_x < 0.05f * std::sqrt( fDelta1_yz ))return false;
+    if (fDelta1_y < 0.05f * std::sqrt( fDelta1_z * fDelta1_x ))return false;
+    if (fDelta1_z < 0.05f * std::sqrt( fDelta1_y * fDelta1_x ))return false;
+
+    // now compare the volumes of the bounding boxes
+    if (std::fabs(fDelta0_x * fDelta0_y * fDelta0_z) < std::fabs(fDelta1_x * fDelta1_yz)) {
+        if (!DefaultLogger::isNullLogger()) {
+            ASSIMP_LOG_INFO("Mesh ", index, ": Normals are facing inwards (or the mesh is planar)", index);
+        }
+
+        // Invert normals
+        for (unsigned int i = 0; i < pcMesh->mNumVertices;++i)
+            pcMesh->mNormals[i] *= -1.0f;
+
+        // ... and flip faces
+        for (unsigned int i = 0; i < pcMesh->mNumFaces;++i)
+        {
+            aiFace& face = pcMesh->mFaces[i];
+            for( unsigned int b = 0; b < face.mNumIndices / 2; b++)
+                std::swap( face.mIndices[b], face.mIndices[ face.mNumIndices - 1 - b]);
+        }
+        return true;
+    }
+    return false;
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/FixNormalsStep.h b/src/mesh/assimp-master/code/PostProcessing/FixNormalsStep.h
new file mode 100644
index 0000000..b7d3ba3
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/FixNormalsStep.h
@@ -0,0 +1,91 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+
+/** @file Defines a post processing step to fix infacing normals */
+#ifndef AI_FIXNORMALSPROCESS_H_INC
+#define AI_FIXNORMALSPROCESS_H_INC
+
+#include "Common/BaseProcess.h"
+
+struct aiMesh;
+
+namespace Assimp
+{
+
+// ---------------------------------------------------------------------------
+/** The FixInfacingNormalsProcess tries to determine whether the normal
+ * vectors of an object are facing inwards. In this case they will be
+ * flipped.
+ */
+class FixInfacingNormalsProcess : public BaseProcess {
+public:
+    FixInfacingNormalsProcess();
+    ~FixInfacingNormalsProcess();
+
+    // -------------------------------------------------------------------
+    /** Returns whether the processing step is present in the given flag field.
+     * @param pFlags The processing flags the importer was called with. A bitwise
+     *   combination of #aiPostProcessSteps.
+     * @return true if the process is present in this flag fields, false if not.
+    */
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    /** Executes the post processing step on the given imported data.
+    * At the moment a process is not supposed to fail.
+    * @param pScene The imported data to work at.
+    */
+    void Execute( aiScene* pScene);
+
+protected:
+
+    // -------------------------------------------------------------------
+    /** Executes the step on the given mesh
+     * @param pMesh The mesh to process.
+     */
+    bool ProcessMesh( aiMesh* pMesh, unsigned int index);
+};
+
+} // end of namespace Assimp
+
+#endif // AI_FIXNORMALSPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/GenBoundingBoxesProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/GenBoundingBoxesProcess.cpp
new file mode 100644
index 0000000..1c20b6f
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/GenBoundingBoxesProcess.cpp
@@ -0,0 +1,115 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+#ifndef ASSIMP_BUILD_NO_GENBOUNDINGBOXES_PROCESS
+
+#include "PostProcessing/GenBoundingBoxesProcess.h"
+
+#include <assimp/postprocess.h>
+#include <assimp/scene.h>
+
+namespace Assimp {
+
+GenBoundingBoxesProcess::GenBoundingBoxesProcess()
+: BaseProcess() {
+
+}
+
+GenBoundingBoxesProcess::~GenBoundingBoxesProcess() {
+    // empty
+}
+
+bool GenBoundingBoxesProcess::IsActive(unsigned int pFlags) const {
+    return 0 != ( pFlags & aiProcess_GenBoundingBoxes );
+}
+
+void checkMesh(aiMesh* mesh, aiVector3D& min, aiVector3D& max) {
+    ai_assert(nullptr != mesh);
+
+    if (0 == mesh->mNumVertices) {
+        return;
+    }
+
+    for (unsigned int i = 0; i < mesh->mNumVertices; ++i) {
+        const aiVector3D &pos = mesh->mVertices[i];
+        if (pos.x < min.x) {
+            min.x = pos.x;
+        }
+        if (pos.y < min.y) {
+            min.y = pos.y;
+        }
+        if (pos.z < min.z) {
+            min.z = pos.z;
+        }
+
+        if (pos.x > max.x) {
+            max.x = pos.x;
+        }
+        if (pos.y > max.y) {
+            max.y = pos.y;
+        }
+        if (pos.z > max.z) {
+            max.z = pos.z;
+        }
+    }
+}
+
+void GenBoundingBoxesProcess::Execute(aiScene* pScene) {
+    if (nullptr == pScene) {
+        return;
+    }
+
+    for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
+        aiMesh* mesh = pScene->mMeshes[i];
+        if (nullptr == mesh) {
+            continue;
+        }
+
+        aiVector3D min(999999, 999999, 999999), max(-999999, -999999, -999999);
+        checkMesh(mesh, min, max);
+        mesh->mAABB.mMin = min;
+        mesh->mAABB.mMax = max;
+    }
+}
+
+} // Namespace Assimp
+
+#endif // ASSIMP_BUILD_NO_GENBOUNDINGBOXES_PROCESS
diff --git a/src/mesh/assimp-master/code/PostProcessing/GenBoundingBoxesProcess.h b/src/mesh/assimp-master/code/PostProcessing/GenBoundingBoxesProcess.h
new file mode 100644
index 0000000..0b7591b
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/GenBoundingBoxesProcess.h
@@ -0,0 +1,76 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file Defines a post-processing step to generate Axis-aligned bounding
+ *        volumes for all meshes.
+ */
+
+#pragma once
+
+#ifndef AI_GENBOUNDINGBOXESPROCESS_H_INC
+#define AI_GENBOUNDINGBOXESPROCESS_H_INC
+
+#ifndef ASSIMP_BUILD_NO_GENBOUNDINGBOXES_PROCESS
+
+#include "Common/BaseProcess.h"
+
+namespace Assimp {
+
+/** Post-processing process to find axis-aligned bounding volumes for amm meshes
+ *  used in a scene
+ */
+class ASSIMP_API GenBoundingBoxesProcess : public BaseProcess {
+public:
+    /// The class constructor.
+    GenBoundingBoxesProcess();
+    /// The class destructor.
+    ~GenBoundingBoxesProcess();
+    /// Will return true, if aiProcess_GenBoundingBoxes is defined.
+    bool IsActive(unsigned int pFlags) const override;
+    /// The execution callback.
+    void Execute(aiScene* pScene) override;
+};
+
+} // Namespace Assimp
+
+#endif // #ifndef ASSIMP_BUILD_NO_GENBOUNDINGBOXES_PROCESS
+
+#endif // AI_GENBOUNDINGBOXESPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/GenFaceNormalsProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/GenFaceNormalsProcess.cpp
new file mode 100644
index 0000000..517dd3b
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/GenFaceNormalsProcess.cpp
@@ -0,0 +1,147 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file Implementation of the post processing step to generate face
+* normals for all imported faces.
+*/
+
+#include "GenFaceNormalsProcess.h"
+#include <assimp/Exceptional.h>
+#include <assimp/postprocess.h>
+#include <assimp/qnan.h>
+#include <assimp/scene.h>
+#include <assimp/DefaultLogger.hpp>
+
+using namespace Assimp;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+GenFaceNormalsProcess::GenFaceNormalsProcess() {
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+GenFaceNormalsProcess::~GenFaceNormalsProcess() {
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool GenFaceNormalsProcess::IsActive(unsigned int pFlags) const {
+    force_ = (pFlags & aiProcess_ForceGenNormals) != 0;
+    flippedWindingOrder_ = (pFlags & aiProcess_FlipWindingOrder) != 0;
+    return (pFlags & aiProcess_GenNormals) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void GenFaceNormalsProcess::Execute(aiScene *pScene) {
+    ASSIMP_LOG_DEBUG("GenFaceNormalsProcess begin");
+
+    if (pScene->mFlags & AI_SCENE_FLAGS_NON_VERBOSE_FORMAT) {
+        throw DeadlyImportError("Post-processing order mismatch: expecting pseudo-indexed (\"verbose\") vertices here");
+    }
+
+    bool bHas = false;
+    for (unsigned int a = 0; a < pScene->mNumMeshes; a++) {
+        if (this->GenMeshFaceNormals(pScene->mMeshes[a])) {
+            bHas = true;
+        }
+    }
+    if (bHas) {
+        ASSIMP_LOG_INFO("GenFaceNormalsProcess finished. "
+                        "Face normals have been calculated");
+    } else {
+        ASSIMP_LOG_DEBUG("GenFaceNormalsProcess finished. "
+                         "Normals are already there");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+bool GenFaceNormalsProcess::GenMeshFaceNormals(aiMesh *pMesh) {
+    if (nullptr != pMesh->mNormals) {
+        if (force_) {
+            delete[] pMesh->mNormals;
+        } else {
+            return false;
+        }
+    }
+
+    // If the mesh consists of lines and/or points but not of
+    // triangles or higher-order polygons the normal vectors
+    // are undefined.
+    if (!(pMesh->mPrimitiveTypes & (aiPrimitiveType_TRIANGLE | aiPrimitiveType_POLYGON))) {
+        ASSIMP_LOG_INFO("Normal vectors are undefined for line and point meshes");
+        return false;
+    }
+
+    // allocate an array to hold the output normals
+    pMesh->mNormals = new aiVector3D[pMesh->mNumVertices];
+    const float qnan = get_qnan();
+
+    // iterate through all faces and compute per-face normals but store them per-vertex.
+    for (unsigned int a = 0; a < pMesh->mNumFaces; a++) {
+        const aiFace &face = pMesh->mFaces[a];
+        if (face.mNumIndices < 3) {
+            // either a point or a line -> no well-defined normal vector
+            for (unsigned int i = 0; i < face.mNumIndices; ++i) {
+                pMesh->mNormals[face.mIndices[i]] = aiVector3D(qnan);
+            }
+            continue;
+        }
+
+        const aiVector3D *pV1 = &pMesh->mVertices[face.mIndices[0]];
+        const aiVector3D *pV2 = &pMesh->mVertices[face.mIndices[1]];
+        const aiVector3D *pV3 = &pMesh->mVertices[face.mIndices[face.mNumIndices - 1]];
+        if (flippedWindingOrder_)
+            std::swap( pV2, pV3 );
+        const aiVector3D vNor = ((*pV2 - *pV1) ^ (*pV3 - *pV1)).NormalizeSafe();
+
+        for (unsigned int i = 0; i < face.mNumIndices; ++i) {
+            pMesh->mNormals[face.mIndices[i]] = vNor;
+        }
+    }
+    return true;
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/GenFaceNormalsProcess.h b/src/mesh/assimp-master/code/PostProcessing/GenFaceNormalsProcess.h
new file mode 100644
index 0000000..586c490
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/GenFaceNormalsProcess.h
@@ -0,0 +1,88 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file Defines a post processing step to compute face normals for all loaded faces*/
+#ifndef AI_GENFACENORMALPROCESS_H_INC
+#define AI_GENFACENORMALPROCESS_H_INC
+
+#include "Common/BaseProcess.h"
+#include <assimp/mesh.h>
+
+namespace Assimp
+{
+
+// ---------------------------------------------------------------------------
+/** The GenFaceNormalsProcess computes face normals for all faces of all meshes
+*/
+class ASSIMP_API_WINONLY GenFaceNormalsProcess : public BaseProcess
+{
+public:
+
+    GenFaceNormalsProcess();
+    ~GenFaceNormalsProcess();
+
+public:
+    // -------------------------------------------------------------------
+    /** Returns whether the processing step is present in the given flag field.
+    * @param pFlags The processing flags the importer was called with. A bitwise
+    *   combination of #aiPostProcessSteps.
+    * @return true if the process is present in this flag fields, false if not.
+    */
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    /** Executes the post processing step on the given imported data.
+    * At the moment a process is not supposed to fail.
+    * @param pScene The imported data to work at.
+    */
+    void Execute( aiScene* pScene);
+
+
+private:
+    bool GenMeshFaceNormals(aiMesh* pcMesh);
+    mutable bool force_ = false;
+    mutable bool flippedWindingOrder_ = false;
+};
+
+} // end of namespace Assimp
+
+#endif // !!AI_GENFACENORMALPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/GenVertexNormalsProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/GenVertexNormalsProcess.cpp
new file mode 100644
index 0000000..1a8afc5
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/GenVertexNormalsProcess.cpp
@@ -0,0 +1,233 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file Implementation of the post processing step to generate face
+* normals for all imported faces.
+*/
+
+// internal headers
+#include "GenVertexNormalsProcess.h"
+#include "ProcessHelper.h"
+#include <assimp/Exceptional.h>
+#include <assimp/qnan.h>
+
+using namespace Assimp;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+GenVertexNormalsProcess::GenVertexNormalsProcess() :
+        configMaxAngle(AI_DEG_TO_RAD(175.f)) {
+    // empty
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+GenVertexNormalsProcess::~GenVertexNormalsProcess() {
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool GenVertexNormalsProcess::IsActive(unsigned int pFlags) const {
+    force_ = (pFlags & aiProcess_ForceGenNormals) != 0;
+    flippedWindingOrder_ = (pFlags & aiProcess_FlipWindingOrder) != 0;
+    return (pFlags & aiProcess_GenSmoothNormals) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void GenVertexNormalsProcess::SetupProperties(const Importer *pImp) {
+    // Get the current value of the AI_CONFIG_PP_GSN_MAX_SMOOTHING_ANGLE property
+    configMaxAngle = pImp->GetPropertyFloat(AI_CONFIG_PP_GSN_MAX_SMOOTHING_ANGLE, (ai_real)175.0);
+    configMaxAngle = AI_DEG_TO_RAD(std::max(std::min(configMaxAngle, (ai_real)175.0), (ai_real)0.0));
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void GenVertexNormalsProcess::Execute(aiScene *pScene) {
+    ASSIMP_LOG_DEBUG("GenVertexNormalsProcess begin");
+
+    if (pScene->mFlags & AI_SCENE_FLAGS_NON_VERBOSE_FORMAT) {
+        throw DeadlyImportError("Post-processing order mismatch: expecting pseudo-indexed (\"verbose\") vertices here");
+    }
+
+    bool bHas = false;
+    for (unsigned int a = 0; a < pScene->mNumMeshes; ++a) {
+        if (GenMeshVertexNormals(pScene->mMeshes[a], a))
+            bHas = true;
+    }
+
+    if (bHas) {
+        ASSIMP_LOG_INFO("GenVertexNormalsProcess finished. "
+                        "Vertex normals have been calculated");
+    } else {
+        ASSIMP_LOG_DEBUG("GenVertexNormalsProcess finished. "
+                         "Normals are already there");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+bool GenVertexNormalsProcess::GenMeshVertexNormals(aiMesh *pMesh, unsigned int meshIndex) {
+    if (nullptr != pMesh->mNormals) {
+        if (force_)
+            delete[] pMesh->mNormals;
+        else
+            return false;
+    }
+
+    // If the mesh consists of lines and/or points but not of
+    // triangles or higher-order polygons the normal vectors
+    // are undefined.
+    if (!(pMesh->mPrimitiveTypes & (aiPrimitiveType_TRIANGLE | aiPrimitiveType_POLYGON))) {
+        ASSIMP_LOG_INFO("Normal vectors are undefined for line and point meshes");
+        return false;
+    }
+
+    // Allocate the array to hold the output normals
+    const float qnan = std::numeric_limits<ai_real>::quiet_NaN();
+    pMesh->mNormals = new aiVector3D[pMesh->mNumVertices];
+
+    // Compute per-face normals but store them per-vertex
+    for (unsigned int a = 0; a < pMesh->mNumFaces; a++) {
+        const aiFace &face = pMesh->mFaces[a];
+        if (face.mNumIndices < 3) {
+            // either a point or a line -> no normal vector
+            for (unsigned int i = 0; i < face.mNumIndices; ++i) {
+                pMesh->mNormals[face.mIndices[i]] = aiVector3D(qnan);
+            }
+
+            continue;
+        }
+
+        const aiVector3D *pV1 = &pMesh->mVertices[face.mIndices[0]];
+        const aiVector3D *pV2 = &pMesh->mVertices[face.mIndices[1]];
+        const aiVector3D *pV3 = &pMesh->mVertices[face.mIndices[face.mNumIndices - 1]];
+        if (flippedWindingOrder_)
+            std::swap( pV2, pV3 );
+        const aiVector3D vNor = ((*pV2 - *pV1) ^ (*pV3 - *pV1)).NormalizeSafe();
+
+        for (unsigned int i = 0; i < face.mNumIndices; ++i) {
+            pMesh->mNormals[face.mIndices[i]] = vNor;
+        }
+    }
+
+    // Set up a SpatialSort to quickly find all vertices close to a given position
+    // check whether we can reuse the SpatialSort of a previous step.
+    SpatialSort *vertexFinder = nullptr;
+    SpatialSort _vertexFinder;
+    ai_real posEpsilon = ai_real(1e-5);
+    if (shared) {
+        std::vector<std::pair<SpatialSort, ai_real>> *avf;
+        shared->GetProperty(AI_SPP_SPATIAL_SORT, avf);
+        if (avf) {
+            std::pair<SpatialSort, ai_real> &blubb = avf->operator[](meshIndex);
+            vertexFinder = &blubb.first;
+            posEpsilon = blubb.second;
+        }
+    }
+    if (!vertexFinder) {
+        _vertexFinder.Fill(pMesh->mVertices, pMesh->mNumVertices, sizeof(aiVector3D));
+        vertexFinder = &_vertexFinder;
+        posEpsilon = ComputePositionEpsilon(pMesh);
+    }
+    std::vector<unsigned int> verticesFound;
+    aiVector3D *pcNew = new aiVector3D[pMesh->mNumVertices];
+
+    if (configMaxAngle >= AI_DEG_TO_RAD(175.f)) {
+        // There is no angle limit. Thus all vertices with positions close
+        // to each other will receive the same vertex normal. This allows us
+        // to optimize the whole algorithm a little bit ...
+        std::vector<bool> abHad(pMesh->mNumVertices, false);
+        for (unsigned int i = 0; i < pMesh->mNumVertices; ++i) {
+            if (abHad[i]) {
+                continue;
+            }
+
+            // Get all vertices that share this one ...
+            vertexFinder->FindPositions(pMesh->mVertices[i], posEpsilon, verticesFound);
+
+            aiVector3D pcNor;
+            for (unsigned int a = 0; a < verticesFound.size(); ++a) {
+                const aiVector3D &v = pMesh->mNormals[verticesFound[a]];
+                if (is_not_qnan(v.x)) pcNor += v;
+            }
+            pcNor.NormalizeSafe();
+
+            // Write the smoothed normal back to all affected normals
+            for (unsigned int a = 0; a < verticesFound.size(); ++a) {
+                unsigned int vidx = verticesFound[a];
+                pcNew[vidx] = pcNor;
+                abHad[vidx] = true;
+            }
+        }
+    }
+    // Slower code path if a smooth angle is set. There are many ways to achieve
+    // the effect, this one is the most straightforward one.
+    else {
+        const ai_real fLimit = std::cos(configMaxAngle);
+        for (unsigned int i = 0; i < pMesh->mNumVertices; ++i) {
+            // Get all vertices that share this one ...
+            vertexFinder->FindPositions(pMesh->mVertices[i], posEpsilon, verticesFound);
+
+            aiVector3D vr = pMesh->mNormals[i];
+
+            aiVector3D pcNor;
+            for (unsigned int a = 0; a < verticesFound.size(); ++a) {
+                aiVector3D v = pMesh->mNormals[verticesFound[a]];
+
+                // Check whether the angle between the two normals is not too large.
+                // Skip the angle check on our own normal to avoid false negatives
+                // (v*v is not guaranteed to be 1.0 for all unit vectors v)
+                if (is_not_qnan(v.x) && (verticesFound[a] == i || (v * vr >= fLimit)))
+                    pcNor += v;
+            }
+            pcNew[i] = pcNor.NormalizeSafe();
+        }
+    }
+
+    delete[] pMesh->mNormals;
+    pMesh->mNormals = pcNew;
+
+    return true;
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/GenVertexNormalsProcess.h b/src/mesh/assimp-master/code/PostProcessing/GenVertexNormalsProcess.h
new file mode 100644
index 0000000..0dcae79
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/GenVertexNormalsProcess.h
@@ -0,0 +1,112 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file Defines a post processing step to compute vertex normals
+    for all loaded vertizes */
+#ifndef AI_GENVERTEXNORMALPROCESS_H_INC
+#define AI_GENVERTEXNORMALPROCESS_H_INC
+
+#include "Common/assbin_chunks.h"
+#include "Common/BaseProcess.h"
+
+#include <assimp/mesh.h>
+
+// Forward declarations
+class GenNormalsTest;
+
+namespace Assimp {
+
+// ---------------------------------------------------------------------------
+/** The GenFaceNormalsProcess computes vertex normals for all vertices
+*/
+class ASSIMP_API GenVertexNormalsProcess : public BaseProcess {
+public:
+    GenVertexNormalsProcess();
+    ~GenVertexNormalsProcess();
+
+    // -------------------------------------------------------------------
+    /** Returns whether the processing step is present in the given flag.
+    * @param pFlags The processing flags the importer was called with.
+    *   A bitwise combination of #aiPostProcessSteps.
+    * @return true if the process is present in this flag fields,
+    *   false if not.
+    */
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    /** Called prior to ExecuteOnScene().
+    * The function is a request to the process to update its configuration
+    * basing on the Importer's configuration property list.
+    */
+    void SetupProperties(const Importer* pImp);
+
+    // -------------------------------------------------------------------
+    /** Executes the post processing step on the given imported data.
+    * At the moment a process is not supposed to fail.
+    * @param pScene The imported data to work at.
+    */
+    void Execute( aiScene* pScene);
+
+
+    // setter for configMaxAngle
+    inline void SetMaxSmoothAngle(ai_real f) {
+        configMaxAngle =f;
+    }
+
+    // -------------------------------------------------------------------
+    /** Computes normals for a specific mesh
+    *  @param pcMesh Mesh
+    *  @param meshIndex Index of the mesh
+    *  @return true if vertex normals have been computed
+    */
+    bool GenMeshVertexNormals (aiMesh* pcMesh, unsigned int meshIndex);
+
+private:
+    /** Configuration option: maximum smoothing angle, in radians*/
+    ai_real configMaxAngle;
+    mutable bool force_ = false;
+    mutable bool flippedWindingOrder_ = false;
+};
+
+} // end of namespace Assimp
+
+#endif // !!AI_GENVERTEXNORMALPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/ImproveCacheLocality.cpp b/src/mesh/assimp-master/code/PostProcessing/ImproveCacheLocality.cpp
new file mode 100644
index 0000000..56bdfc4
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/ImproveCacheLocality.cpp
@@ -0,0 +1,379 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file Implementation of the post processing step to improve the cache locality of a mesh.
+ * <br>
+ * The algorithm is roughly basing on this paper:
+ * http://www.cs.princeton.edu/gfx/pubs/Sander_2007_%3ETR/tipsy.pdf
+ *   .. although overdraw reduction isn't implemented yet ...
+ */
+
+// internal headers
+#include "PostProcessing/ImproveCacheLocality.h"
+#include "Common/VertexTriangleAdjacency.h"
+
+#include <assimp/StringUtils.h>
+#include <assimp/postprocess.h>
+#include <assimp/scene.h>
+#include <assimp/DefaultLogger.hpp>
+#include <stdio.h>
+#include <stack>
+
+using namespace Assimp;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+ImproveCacheLocalityProcess::ImproveCacheLocalityProcess()
+: mConfigCacheDepth(PP_ICL_PTCACHE_SIZE) {
+    // empty
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+ImproveCacheLocalityProcess::~ImproveCacheLocalityProcess() {
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool ImproveCacheLocalityProcess::IsActive( unsigned int pFlags) const {
+    return (pFlags & aiProcess_ImproveCacheLocality) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Setup configuration
+void ImproveCacheLocalityProcess::SetupProperties(const Importer* pImp) {
+    // AI_CONFIG_PP_ICL_PTCACHE_SIZE controls the target cache size for the optimizer
+    mConfigCacheDepth = pImp->GetPropertyInteger(AI_CONFIG_PP_ICL_PTCACHE_SIZE,PP_ICL_PTCACHE_SIZE);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void ImproveCacheLocalityProcess::Execute( aiScene* pScene) {
+    if (!pScene->mNumMeshes) {
+        ASSIMP_LOG_DEBUG("ImproveCacheLocalityProcess skipped; there are no meshes");
+        return;
+    }
+
+    ASSIMP_LOG_DEBUG("ImproveCacheLocalityProcess begin");
+
+    float out = 0.f;
+    unsigned int numf = 0, numm = 0;
+    for( unsigned int a = 0; a < pScene->mNumMeshes; ++a ){
+        const float res = ProcessMesh( pScene->mMeshes[a],a);
+        if (res) {
+            numf += pScene->mMeshes[a]->mNumFaces;
+            out  += res;
+            ++numm;
+        }
+    }
+    if (!DefaultLogger::isNullLogger()) {
+        if (numf > 0) {
+            ASSIMP_LOG_INFO("Cache relevant are ", numm, " meshes (", numf, " faces). Average output ACMR is ", out / numf);
+        }
+        ASSIMP_LOG_DEBUG("ImproveCacheLocalityProcess finished. ");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Improves the cache coherency of a specific mesh
+ai_real ImproveCacheLocalityProcess::ProcessMesh( aiMesh* pMesh, unsigned int meshNum) {
+    // TODO: rewrite this to use std::vector or boost::shared_array
+    ai_assert(nullptr != pMesh);
+
+    // Check whether the input data is valid
+    // - there must be vertices and faces
+    // - all faces must be triangulated or we can't operate on them
+    if (!pMesh->HasFaces() || !pMesh->HasPositions())
+        return static_cast<ai_real>(0.f);
+
+    if (pMesh->mPrimitiveTypes != aiPrimitiveType_TRIANGLE) {
+        ASSIMP_LOG_ERROR("This algorithm works on triangle meshes only");
+        return static_cast<ai_real>(0.f);
+    }
+
+    if(pMesh->mNumVertices <= mConfigCacheDepth) {
+        return static_cast<ai_real>(0.f);
+    }
+
+    ai_real fACMR = 3.f;
+    const aiFace* const pcEnd = pMesh->mFaces+pMesh->mNumFaces;
+
+    // Input ACMR is for logging purposes only
+    if (!DefaultLogger::isNullLogger())     {
+
+        unsigned int* piFIFOStack = new unsigned int[mConfigCacheDepth];
+        memset(piFIFOStack,0xff,mConfigCacheDepth*sizeof(unsigned int));
+        unsigned int* piCur = piFIFOStack;
+        const unsigned int* const piCurEnd = piFIFOStack + mConfigCacheDepth;
+
+        // count the number of cache misses
+        unsigned int iCacheMisses = 0;
+        for (const aiFace* pcFace = pMesh->mFaces;pcFace != pcEnd;++pcFace) {
+            for (unsigned int qq = 0; qq < 3;++qq) {
+                bool bInCache = false;
+                for (unsigned int* pp = piFIFOStack;pp < piCurEnd;++pp) {
+                    if (*pp == pcFace->mIndices[qq])    {
+                        // the vertex is in cache
+                        bInCache = true;
+                        break;
+                    }
+                }
+                if (!bInCache)  {
+                    ++iCacheMisses;
+                    if (piCurEnd == piCur) {
+                        piCur = piFIFOStack;
+                    }
+                    *piCur++ = pcFace->mIndices[qq];
+                }
+            }
+        }
+        delete[] piFIFOStack;
+        fACMR = (ai_real) iCacheMisses / pMesh->mNumFaces;
+        if (3.0 == fACMR)   {
+            char szBuff[128]; // should be sufficiently large in every case
+
+            // the JoinIdenticalVertices process has not been executed on this
+            // mesh, otherwise this value would normally be at least minimally
+            // smaller than 3.0 ...
+            ai_snprintf(szBuff,128,"Mesh %u: Not suitable for vcache optimization",meshNum);
+            ASSIMP_LOG_WARN(szBuff);
+            return static_cast<ai_real>(0.f);
+        }
+    }
+
+    // first we need to build a vertex-triangle adjacency list
+    VertexTriangleAdjacency adj(pMesh->mFaces,pMesh->mNumFaces, pMesh->mNumVertices,true);
+
+    // build a list to store per-vertex caching time stamps
+    unsigned int* const piCachingStamps = new unsigned int[pMesh->mNumVertices];
+    memset(piCachingStamps,0x0,pMesh->mNumVertices*sizeof(unsigned int));
+
+    // allocate an empty output index buffer. We store the output indices in one large array.
+    // Since the number of triangles won't change the input faces can be reused. This is how
+    // we save thousands of redundant mini allocations for aiFace::mIndices
+    const unsigned int iIdxCnt = pMesh->mNumFaces*3;
+    unsigned int* const piIBOutput = new unsigned int[iIdxCnt];
+    unsigned int* piCSIter = piIBOutput;
+
+    // allocate the flag array to hold the information
+    // whether a face has already been emitted or not
+    std::vector<bool> abEmitted(pMesh->mNumFaces,false);
+
+    // dead-end vertex index stack
+    std::stack<unsigned int, std::vector<unsigned int> > sDeadEndVStack;
+
+    // create a copy of the piNumTriPtr buffer
+    unsigned int* const piNumTriPtr = adj.mLiveTriangles;
+    const std::vector<unsigned int> piNumTriPtrNoModify(piNumTriPtr, piNumTriPtr + pMesh->mNumVertices);
+
+    // get the largest number of referenced triangles and allocate the "candidate buffer"
+    unsigned int iMaxRefTris = 0; {
+        const unsigned int* piCur = adj.mLiveTriangles;
+        const unsigned int* const piCurEnd = adj.mLiveTriangles+pMesh->mNumVertices;
+        for (;piCur != piCurEnd;++piCur) {
+            iMaxRefTris = std::max(iMaxRefTris,*piCur);
+        }
+    }
+    ai_assert(iMaxRefTris > 0);
+    unsigned int* piCandidates = new unsigned int[iMaxRefTris*3];
+    unsigned int iCacheMisses = 0;
+
+    // ...................................................................................
+    /** PSEUDOCODE for the algorithm
+
+        A = Build-Adjacency(I) Vertex-triangle adjacency
+        L = Get-Triangle-Counts(A) Per-vertex live triangle counts
+        C = Zero(Vertex-Count(I)) Per-vertex caching time stamps
+        D = Empty-Stack() Dead-end vertex stack
+        E = False(Triangle-Count(I)) Per triangle emitted flag
+        O = Empty-Index-Buffer() Empty output buffer
+        f = 0 Arbitrary starting vertex
+        s = k+1, i = 1 Time stamp and cursor
+        while f >= 0 For all valid fanning vertices
+            N = Empty-Set() 1-ring of next candidates
+            for each Triangle t in Neighbors(A, f)
+                if !Emitted(E,t)
+                    for each Vertex v in t
+                        Append(O,v) Output vertex
+                        Push(D,v) Add to dead-end stack
+                        Insert(N,v) Register as candidate
+                        L[v] = L[v]-1 Decrease live triangle count
+                        if s-C[v] > k If not in cache
+                            C[v] = s Set time stamp
+                            s = s+1 Increment time stamp
+                    E[t] = true Flag triangle as emitted
+            Select next fanning vertex
+            f = Get-Next-Vertex(I,i,k,N,C,s,L,D)
+        return O
+        */
+    // ...................................................................................
+
+    int ivdx = 0;
+    int ics = 1;
+    int iStampCnt = mConfigCacheDepth+1;
+    while (ivdx >= 0)   {
+
+        unsigned int icnt = piNumTriPtrNoModify[ivdx];
+        unsigned int* piList = adj.GetAdjacentTriangles(ivdx);
+        unsigned int* piCurCandidate = piCandidates;
+
+        // get all triangles in the neighborhood
+        for (unsigned int tri = 0; tri < icnt;++tri)    {
+
+            // if they have not yet been emitted, add them to the output IB
+            const unsigned int fidx = *piList++;
+            if (!abEmitted[fidx])   {
+
+                // so iterate through all vertices of the current triangle
+                const aiFace* pcFace = &pMesh->mFaces[ fidx ];
+                unsigned nind = pcFace->mNumIndices;
+                for (unsigned ind = 0; ind < nind; ind++) {
+                    unsigned dp = pcFace->mIndices[ind];
+
+                    // the current vertex won't have any free triangles after this step
+                    if (ivdx != (int)dp) {
+                        // append the vertex to the dead-end stack
+                        sDeadEndVStack.push(dp);
+
+                        // register as candidate for the next step
+                        *piCurCandidate++ = dp;
+
+                        // decrease the per-vertex triangle counts
+                        piNumTriPtr[dp]--;
+                    }
+
+                    // append the vertex to the output index buffer
+                    *piCSIter++ = dp;
+
+                    // if the vertex is not yet in cache, set its cache count
+                    if (iStampCnt-piCachingStamps[dp] > mConfigCacheDepth) {
+                        piCachingStamps[dp] = iStampCnt++;
+                        ++iCacheMisses;
+                    }
+                }
+                // flag triangle as emitted
+                abEmitted[fidx] = true;
+            }
+        }
+
+        // the vertex has now no living adjacent triangles anymore
+        piNumTriPtr[ivdx] = 0;
+
+        // get next fanning vertex
+        ivdx = -1;
+        int max_priority = -1;
+        for (unsigned int* piCur = piCandidates;piCur != piCurCandidate;++piCur)    {
+            const unsigned int dp = *piCur;
+
+            // must have live triangles
+            if (piNumTriPtr[dp] > 0)    {
+                int priority = 0;
+
+                // will the vertex be in cache, even after fanning occurs?
+                unsigned int tmp;
+                if ((tmp = iStampCnt-piCachingStamps[dp]) + 2*piNumTriPtr[dp] <= mConfigCacheDepth) {
+                    priority = tmp;
+                }
+
+                // keep best candidate
+                if (priority > max_priority) {
+                    max_priority = priority;
+                    ivdx = dp;
+                }
+            }
+        }
+        // did we reach a dead end?
+        if (-1 == ivdx) {
+            // need to get a non-local vertex for which we have a good chance that it is still
+            // in the cache ...
+            while (!sDeadEndVStack.empty()) {
+                unsigned int iCachedIdx = sDeadEndVStack.top();
+                sDeadEndVStack.pop();
+                if (piNumTriPtr[ iCachedIdx ] > 0)  {
+                    ivdx = iCachedIdx;
+                    break;
+                }
+            }
+
+            if (-1 == ivdx) {
+                // well, there isn't such a vertex. Simply get the next vertex in input order and
+                // hope it is not too bad ...
+                while (ics < (int)pMesh->mNumVertices)  {
+                    ++ics;
+                    if (piNumTriPtr[ics] > 0)   {
+                        ivdx = ics;
+                        break;
+                    }
+                }
+            }
+        }
+    }
+    ai_real fACMR2 = 0.0f;
+    if (!DefaultLogger::isNullLogger()) {
+        fACMR2 = (float)iCacheMisses / pMesh->mNumFaces;
+
+        // very intense verbose logging ... prepare for much text if there are many meshes
+        if ( DefaultLogger::get()->getLogSeverity() == Logger::VERBOSE) {
+            ASSIMP_LOG_VERBOSE_DEBUG("Mesh %u | ACMR in: ", meshNum, " out: ", fACMR, " | ~", fACMR2, ((fACMR - fACMR2) / fACMR) * 100.f);
+        }
+
+        fACMR2 *= pMesh->mNumFaces;
+    }
+    // sort the output index buffer back to the input array
+    piCSIter = piIBOutput;
+    for (aiFace* pcFace = pMesh->mFaces; pcFace != pcEnd;++pcFace)  {
+        unsigned nind = pcFace->mNumIndices;
+        unsigned * ind = pcFace->mIndices;
+        if (nind > 0) ind[0] = *piCSIter++;
+        if (nind > 1) ind[1] = *piCSIter++;
+        if (nind > 2) ind[2] = *piCSIter++;
+    }
+
+    // delete temporary storage
+    delete[] piCachingStamps;
+    delete[] piIBOutput;
+    delete[] piCandidates;
+
+    return fACMR2;
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/ImproveCacheLocality.h b/src/mesh/assimp-master/code/PostProcessing/ImproveCacheLocality.h
new file mode 100644
index 0000000..b2074a1
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/ImproveCacheLocality.h
@@ -0,0 +1,101 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file Defines a post processing step to reorder faces for
+ better cache locality*/
+#ifndef AI_IMPROVECACHELOCALITY_H_INC
+#define AI_IMPROVECACHELOCALITY_H_INC
+
+#include "Common/BaseProcess.h"
+
+#include <assimp/types.h>
+
+struct aiMesh;
+
+namespace Assimp
+{
+
+// ---------------------------------------------------------------------------
+/** The ImproveCacheLocalityProcess reorders all faces for improved vertex
+ *  cache locality. It tries to arrange all faces to fans and to render
+ *  faces which share vertices directly one after the other.
+ *
+ *  @note This step expects triagulated input data.
+ */
+class ImproveCacheLocalityProcess : public BaseProcess
+{
+public:
+
+    ImproveCacheLocalityProcess();
+    ~ImproveCacheLocalityProcess();
+
+public:
+
+    // -------------------------------------------------------------------
+    // Check whether the pp step is active
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    // Executes the pp step on a given scene
+    void Execute( aiScene* pScene);
+
+    // -------------------------------------------------------------------
+    // Configures the pp step
+    void SetupProperties(const Importer* pImp);
+
+protected:
+    // -------------------------------------------------------------------
+    /** Executes the postprocessing step on the given mesh
+     * @param pMesh The mesh to process.
+     * @param meshNum Index of the mesh to process
+     */
+    ai_real ProcessMesh( aiMesh* pMesh, unsigned int meshNum);
+
+private:
+    //! Configuration parameter: specifies the size of the cache to
+    //! optimize the vertex data for.
+    unsigned int mConfigCacheDepth;
+};
+
+} // end of namespace Assimp
+
+#endif // AI_IMPROVECACHELOCALITY_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/JoinVerticesProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/JoinVerticesProcess.cpp
new file mode 100644
index 0000000..184e8d7
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/JoinVerticesProcess.cpp
@@ -0,0 +1,438 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file Implementation of the post processing step to join identical vertices
+ * for all imported meshes
+ */
+
+
+#ifndef ASSIMP_BUILD_NO_JOINVERTICES_PROCESS
+
+#include "JoinVerticesProcess.h"
+#include "ProcessHelper.h"
+#include <assimp/Vertex.h>
+#include <assimp/TinyFormatter.h>
+#include <stdio.h>
+#include <unordered_set>
+
+using namespace Assimp;
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+JoinVerticesProcess::JoinVerticesProcess()
+{
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+JoinVerticesProcess::~JoinVerticesProcess()
+{
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool JoinVerticesProcess::IsActive( unsigned int pFlags) const
+{
+    return (pFlags & aiProcess_JoinIdenticalVertices) != 0;
+}
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void JoinVerticesProcess::Execute( aiScene* pScene)
+{
+    ASSIMP_LOG_DEBUG("JoinVerticesProcess begin");
+
+    // get the total number of vertices BEFORE the step is executed
+    int iNumOldVertices = 0;
+    if (!DefaultLogger::isNullLogger()) {
+        for( unsigned int a = 0; a < pScene->mNumMeshes; a++)   {
+            iNumOldVertices +=  pScene->mMeshes[a]->mNumVertices;
+        }
+    }
+
+    // execute the step
+    int iNumVertices = 0;
+    for( unsigned int a = 0; a < pScene->mNumMeshes; a++)
+        iNumVertices += ProcessMesh( pScene->mMeshes[a],a);
+
+    // if logging is active, print detailed statistics
+    if (!DefaultLogger::isNullLogger()) {
+        if (iNumOldVertices == iNumVertices) {
+            ASSIMP_LOG_DEBUG("JoinVerticesProcess finished ");
+        } else {
+            ASSIMP_LOG_INFO("JoinVerticesProcess finished | Verts in: ", iNumOldVertices,
+                " out: ", iNumVertices, " | ~",
+                ((iNumOldVertices - iNumVertices) / (float)iNumOldVertices) * 100.f );
+        }
+    }
+
+    pScene->mFlags |= AI_SCENE_FLAGS_NON_VERBOSE_FORMAT;
+}
+
+namespace {
+
+bool areVerticesEqual(const Vertex &lhs, const Vertex &rhs, bool complex)
+{
+    // A little helper to find locally close vertices faster.
+    // Try to reuse the lookup table from the last step.
+    const static float epsilon = 1e-5f;
+    // Squared because we check against squared length of the vector difference
+    static const float squareEpsilon = epsilon * epsilon;
+
+    // Square compare is useful for animeshes vertices compare
+    if ((lhs.position - rhs.position).SquareLength() > squareEpsilon) {
+        return false;
+    }
+
+    // We just test the other attributes even if they're not present in the mesh.
+    // In this case they're initialized to 0 so the comparison succeeds.
+    // By this method the non-present attributes are effectively ignored in the comparison.
+    if ((lhs.normal - rhs.normal).SquareLength() > squareEpsilon) {
+        return false;
+    }
+
+    if ((lhs.texcoords[0] - rhs.texcoords[0]).SquareLength() > squareEpsilon) {
+        return false;
+    }
+
+    if ((lhs.tangent - rhs.tangent).SquareLength() > squareEpsilon) {
+        return false;
+    }
+
+    if ((lhs.bitangent - rhs.bitangent).SquareLength() > squareEpsilon) {
+        return false;
+    }
+
+    // Usually we won't have vertex colors or multiple UVs, so we can skip from here
+    // Actually this increases runtime performance slightly, at least if branch
+    // prediction is on our side.
+    if (complex) {
+        for (int i = 0; i < 8; i++) {
+            if (i > 0 && (lhs.texcoords[i] - rhs.texcoords[i]).SquareLength() > squareEpsilon) {
+                return false;
+            }
+            if (GetColorDifference(lhs.colors[i], rhs.colors[i]) > squareEpsilon) {
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+template<class XMesh>
+void updateXMeshVertices(XMesh *pMesh, std::vector<Vertex> &uniqueVertices) {
+    // replace vertex data with the unique data sets
+    pMesh->mNumVertices = (unsigned int)uniqueVertices.size();
+
+    // ----------------------------------------------------------------------------
+    // NOTE - we're *not* calling Vertex::SortBack() because it would check for
+    // presence of every single vertex component once PER VERTEX. And our CPU
+    // dislikes branches, even if they're easily predictable.
+    // ----------------------------------------------------------------------------
+
+    // Position, if present (check made for aiAnimMesh)
+    if (pMesh->mVertices)
+    {
+        delete [] pMesh->mVertices;
+        pMesh->mVertices = new aiVector3D[pMesh->mNumVertices];
+        for (unsigned int a = 0; a < pMesh->mNumVertices; a++) {
+            pMesh->mVertices[a] = uniqueVertices[a].position;
+        }
+    }
+
+    // Normals, if present
+    if (pMesh->mNormals)
+    {
+        delete [] pMesh->mNormals;
+        pMesh->mNormals = new aiVector3D[pMesh->mNumVertices];
+        for( unsigned int a = 0; a < pMesh->mNumVertices; a++) {
+            pMesh->mNormals[a] = uniqueVertices[a].normal;
+        }
+    }
+    // Tangents, if present
+    if (pMesh->mTangents)
+    {
+        delete [] pMesh->mTangents;
+        pMesh->mTangents = new aiVector3D[pMesh->mNumVertices];
+        for (unsigned int a = 0; a < pMesh->mNumVertices; a++) {
+            pMesh->mTangents[a] = uniqueVertices[a].tangent;
+        }
+    }
+    // Bitangents as well
+    if (pMesh->mBitangents)
+    {
+        delete [] pMesh->mBitangents;
+        pMesh->mBitangents = new aiVector3D[pMesh->mNumVertices];
+        for (unsigned int a = 0; a < pMesh->mNumVertices; a++) {
+            pMesh->mBitangents[a] = uniqueVertices[a].bitangent;
+        }
+    }
+    // Vertex colors
+    for (unsigned int a = 0; pMesh->HasVertexColors(a); a++)
+    {
+        delete [] pMesh->mColors[a];
+        pMesh->mColors[a] = new aiColor4D[pMesh->mNumVertices];
+        for( unsigned int b = 0; b < pMesh->mNumVertices; b++) {
+            pMesh->mColors[a][b] = uniqueVertices[b].colors[a];
+        }
+    }
+    // Texture coords
+    for (unsigned int a = 0; pMesh->HasTextureCoords(a); a++)
+    {
+        delete [] pMesh->mTextureCoords[a];
+        pMesh->mTextureCoords[a] = new aiVector3D[pMesh->mNumVertices];
+        for (unsigned int b = 0; b < pMesh->mNumVertices; b++) {
+            pMesh->mTextureCoords[a][b] = uniqueVertices[b].texcoords[a];
+        }
+    }
+}
+} // namespace
+
+// ------------------------------------------------------------------------------------------------
+// Unites identical vertices in the given mesh
+int JoinVerticesProcess::ProcessMesh( aiMesh* pMesh, unsigned int meshIndex)
+{
+    static_assert( AI_MAX_NUMBER_OF_COLOR_SETS    == 8, "AI_MAX_NUMBER_OF_COLOR_SETS    == 8");
+	static_assert( AI_MAX_NUMBER_OF_TEXTURECOORDS == 8, "AI_MAX_NUMBER_OF_TEXTURECOORDS == 8");
+
+    // Return early if we don't have any positions
+    if (!pMesh->HasPositions() || !pMesh->HasFaces()) {
+        return 0;
+    }
+
+    // We should care only about used vertices, not all of them
+    // (this can happen due to original file vertices buffer being used by
+    // multiple meshes)
+    std::unordered_set<unsigned int> usedVertexIndices;
+    usedVertexIndices.reserve(pMesh->mNumVertices);
+    for( unsigned int a = 0; a < pMesh->mNumFaces; a++)
+    {
+        aiFace& face = pMesh->mFaces[a];
+        for( unsigned int b = 0; b < face.mNumIndices; b++) {
+            usedVertexIndices.insert(face.mIndices[b]);
+        }
+    }
+
+    // We'll never have more vertices afterwards.
+    std::vector<Vertex> uniqueVertices;
+    uniqueVertices.reserve( pMesh->mNumVertices);
+
+    // For each vertex the index of the vertex it was replaced by.
+    // Since the maximal number of vertices is 2^31-1, the most significand bit can be used to mark
+    //  whether a new vertex was created for the index (true) or if it was replaced by an existing
+    //  unique vertex (false). This saves an additional std::vector<bool> and greatly enhances
+    //  branching performance.
+    static_assert(AI_MAX_VERTICES == 0x7fffffff, "AI_MAX_VERTICES == 0x7fffffff");
+    std::vector<unsigned int> replaceIndex( pMesh->mNumVertices, 0xffffffff);
+
+    // float posEpsilonSqr;
+    SpatialSort *vertexFinder = nullptr;
+    SpatialSort _vertexFinder;
+
+    typedef std::pair<SpatialSort,float> SpatPair;
+    if (shared) {
+        std::vector<SpatPair >* avf;
+        shared->GetProperty(AI_SPP_SPATIAL_SORT,avf);
+        if (avf)    {
+            SpatPair& blubb = (*avf)[meshIndex];
+            vertexFinder  = &blubb.first;
+            // posEpsilonSqr = blubb.second;
+        }
+    }
+    if (!vertexFinder)  {
+        // bad, need to compute it.
+        _vertexFinder.Fill(pMesh->mVertices, pMesh->mNumVertices, sizeof( aiVector3D));
+        vertexFinder = &_vertexFinder;
+        // posEpsilonSqr = ComputePositionEpsilon(pMesh);
+    }
+
+    // Again, better waste some bytes than a realloc ...
+    std::vector<unsigned int> verticesFound;
+    verticesFound.reserve(10);
+
+    // Run an optimized code path if we don't have multiple UVs or vertex colors.
+    // This should yield false in more than 99% of all imports ...
+    const bool complex = ( pMesh->GetNumColorChannels() > 0 || pMesh->GetNumUVChannels() > 1);
+    const bool hasAnimMeshes = pMesh->mNumAnimMeshes > 0;
+
+    // We'll never have more vertices afterwards.
+    std::vector<std::vector<Vertex>> uniqueAnimatedVertices;
+    if (hasAnimMeshes) {
+        uniqueAnimatedVertices.resize(pMesh->mNumAnimMeshes);
+        for (unsigned int animMeshIndex = 0; animMeshIndex < pMesh->mNumAnimMeshes; animMeshIndex++) {
+            uniqueAnimatedVertices[animMeshIndex].reserve(pMesh->mNumVertices);
+        }
+    }
+
+    // Now check each vertex if it brings something new to the table
+    for( unsigned int a = 0; a < pMesh->mNumVertices; a++)  {
+        if (usedVertexIndices.find(a) == usedVertexIndices.end()) {
+            continue;
+        }
+
+        // collect the vertex data
+        Vertex v(pMesh,a);
+
+        // collect all vertices that are close enough to the given position
+        vertexFinder->FindIdenticalPositions( v.position, verticesFound);
+        unsigned int matchIndex = 0xffffffff;
+
+        // check all unique vertices close to the position if this vertex is already present among them
+        for( unsigned int b = 0; b < verticesFound.size(); b++) {
+            const unsigned int vidx = verticesFound[b];
+            const unsigned int uidx = replaceIndex[ vidx];
+            if( uidx & 0x80000000)
+                continue;
+
+            const Vertex& uv = uniqueVertices[ uidx];
+
+            if (!areVerticesEqual(v, uv, complex)) {
+                continue;
+            }
+
+            if (hasAnimMeshes) {
+                // If given vertex is animated, then it has to be preserver 1 to 1 (base mesh and animated mesh require same topology)
+                // NOTE: not doing this totaly breaks anim meshes as they don't have their own faces (they use pMesh->mFaces)
+                bool breaksAnimMesh = false;
+                for (unsigned int animMeshIndex = 0; animMeshIndex < pMesh->mNumAnimMeshes; animMeshIndex++) {
+                    const Vertex& animatedUV = uniqueAnimatedVertices[animMeshIndex][ uidx];
+                    Vertex aniMeshVertex(pMesh->mAnimMeshes[animMeshIndex], a);
+                    if (!areVerticesEqual(aniMeshVertex, animatedUV, complex)) {
+                        breaksAnimMesh = true;
+                        break;
+                    }
+                }
+                if (breaksAnimMesh) {
+                    continue;
+                }
+            }
+
+            // we're still here -> this vertex perfectly matches our given vertex
+            matchIndex = uidx;
+            break;
+        }
+
+        // found a replacement vertex among the uniques?
+        if( matchIndex != 0xffffffff)
+        {
+            // store where to found the matching unique vertex
+            replaceIndex[a] = matchIndex | 0x80000000;
+        }
+        else
+        {
+            // no unique vertex matches it up to now -> so add it
+            replaceIndex[a] = (unsigned int)uniqueVertices.size();
+            uniqueVertices.push_back( v);
+            if (hasAnimMeshes) {
+                for (unsigned int animMeshIndex = 0; animMeshIndex < pMesh->mNumAnimMeshes; animMeshIndex++) {
+                    Vertex aniMeshVertex(pMesh->mAnimMeshes[animMeshIndex], a);
+                    uniqueAnimatedVertices[animMeshIndex].push_back(aniMeshVertex);
+                }
+            }
+        }
+    }
+
+    if (!DefaultLogger::isNullLogger() && DefaultLogger::get()->getLogSeverity() == Logger::VERBOSE)    {
+        ASSIMP_LOG_VERBOSE_DEBUG(
+            "Mesh ",meshIndex,
+            " (",
+            (pMesh->mName.length ? pMesh->mName.data : "unnamed"),
+            ") | Verts in: ",pMesh->mNumVertices,
+            " out: ",
+            uniqueVertices.size(),
+            " | ~",
+            ((pMesh->mNumVertices - uniqueVertices.size()) / (float)pMesh->mNumVertices) * 100.f,
+            "%"
+        );
+    }
+
+    updateXMeshVertices(pMesh, uniqueVertices);
+    if (hasAnimMeshes) {
+        for (unsigned int animMeshIndex = 0; animMeshIndex < pMesh->mNumAnimMeshes; animMeshIndex++) {
+            updateXMeshVertices(pMesh->mAnimMeshes[animMeshIndex], uniqueAnimatedVertices[animMeshIndex]);
+        }
+    }
+
+    // adjust the indices in all faces
+    for( unsigned int a = 0; a < pMesh->mNumFaces; a++)
+    {
+        aiFace& face = pMesh->mFaces[a];
+        for( unsigned int b = 0; b < face.mNumIndices; b++) {
+            face.mIndices[b] = replaceIndex[face.mIndices[b]] & ~0x80000000;
+        }
+    }
+
+    // adjust bone vertex weights.
+    for( int a = 0; a < (int)pMesh->mNumBones; a++) {
+        aiBone* bone = pMesh->mBones[a];
+        std::vector<aiVertexWeight> newWeights;
+        newWeights.reserve( bone->mNumWeights);
+
+        if (nullptr != bone->mWeights) {
+            for ( unsigned int b = 0; b < bone->mNumWeights; b++ ) {
+                const aiVertexWeight& ow = bone->mWeights[ b ];
+                // if the vertex is a unique one, translate it
+                if ( !( replaceIndex[ ow.mVertexId ] & 0x80000000 ) ) {
+                    aiVertexWeight nw;
+                    nw.mVertexId = replaceIndex[ ow.mVertexId ];
+                    nw.mWeight = ow.mWeight;
+                    newWeights.push_back( nw );
+                }
+            }
+        } else {
+            ASSIMP_LOG_ERROR( "X-Export: aiBone shall contain weights, but pointer to them is nullptr." );
+        }
+
+        if (newWeights.size() > 0) {
+            // kill the old and replace them with the translated weights
+            delete [] bone->mWeights;
+            bone->mNumWeights = (unsigned int)newWeights.size();
+
+            bone->mWeights = new aiVertexWeight[bone->mNumWeights];
+            memcpy( bone->mWeights, &newWeights[0], bone->mNumWeights * sizeof( aiVertexWeight));
+        }
+    }
+    return pMesh->mNumVertices;
+}
+
+#endif // !! ASSIMP_BUILD_NO_JOINVERTICES_PROCESS
diff --git a/src/mesh/assimp-master/code/PostProcessing/JoinVerticesProcess.h b/src/mesh/assimp-master/code/PostProcessing/JoinVerticesProcess.h
new file mode 100644
index 0000000..f95236e
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/JoinVerticesProcess.h
@@ -0,0 +1,95 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file Defines a post processing step to join identical vertices
+    on all imported meshes.*/
+#ifndef AI_JOINVERTICESPROCESS_H_INC
+#define AI_JOINVERTICESPROCESS_H_INC
+
+#include "Common/BaseProcess.h"
+
+#include <assimp/types.h>
+
+struct aiMesh;
+
+namespace Assimp
+{
+
+// ---------------------------------------------------------------------------
+/** The JoinVerticesProcess unites identical vertices in all imported meshes.
+ * By default the importer returns meshes where each face addressed its own
+ * set of vertices even if that means that identical vertices are stored multiple
+ * times. The JoinVerticesProcess finds these identical vertices and
+ * erases all but one of the copies. This usually reduces the number of vertices
+ * in a mesh by a serious amount and is the standard form to render a mesh.
+ */
+class ASSIMP_API JoinVerticesProcess : public BaseProcess {
+public:
+    JoinVerticesProcess();
+    ~JoinVerticesProcess();
+
+    // -------------------------------------------------------------------
+    /** Returns whether the processing step is present in the given flag field.
+     * @param pFlags The processing flags the importer was called with. A bitwise
+     *   combination of #aiPostProcessSteps.
+     * @return true if the process is present in this flag fields, false if not.
+    */
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    /** Executes the post processing step on the given imported data.
+    * At the moment a process is not supposed to fail.
+    * @param pScene The imported data to work at.
+    */
+    void Execute( aiScene* pScene);
+
+    // -------------------------------------------------------------------
+    /** Unites identical vertices in the given mesh.
+     * @param pMesh The mesh to process.
+     * @param meshIndex Index of the mesh to process
+     */
+    int ProcessMesh( aiMesh* pMesh, unsigned int meshIndex);
+};
+
+} // end of namespace Assimp
+
+#endif // AI_CALCTANGENTSPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/LimitBoneWeightsProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/LimitBoneWeightsProcess.cpp
new file mode 100644
index 0000000..63f6bf9
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/LimitBoneWeightsProcess.cpp
@@ -0,0 +1,196 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** Implementation of the LimitBoneWeightsProcess post processing step */
+
+
+#include "LimitBoneWeightsProcess.h"
+#include <assimp/SmallVector.h>
+#include <assimp/StringUtils.h>
+#include <assimp/postprocess.h>
+#include <assimp/DefaultLogger.hpp>
+#include <assimp/scene.h>
+#include <stdio.h>
+
+using namespace Assimp;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+LimitBoneWeightsProcess::LimitBoneWeightsProcess()
+{
+    mMaxWeights = AI_LMW_MAX_WEIGHTS;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+LimitBoneWeightsProcess::~LimitBoneWeightsProcess()
+{
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool LimitBoneWeightsProcess::IsActive( unsigned int pFlags) const
+{
+    return (pFlags & aiProcess_LimitBoneWeights) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void LimitBoneWeightsProcess::Execute( aiScene* pScene)
+{
+    ASSIMP_LOG_DEBUG("LimitBoneWeightsProcess begin");
+
+    for (unsigned int m = 0; m < pScene->mNumMeshes; ++m) {
+        ProcessMesh(pScene->mMeshes[m]);
+    }
+
+    ASSIMP_LOG_DEBUG("LimitBoneWeightsProcess end");
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void LimitBoneWeightsProcess::SetupProperties(const Importer* pImp)
+{
+    // get the current value of the property
+    this->mMaxWeights = pImp->GetPropertyInteger(AI_CONFIG_PP_LBW_MAX_WEIGHTS,AI_LMW_MAX_WEIGHTS);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Unites identical vertices in the given mesh
+void LimitBoneWeightsProcess::ProcessMesh(aiMesh* pMesh)
+{
+    if (!pMesh->HasBones())
+        return;
+
+    // collect all bone weights per vertex
+    typedef SmallVector<Weight,8> VertexWeightArray;
+    typedef std::vector<VertexWeightArray> WeightsPerVertex;
+    WeightsPerVertex vertexWeights(pMesh->mNumVertices);
+    size_t maxVertexWeights = 0;
+
+    for (unsigned int b = 0; b < pMesh->mNumBones; ++b)
+    {
+        const aiBone* bone = pMesh->mBones[b];
+        for (unsigned int w = 0; w < bone->mNumWeights; ++w)
+        {
+            const aiVertexWeight& vw = bone->mWeights[w];
+
+            if (vertexWeights.size() <= vw.mVertexId)
+                continue;
+
+            vertexWeights[vw.mVertexId].push_back(Weight(b, vw.mWeight));
+            maxVertexWeights = std::max(maxVertexWeights, vertexWeights[vw.mVertexId].size());
+        }
+    }
+
+    if (maxVertexWeights <= mMaxWeights)
+        return;
+
+    unsigned int removed = 0, old_bones = pMesh->mNumBones;
+
+    // now cut the weight count if it exceeds the maximum
+    for (WeightsPerVertex::iterator vit = vertexWeights.begin(); vit != vertexWeights.end(); ++vit)
+    {
+        if (vit->size() <= mMaxWeights)
+            continue;
+
+        // more than the defined maximum -> first sort by weight in descending order. That's
+        // why we defined the < operator in such a weird way.
+        std::sort(vit->begin(), vit->end());
+
+        // now kill everything beyond the maximum count
+        unsigned int m = static_cast<unsigned int>(vit->size());
+        vit->resize(mMaxWeights);
+        removed += static_cast<unsigned int>(m - vit->size());
+
+        // and renormalize the weights
+        float sum = 0.0f;
+        for(const Weight* it = vit->begin(); it != vit->end(); ++it) {
+            sum += it->mWeight;
+        }
+        if (0.0f != sum) {
+            const float invSum = 1.0f / sum;
+            for(Weight* it = vit->begin(); it != vit->end(); ++it) {
+                it->mWeight *= invSum;
+            }
+        }
+    }
+
+    // clear weight count for all bone
+    for (unsigned int a = 0; a < pMesh->mNumBones; ++a)
+    {
+        pMesh->mBones[a]->mNumWeights = 0;
+    }
+
+    // rebuild the vertex weight array for all bones
+    for (unsigned int a = 0; a < vertexWeights.size(); ++a)
+    {
+        const VertexWeightArray& vw = vertexWeights[a];
+        for (const Weight* it = vw.begin(); it != vw.end(); ++it)
+        {
+            aiBone* bone = pMesh->mBones[it->mBone];
+            bone->mWeights[bone->mNumWeights++] = aiVertexWeight(a, it->mWeight);
+        }
+    }
+
+    // remove empty bones
+    unsigned int writeBone = 0;
+
+    for (unsigned int readBone = 0; readBone< pMesh->mNumBones; ++readBone)
+    {
+        aiBone* bone = pMesh->mBones[readBone];
+        if (bone->mNumWeights > 0)
+        {
+            pMesh->mBones[writeBone++] = bone;
+        }
+        else
+        {
+            delete bone;
+        }
+    }
+    pMesh->mNumBones = writeBone;
+
+    if (!DefaultLogger::isNullLogger()) {
+        ASSIMP_LOG_INFO("Removed ", removed, " weights. Input bones: ", old_bones, ". Output bones: ", pMesh->mNumBones);
+    }
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/LimitBoneWeightsProcess.h b/src/mesh/assimp-master/code/PostProcessing/LimitBoneWeightsProcess.h
new file mode 100644
index 0000000..22d286b
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/LimitBoneWeightsProcess.h
@@ -0,0 +1,138 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** Defines a post processing step to limit the number of bones affecting a single vertex. */
+#ifndef AI_LIMITBONEWEIGHTSPROCESS_H_INC
+#define AI_LIMITBONEWEIGHTSPROCESS_H_INC
+
+#include "Common/BaseProcess.h"
+
+// Forward declarations
+struct aiMesh;
+
+class LimitBoneWeightsTest;
+
+namespace Assimp {
+
+// NOTE: If you change these limits, don't forget to change the
+// corresponding values in all Assimp ports
+
+// **********************************************************
+// Java: ConfigProperty.java,
+//  ConfigProperty.DEFAULT_BONE_WEIGHT_LIMIT
+// **********************************************************
+
+#if (!defined AI_LMW_MAX_WEIGHTS)
+#   define AI_LMW_MAX_WEIGHTS   0x4
+#endif // !! AI_LMW_MAX_WEIGHTS
+
+// ---------------------------------------------------------------------------
+/** This post processing step limits the number of bones affecting a vertex
+* to a certain maximum value. If a vertex is affected by more than that number
+* of bones, the bone weight with the least influence on this vertex are removed.
+* The other weights on this bone are then renormalized to assure the sum weight
+* to be 1.
+*/
+class ASSIMP_API LimitBoneWeightsProcess : public BaseProcess {
+public:
+    LimitBoneWeightsProcess();
+    ~LimitBoneWeightsProcess();
+
+    // -------------------------------------------------------------------
+    /** Returns whether the processing step is present in the given flag.
+    * @param pFlags The processing flags the importer was called with.
+    *   A bitwise combination of #aiPostProcessSteps.
+    * @return true if the process is present in this flag fields,
+    *   false if not.
+    */
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    /** Called prior to ExecuteOnScene().
+    * The function is a request to the process to update its configuration
+    * basing on the Importer's configuration property list.
+    */
+    void SetupProperties(const Importer* pImp);
+
+    // -------------------------------------------------------------------
+    /** Limits the bone weight count for all vertices in the given mesh.
+    * @param pMesh The mesh to process.
+    */
+    void ProcessMesh( aiMesh* pMesh);
+
+    // -------------------------------------------------------------------
+    /** Executes the post processing step on the given imported data.
+    * At the moment a process is not supposed to fail.
+    * @param pScene The imported data to work at.
+    */
+    void Execute( aiScene* pScene);
+
+    // -------------------------------------------------------------------
+    /** Describes a bone weight on a vertex */
+    struct Weight {
+        unsigned int mBone; ///< Index of the bone
+        float mWeight;      ///< Weight of that bone on this vertex
+        Weight() AI_NO_EXCEPT
+        : mBone(0)
+        , mWeight(0.0f) {
+            // empty
+        }
+
+        Weight( unsigned int pBone, float pWeight)
+        : mBone(pBone)
+        , mWeight(pWeight) {
+            // empty
+        }
+
+        /** Comparison operator to sort bone weights by descending weight */
+        bool operator < (const Weight& pWeight) const {
+            return mWeight > pWeight.mWeight;
+        }
+    };
+
+    /** Maximum number of bones influencing any single vertex. */
+    unsigned int mMaxWeights;
+};
+
+} // end of namespace Assimp
+
+#endif // AI_LIMITBONEWEIGHTSPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/MakeVerboseFormat.cpp b/src/mesh/assimp-master/code/PostProcessing/MakeVerboseFormat.cpp
new file mode 100644
index 0000000..75e2a0f
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/MakeVerboseFormat.cpp
@@ -0,0 +1,231 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+/** @file Implementation of the post processing step "MakeVerboseFormat"
+*/
+
+#include "MakeVerboseFormat.h"
+#include <assimp/scene.h>
+#include <assimp/DefaultLogger.hpp>
+
+using namespace Assimp;
+
+// ------------------------------------------------------------------------------------------------
+MakeVerboseFormatProcess::MakeVerboseFormatProcess() {
+    // nothing to do here
+}
+// ------------------------------------------------------------------------------------------------
+MakeVerboseFormatProcess::~MakeVerboseFormatProcess() {
+    // nothing to do here
+}
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void MakeVerboseFormatProcess::Execute(aiScene *pScene) {
+    ai_assert(nullptr != pScene);
+    ASSIMP_LOG_DEBUG("MakeVerboseFormatProcess begin");
+
+    bool bHas = false;
+    for (unsigned int a = 0; a < pScene->mNumMeshes; a++) {
+        if (MakeVerboseFormat(pScene->mMeshes[a]))
+            bHas = true;
+    }
+    if (bHas) {
+        ASSIMP_LOG_INFO("MakeVerboseFormatProcess finished. There was much work to do ...");
+    } else {
+        ASSIMP_LOG_DEBUG("MakeVerboseFormatProcess. There was nothing to do.");
+    }
+
+    pScene->mFlags &= ~AI_SCENE_FLAGS_NON_VERBOSE_FORMAT;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+bool MakeVerboseFormatProcess::MakeVerboseFormat(aiMesh *pcMesh) {
+    ai_assert(nullptr != pcMesh);
+
+    unsigned int iOldNumVertices = pcMesh->mNumVertices;
+    const unsigned int iNumVerts = pcMesh->mNumFaces * 3;
+
+    aiVector3D *pvPositions = new aiVector3D[iNumVerts];
+
+    aiVector3D *pvNormals = nullptr;
+    if (pcMesh->HasNormals()) {
+        pvNormals = new aiVector3D[iNumVerts];
+    }
+    aiVector3D *pvTangents = nullptr, *pvBitangents = nullptr;
+    if (pcMesh->HasTangentsAndBitangents()) {
+        pvTangents = new aiVector3D[iNumVerts];
+        pvBitangents = new aiVector3D[iNumVerts];
+    }
+
+    aiVector3D *apvTextureCoords[AI_MAX_NUMBER_OF_TEXTURECOORDS] = { 0 };
+    aiColor4D *apvColorSets[AI_MAX_NUMBER_OF_COLOR_SETS] = { 0 };
+
+    unsigned int p = 0;
+    while (pcMesh->HasTextureCoords(p))
+        apvTextureCoords[p++] = new aiVector3D[iNumVerts];
+
+    p = 0;
+    while (pcMesh->HasVertexColors(p))
+        apvColorSets[p++] = new aiColor4D[iNumVerts];
+
+    // allocate enough memory to hold output bones and vertex weights ...
+    std::vector<aiVertexWeight> *newWeights = new std::vector<aiVertexWeight>[pcMesh->mNumBones];
+    for (unsigned int i = 0; i < pcMesh->mNumBones; ++i) {
+        newWeights[i].reserve(pcMesh->mBones[i]->mNumWeights * 3);
+    }
+
+    // iterate through all faces and build a clean list
+    unsigned int iIndex = 0;
+    for (unsigned int a = 0; a < pcMesh->mNumFaces; ++a) {
+        aiFace *pcFace = &pcMesh->mFaces[a];
+        for (unsigned int q = 0; q < pcFace->mNumIndices; ++q, ++iIndex) {
+            // need to build a clean list of bones, too
+            for (unsigned int i = 0; i < pcMesh->mNumBones; ++i) {
+                for (unsigned int boneIdx = 0; boneIdx < pcMesh->mBones[i]->mNumWeights; ++boneIdx) {
+                    const aiVertexWeight &w = pcMesh->mBones[i]->mWeights[boneIdx];
+                    if (pcFace->mIndices[q] == w.mVertexId) {
+                        aiVertexWeight wNew;
+                        wNew.mVertexId = iIndex;
+                        wNew.mWeight = w.mWeight;
+                        newWeights[i].push_back(wNew);
+                    }
+                }
+            }
+
+            pvPositions[iIndex] = pcMesh->mVertices[pcFace->mIndices[q]];
+
+            if (pcMesh->HasNormals()) {
+                pvNormals[iIndex] = pcMesh->mNormals[pcFace->mIndices[q]];
+            }
+            if (pcMesh->HasTangentsAndBitangents()) {
+                pvTangents[iIndex] = pcMesh->mTangents[pcFace->mIndices[q]];
+                pvBitangents[iIndex] = pcMesh->mBitangents[pcFace->mIndices[q]];
+            }
+
+            unsigned int pp = 0;
+            while (pcMesh->HasTextureCoords(pp)) {
+                apvTextureCoords[pp][iIndex] = pcMesh->mTextureCoords[pp][pcFace->mIndices[q]];
+                ++pp;
+            }
+            pp = 0;
+            while (pcMesh->HasVertexColors(pp)) {
+                apvColorSets[pp][iIndex] = pcMesh->mColors[pp][pcFace->mIndices[q]];
+                ++pp;
+            }
+            pcFace->mIndices[q] = iIndex;
+        }
+    }
+
+    // build output vertex weights
+    for (unsigned int i = 0; i < pcMesh->mNumBones; ++i) {
+        delete[] pcMesh->mBones[i]->mWeights;
+        if (!newWeights[i].empty()) {
+            pcMesh->mBones[i]->mWeights = new aiVertexWeight[newWeights[i].size()];
+            pcMesh->mBones[i]->mNumWeights = static_cast<unsigned int>(newWeights[i].size());
+            aiVertexWeight *weightToCopy = &(newWeights[i][0]);
+            memcpy(pcMesh->mBones[i]->mWeights, weightToCopy,
+                    sizeof(aiVertexWeight) * newWeights[i].size());
+        } else {
+            pcMesh->mBones[i]->mWeights = nullptr;
+        }
+    }
+    delete[] newWeights;
+
+    // delete the old members
+    delete[] pcMesh->mVertices;
+    pcMesh->mVertices = pvPositions;
+
+    p = 0;
+    while (pcMesh->HasTextureCoords(p)) {
+        delete[] pcMesh->mTextureCoords[p];
+        pcMesh->mTextureCoords[p] = apvTextureCoords[p];
+        ++p;
+    }
+    p = 0;
+    while (pcMesh->HasVertexColors(p)) {
+        delete[] pcMesh->mColors[p];
+        pcMesh->mColors[p] = apvColorSets[p];
+        ++p;
+    }
+    pcMesh->mNumVertices = iNumVerts;
+
+    if (pcMesh->HasNormals()) {
+        delete[] pcMesh->mNormals;
+        pcMesh->mNormals = pvNormals;
+    }
+    if (pcMesh->HasTangentsAndBitangents()) {
+        delete[] pcMesh->mTangents;
+        pcMesh->mTangents = pvTangents;
+        delete[] pcMesh->mBitangents;
+        pcMesh->mBitangents = pvBitangents;
+    }
+    return (pcMesh->mNumVertices != iOldNumVertices);
+}
+
+// ------------------------------------------------------------------------------------------------
+bool IsMeshInVerboseFormat(const aiMesh *mesh) {
+    // avoid slow vector<bool> specialization
+    std::vector<unsigned int> seen(mesh->mNumVertices, 0);
+    for (unsigned int i = 0; i < mesh->mNumFaces; ++i) {
+        const aiFace &f = mesh->mFaces[i];
+        for (unsigned int j = 0; j < f.mNumIndices; ++j) {
+            if (++seen[f.mIndices[j]] == 2) {
+                // found a duplicate index
+                return false;
+            }
+        }
+    }
+
+    return true;
+}
+
+// ------------------------------------------------------------------------------------------------
+bool MakeVerboseFormatProcess::IsVerboseFormat(const aiScene *pScene) {
+    for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
+        if (!IsMeshInVerboseFormat(pScene->mMeshes[i])) {
+            return false;
+        }
+    }
+
+    return true;
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/MakeVerboseFormat.h b/src/mesh/assimp-master/code/PostProcessing/MakeVerboseFormat.h
new file mode 100644
index 0000000..6b81da6
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/MakeVerboseFormat.h
@@ -0,0 +1,113 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file Defines a post processing step to bring a given scene
+ into the verbose format that is expected by most postprocess steps.
+ This is the inverse of the "JoinIdenticalVertices" step. */
+#ifndef AI_MAKEVERBOSEFORMAT_H_INC
+#define AI_MAKEVERBOSEFORMAT_H_INC
+
+#include "Common/BaseProcess.h"
+
+struct aiMesh;
+
+namespace Assimp    {
+
+// ---------------------------------------------------------------------------
+/** MakeVerboseFormatProcess: Class to convert an asset to the verbose
+ *  format which is expected by most postprocess steps.
+ *
+ * This is the inverse of what the "JoinIdenticalVertices" step is doing.
+ * This step has no official flag (since it wouldn't make sense to run it
+ * during import). It is intended for applications intending to modify the
+ * returned aiScene. After this step has been executed, they can execute
+ * other postprocess steps on the data. The code might also be useful to
+ * quickly adapt code that doesn't result in a verbose representation of
+ * the scene data.
+ * The step has been added because it was required by the viewer, however
+ * it has been moved to the main library since others might find it
+ * useful, too. */
+class ASSIMP_API_WINONLY MakeVerboseFormatProcess : public BaseProcess
+{
+public:
+
+
+    MakeVerboseFormatProcess();
+    ~MakeVerboseFormatProcess();
+
+public:
+
+    // -------------------------------------------------------------------
+    /** Returns whether the processing step is present in the given flag field.
+    * @param pFlags The processing flags the importer was called with. A bitwise
+    *   combination of #aiPostProcessSteps.
+    * @return true if the process is present in this flag fields, false if not */
+    bool IsActive( unsigned int /*pFlags*/ ) const
+    {
+        // NOTE: There is no direct flag that corresponds to
+        // this postprocess step.
+        return false;
+    }
+
+    // -------------------------------------------------------------------
+    /** Executes the post processing step on the given imported data.
+    * At the moment a process is not supposed to fail.
+    * @param pScene The imported data to work at. */
+    void Execute( aiScene* pScene);
+
+public:
+
+    // -------------------------------------------------------------------
+    /** Checks whether the scene is already in verbose format.
+    * @param pScene The data to check.
+    * @return true if the scene is already in verbose format. */
+    static bool IsVerboseFormat(const aiScene* pScene);
+
+private:
+
+    //! Apply the postprocess step to a given submesh
+    bool MakeVerboseFormat (aiMesh* pcMesh);
+};
+
+} // end of namespace Assimp
+
+#endif // !!AI_KILLNORMALPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/OptimizeGraph.cpp b/src/mesh/assimp-master/code/PostProcessing/OptimizeGraph.cpp
new file mode 100644
index 0000000..ea44eb3
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/OptimizeGraph.cpp
@@ -0,0 +1,358 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file  OptimizeGraph.cpp
+ *  @brief Implementation of the aiProcess_OptimizGraph step
+ */
+
+#ifndef ASSIMP_BUILD_NO_OPTIMIZEGRAPH_PROCESS
+
+#include "OptimizeGraph.h"
+#include "ProcessHelper.h"
+#include "ConvertToLHProcess.h"
+#include <assimp/Exceptional.h>
+#include <assimp/SceneCombiner.h>
+#include <stdio.h>
+
+using namespace Assimp;
+
+#define AI_RESERVED_NODE_NAME "$Reserved_And_Evil"
+
+/* AI_OG_USE_HASHING enables the use of hashing to speed-up std::set lookups.
+ * The unhashed variant should be faster, except for *very* large data sets
+ */
+#ifdef AI_OG_USE_HASHING
+// Use our standard hashing function to compute the hash
+#define AI_OG_GETKEY(str) SuperFastHash(str.data, str.length)
+#else
+// Otherwise hope that std::string will utilize a static buffer
+// for shorter node names. This would avoid endless heap copying.
+#define AI_OG_GETKEY(str) std::string(str.data)
+#endif
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+OptimizeGraphProcess::OptimizeGraphProcess() :
+		mScene(),
+		nodes_in(),
+		nodes_out(),
+		count_merged() {
+	// empty
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+OptimizeGraphProcess::~OptimizeGraphProcess() {
+	// empty
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool OptimizeGraphProcess::IsActive(unsigned int pFlags) const {
+	return (0 != (pFlags & aiProcess_OptimizeGraph));
+}
+
+// ------------------------------------------------------------------------------------------------
+// Setup properties for the post-processing step
+void OptimizeGraphProcess::SetupProperties(const Importer *pImp) {
+	// Get value of AI_CONFIG_PP_OG_EXCLUDE_LIST
+	std::string tmp = pImp->GetPropertyString(AI_CONFIG_PP_OG_EXCLUDE_LIST, "");
+	AddLockedNodeList(tmp);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Collect new children
+void OptimizeGraphProcess::CollectNewChildren(aiNode *nd, std::list<aiNode *> &nodes) {
+	nodes_in += nd->mNumChildren;
+
+	// Process children
+	std::list<aiNode *> child_nodes;
+	for (unsigned int i = 0; i < nd->mNumChildren; ++i) {
+		CollectNewChildren(nd->mChildren[i], child_nodes);
+		nd->mChildren[i] = nullptr;
+	}
+
+	// Check whether we need this node; if not we can replace it by our own children (warn, danger of incest).
+	if (locked.find(AI_OG_GETKEY(nd->mName)) == locked.end()) {
+		for (std::list<aiNode *>::iterator it = child_nodes.begin(); it != child_nodes.end();) {
+
+			if (locked.find(AI_OG_GETKEY((*it)->mName)) == locked.end()) {
+				(*it)->mTransformation = nd->mTransformation * (*it)->mTransformation;
+				nodes.push_back(*it);
+
+				it = child_nodes.erase(it);
+				continue;
+			}
+			++it;
+		}
+
+		if (nd->mNumMeshes || !child_nodes.empty()) {
+			nodes.push_back(nd);
+		} else {
+			delete nd; /* bye, node */
+			return;
+		}
+	} else {
+
+		// Retain our current position in the hierarchy
+		nodes.push_back(nd);
+
+		// Now check for possible optimizations in our list of child nodes. join as many as possible
+		aiNode *join_master = nullptr;
+		aiMatrix4x4 inv;
+
+		const LockedSetType::const_iterator end = locked.end();
+
+		std::list<aiNode *> join;
+		for (std::list<aiNode *>::iterator it = child_nodes.begin(); it != child_nodes.end();) {
+			aiNode *child = *it;
+			if (child->mNumChildren == 0 && locked.find(AI_OG_GETKEY(child->mName)) == end) {
+
+				// There may be no instanced meshes
+				unsigned int n = 0;
+				for (; n < child->mNumMeshes; ++n) {
+					if (meshes[child->mMeshes[n]] > 1) {
+						break;
+					}
+				}
+				if (n == child->mNumMeshes) {
+					if (!join_master) {
+						join_master = child;
+						inv = join_master->mTransformation;
+						inv.Inverse();
+					} else {
+						child->mTransformation = inv * child->mTransformation;
+
+						join.push_back(child);
+						it = child_nodes.erase(it);
+						continue;
+					}
+				}
+			}
+			++it;
+		}
+		if (join_master && !join.empty()) {
+			join_master->mName.length = ::ai_snprintf(join_master->mName.data, MAXLEN, "$MergedNode_%u", count_merged++);
+
+			unsigned int out_meshes = 0;
+			for (std::list<aiNode *>::const_iterator it = join.cbegin(); it != join.cend(); ++it) {
+				out_meshes += (*it)->mNumMeshes;
+			}
+
+			// copy all mesh references in one array
+			if (out_meshes) {
+				unsigned int *meshIdxs = new unsigned int[out_meshes + join_master->mNumMeshes], *tmp = meshIdxs;
+				for (unsigned int n = 0; n < join_master->mNumMeshes; ++n) {
+					*tmp++ = join_master->mMeshes[n];
+				}
+
+				for (const aiNode *join_node : join) {
+					for (unsigned int n = 0; n < join_node->mNumMeshes; ++n) {
+
+						*tmp = join_node->mMeshes[n];
+						aiMesh *mesh = mScene->mMeshes[*tmp++];
+
+						// Assume the transformation is affine
+						// manually move the mesh into the right coordinate system
+
+						// Check for odd negative scale (mirror)
+						if (join_node->mTransformation.Determinant() < 0) {
+							// Reverse the mesh face winding order
+                            FlipWindingOrderProcess::ProcessMesh(mesh);
+						}
+
+                        // Update positions, normals and tangents
+						const aiMatrix3x3 IT = aiMatrix3x3(join_node->mTransformation).Inverse().Transpose();
+						for (unsigned int a = 0; a < mesh->mNumVertices; ++a) {
+
+							mesh->mVertices[a] *= join_node->mTransformation;
+
+							if (mesh->HasNormals())
+								mesh->mNormals[a] *= IT;
+
+							if (mesh->HasTangentsAndBitangents()) {
+								mesh->mTangents[a] *= IT;
+								mesh->mBitangents[a] *= IT;
+							}
+						}
+					}
+					delete join_node; // bye, node
+				}
+				delete[] join_master->mMeshes;
+				join_master->mMeshes = meshIdxs;
+				join_master->mNumMeshes += out_meshes;
+			}
+		}
+	}
+	// reassign children if something changed
+	if (child_nodes.empty() || child_nodes.size() > nd->mNumChildren) {
+
+		delete[] nd->mChildren;
+
+		if (!child_nodes.empty()) {
+			nd->mChildren = new aiNode *[child_nodes.size()];
+		} else
+			nd->mChildren = nullptr;
+	}
+
+	nd->mNumChildren = static_cast<unsigned int>(child_nodes.size());
+
+	if (nd->mChildren) {
+		aiNode **tmp = nd->mChildren;
+		for (std::list<aiNode *>::iterator it = child_nodes.begin(); it != child_nodes.end(); ++it) {
+			aiNode *node = *tmp++ = *it;
+			node->mParent = nd;
+		}
+	}
+
+	nodes_out += static_cast<unsigned int>(child_nodes.size());
+}
+
+// ------------------------------------------------------------------------------------------------
+// Execute the post-processing step on the given scene
+void OptimizeGraphProcess::Execute(aiScene *pScene) {
+	ASSIMP_LOG_DEBUG("OptimizeGraphProcess begin");
+	nodes_in = nodes_out = count_merged = 0;
+	mScene = pScene;
+
+	meshes.resize(pScene->mNumMeshes, 0);
+	FindInstancedMeshes(pScene->mRootNode);
+
+	// build a blacklist of identifiers. If the name of a node matches one of these, we won't touch it
+	locked.clear();
+	for (std::list<std::string>::const_iterator it = locked_nodes.begin(); it != locked_nodes.end(); ++it) {
+#ifdef AI_OG_USE_HASHING
+		locked.insert(SuperFastHash((*it).c_str()));
+#else
+		locked.insert(*it);
+#endif
+	}
+
+	for (unsigned int i = 0; i < pScene->mNumAnimations; ++i) {
+		for (unsigned int a = 0; a < pScene->mAnimations[i]->mNumChannels; ++a) {
+			aiNodeAnim *anim = pScene->mAnimations[i]->mChannels[a];
+			locked.insert(AI_OG_GETKEY(anim->mNodeName));
+		}
+	}
+
+	for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
+		for (unsigned int a = 0; a < pScene->mMeshes[i]->mNumBones; ++a) {
+
+			aiBone *bone = pScene->mMeshes[i]->mBones[a];
+			locked.insert(AI_OG_GETKEY(bone->mName));
+
+			// HACK: Meshes referencing bones may not be transformed; we need to look them.
+			// The easiest way to do this is to increase their reference counters ...
+			meshes[i] += 2;
+		}
+	}
+
+	for (unsigned int i = 0; i < pScene->mNumCameras; ++i) {
+		aiCamera *cam = pScene->mCameras[i];
+		locked.insert(AI_OG_GETKEY(cam->mName));
+	}
+
+	for (unsigned int i = 0; i < pScene->mNumLights; ++i) {
+		aiLight *lgh = pScene->mLights[i];
+		locked.insert(AI_OG_GETKEY(lgh->mName));
+	}
+
+	// Insert a dummy master node and make it read-only
+	aiNode *dummy_root = new aiNode(AI_RESERVED_NODE_NAME);
+	locked.insert(AI_OG_GETKEY(dummy_root->mName));
+
+	const aiString prev = pScene->mRootNode->mName;
+	pScene->mRootNode->mParent = dummy_root;
+
+	dummy_root->mChildren = new aiNode *[dummy_root->mNumChildren = 1];
+	dummy_root->mChildren[0] = pScene->mRootNode;
+
+	// Do our recursive processing of scenegraph nodes. For each node collect
+	// a fully new list of children and allow their children to place themselves
+	// on the same hierarchy layer as their parents.
+	std::list<aiNode *> nodes;
+	CollectNewChildren(dummy_root, nodes);
+
+	ai_assert(nodes.size() == 1);
+
+	if (dummy_root->mNumChildren == 0) {
+		pScene->mRootNode = nullptr;
+		throw DeadlyImportError("After optimizing the scene graph, no data remains");
+	}
+
+	if (dummy_root->mNumChildren > 1) {
+		pScene->mRootNode = dummy_root;
+
+		// Keep the dummy node but assign the name of the old root node to it
+		pScene->mRootNode->mName = prev;
+	} else {
+
+		// Remove the dummy root node again.
+		pScene->mRootNode = dummy_root->mChildren[0];
+
+		dummy_root->mChildren[0] = nullptr;
+		delete dummy_root;
+	}
+
+	pScene->mRootNode->mParent = nullptr;
+	if (!DefaultLogger::isNullLogger()) {
+		if (nodes_in != nodes_out) {
+			ASSIMP_LOG_INFO("OptimizeGraphProcess finished; Input nodes: ", nodes_in, ", Output nodes: ", nodes_out);
+		} else {
+			ASSIMP_LOG_DEBUG("OptimizeGraphProcess finished");
+		}
+	}
+	meshes.clear();
+	locked.clear();
+}
+
+// ------------------------------------------------------------------------------------------------
+// Build a LUT of all instanced meshes
+void OptimizeGraphProcess::FindInstancedMeshes(aiNode *pNode) {
+	for (unsigned int i = 0; i < pNode->mNumMeshes; ++i) {
+		++meshes[pNode->mMeshes[i]];
+	}
+
+	for (unsigned int i = 0; i < pNode->mNumChildren; ++i)
+		FindInstancedMeshes(pNode->mChildren[i]);
+}
+
+#endif // !! ASSIMP_BUILD_NO_OPTIMIZEGRAPH_PROCESS
diff --git a/src/mesh/assimp-master/code/PostProcessing/OptimizeGraph.h b/src/mesh/assimp-master/code/PostProcessing/OptimizeGraph.h
new file mode 100644
index 0000000..f5caa13
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/OptimizeGraph.h
@@ -0,0 +1,140 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file  OptimizeGraph.h
+ *  @brief Declares a post processing step to optimize the scenegraph
+ */
+#ifndef AI_OPTIMIZEGRAPHPROCESS_H_INC
+#define AI_OPTIMIZEGRAPHPROCESS_H_INC
+
+#include "Common/BaseProcess.h"
+#include "PostProcessing/ProcessHelper.h"
+
+#include <assimp/types.h>
+
+#include <set>
+
+// Forward declarations
+struct aiMesh;
+
+class OptimizeGraphProcessTest;
+
+namespace Assimp    {
+
+// -----------------------------------------------------------------------------
+/** @brief Postprocessing step to optimize the scenegraph
+ *
+ *  The implementation tries to merge nodes, even if they use different
+ *  transformations. Animations are preserved.
+ *
+ *  @see aiProcess_OptimizeGraph for a detailed description of the
+ *  algorithm being applied.
+ */
+class OptimizeGraphProcess : public BaseProcess {
+public:
+    OptimizeGraphProcess();
+    ~OptimizeGraphProcess();
+
+    // -------------------------------------------------------------------
+    bool IsActive( unsigned int pFlags) const override;
+
+    // -------------------------------------------------------------------
+    void Execute( aiScene* pScene) override;
+
+    // -------------------------------------------------------------------
+    void SetupProperties(const Importer* pImp) override;
+
+    // -------------------------------------------------------------------
+    /** @brief Add a list of node names to be locked and not modified.
+     *  @param in List of nodes. See #AI_CONFIG_PP_OG_EXCLUDE_LIST for
+     *    format explanations.
+     */
+    inline void AddLockedNodeList(std::string& in) {
+        ConvertListToStrings (in,locked_nodes);
+    }
+
+    // -------------------------------------------------------------------
+    /** @brief Add another node to be locked and not modified.
+     *  @param name Name to be locked
+     */
+    inline void AddLockedNode(std::string& name) {
+        locked_nodes.push_back(name);
+    }
+
+    // -------------------------------------------------------------------
+    /** @brief Remove a node from the list of locked nodes.
+     *  @param name Name to be unlocked
+     */
+    inline void RemoveLockedNode(std::string& name) {
+        locked_nodes.remove(name);
+    }
+
+protected:
+    void CollectNewChildren(aiNode* nd, std::list<aiNode*>& nodes);
+    void FindInstancedMeshes (aiNode* pNode);
+
+private:
+#ifdef AI_OG_USE_HASHING
+    typedef std::set<unsigned int> LockedSetType;
+#else
+    typedef std::set<std::string> LockedSetType;
+#endif
+
+    //! Scene we're working with
+    aiScene* mScene;
+
+    //! List of locked names. Stored is the hash of the name
+    LockedSetType locked;
+
+    //! List of nodes to be locked in addition to those with animations, lights or cameras assigned.
+    std::list<std::string> locked_nodes;
+
+    //! Node counters for logging purposes
+    unsigned int nodes_in,nodes_out, count_merged;
+
+    //! Reference counters for meshes
+    std::vector<unsigned int> meshes;
+};
+
+} // end of namespace Assimp
+
+#endif // AI_OPTIMIZEGRAPHPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/OptimizeMeshes.cpp b/src/mesh/assimp-master/code/PostProcessing/OptimizeMeshes.cpp
new file mode 100644
index 0000000..e624bb1
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/OptimizeMeshes.cpp
@@ -0,0 +1,256 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file  OptimizeMeshes.cpp
+ *  @brief Implementation of the aiProcess_OptimizeMeshes step
+ */
+
+
+#ifndef ASSIMP_BUILD_NO_OPTIMIZEMESHES_PROCESS
+
+
+#include "OptimizeMeshes.h"
+#include "ProcessHelper.h"
+#include <assimp/SceneCombiner.h>
+#include <assimp/Exceptional.h>
+
+using namespace Assimp;
+
+static const unsigned int NotSet   = 0xffffffff;
+static const unsigned int DeadBeef = 0xdeadbeef;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+OptimizeMeshesProcess::OptimizeMeshesProcess()
+    : mScene()
+    , pts(false)
+    , max_verts( NotSet )
+    , max_faces( NotSet ) {
+    // empty
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+OptimizeMeshesProcess::~OptimizeMeshesProcess() {
+    // empty
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool OptimizeMeshesProcess::IsActive( unsigned int pFlags) const
+{
+    // Our behaviour needs to be different if the SortByPType or SplitLargeMeshes
+    // steps are active. Thus we need to query their flags here and store the
+    // information, although we're breaking const-correctness.
+    // That's a serious design flaw, consider redesign.
+    if( 0 != (pFlags & aiProcess_OptimizeMeshes) ) {
+        pts = (0 != (pFlags & aiProcess_SortByPType));
+        max_verts = ( 0 != ( pFlags & aiProcess_SplitLargeMeshes ) ) ? DeadBeef : max_verts;
+        return true;
+    }
+    return false;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Setup properties for the post-processing step
+void OptimizeMeshesProcess::SetupProperties(const Importer* pImp)
+{
+    if( max_verts == DeadBeef /* magic hack */ ) {
+        max_faces = pImp->GetPropertyInteger(AI_CONFIG_PP_SLM_TRIANGLE_LIMIT,AI_SLM_DEFAULT_MAX_TRIANGLES);
+        max_verts = pImp->GetPropertyInteger(AI_CONFIG_PP_SLM_VERTEX_LIMIT,AI_SLM_DEFAULT_MAX_VERTICES);
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Execute step
+void OptimizeMeshesProcess::Execute( aiScene* pScene)
+{
+    const unsigned int num_old = pScene->mNumMeshes;
+    if (num_old <= 1) {
+        ASSIMP_LOG_DEBUG("Skipping OptimizeMeshesProcess");
+        return;
+    }
+
+    ASSIMP_LOG_DEBUG("OptimizeMeshesProcess begin");
+    mScene = pScene;
+
+    // need to clear persistent members from previous runs
+    merge_list.resize( 0 );
+    output.resize( 0 );
+
+    // ensure we have the right sizes
+    merge_list.reserve(pScene->mNumMeshes);
+    output.reserve(pScene->mNumMeshes);
+
+    // Prepare lookup tables
+    meshes.resize(pScene->mNumMeshes);
+    FindInstancedMeshes(pScene->mRootNode);
+    if( max_verts == DeadBeef ) /* undo the magic hack */
+        max_verts = NotSet;
+
+    // ... instanced meshes are immediately processed and added to the output list
+    for (unsigned int i = 0, n = 0; i < pScene->mNumMeshes;++i) {
+        meshes[i].vertex_format = GetMeshVFormatUnique(pScene->mMeshes[i]);
+
+        if (meshes[i].instance_cnt > 1 && meshes[i].output_id == NotSet ) {
+            meshes[i].output_id = n++;
+            output.push_back(mScene->mMeshes[i]);
+        }
+    }
+
+    // and process all nodes in the scenegraph recursively
+    ProcessNode(pScene->mRootNode);
+    if (!output.size()) {
+        throw DeadlyImportError("OptimizeMeshes: No meshes remaining; there's definitely something wrong");
+    }
+
+    meshes.resize( 0 );
+    ai_assert(output.size() <= num_old);
+
+    mScene->mNumMeshes = static_cast<unsigned int>(output.size());
+    std::copy(output.begin(),output.end(),mScene->mMeshes);
+
+    if (output.size() != num_old) {
+        ASSIMP_LOG_DEBUG("OptimizeMeshesProcess finished. Input meshes: ", num_old, ", Output meshes: ", pScene->mNumMeshes);
+    } else {
+        ASSIMP_LOG_DEBUG( "OptimizeMeshesProcess finished" );
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Process meshes for a single node
+void OptimizeMeshesProcess::ProcessNode( aiNode* pNode)
+{
+    for (unsigned int i = 0; i < pNode->mNumMeshes;++i) {
+        unsigned int& im = pNode->mMeshes[i];
+
+        if (meshes[im].instance_cnt > 1) {
+            im = meshes[im].output_id;
+        }
+        else  {
+            merge_list.resize( 0 );
+            unsigned int verts = 0, faces = 0;
+
+            // Find meshes to merge with us
+            for (unsigned int a = i+1; a < pNode->mNumMeshes;++a) {
+                unsigned int am = pNode->mMeshes[a];
+                if (meshes[am].instance_cnt == 1 && CanJoin(im,am,verts,faces)) {
+
+                    merge_list.push_back(mScene->mMeshes[am]);
+                    verts += mScene->mMeshes[am]->mNumVertices;
+                    faces += mScene->mMeshes[am]->mNumFaces;
+
+                    pNode->mMeshes[a] = pNode->mMeshes[pNode->mNumMeshes - 1];
+                    --pNode->mNumMeshes;
+                    --a;
+                }
+            }
+
+            // and merge all meshes which we found, replace the old ones
+            if (!merge_list.empty()) {
+                merge_list.push_back(mScene->mMeshes[im]);
+
+                aiMesh* out;
+                SceneCombiner::MergeMeshes(&out,0,merge_list.begin(),merge_list.end());
+                output.push_back(out);
+            } else {
+                output.push_back(mScene->mMeshes[im]);
+            }
+            im = static_cast<unsigned int>(output.size()-1);
+        }
+    }
+
+
+    for( unsigned int i = 0; i < pNode->mNumChildren; ++i ) {
+        ProcessNode( pNode->mChildren[ i ] );
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Check whether two meshes can be joined
+bool OptimizeMeshesProcess::CanJoin ( unsigned int a, unsigned int b, unsigned int verts, unsigned int faces )
+{
+    if (meshes[a].vertex_format != meshes[b].vertex_format)
+        return false;
+
+    aiMesh* ma = mScene->mMeshes[a], *mb = mScene->mMeshes[b];
+
+    if ((NotSet != max_verts && verts+mb->mNumVertices > max_verts) ||
+        (NotSet != max_faces && faces+mb->mNumFaces    > max_faces)) {
+        return false;
+    }
+
+    // Never merge unskinned meshes with skinned meshes
+    if (ma->mMaterialIndex != mb->mMaterialIndex || ma->HasBones() != mb->HasBones())
+        return false;
+
+    // Never merge meshes with different kinds of primitives if SortByPType did already
+    // do its work. We would destroy everything again ...
+    if (pts && ma->mPrimitiveTypes != mb->mPrimitiveTypes)
+        return false;
+
+    // If both meshes are skinned, check whether we have many bones defined in both meshes.
+    // If yes, we can join them.
+    if (ma->HasBones()) {
+        // TODO
+        return false;
+    }
+    return true;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Build a LUT of all instanced meshes
+void OptimizeMeshesProcess::FindInstancedMeshes (aiNode* pNode)
+{
+    for( unsigned int i = 0; i < pNode->mNumMeshes; ++i ) {
+        ++meshes[ pNode->mMeshes[ i ] ].instance_cnt;
+    }
+
+    for( unsigned int i = 0; i < pNode->mNumChildren; ++i ) {
+        FindInstancedMeshes( pNode->mChildren[ i ] );
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+
+#endif // !! ASSIMP_BUILD_NO_OPTIMIZEMESHES_PROCESS
diff --git a/src/mesh/assimp-master/code/PostProcessing/OptimizeMeshes.h b/src/mesh/assimp-master/code/PostProcessing/OptimizeMeshes.h
new file mode 100644
index 0000000..b80f98d
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/OptimizeMeshes.h
@@ -0,0 +1,186 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file  OptimizeMeshes.h
+ *  @brief Declares a post processing step to join meshes, if possible
+ */
+#ifndef AI_OPTIMIZEMESHESPROCESS_H_INC
+#define AI_OPTIMIZEMESHESPROCESS_H_INC
+
+#include "Common/BaseProcess.h"
+
+#include <assimp/types.h>
+
+#include <vector>
+
+struct aiMesh;
+struct aiNode;
+class OptimizeMeshesProcessTest;
+
+namespace Assimp    {
+
+// ---------------------------------------------------------------------------
+/** @brief Postprocessing step to optimize mesh usage
+ *
+ *  The implementation looks for meshes that could be joined and joins them.
+ *  Usually this will reduce the number of drawcalls.
+ *
+ *  @note Instanced meshes are currently not processed.
+ */
+class OptimizeMeshesProcess : public BaseProcess {
+public:
+    /// @brief  The class constructor.
+    OptimizeMeshesProcess();
+
+    /// @brief  The class destructor.
+    ~OptimizeMeshesProcess();
+
+    /** @brief Internal utility to store additional mesh info
+     */
+    struct MeshInfo {
+        MeshInfo() AI_NO_EXCEPT
+        : instance_cnt(0)
+        , vertex_format(0)
+        , output_id(0xffffffff) {
+            // empty
+        }
+
+        //! Number of times this mesh is referenced
+        unsigned int instance_cnt;
+
+        //! Vertex format id
+        unsigned int vertex_format;
+
+        //! Output ID
+        unsigned int output_id;
+    };
+
+public:
+    // -------------------------------------------------------------------
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    void Execute( aiScene* pScene);
+
+    // -------------------------------------------------------------------
+    void SetupProperties(const Importer* pImp);
+
+
+    // -------------------------------------------------------------------
+    /** @brief Specify whether you want meshes with different
+     *   primitive types to be merged as well.
+     *
+     *  IsActive() sets this property automatically to true if the
+     *  aiProcess_SortByPType flag is found.
+     */
+    void EnablePrimitiveTypeSorting(bool enable) {
+        pts = enable;
+    }
+
+    // Getter
+    bool IsPrimitiveTypeSortingEnabled () const {
+        return pts;
+    }
+
+
+    // -------------------------------------------------------------------
+    /** @brief Specify a maximum size of a single output mesh.
+     *
+     *  If a single input mesh already exceeds this limit, it won't
+     *  be split.
+     *  @param verts Maximum number of vertices per mesh
+     *  @param faces Maximum number of faces per mesh
+     */
+    void SetPreferredMeshSizeLimit (unsigned int verts, unsigned int faces)
+    {
+        max_verts = verts;
+        max_faces = faces;
+    }
+
+
+protected:
+
+    // -------------------------------------------------------------------
+    /** @brief Do the actual optimization on all meshes of this node
+     *  @param pNode Node we're working with
+     */
+    void ProcessNode( aiNode* pNode);
+
+    // -------------------------------------------------------------------
+    /** @brief Returns true if b can be joined with a
+     *
+     *  @param verts Number of output verts up to now
+     *  @param faces Number of output faces up to now
+     */
+    bool CanJoin ( unsigned int a, unsigned int b,
+        unsigned int verts, unsigned int faces );
+
+    // -------------------------------------------------------------------
+    /** @brief Find instanced meshes, for the moment we're excluding
+     *   them from all optimizations
+     */
+    void FindInstancedMeshes (aiNode* pNode);
+
+private:
+
+    //! Scene we're working with
+    aiScene* mScene;
+
+    //! Per mesh info
+    std::vector<MeshInfo> meshes;
+
+    //! Output meshes
+    std::vector<aiMesh*> output;
+
+    //! @see EnablePrimitiveTypeSorting
+    mutable bool pts;
+
+    //! @see SetPreferredMeshSizeLimit
+    mutable unsigned int max_verts,max_faces;
+
+    //! Temporary storage
+    std::vector<aiMesh*> merge_list;
+};
+
+} // end of namespace Assimp
+
+#endif // AI_CALCTANGENTSPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/PretransformVertices.cpp b/src/mesh/assimp-master/code/PostProcessing/PretransformVertices.cpp
new file mode 100644
index 0000000..ec7b878
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/PretransformVertices.cpp
@@ -0,0 +1,688 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file PretransformVertices.cpp
+ *  @brief Implementation of the "PretransformVertices" post processing step
+*/
+
+#include "PretransformVertices.h"
+#include "ConvertToLHProcess.h"
+#include "ProcessHelper.h"
+#include <assimp/Exceptional.h>
+#include <assimp/SceneCombiner.h>
+
+using namespace Assimp;
+
+// some array offsets
+#define AI_PTVS_VERTEX 0x0
+#define AI_PTVS_FACE 0x1
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+PretransformVertices::PretransformVertices() :
+		configKeepHierarchy(false),
+		configNormalize(false),
+		configTransform(false),
+		configTransformation(),
+		mConfigPointCloud(false) {
+	// empty
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+PretransformVertices::~PretransformVertices() {
+	// nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool PretransformVertices::IsActive(unsigned int pFlags) const {
+	return (pFlags & aiProcess_PreTransformVertices) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Setup import configuration
+void PretransformVertices::SetupProperties(const Importer *pImp) {
+	// Get the current value of AI_CONFIG_PP_PTV_KEEP_HIERARCHY, AI_CONFIG_PP_PTV_NORMALIZE,
+	// AI_CONFIG_PP_PTV_ADD_ROOT_TRANSFORMATION and AI_CONFIG_PP_PTV_ROOT_TRANSFORMATION
+	configKeepHierarchy = (0 != pImp->GetPropertyInteger(AI_CONFIG_PP_PTV_KEEP_HIERARCHY, 0));
+	configNormalize = (0 != pImp->GetPropertyInteger(AI_CONFIG_PP_PTV_NORMALIZE, 0));
+	configTransform = (0 != pImp->GetPropertyInteger(AI_CONFIG_PP_PTV_ADD_ROOT_TRANSFORMATION, 0));
+
+	configTransformation = pImp->GetPropertyMatrix(AI_CONFIG_PP_PTV_ROOT_TRANSFORMATION, aiMatrix4x4());
+
+	mConfigPointCloud = pImp->GetPropertyBool(AI_CONFIG_EXPORT_POINT_CLOUDS);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Count the number of nodes
+unsigned int PretransformVertices::CountNodes(const aiNode *pcNode) const {
+	unsigned int iRet = 1;
+	for (unsigned int i = 0; i < pcNode->mNumChildren; ++i) {
+		iRet += CountNodes(pcNode->mChildren[i]);
+	}
+	return iRet;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Get a bitwise combination identifying the vertex format of a mesh
+unsigned int PretransformVertices::GetMeshVFormat(aiMesh *pcMesh) const {
+	// the vertex format is stored in aiMesh::mBones for later retrieval.
+	// there isn't a good reason to compute it a few hundred times
+	// from scratch. The pointer is unused as animations are lost
+	// during PretransformVertices.
+	if (pcMesh->mBones)
+		return (unsigned int)(uint64_t)pcMesh->mBones;
+
+	const unsigned int iRet = GetMeshVFormatUnique(pcMesh);
+
+	// store the value for later use
+	pcMesh->mBones = (aiBone **)(uint64_t)iRet;
+	return iRet;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Count the number of vertices in the whole scene and a given
+// material index
+void PretransformVertices::CountVerticesAndFaces(const aiScene *pcScene, const aiNode *pcNode, unsigned int iMat,
+		unsigned int iVFormat, unsigned int *piFaces, unsigned int *piVertices) const {
+	for (unsigned int i = 0; i < pcNode->mNumMeshes; ++i) {
+		aiMesh *pcMesh = pcScene->mMeshes[pcNode->mMeshes[i]];
+		if (iMat == pcMesh->mMaterialIndex && iVFormat == GetMeshVFormat(pcMesh)) {
+			*piVertices += pcMesh->mNumVertices;
+			*piFaces += pcMesh->mNumFaces;
+		}
+	}
+	for (unsigned int i = 0; i < pcNode->mNumChildren; ++i) {
+		CountVerticesAndFaces(pcScene, pcNode->mChildren[i], iMat,
+				iVFormat, piFaces, piVertices);
+	}
+}
+
+// ------------------------------------------------------------------------------------------------
+// Collect vertex/face data
+void PretransformVertices::CollectData(const aiScene *pcScene, const aiNode *pcNode, unsigned int iMat,
+		unsigned int iVFormat, aiMesh *pcMeshOut,
+		unsigned int aiCurrent[2], unsigned int *num_refs) const {
+	// No need to multiply if there's no transformation
+	const bool identity = pcNode->mTransformation.IsIdentity();
+	for (unsigned int i = 0; i < pcNode->mNumMeshes; ++i) {
+		aiMesh *pcMesh = pcScene->mMeshes[pcNode->mMeshes[i]];
+		if (iMat == pcMesh->mMaterialIndex && iVFormat == GetMeshVFormat(pcMesh)) {
+			// Decrement mesh reference counter
+			unsigned int &num_ref = num_refs[pcNode->mMeshes[i]];
+			ai_assert(0 != num_ref);
+			--num_ref;
+			// Save the name of the last mesh
+			if (num_ref == 0) {
+				pcMeshOut->mName = pcMesh->mName;
+			}
+
+			if (identity) {
+				// copy positions without modifying them
+				::memcpy(pcMeshOut->mVertices + aiCurrent[AI_PTVS_VERTEX],
+						pcMesh->mVertices,
+						pcMesh->mNumVertices * sizeof(aiVector3D));
+
+				if (iVFormat & 0x2) {
+					// copy normals without modifying them
+					::memcpy(pcMeshOut->mNormals + aiCurrent[AI_PTVS_VERTEX],
+							pcMesh->mNormals,
+							pcMesh->mNumVertices * sizeof(aiVector3D));
+				}
+				if (iVFormat & 0x4) {
+					// copy tangents without modifying them
+					::memcpy(pcMeshOut->mTangents + aiCurrent[AI_PTVS_VERTEX],
+							pcMesh->mTangents,
+							pcMesh->mNumVertices * sizeof(aiVector3D));
+					// copy bitangents without modifying them
+					::memcpy(pcMeshOut->mBitangents + aiCurrent[AI_PTVS_VERTEX],
+							pcMesh->mBitangents,
+							pcMesh->mNumVertices * sizeof(aiVector3D));
+				}
+			} else {
+				// copy positions, transform them to worldspace
+				for (unsigned int n = 0; n < pcMesh->mNumVertices; ++n) {
+					pcMeshOut->mVertices[aiCurrent[AI_PTVS_VERTEX] + n] = pcNode->mTransformation * pcMesh->mVertices[n];
+				}
+				aiMatrix4x4 mWorldIT = pcNode->mTransformation;
+				mWorldIT.Inverse().Transpose();
+
+				// TODO: implement Inverse() for aiMatrix3x3
+				aiMatrix3x3 m = aiMatrix3x3(mWorldIT);
+
+				if (iVFormat & 0x2) {
+					// copy normals, transform them to worldspace
+					for (unsigned int n = 0; n < pcMesh->mNumVertices; ++n) {
+						pcMeshOut->mNormals[aiCurrent[AI_PTVS_VERTEX] + n] =
+								(m * pcMesh->mNormals[n]).Normalize();
+					}
+				}
+				if (iVFormat & 0x4) {
+					// copy tangents and bitangents, transform them to worldspace
+					for (unsigned int n = 0; n < pcMesh->mNumVertices; ++n) {
+						pcMeshOut->mTangents[aiCurrent[AI_PTVS_VERTEX] + n] = (m * pcMesh->mTangents[n]).Normalize();
+						pcMeshOut->mBitangents[aiCurrent[AI_PTVS_VERTEX] + n] = (m * pcMesh->mBitangents[n]).Normalize();
+					}
+				}
+			}
+			unsigned int p = 0;
+			while (iVFormat & (0x100 << p)) {
+				// copy texture coordinates
+				memcpy(pcMeshOut->mTextureCoords[p] + aiCurrent[AI_PTVS_VERTEX],
+						pcMesh->mTextureCoords[p],
+						pcMesh->mNumVertices * sizeof(aiVector3D));
+				++p;
+			}
+			p = 0;
+			while (iVFormat & (0x1000000 << p)) {
+				// copy vertex colors
+				memcpy(pcMeshOut->mColors[p] + aiCurrent[AI_PTVS_VERTEX],
+						pcMesh->mColors[p],
+						pcMesh->mNumVertices * sizeof(aiColor4D));
+				++p;
+			}
+			// now we need to copy all faces. since we will delete the source mesh afterwards,
+			// we don't need to reallocate the array of indices except if this mesh is
+			// referenced multiple times.
+			for (unsigned int planck = 0; planck < pcMesh->mNumFaces; ++planck) {
+				aiFace &f_src = pcMesh->mFaces[planck];
+				aiFace &f_dst = pcMeshOut->mFaces[aiCurrent[AI_PTVS_FACE] + planck];
+
+				const unsigned int num_idx = f_src.mNumIndices;
+
+				f_dst.mNumIndices = num_idx;
+
+				unsigned int *pi;
+				if (!num_ref) { /* if last time the mesh is referenced -> no reallocation */
+					pi = f_dst.mIndices = f_src.mIndices;
+
+					// offset all vertex indices
+					for (unsigned int hahn = 0; hahn < num_idx; ++hahn) {
+						pi[hahn] += aiCurrent[AI_PTVS_VERTEX];
+					}
+				} else {
+					pi = f_dst.mIndices = new unsigned int[num_idx];
+
+					// copy and offset all vertex indices
+					for (unsigned int hahn = 0; hahn < num_idx; ++hahn) {
+						pi[hahn] = f_src.mIndices[hahn] + aiCurrent[AI_PTVS_VERTEX];
+					}
+				}
+
+				// Update the mPrimitiveTypes member of the mesh
+				switch (pcMesh->mFaces[planck].mNumIndices) {
+					case 0x1:
+						pcMeshOut->mPrimitiveTypes |= aiPrimitiveType_POINT;
+						break;
+					case 0x2:
+						pcMeshOut->mPrimitiveTypes |= aiPrimitiveType_LINE;
+						break;
+					case 0x3:
+						pcMeshOut->mPrimitiveTypes |= aiPrimitiveType_TRIANGLE;
+						break;
+					default:
+						pcMeshOut->mPrimitiveTypes |= aiPrimitiveType_POLYGON;
+						break;
+				};
+			}
+			aiCurrent[AI_PTVS_VERTEX] += pcMesh->mNumVertices;
+			aiCurrent[AI_PTVS_FACE] += pcMesh->mNumFaces;
+		}
+	}
+
+	// append all children of us
+	for (unsigned int i = 0; i < pcNode->mNumChildren; ++i) {
+		CollectData(pcScene, pcNode->mChildren[i], iMat,
+				iVFormat, pcMeshOut, aiCurrent, num_refs);
+	}
+}
+
+// ------------------------------------------------------------------------------------------------
+// Get a list of all vertex formats that occur for a given material index
+// The output list contains duplicate elements
+void PretransformVertices::GetVFormatList(const aiScene *pcScene, unsigned int iMat,
+		std::list<unsigned int> &aiOut) const {
+	for (unsigned int i = 0; i < pcScene->mNumMeshes; ++i) {
+		aiMesh *pcMesh = pcScene->mMeshes[i];
+		if (iMat == pcMesh->mMaterialIndex) {
+			aiOut.push_back(GetMeshVFormat(pcMesh));
+		}
+	}
+}
+
+// ------------------------------------------------------------------------------------------------
+// Compute the absolute transformation matrices of each node
+void PretransformVertices::ComputeAbsoluteTransform(aiNode *pcNode) {
+	if (pcNode->mParent) {
+		pcNode->mTransformation = pcNode->mParent->mTransformation * pcNode->mTransformation;
+	}
+
+	for (unsigned int i = 0; i < pcNode->mNumChildren; ++i) {
+		ComputeAbsoluteTransform(pcNode->mChildren[i]);
+	}
+}
+
+// ------------------------------------------------------------------------------------------------
+// Apply the node transformation to a mesh
+void PretransformVertices::ApplyTransform(aiMesh *mesh, const aiMatrix4x4 &mat) const {
+	// Check whether we need to transform the coordinates at all
+	if (!mat.IsIdentity()) {
+
+		// Check for odd negative scale (mirror)
+		if (mesh->HasFaces() && mat.Determinant() < 0) {
+			// Reverse the mesh face winding order
+			FlipWindingOrderProcess::ProcessMesh(mesh);
+		}
+
+		// Update positions
+		if (mesh->HasPositions()) {
+			for (unsigned int i = 0; i < mesh->mNumVertices; ++i) {
+				mesh->mVertices[i] = mat * mesh->mVertices[i];
+			}
+		}
+
+		// Update normals and tangents
+		if (mesh->HasNormals() || mesh->HasTangentsAndBitangents()) {
+			const aiMatrix3x3 m = aiMatrix3x3(mat).Inverse().Transpose();
+
+			if (mesh->HasNormals()) {
+				for (unsigned int i = 0; i < mesh->mNumVertices; ++i) {
+					mesh->mNormals[i] = (m * mesh->mNormals[i]).Normalize();
+				}
+			}
+			if (mesh->HasTangentsAndBitangents()) {
+				for (unsigned int i = 0; i < mesh->mNumVertices; ++i) {
+					mesh->mTangents[i] = (m * mesh->mTangents[i]).Normalize();
+					mesh->mBitangents[i] = (m * mesh->mBitangents[i]).Normalize();
+				}
+			}
+		}
+	}
+}
+
+// ------------------------------------------------------------------------------------------------
+// Simple routine to build meshes in worldspace, no further optimization
+void PretransformVertices::BuildWCSMeshes(std::vector<aiMesh *> &out, aiMesh **in,
+		unsigned int numIn, aiNode *node) const {
+	// NOTE:
+	//  aiMesh::mNumBones store original source mesh, or UINT_MAX if not a copy
+	//  aiMesh::mBones store reference to abs. transform we multiplied with
+
+	// process meshes
+	for (unsigned int i = 0; i < node->mNumMeshes; ++i) {
+		aiMesh *mesh = in[node->mMeshes[i]];
+
+		// check whether we can operate on this mesh
+		if (!mesh->mBones || *reinterpret_cast<aiMatrix4x4 *>(mesh->mBones) == node->mTransformation) {
+			// yes, we can.
+			mesh->mBones = reinterpret_cast<aiBone **>(&node->mTransformation);
+			mesh->mNumBones = UINT_MAX;
+		} else {
+
+			// try to find us in the list of newly created meshes
+			for (unsigned int n = 0; n < out.size(); ++n) {
+				aiMesh *ctz = out[n];
+				if (ctz->mNumBones == node->mMeshes[i] && *reinterpret_cast<aiMatrix4x4 *>(ctz->mBones) == node->mTransformation) {
+
+					// ok, use this one. Update node mesh index
+					node->mMeshes[i] = numIn + n;
+				}
+			}
+			if (node->mMeshes[i] < numIn) {
+				// Worst case. Need to operate on a full copy of the mesh
+				ASSIMP_LOG_INFO("PretransformVertices: Copying mesh due to mismatching transforms");
+				aiMesh *ntz;
+
+				const unsigned int tmp = mesh->mNumBones; //
+				mesh->mNumBones = 0;
+				SceneCombiner::Copy(&ntz, mesh);
+				mesh->mNumBones = tmp;
+
+				ntz->mNumBones = node->mMeshes[i];
+				ntz->mBones = reinterpret_cast<aiBone **>(&node->mTransformation);
+
+				out.push_back(ntz);
+
+				node->mMeshes[i] = static_cast<unsigned int>(numIn + out.size() - 1);
+			}
+		}
+	}
+
+	// call children
+	for (unsigned int i = 0; i < node->mNumChildren; ++i)
+		BuildWCSMeshes(out, in, numIn, node->mChildren[i]);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Reset transformation matrices to identity
+void PretransformVertices::MakeIdentityTransform(aiNode *nd) const {
+	nd->mTransformation = aiMatrix4x4();
+
+	// call children
+	for (unsigned int i = 0; i < nd->mNumChildren; ++i)
+		MakeIdentityTransform(nd->mChildren[i]);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Build reference counters for all meshes
+void PretransformVertices::BuildMeshRefCountArray(const aiNode *nd, unsigned int *refs) const {
+	for (unsigned int i = 0; i < nd->mNumMeshes; ++i)
+		refs[nd->mMeshes[i]]++;
+
+	// call children
+	for (unsigned int i = 0; i < nd->mNumChildren; ++i)
+		BuildMeshRefCountArray(nd->mChildren[i], refs);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void PretransformVertices::Execute(aiScene *pScene) {
+	ASSIMP_LOG_DEBUG("PretransformVerticesProcess begin");
+
+	// Return immediately if we have no meshes
+	if (!pScene->mNumMeshes)
+		return;
+
+	const unsigned int iOldMeshes = pScene->mNumMeshes;
+	const unsigned int iOldAnimationChannels = pScene->mNumAnimations;
+	const unsigned int iOldNodes = CountNodes(pScene->mRootNode);
+
+	if (configTransform) {
+		pScene->mRootNode->mTransformation = configTransformation * pScene->mRootNode->mTransformation;
+	}
+
+	// first compute absolute transformation matrices for all nodes
+	ComputeAbsoluteTransform(pScene->mRootNode);
+
+	// Delete aiMesh::mBones for all meshes. The bones are
+	// removed during this step and we need the pointer as
+	// temporary storage
+	for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
+		aiMesh *mesh = pScene->mMeshes[i];
+
+		for (unsigned int a = 0; a < mesh->mNumBones; ++a)
+			delete mesh->mBones[a];
+
+		delete[] mesh->mBones;
+        mesh->mBones = nullptr;
+	}
+
+	// now build a list of output meshes
+	std::vector<aiMesh *> apcOutMeshes;
+
+	// Keep scene hierarchy? It's an easy job in this case ...
+	// we go on and transform all meshes, if one is referenced by nodes
+	// with different absolute transformations a depth copy of the mesh
+	// is required.
+	if (configKeepHierarchy) {
+
+		// Hack: store the matrix we're transforming a mesh with in aiMesh::mBones
+		BuildWCSMeshes(apcOutMeshes, pScene->mMeshes, pScene->mNumMeshes, pScene->mRootNode);
+
+		// ... if new meshes have been generated, append them to the end of the scene
+		if (apcOutMeshes.size() > 0) {
+			aiMesh **npp = new aiMesh *[pScene->mNumMeshes + apcOutMeshes.size()];
+
+			memcpy(npp, pScene->mMeshes, sizeof(aiMesh *) * pScene->mNumMeshes);
+			memcpy(npp + pScene->mNumMeshes, &apcOutMeshes[0], sizeof(aiMesh *) * apcOutMeshes.size());
+
+			pScene->mNumMeshes += static_cast<unsigned int>(apcOutMeshes.size());
+			delete[] pScene->mMeshes;
+			pScene->mMeshes = npp;
+		}
+
+		// now iterate through all meshes and transform them to world-space
+		for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
+			ApplyTransform(pScene->mMeshes[i], *reinterpret_cast<aiMatrix4x4 *>(pScene->mMeshes[i]->mBones));
+
+			// prevent improper destruction
+            pScene->mMeshes[i]->mBones = nullptr;
+			pScene->mMeshes[i]->mNumBones = 0;
+		}
+	} else {
+		apcOutMeshes.reserve(static_cast<size_t>(pScene->mNumMaterials) << 1u);
+		std::list<unsigned int> aiVFormats;
+
+		std::vector<unsigned int> s(pScene->mNumMeshes, 0);
+		BuildMeshRefCountArray(pScene->mRootNode, &s[0]);
+
+		for (unsigned int i = 0; i < pScene->mNumMaterials; ++i) {
+			// get the list of all vertex formats for this material
+			aiVFormats.clear();
+			GetVFormatList(pScene, i, aiVFormats);
+			aiVFormats.sort();
+			aiVFormats.unique();
+			for (std::list<unsigned int>::const_iterator j = aiVFormats.begin(); j != aiVFormats.end(); ++j) {
+				unsigned int iVertices = 0;
+				unsigned int iFaces = 0;
+				CountVerticesAndFaces(pScene, pScene->mRootNode, i, *j, &iFaces, &iVertices);
+				if (0 != iFaces && 0 != iVertices) {
+					apcOutMeshes.push_back(new aiMesh());
+					aiMesh *pcMesh = apcOutMeshes.back();
+					pcMesh->mNumFaces = iFaces;
+					pcMesh->mNumVertices = iVertices;
+					pcMesh->mFaces = new aiFace[iFaces];
+					pcMesh->mVertices = new aiVector3D[iVertices];
+					pcMesh->mMaterialIndex = i;
+					if ((*j) & 0x2) pcMesh->mNormals = new aiVector3D[iVertices];
+					if ((*j) & 0x4) {
+						pcMesh->mTangents = new aiVector3D[iVertices];
+						pcMesh->mBitangents = new aiVector3D[iVertices];
+					}
+					iFaces = 0;
+					while ((*j) & (0x100 << iFaces)) {
+						pcMesh->mTextureCoords[iFaces] = new aiVector3D[iVertices];
+						if ((*j) & (0x10000 << iFaces))
+							pcMesh->mNumUVComponents[iFaces] = 3;
+						else
+							pcMesh->mNumUVComponents[iFaces] = 2;
+						iFaces++;
+					}
+					iFaces = 0;
+					while ((*j) & (0x1000000 << iFaces))
+						pcMesh->mColors[iFaces++] = new aiColor4D[iVertices];
+
+					// fill the mesh ...
+					unsigned int aiTemp[2] = { 0, 0 };
+					CollectData(pScene, pScene->mRootNode, i, *j, pcMesh, aiTemp, &s[0]);
+				}
+			}
+		}
+
+		// If no meshes are referenced in the node graph it is possible that we get no output meshes.
+		if (apcOutMeshes.empty()) {
+
+			throw DeadlyImportError("No output meshes: all meshes are orphaned and are not referenced by any nodes");
+		} else {
+			// now delete all meshes in the scene and build a new mesh list
+			for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
+				aiMesh *mesh = pScene->mMeshes[i];
+				mesh->mNumBones = 0;
+                mesh->mBones = nullptr;
+
+				// we're reusing the face index arrays. avoid destruction
+				for (unsigned int a = 0; a < mesh->mNumFaces; ++a) {
+					mesh->mFaces[a].mNumIndices = 0;
+                    mesh->mFaces[a].mIndices = nullptr;
+				}
+
+				delete mesh;
+
+				// Invalidate the contents of the old mesh array. We will most
+				// likely have less output meshes now, so the last entries of
+				// the mesh array are not overridden. We set them to nullptr to
+				// make sure the developer gets notified when his application
+				// attempts to access these fields ...
+                mesh = nullptr;
+			}
+
+			// It is impossible that we have more output meshes than
+			// input meshes, so we can easily reuse the old mesh array
+			pScene->mNumMeshes = (unsigned int)apcOutMeshes.size();
+			for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
+				pScene->mMeshes[i] = apcOutMeshes[i];
+			}
+		}
+	}
+
+	// remove all animations from the scene
+	for (unsigned int i = 0; i < pScene->mNumAnimations; ++i)
+		delete pScene->mAnimations[i];
+	delete[] pScene->mAnimations;
+
+	pScene->mAnimations = nullptr;
+	pScene->mNumAnimations = 0;
+
+	// --- we need to keep all cameras and lights
+	for (unsigned int i = 0; i < pScene->mNumCameras; ++i) {
+		aiCamera *cam = pScene->mCameras[i];
+		const aiNode *nd = pScene->mRootNode->FindNode(cam->mName);
+        ai_assert(nullptr != nd);
+
+		// multiply all properties of the camera with the absolute
+		// transformation of the corresponding node
+		cam->mPosition = nd->mTransformation * cam->mPosition;
+		cam->mLookAt = aiMatrix3x3(nd->mTransformation) * cam->mLookAt;
+		cam->mUp = aiMatrix3x3(nd->mTransformation) * cam->mUp;
+	}
+
+	for (unsigned int i = 0; i < pScene->mNumLights; ++i) {
+		aiLight *l = pScene->mLights[i];
+		const aiNode *nd = pScene->mRootNode->FindNode(l->mName);
+        ai_assert(nullptr != nd);
+
+		// multiply all properties of the camera with the absolute
+		// transformation of the corresponding node
+		l->mPosition = nd->mTransformation * l->mPosition;
+		l->mDirection = aiMatrix3x3(nd->mTransformation) * l->mDirection;
+		l->mUp = aiMatrix3x3(nd->mTransformation) * l->mUp;
+	}
+
+	if (!configKeepHierarchy) {
+
+		// now delete all nodes in the scene and build a new
+		// flat node graph with a root node and some level 1 children
+		aiNode *newRoot = new aiNode();
+		newRoot->mName = pScene->mRootNode->mName;
+		delete pScene->mRootNode;
+		pScene->mRootNode = newRoot;
+
+		if (1 == pScene->mNumMeshes && !pScene->mNumLights && !pScene->mNumCameras) {
+			pScene->mRootNode->mNumMeshes = 1;
+			pScene->mRootNode->mMeshes = new unsigned int[1];
+			pScene->mRootNode->mMeshes[0] = 0;
+		} else {
+			pScene->mRootNode->mNumChildren = pScene->mNumMeshes + pScene->mNumLights + pScene->mNumCameras;
+			aiNode **nodes = pScene->mRootNode->mChildren = new aiNode *[pScene->mRootNode->mNumChildren];
+
+			// generate mesh nodes
+			for (unsigned int i = 0; i < pScene->mNumMeshes; ++i, ++nodes) {
+				aiNode *pcNode = new aiNode();
+				*nodes = pcNode;
+				pcNode->mParent = pScene->mRootNode;
+				pcNode->mName = pScene->mMeshes[i]->mName;
+
+				// setup mesh indices
+				pcNode->mNumMeshes = 1;
+				pcNode->mMeshes = new unsigned int[1];
+				pcNode->mMeshes[0] = i;
+			}
+			// generate light nodes
+			for (unsigned int i = 0; i < pScene->mNumLights; ++i, ++nodes) {
+				aiNode *pcNode = new aiNode();
+				*nodes = pcNode;
+				pcNode->mParent = pScene->mRootNode;
+				pcNode->mName.length = ai_snprintf(pcNode->mName.data, MAXLEN, "light_%u", i);
+				pScene->mLights[i]->mName = pcNode->mName;
+			}
+			// generate camera nodes
+			for (unsigned int i = 0; i < pScene->mNumCameras; ++i, ++nodes) {
+				aiNode *pcNode = new aiNode();
+				*nodes = pcNode;
+				pcNode->mParent = pScene->mRootNode;
+				pcNode->mName.length = ::ai_snprintf(pcNode->mName.data, MAXLEN, "cam_%u", i);
+				pScene->mCameras[i]->mName = pcNode->mName;
+			}
+		}
+	} else {
+		// ... and finally set the transformation matrix of all nodes to identity
+		MakeIdentityTransform(pScene->mRootNode);
+	}
+
+	if (configNormalize) {
+		// compute the boundary of all meshes
+		aiVector3D min, max;
+		MinMaxChooser<aiVector3D>()(min, max);
+
+		for (unsigned int a = 0; a < pScene->mNumMeshes; ++a) {
+			aiMesh *m = pScene->mMeshes[a];
+			for (unsigned int i = 0; i < m->mNumVertices; ++i) {
+				min = std::min(m->mVertices[i], min);
+				max = std::max(m->mVertices[i], max);
+			}
+		}
+
+		// find the dominant axis
+		aiVector3D d = max - min;
+		const ai_real div = std::max(d.x, std::max(d.y, d.z)) * ai_real(0.5);
+
+		d = min + d * (ai_real)0.5;
+		for (unsigned int a = 0; a < pScene->mNumMeshes; ++a) {
+			aiMesh *m = pScene->mMeshes[a];
+			for (unsigned int i = 0; i < m->mNumVertices; ++i) {
+				m->mVertices[i] = (m->mVertices[i] - d) / div;
+			}
+		}
+	}
+
+	// print statistics
+	if (!DefaultLogger::isNullLogger()) {
+		ASSIMP_LOG_DEBUG("PretransformVerticesProcess finished");
+
+		ASSIMP_LOG_INFO("Removed ", iOldNodes, " nodes and ", iOldAnimationChannels, " animation channels (",
+				CountNodes(pScene->mRootNode), " output nodes)");
+		ASSIMP_LOG_INFO("Kept ", pScene->mNumLights, " lights and ", pScene->mNumCameras, " cameras.");
+		ASSIMP_LOG_INFO("Moved ", iOldMeshes, " meshes to WCS (number of output meshes: ", pScene->mNumMeshes, ")");
+	}
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/PretransformVertices.h b/src/mesh/assimp-master/code/PostProcessing/PretransformVertices.h
new file mode 100644
index 0000000..14e5139
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/PretransformVertices.h
@@ -0,0 +1,166 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file PretransformVertices.h
+ *  @brief Defines a post processing step to pretransform all
+ *    vertices in the scenegraph
+ */
+#ifndef AI_PRETRANSFORMVERTICES_H_INC
+#define AI_PRETRANSFORMVERTICES_H_INC
+
+#include "Common/BaseProcess.h"
+
+#include <assimp/mesh.h>
+
+#include <list>
+#include <vector>
+
+// Forward declarations
+struct aiNode;
+
+class PretransformVerticesTest;
+
+namespace Assimp {
+
+// ---------------------------------------------------------------------------
+/** The PretransformVertices pre-transforms all vertices in the node tree
+ *  and removes the whole graph. The output is a list of meshes, one for
+ *  each material.
+*/
+class ASSIMP_API PretransformVertices : public BaseProcess {
+public:
+	PretransformVertices();
+	~PretransformVertices();
+
+	// -------------------------------------------------------------------
+	// Check whether step is active
+	bool IsActive(unsigned int pFlags) const override;
+
+	// -------------------------------------------------------------------
+	// Execute step on a given scene
+	void Execute(aiScene *pScene) override;
+
+	// -------------------------------------------------------------------
+	// Setup import settings
+	void SetupProperties(const Importer *pImp) override;
+
+	// -------------------------------------------------------------------
+	/** @brief Toggle the 'keep hierarchy' option
+     *  @param keep    true for keep configuration.
+     */
+	void KeepHierarchy(bool keep) {
+		configKeepHierarchy = keep;
+	}
+
+	// -------------------------------------------------------------------
+	/** @brief Check whether 'keep hierarchy' is currently enabled.
+     *  @return ...
+     */
+	bool IsHierarchyKept() const {
+		return configKeepHierarchy;
+	}
+
+private:
+	// -------------------------------------------------------------------
+	// Count the number of nodes
+	unsigned int CountNodes(const aiNode *pcNode) const;
+
+	// -------------------------------------------------------------------
+	// Get a bitwise combination identifying the vertex format of a mesh
+	unsigned int GetMeshVFormat(aiMesh *pcMesh) const;
+
+	// -------------------------------------------------------------------
+	// Count the number of vertices in the whole scene and a given
+	// material index
+	void CountVerticesAndFaces(const aiScene *pcScene, const aiNode *pcNode,
+			unsigned int iMat,
+			unsigned int iVFormat,
+			unsigned int *piFaces,
+			unsigned int *piVertices) const;
+
+	// -------------------------------------------------------------------
+	// Collect vertex/face data
+	void CollectData(const aiScene *pcScene, const aiNode *pcNode,
+			unsigned int iMat,
+			unsigned int iVFormat,
+			aiMesh *pcMeshOut,
+			unsigned int aiCurrent[2],
+			unsigned int *num_refs) const;
+
+	// -------------------------------------------------------------------
+	// Get a list of all vertex formats that occur for a given material
+	// The output list contains duplicate elements
+	void GetVFormatList(const aiScene *pcScene, unsigned int iMat,
+			std::list<unsigned int> &aiOut) const;
+
+	// -------------------------------------------------------------------
+	// Compute the absolute transformation matrices of each node
+	void ComputeAbsoluteTransform(aiNode *pcNode);
+
+	// -------------------------------------------------------------------
+	// Simple routine to build meshes in worldspace, no further optimization
+	void BuildWCSMeshes(std::vector<aiMesh *> &out, aiMesh **in,
+			unsigned int numIn, aiNode *node) const;
+
+	// -------------------------------------------------------------------
+	// Apply the node transformation to a mesh
+	void ApplyTransform(aiMesh *mesh, const aiMatrix4x4 &mat) const;
+
+	// -------------------------------------------------------------------
+	// Reset transformation matrices to identity
+	void MakeIdentityTransform(aiNode *nd) const;
+
+	// -------------------------------------------------------------------
+	// Build reference counters for all meshes
+	void BuildMeshRefCountArray(const aiNode *nd, unsigned int *refs) const;
+
+	//! Configuration option: keep scene hierarchy as long as possible
+	bool configKeepHierarchy;
+	bool configNormalize;
+	bool configTransform;
+	aiMatrix4x4 configTransformation;
+	bool mConfigPointCloud;
+};
+
+} // end of namespace Assimp
+
+#endif // !!AI_GENFACENORMALPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/ProcessHelper.cpp b/src/mesh/assimp-master/code/PostProcessing/ProcessHelper.cpp
new file mode 100644
index 0000000..6f0a798
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/ProcessHelper.cpp
@@ -0,0 +1,383 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/// @file ProcessHelper.cpp
+/** Implement shared utility functions for postprocessing steps */
+
+#include "ProcessHelper.h"
+
+#include <limits>
+
+namespace Assimp {
+
+// -------------------------------------------------------------------------------
+void ConvertListToStrings(const std::string &in, std::list<std::string> &out) {
+    const char *s = in.c_str();
+    while (*s) {
+        SkipSpacesAndLineEnd(&s);
+        if (*s == '\'') {
+            const char *base = ++s;
+            while (*s != '\'') {
+                ++s;
+                if (*s == '\0') {
+                    ASSIMP_LOG_ERROR("ConvertListToString: String list is ill-formatted");
+                    return;
+                }
+            }
+            out.push_back(std::string(base, (size_t)(s - base)));
+            ++s;
+        } else {
+            out.push_back(GetNextToken(s));
+        }
+    }
+}
+
+// -------------------------------------------------------------------------------
+void FindAABBTransformed(const aiMesh *mesh, aiVector3D &min, aiVector3D &max,
+        const aiMatrix4x4 &m) {
+    min = aiVector3D(ai_real(10e10), ai_real(10e10), ai_real(10e10));
+    max = aiVector3D(ai_real(-10e10), ai_real(-10e10), ai_real(-10e10));
+    for (unsigned int i = 0; i < mesh->mNumVertices; ++i) {
+        const aiVector3D v = m * mesh->mVertices[i];
+        min = std::min(v, min);
+        max = std::max(v, max);
+    }
+}
+
+// -------------------------------------------------------------------------------
+void FindMeshCenter(aiMesh *mesh, aiVector3D &out, aiVector3D &min, aiVector3D &max) {
+    ArrayBounds(mesh->mVertices, mesh->mNumVertices, min, max);
+    out = min + (max - min) * (ai_real)0.5;
+}
+
+// -------------------------------------------------------------------------------
+void FindSceneCenter(aiScene *scene, aiVector3D &out, aiVector3D &min, aiVector3D &max) {
+    if (nullptr == scene) {
+        return;
+    }
+
+    if (0 == scene->mNumMeshes) {
+        return;
+    }
+    FindMeshCenter(scene->mMeshes[0], out, min, max);
+    for (unsigned int i = 1; i < scene->mNumMeshes; ++i) {
+        aiVector3D tout, tmin, tmax;
+        FindMeshCenter(scene->mMeshes[i], tout, tmin, tmax);
+        if (min[0] > tmin[0]) min[0] = tmin[0];
+        if (min[1] > tmin[1]) min[1] = tmin[1];
+        if (min[2] > tmin[2]) min[2] = tmin[2];
+        if (max[0] < tmax[0]) max[0] = tmax[0];
+        if (max[1] < tmax[1]) max[1] = tmax[1];
+        if (max[2] < tmax[2]) max[2] = tmax[2];
+    }
+    out = min + (max - min) * (ai_real)0.5;
+}
+
+// -------------------------------------------------------------------------------
+void FindMeshCenterTransformed(aiMesh *mesh, aiVector3D &out, aiVector3D &min,
+        aiVector3D &max, const aiMatrix4x4 &m) {
+    FindAABBTransformed(mesh, min, max, m);
+    out = min + (max - min) * (ai_real)0.5;
+}
+
+// -------------------------------------------------------------------------------
+void FindMeshCenter(aiMesh *mesh, aiVector3D &out) {
+    aiVector3D min, max;
+    FindMeshCenter(mesh, out, min, max);
+}
+
+// -------------------------------------------------------------------------------
+void FindMeshCenterTransformed(aiMesh *mesh, aiVector3D &out,
+        const aiMatrix4x4 &m) {
+    aiVector3D min, max;
+    FindMeshCenterTransformed(mesh, out, min, max, m);
+}
+
+// -------------------------------------------------------------------------------
+ai_real ComputePositionEpsilon(const aiMesh *pMesh) {
+    const ai_real epsilon = ai_real(1e-4);
+
+    // calculate the position bounds so we have a reliable epsilon to check position differences against
+    aiVector3D minVec, maxVec;
+    ArrayBounds(pMesh->mVertices, pMesh->mNumVertices, minVec, maxVec);
+    return (maxVec - minVec).Length() * epsilon;
+}
+
+// -------------------------------------------------------------------------------
+ai_real ComputePositionEpsilon(const aiMesh *const *pMeshes, size_t num) {
+    ai_assert(nullptr != pMeshes);
+
+    const ai_real epsilon = ai_real(1e-4);
+
+    // calculate the position bounds so we have a reliable epsilon to check position differences against
+    aiVector3D minVec, maxVec, mi, ma;
+    MinMaxChooser<aiVector3D>()(minVec, maxVec);
+
+    for (size_t a = 0; a < num; ++a) {
+        const aiMesh *pMesh = pMeshes[a];
+        ArrayBounds(pMesh->mVertices, pMesh->mNumVertices, mi, ma);
+
+        minVec = std::min(minVec, mi);
+        maxVec = std::max(maxVec, ma);
+    }
+    return (maxVec - minVec).Length() * epsilon;
+}
+
+// -------------------------------------------------------------------------------
+unsigned int GetMeshVFormatUnique(const aiMesh *pcMesh) {
+    ai_assert(nullptr != pcMesh);
+
+    // FIX: the hash may never be 0. Otherwise a comparison against
+    // nullptr could be successful
+    unsigned int iRet = 1;
+
+    // normals
+    if (pcMesh->HasNormals()) iRet |= 0x2;
+    // tangents and bitangents
+    if (pcMesh->HasTangentsAndBitangents()) iRet |= 0x4;
+
+#ifdef BOOST_STATIC_ASSERT
+    BOOST_STATIC_ASSERT(8 >= AI_MAX_NUMBER_OF_COLOR_SETS);
+    BOOST_STATIC_ASSERT(8 >= AI_MAX_NUMBER_OF_TEXTURECOORDS);
+#endif
+
+    // texture coordinates
+    unsigned int p = 0;
+    while (pcMesh->HasTextureCoords(p)) {
+        iRet |= (0x100 << p);
+        if (3 == pcMesh->mNumUVComponents[p])
+            iRet |= (0x10000 << p);
+
+        ++p;
+    }
+    // vertex colors
+    p = 0;
+    while (pcMesh->HasVertexColors(p))
+        iRet |= (0x1000000 << p++);
+    return iRet;
+}
+
+// -------------------------------------------------------------------------------
+VertexWeightTable *ComputeVertexBoneWeightTable(const aiMesh *pMesh) {
+    if (!pMesh || !pMesh->mNumVertices || !pMesh->mNumBones) {
+        return nullptr;
+    }
+
+    VertexWeightTable *avPerVertexWeights = new VertexWeightTable[pMesh->mNumVertices];
+    for (unsigned int i = 0; i < pMesh->mNumBones; ++i) {
+
+        aiBone *bone = pMesh->mBones[i];
+        for (unsigned int a = 0; a < bone->mNumWeights; ++a) {
+            const aiVertexWeight &weight = bone->mWeights[a];
+            avPerVertexWeights[weight.mVertexId].push_back(std::pair<unsigned int, float>(i, weight.mWeight));
+        }
+    }
+    return avPerVertexWeights;
+}
+
+// -------------------------------------------------------------------------------
+const char *MappingTypeToString(aiTextureMapping in) {
+    switch (in) {
+    case aiTextureMapping_UV:
+        return "UV";
+    case aiTextureMapping_BOX:
+        return "Box";
+    case aiTextureMapping_SPHERE:
+        return "Sphere";
+    case aiTextureMapping_CYLINDER:
+        return "Cylinder";
+    case aiTextureMapping_PLANE:
+        return "Plane";
+    case aiTextureMapping_OTHER:
+        return "Other";
+    default:
+        break;
+    }
+
+    ai_assert(false);
+    return "BUG";
+}
+
+// -------------------------------------------------------------------------------
+aiMesh *MakeSubmesh(const aiMesh *pMesh, const std::vector<unsigned int> &subMeshFaces, unsigned int subFlags) {
+    aiMesh *oMesh = new aiMesh();
+    std::vector<unsigned int> vMap(pMesh->mNumVertices, UINT_MAX);
+
+    size_t numSubVerts = 0;
+    size_t numSubFaces = subMeshFaces.size();
+
+    for (unsigned int i = 0; i < numSubFaces; i++) {
+        const aiFace &f = pMesh->mFaces[subMeshFaces[i]];
+
+        for (unsigned int j = 0; j < f.mNumIndices; j++) {
+            if (vMap[f.mIndices[j]] == UINT_MAX) {
+                vMap[f.mIndices[j]] = static_cast<unsigned int>(numSubVerts++);
+            }
+        }
+    }
+
+    oMesh->mName = pMesh->mName;
+
+    oMesh->mMaterialIndex = pMesh->mMaterialIndex;
+    oMesh->mPrimitiveTypes = pMesh->mPrimitiveTypes;
+
+    // create all the arrays for this mesh if the old mesh contained them
+
+    oMesh->mNumFaces = static_cast<unsigned int>(subMeshFaces.size());
+    oMesh->mNumVertices = static_cast<unsigned int>(numSubVerts);
+    oMesh->mVertices = new aiVector3D[numSubVerts];
+    if (pMesh->HasNormals()) {
+        oMesh->mNormals = new aiVector3D[numSubVerts];
+    }
+
+    if (pMesh->HasTangentsAndBitangents()) {
+        oMesh->mTangents = new aiVector3D[numSubVerts];
+        oMesh->mBitangents = new aiVector3D[numSubVerts];
+    }
+
+    for (size_t a = 0; pMesh->HasTextureCoords(static_cast<unsigned int>(a)); ++a) {
+        oMesh->mTextureCoords[a] = new aiVector3D[numSubVerts];
+        oMesh->mNumUVComponents[a] = pMesh->mNumUVComponents[a];
+    }
+
+    for (size_t a = 0; pMesh->HasVertexColors(static_cast<unsigned int>(a)); ++a) {
+        oMesh->mColors[a] = new aiColor4D[numSubVerts];
+    }
+
+    // and copy over the data, generating faces with linear indices along the way
+    oMesh->mFaces = new aiFace[numSubFaces];
+
+    for (unsigned int a = 0; a < numSubFaces; ++a) {
+
+        const aiFace &srcFace = pMesh->mFaces[subMeshFaces[a]];
+        aiFace &dstFace = oMesh->mFaces[a];
+        dstFace.mNumIndices = srcFace.mNumIndices;
+        dstFace.mIndices = new unsigned int[dstFace.mNumIndices];
+
+        // accumulate linearly all the vertices of the source face
+        for (size_t b = 0; b < dstFace.mNumIndices; ++b) {
+            dstFace.mIndices[b] = vMap[srcFace.mIndices[b]];
+        }
+    }
+
+    for (unsigned int srcIndex = 0; srcIndex < pMesh->mNumVertices; ++srcIndex) {
+        unsigned int nvi = vMap[srcIndex];
+        if (nvi == UINT_MAX) {
+            continue;
+        }
+
+        oMesh->mVertices[nvi] = pMesh->mVertices[srcIndex];
+        if (pMesh->HasNormals()) {
+            oMesh->mNormals[nvi] = pMesh->mNormals[srcIndex];
+        }
+
+        if (pMesh->HasTangentsAndBitangents()) {
+            oMesh->mTangents[nvi] = pMesh->mTangents[srcIndex];
+            oMesh->mBitangents[nvi] = pMesh->mBitangents[srcIndex];
+        }
+        for (size_t c = 0, cc = pMesh->GetNumUVChannels(); c < cc; ++c) {
+            oMesh->mTextureCoords[c][nvi] = pMesh->mTextureCoords[c][srcIndex];
+        }
+        for (size_t c = 0, cc = pMesh->GetNumColorChannels(); c < cc; ++c) {
+            oMesh->mColors[c][nvi] = pMesh->mColors[c][srcIndex];
+        }
+    }
+
+    if (~subFlags & AI_SUBMESH_FLAGS_SANS_BONES) {
+        std::vector<unsigned int> subBones(pMesh->mNumBones, 0);
+
+        for (unsigned int a = 0; a < pMesh->mNumBones; ++a) {
+            const aiBone *bone = pMesh->mBones[a];
+
+            for (unsigned int b = 0; b < bone->mNumWeights; b++) {
+                unsigned int v = vMap[bone->mWeights[b].mVertexId];
+
+                if (v != UINT_MAX) {
+                    subBones[a]++;
+                }
+            }
+        }
+
+        for (unsigned int a = 0; a < pMesh->mNumBones; ++a) {
+            if (subBones[a] > 0) {
+                oMesh->mNumBones++;
+            }
+        }
+
+        if (oMesh->mNumBones) {
+            oMesh->mBones = new aiBone *[oMesh->mNumBones]();
+            unsigned int nbParanoia = oMesh->mNumBones;
+
+            oMesh->mNumBones = 0; //rewind
+
+            for (unsigned int a = 0; a < pMesh->mNumBones; ++a) {
+                if (subBones[a] == 0) {
+                    continue;
+                }
+                aiBone *newBone = new aiBone;
+                oMesh->mBones[oMesh->mNumBones++] = newBone;
+
+                const aiBone *bone = pMesh->mBones[a];
+
+                newBone->mName = bone->mName;
+                newBone->mOffsetMatrix = bone->mOffsetMatrix;
+                newBone->mWeights = new aiVertexWeight[subBones[a]];
+
+                for (unsigned int b = 0; b < bone->mNumWeights; b++) {
+                    const unsigned int v = vMap[bone->mWeights[b].mVertexId];
+
+                    if (v != UINT_MAX) {
+                        aiVertexWeight w(v, bone->mWeights[b].mWeight);
+                        newBone->mWeights[newBone->mNumWeights++] = w;
+                    }
+                }
+            }
+
+            ai_assert(nbParanoia == oMesh->mNumBones);
+            (void)nbParanoia; // remove compiler warning on release build
+        }
+    }
+
+    return oMesh;
+}
+
+} // namespace Assimp
diff --git a/src/mesh/assimp-master/code/PostProcessing/ProcessHelper.h b/src/mesh/assimp-master/code/PostProcessing/ProcessHelper.h
new file mode 100644
index 0000000..78df94c
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/ProcessHelper.h
@@ -0,0 +1,376 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+#ifndef AI_PROCESS_HELPER_H_INCLUDED
+#define AI_PROCESS_HELPER_H_INCLUDED
+
+#include <assimp/anim.h>
+#include <assimp/material.h>
+#include <assimp/mesh.h>
+#include <assimp/postprocess.h>
+#include <assimp/scene.h>
+#include <assimp/DefaultLogger.hpp>
+
+#include "Common/BaseProcess.h"
+#include <assimp/ParsingUtils.h>
+#include <assimp/SpatialSort.h>
+
+#include <list>
+
+// -------------------------------------------------------------------------------
+// Some extensions to std namespace. Mainly std::min and std::max for all
+// flat data types in the aiScene. They're used to quickly determine the
+// min/max bounds of data arrays.
+#ifdef __cplusplus
+namespace std {
+
+// std::min for aiVector3D
+template <typename TReal>
+inline ::aiVector3t<TReal> min(const ::aiVector3t<TReal> &a, const ::aiVector3t<TReal> &b) {
+    return ::aiVector3t<TReal>(min(a.x, b.x), min(a.y, b.y), min(a.z, b.z));
+}
+
+// std::max for aiVector3t<TReal>
+template <typename TReal>
+inline ::aiVector3t<TReal> max(const ::aiVector3t<TReal> &a, const ::aiVector3t<TReal> &b) {
+    return ::aiVector3t<TReal>(max(a.x, b.x), max(a.y, b.y), max(a.z, b.z));
+}
+
+// std::min for aiVector2t<TReal>
+template <typename TReal>
+inline ::aiVector2t<TReal> min(const ::aiVector2t<TReal> &a, const ::aiVector2t<TReal> &b) {
+    return ::aiVector2t<TReal>(min(a.x, b.x), min(a.y, b.y));
+}
+
+// std::max for aiVector2t<TReal>
+template <typename TReal>
+inline ::aiVector2t<TReal> max(const ::aiVector2t<TReal> &a, const ::aiVector2t<TReal> &b) {
+    return ::aiVector2t<TReal>(max(a.x, b.x), max(a.y, b.y));
+}
+
+// std::min for aiColor4D
+template <typename TReal>
+inline ::aiColor4t<TReal> min(const ::aiColor4t<TReal> &a, const ::aiColor4t<TReal> &b) {
+    return ::aiColor4t<TReal>(min(a.r, b.r), min(a.g, b.g), min(a.b, b.b), min(a.a, b.a));
+}
+
+// std::max for aiColor4D
+template <typename TReal>
+inline ::aiColor4t<TReal> max(const ::aiColor4t<TReal> &a, const ::aiColor4t<TReal> &b) {
+    return ::aiColor4t<TReal>(max(a.r, b.r), max(a.g, b.g), max(a.b, b.b), max(a.a, b.a));
+}
+
+// std::min for aiQuaterniont<TReal>
+template <typename TReal>
+inline ::aiQuaterniont<TReal> min(const ::aiQuaterniont<TReal> &a, const ::aiQuaterniont<TReal> &b) {
+    return ::aiQuaterniont<TReal>(min(a.w, b.w), min(a.x, b.x), min(a.y, b.y), min(a.z, b.z));
+}
+
+// std::max for aiQuaterniont<TReal>
+template <typename TReal>
+inline ::aiQuaterniont<TReal> max(const ::aiQuaterniont<TReal> &a, const ::aiQuaterniont<TReal> &b) {
+    return ::aiQuaterniont<TReal>(max(a.w, b.w), max(a.x, b.x), max(a.y, b.y), max(a.z, b.z));
+}
+
+// std::min for aiVectorKey
+inline ::aiVectorKey min(const ::aiVectorKey &a, const ::aiVectorKey &b) {
+    return ::aiVectorKey(min(a.mTime, b.mTime), min(a.mValue, b.mValue));
+}
+
+// std::max for aiVectorKey
+inline ::aiVectorKey max(const ::aiVectorKey &a, const ::aiVectorKey &b) {
+    return ::aiVectorKey(max(a.mTime, b.mTime), max(a.mValue, b.mValue));
+}
+
+// std::min for aiQuatKey
+inline ::aiQuatKey min(const ::aiQuatKey &a, const ::aiQuatKey &b) {
+    return ::aiQuatKey(min(a.mTime, b.mTime), min(a.mValue, b.mValue));
+}
+
+// std::max for aiQuatKey
+inline ::aiQuatKey max(const ::aiQuatKey &a, const ::aiQuatKey &b) {
+    return ::aiQuatKey(max(a.mTime, b.mTime), max(a.mValue, b.mValue));
+}
+
+// std::min for aiVertexWeight
+inline ::aiVertexWeight min(const ::aiVertexWeight &a, const ::aiVertexWeight &b) {
+    return ::aiVertexWeight(min(a.mVertexId, b.mVertexId),static_cast<ai_real>(min(a.mWeight, b.mWeight)));
+}
+
+// std::max for aiVertexWeight
+inline ::aiVertexWeight max(const ::aiVertexWeight &a, const ::aiVertexWeight &b) {
+    return ::aiVertexWeight(max(a.mVertexId, b.mVertexId), static_cast<ai_real>(max(a.mWeight, b.mWeight)));
+}
+
+} // end namespace std
+#endif // !! C++
+
+namespace Assimp {
+
+// -------------------------------------------------------------------------------
+// Start points for ArrayBounds<T> for all supported Ts
+template <typename T>
+struct MinMaxChooser;
+
+template <>
+struct MinMaxChooser<float> {
+    void operator()(float &min, float &max) {
+        max = -1e10f;
+        min = 1e10f;
+    }
+};
+template <>
+struct MinMaxChooser<double> {
+    void operator()(double &min, double &max) {
+        max = -1e10;
+        min = 1e10;
+    }
+};
+template <>
+struct MinMaxChooser<unsigned int> {
+    void operator()(unsigned int &min, unsigned int &max) {
+        max = 0;
+        min = (1u << (sizeof(unsigned int) * 8 - 1));
+    }
+};
+
+template <typename T>
+struct MinMaxChooser<aiVector3t<T>> {
+    void operator()(aiVector3t<T> &min, aiVector3t<T> &max) {
+        max = aiVector3t<T>(-1e10f, -1e10f, -1e10f);
+        min = aiVector3t<T>(1e10f, 1e10f, 1e10f);
+    }
+};
+template <typename T>
+struct MinMaxChooser<aiVector2t<T>> {
+    void operator()(aiVector2t<T> &min, aiVector2t<T> &max) {
+        max = aiVector2t<T>(-1e10f, -1e10f);
+        min = aiVector2t<T>(1e10f, 1e10f);
+    }
+};
+template <typename T>
+struct MinMaxChooser<aiColor4t<T>> {
+    void operator()(aiColor4t<T> &min, aiColor4t<T> &max) {
+        max = aiColor4t<T>(-1e10f, -1e10f, -1e10f, -1e10f);
+        min = aiColor4t<T>(1e10f, 1e10f, 1e10f, 1e10f);
+    }
+};
+
+template <typename T>
+struct MinMaxChooser<aiQuaterniont<T>> {
+    void operator()(aiQuaterniont<T> &min, aiQuaterniont<T> &max) {
+        max = aiQuaterniont<T>(-1e10f, -1e10f, -1e10f, -1e10f);
+        min = aiQuaterniont<T>(1e10f, 1e10f, 1e10f, 1e10f);
+    }
+};
+
+template <>
+struct MinMaxChooser<aiVectorKey> {
+    void operator()(aiVectorKey &min, aiVectorKey &max) {
+        MinMaxChooser<double>()(min.mTime, max.mTime);
+        MinMaxChooser<aiVector3D>()(min.mValue, max.mValue);
+    }
+};
+template <>
+struct MinMaxChooser<aiQuatKey> {
+    void operator()(aiQuatKey &min, aiQuatKey &max) {
+        MinMaxChooser<double>()(min.mTime, max.mTime);
+        MinMaxChooser<aiQuaternion>()(min.mValue, max.mValue);
+    }
+};
+
+template <>
+struct MinMaxChooser<aiVertexWeight> {
+    void operator()(aiVertexWeight &min, aiVertexWeight &max) {
+        MinMaxChooser<unsigned int>()(min.mVertexId, max.mVertexId);
+        MinMaxChooser<ai_real>()(min.mWeight, max.mWeight);
+    }
+};
+
+// -------------------------------------------------------------------------------
+/** @brief Find the min/max values of an array of Ts
+ *  @param in Input array
+ *  @param size Number of elements to process
+ *  @param[out] min minimum value
+ *  @param[out] max maximum value
+ */
+template <typename T>
+inline void ArrayBounds(const T *in, unsigned int size, T &min, T &max) {
+    MinMaxChooser<T>()(min, max);
+    for (unsigned int i = 0; i < size; ++i) {
+        min = std::min(in[i], min);
+        max = std::max(in[i], max);
+    }
+}
+
+// -------------------------------------------------------------------------------
+/** Little helper function to calculate the quadratic difference
+ * of two colors.
+ * @param pColor1 First color
+ * @param pColor2 second color
+ * @return Quadratic color difference */
+inline ai_real GetColorDifference(const aiColor4D &pColor1, const aiColor4D &pColor2) {
+    const aiColor4D c(pColor1.r - pColor2.r, pColor1.g - pColor2.g, pColor1.b - pColor2.b, pColor1.a - pColor2.a);
+    return c.r * c.r + c.g * c.g + c.b * c.b + c.a * c.a;
+}
+
+// -------------------------------------------------------------------------------
+/** @brief Extract single strings from a list of identifiers
+ *  @param in Input string list.
+ *  @param out Receives a list of clean output strings
+ *  @sdee #AI_CONFIG_PP_OG_EXCLUDE_LIST */
+void ConvertListToStrings(const std::string &in, std::list<std::string> &out);
+
+// -------------------------------------------------------------------------------
+/** @brief Compute the AABB of a mesh after applying a given transform
+ *  @param mesh Input mesh
+ *  @param[out] min Receives minimum transformed vertex
+ *  @param[out] max Receives maximum transformed vertex
+ *  @param m Transformation matrix to be applied */
+void FindAABBTransformed(const aiMesh *mesh, aiVector3D &min, aiVector3D &max, const aiMatrix4x4 &m);
+
+// -------------------------------------------------------------------------------
+/** @brief Helper function to determine the 'real' center of a mesh
+ *
+ *  That is the center of its axis-aligned bounding box.
+ *  @param mesh Input mesh
+ *  @param[out] min Minimum vertex of the mesh
+ *  @param[out] max maximum vertex of the mesh
+ *  @param[out] out Center point */
+void FindMeshCenter(aiMesh *mesh, aiVector3D &out, aiVector3D &min, aiVector3D &max);
+
+// -------------------------------------------------------------------------------
+/** @brief Helper function to determine the 'real' center of a scene
+ *
+ *  That is the center of its axis-aligned bounding box.
+ *  @param scene Input scene
+ *  @param[out] min Minimum vertex of the scene
+ *  @param[out] max maximum vertex of the scene
+ *  @param[out] out Center point */
+void FindSceneCenter(aiScene *scene, aiVector3D &out, aiVector3D &min, aiVector3D &max);
+
+// -------------------------------------------------------------------------------
+// Helper function to determine the 'real' center of a mesh after applying a given transform
+void FindMeshCenterTransformed(aiMesh *mesh, aiVector3D &out, aiVector3D &min, aiVector3D &max, const aiMatrix4x4 &m);
+
+// -------------------------------------------------------------------------------
+// Helper function to determine the 'real' center of a mesh
+void FindMeshCenter(aiMesh *mesh, aiVector3D &out);
+
+// -------------------------------------------------------------------------------
+// Helper function to determine the 'real' center of a mesh after applying a given transform
+void FindMeshCenterTransformed(aiMesh *mesh, aiVector3D &out, const aiMatrix4x4 &m);
+
+// -------------------------------------------------------------------------------
+// Compute a good epsilon value for position comparisons on a mesh
+ai_real ComputePositionEpsilon(const aiMesh *pMesh);
+
+// -------------------------------------------------------------------------------
+// Compute a good epsilon value for position comparisons on a array of meshes
+ai_real ComputePositionEpsilon(const aiMesh *const *pMeshes, size_t num);
+
+// -------------------------------------------------------------------------------
+// Compute an unique value for the vertex format of a mesh
+unsigned int GetMeshVFormatUnique(const aiMesh *pcMesh);
+
+// defs for ComputeVertexBoneWeightTable()
+using PerVertexWeight = std::pair<unsigned int, float>;
+using VertexWeightTable = std::vector<PerVertexWeight>;
+
+// -------------------------------------------------------------------------------
+// Compute a per-vertex bone weight table
+VertexWeightTable *ComputeVertexBoneWeightTable(const aiMesh *pMesh);
+
+// -------------------------------------------------------------------------------
+// Get a string for a given aiTextureMapping
+const char *MappingTypeToString(aiTextureMapping in);
+
+// flags for MakeSubmesh()
+#define AI_SUBMESH_FLAGS_SANS_BONES 0x1
+
+// -------------------------------------------------------------------------------
+// Split a mesh given a list of faces to be contained in the sub mesh
+aiMesh *MakeSubmesh(const aiMesh *superMesh, const std::vector<unsigned int> &subMeshFaces, unsigned int subFlags);
+
+// -------------------------------------------------------------------------------
+// Utility post-process step to share the spatial sort tree between
+// all steps which use it to speedup its computations.
+class ComputeSpatialSortProcess : public BaseProcess {
+    bool IsActive(unsigned int pFlags) const {
+        return nullptr != shared && 0 != (pFlags & (aiProcess_CalcTangentSpace |
+                                                           aiProcess_GenNormals | aiProcess_JoinIdenticalVertices));
+    }
+
+    void Execute(aiScene *pScene) {
+        typedef std::pair<SpatialSort, ai_real> _Type;
+        ASSIMP_LOG_DEBUG("Generate spatially-sorted vertex cache");
+
+        std::vector<_Type> *p = new std::vector<_Type>(pScene->mNumMeshes);
+        std::vector<_Type>::iterator it = p->begin();
+
+        for (unsigned int i = 0; i < pScene->mNumMeshes; ++i, ++it) {
+            aiMesh *mesh = pScene->mMeshes[i];
+            _Type &blubb = *it;
+            blubb.first.Fill(mesh->mVertices, mesh->mNumVertices, sizeof(aiVector3D));
+            blubb.second = ComputePositionEpsilon(mesh);
+        }
+
+        shared->AddProperty(AI_SPP_SPATIAL_SORT, p);
+    }
+};
+
+// -------------------------------------------------------------------------------
+// ... and the same again to cleanup the whole stuff
+class DestroySpatialSortProcess : public BaseProcess {
+    bool IsActive(unsigned int pFlags) const {
+        return nullptr != shared && 0 != (pFlags & (aiProcess_CalcTangentSpace |
+                                                        aiProcess_GenNormals | aiProcess_JoinIdenticalVertices));
+    }
+
+    void Execute(aiScene * /*pScene*/) {
+        shared->RemoveProperty(AI_SPP_SPATIAL_SORT);
+    }
+};
+
+} // namespace Assimp
+
+#endif // !! AI_PROCESS_HELPER_H_INCLUDED
diff --git a/src/mesh/assimp-master/code/PostProcessing/RemoveRedundantMaterials.cpp b/src/mesh/assimp-master/code/PostProcessing/RemoveRedundantMaterials.cpp
new file mode 100644
index 0000000..ac2fa97
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/RemoveRedundantMaterials.cpp
@@ -0,0 +1,224 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+/** @file RemoveRedundantMaterials.cpp
+ *  @brief Implementation of the "RemoveRedundantMaterials" post processing step
+*/
+
+// internal headers
+
+#include "RemoveRedundantMaterials.h"
+#include <assimp/ParsingUtils.h>
+#include "ProcessHelper.h"
+#include "Material/MaterialSystem.h"
+#include <assimp/Exceptional.h>
+#include <stdio.h>
+
+using namespace Assimp;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+RemoveRedundantMatsProcess::RemoveRedundantMatsProcess()
+: mConfigFixedMaterials() {
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+RemoveRedundantMatsProcess::~RemoveRedundantMatsProcess()
+{
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool RemoveRedundantMatsProcess::IsActive( unsigned int pFlags) const
+{
+    return (pFlags & aiProcess_RemoveRedundantMaterials) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Setup import properties
+void RemoveRedundantMatsProcess::SetupProperties(const Importer* pImp)
+{
+    // Get value of AI_CONFIG_PP_RRM_EXCLUDE_LIST
+    mConfigFixedMaterials = pImp->GetPropertyString(AI_CONFIG_PP_RRM_EXCLUDE_LIST,"");
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void RemoveRedundantMatsProcess::Execute( aiScene* pScene)
+{
+    ASSIMP_LOG_DEBUG("RemoveRedundantMatsProcess begin");
+
+    unsigned int redundantRemoved = 0, unreferencedRemoved = 0;
+    if (pScene->mNumMaterials)
+    {
+        // Find out which materials are referenced by meshes
+        std::vector<bool> abReferenced(pScene->mNumMaterials,false);
+        for (unsigned int i = 0;i < pScene->mNumMeshes;++i)
+            abReferenced[pScene->mMeshes[i]->mMaterialIndex] = true;
+
+        // If a list of materials to be excluded was given, match the list with
+        // our imported materials and 'salt' all positive matches to ensure that
+        // we get unique hashes later.
+        if (mConfigFixedMaterials.length()) {
+
+            std::list<std::string> strings;
+            ConvertListToStrings(mConfigFixedMaterials,strings);
+
+            for (unsigned int i = 0; i < pScene->mNumMaterials;++i) {
+                aiMaterial* mat = pScene->mMaterials[i];
+
+                aiString name;
+                mat->Get(AI_MATKEY_NAME,name);
+
+                if (name.length) {
+                    std::list<std::string>::const_iterator it = std::find(strings.begin(), strings.end(), name.data);
+                    if (it != strings.end()) {
+
+                        // Our brilliant 'salt': A single material property with ~ as first
+                        // character to mark it as internal and temporary.
+                        const int dummy = 1;
+                        ((aiMaterial*)mat)->AddProperty(&dummy,1,"~RRM.UniqueMaterial",0,0);
+
+                        // Keep this material even if no mesh references it
+                        abReferenced[i] = true;
+                        ASSIMP_LOG_VERBOSE_DEBUG( "Found positive match in exclusion list: \'", name.data, "\'");
+                    }
+                }
+            }
+        }
+
+        // TODO: re-implement this algorithm to work in-place
+        unsigned int *aiMappingTable = new unsigned int[pScene->mNumMaterials];
+        for ( unsigned int i=0; i<pScene->mNumMaterials; i++ ) {
+            aiMappingTable[ i ] = 0;
+        }
+        unsigned int iNewNum = 0;
+
+        // Iterate through all materials and calculate a hash for them
+        // store all hashes in a list and so a quick search whether
+        // we do already have a specific hash. This allows us to
+        // determine which materials are identical.
+        uint32_t *aiHashes = new uint32_t[ pScene->mNumMaterials ];;
+        for (unsigned int i = 0; i < pScene->mNumMaterials;++i)
+        {
+            // No mesh is referencing this material, remove it.
+            if (!abReferenced[i]) {
+                ++unreferencedRemoved;
+                delete pScene->mMaterials[i];
+                pScene->mMaterials[i] = nullptr;
+                continue;
+            }
+
+            // Check all previously mapped materials for a matching hash.
+            // On a match we can delete this material and just make it ref to the same index.
+            uint32_t me = aiHashes[i] = ComputeMaterialHash(pScene->mMaterials[i]);
+            for (unsigned int a = 0; a < i;++a)
+            {
+                if (abReferenced[a] && me == aiHashes[a]) {
+                    ++redundantRemoved;
+                    me = 0;
+                    aiMappingTable[i] = aiMappingTable[a];
+                    delete pScene->mMaterials[i];
+                    pScene->mMaterials[i] = nullptr;
+                    break;
+                }
+            }
+            // This is a new material that is referenced, add to the map.
+            if (me) {
+                aiMappingTable[i] = iNewNum++;
+            }
+        }
+        // If the new material count differs from the original,
+        // we need to rebuild the material list and remap mesh material indexes.
+        if(iNewNum < 1)
+          throw DeadlyImportError("No materials remaining");
+        if (iNewNum != pScene->mNumMaterials) {
+            ai_assert(iNewNum > 0);
+            aiMaterial** ppcMaterials = new aiMaterial*[iNewNum];
+            ::memset(ppcMaterials,0,sizeof(void*)*iNewNum);
+            for (unsigned int p = 0; p < pScene->mNumMaterials;++p)
+            {
+                // if the material is not referenced ... remove it
+                if (!abReferenced[p]) {
+                    continue;
+                }
+
+                // generate new names for modified materials that had no names
+                const unsigned int idx = aiMappingTable[p];
+                if (ppcMaterials[idx]) {
+                    aiString sz;
+                    if( ppcMaterials[idx]->Get(AI_MATKEY_NAME, sz) != AI_SUCCESS ) {
+                        sz.length = ::ai_snprintf(sz.data,MAXLEN,"JoinedMaterial_#%u",p);
+                        ((aiMaterial*)ppcMaterials[idx])->AddProperty(&sz,AI_MATKEY_NAME);
+                    }
+                } else {
+                    ppcMaterials[idx] = pScene->mMaterials[p];
+                }
+            }
+            // update all material indices
+            for (unsigned int p = 0; p < pScene->mNumMeshes;++p) {
+                aiMesh* mesh = pScene->mMeshes[p];
+                ai_assert(nullptr != mesh);
+                mesh->mMaterialIndex = aiMappingTable[mesh->mMaterialIndex];
+            }
+            // delete the old material list
+            delete[] pScene->mMaterials;
+            pScene->mMaterials = ppcMaterials;
+            pScene->mNumMaterials = iNewNum;
+        }
+        // delete temporary storage
+        delete[] aiHashes;
+        delete[] aiMappingTable;
+    }
+    if (redundantRemoved == 0 && unreferencedRemoved == 0)
+    {
+        ASSIMP_LOG_DEBUG("RemoveRedundantMatsProcess finished ");
+    }
+    else
+    {
+        ASSIMP_LOG_INFO("RemoveRedundantMatsProcess finished. Removed ", redundantRemoved, " redundant and ",
+            unreferencedRemoved, " unused materials.");
+    }
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/RemoveRedundantMaterials.h b/src/mesh/assimp-master/code/PostProcessing/RemoveRedundantMaterials.h
new file mode 100644
index 0000000..e8c1478
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/RemoveRedundantMaterials.h
@@ -0,0 +1,103 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file RemoveRedundantMaterials.h
+ *  @brief Defines a post processing step to remove redundant materials
+ */
+#ifndef AI_REMOVEREDUNDANTMATERIALS_H_INC
+#define AI_REMOVEREDUNDANTMATERIALS_H_INC
+
+#include "Common/BaseProcess.h"
+#include <assimp/mesh.h>
+
+class RemoveRedundantMatsTest;
+
+namespace Assimp    {
+
+// ---------------------------------------------------------------------------
+/** RemoveRedundantMatsProcess: Post-processing step to remove redundant
+ *  materials from the imported scene.
+ */
+class ASSIMP_API RemoveRedundantMatsProcess : public BaseProcess {
+public:
+    /// The default class constructor.
+    RemoveRedundantMatsProcess();
+
+    /// The class destructor.
+    ~RemoveRedundantMatsProcess();
+
+    // -------------------------------------------------------------------
+    // Check whether step is active
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    // Execute step on a given scene
+    void Execute( aiScene* pScene);
+
+    // -------------------------------------------------------------------
+    // Setup import settings
+    void SetupProperties(const Importer* pImp);
+
+    // -------------------------------------------------------------------
+    /** @brief Set list of fixed (inmutable) materials
+     *  @param fixed See #AI_CONFIG_PP_RRM_EXCLUDE_LIST
+     */
+    void SetFixedMaterialsString(const std::string& fixed = std::string()) {
+        mConfigFixedMaterials = fixed;
+    }
+
+    // -------------------------------------------------------------------
+    /** @brief Get list of fixed (inmutable) materials
+     *  @return See #AI_CONFIG_PP_RRM_EXCLUDE_LIST
+     */
+    const std::string& GetFixedMaterialsString() const {
+        return mConfigFixedMaterials;
+    }
+
+private:
+    //! Configuration option: list of all fixed materials
+    std::string mConfigFixedMaterials;
+};
+
+} // end of namespace Assimp
+
+#endif // !!AI_REMOVEREDUNDANTMATERIALS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/RemoveVCProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/RemoveVCProcess.cpp
new file mode 100644
index 0000000..1107736
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/RemoveVCProcess.cpp
@@ -0,0 +1,307 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+/** @file Implementation of the post processing step to remove
+ *        any parts of the mesh structure from the imported data.
+*/
+
+#include "RemoveVCProcess.h"
+#include <assimp/postprocess.h>
+#include <assimp/scene.h>
+#include <assimp/DefaultLogger.hpp>
+
+using namespace Assimp;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+RemoveVCProcess::RemoveVCProcess() :
+        configDeleteFlags(), mScene() {}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+RemoveVCProcess::~RemoveVCProcess() {}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool RemoveVCProcess::IsActive(unsigned int pFlags) const {
+    return (pFlags & aiProcess_RemoveComponent) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Small helper function to delete all elements in a T** array using delete
+template <typename T>
+inline void ArrayDelete(T **&in, unsigned int &num) {
+    for (unsigned int i = 0; i < num; ++i)
+        delete in[i];
+
+    delete[] in;
+    in = nullptr;
+    num = 0;
+}
+
+#if 0
+// ------------------------------------------------------------------------------------------------
+// Updates the node graph - removes all nodes which have the "remove" flag set and the
+// "don't remove" flag not set. Nodes with meshes are never deleted.
+bool UpdateNodeGraph(aiNode* node,std::list<aiNode*>& childsOfParent,bool root)
+{
+    bool b = false;
+
+    std::list<aiNode*> mine;
+    for (unsigned int i = 0; i < node->mNumChildren;++i)
+    {
+        if(UpdateNodeGraph(node->mChildren[i],mine,false))
+            b = true;
+    }
+
+    // somewhat tricky ... mNumMeshes must be originally 0 and MSB2 may not be set,
+    // so we can do a simple comparison against MSB here
+    if (!root && AI_RC_UINT_MSB == node->mNumMeshes )
+    {
+        // this node needs to be removed
+        if(node->mNumChildren)
+        {
+            childsOfParent.insert(childsOfParent.end(),mine.begin(),mine.end());
+
+            // set all children to nullptr to make sure they are not deleted when we delete ourself
+            for (unsigned int i = 0; i < node->mNumChildren;++i)
+                node->mChildren[i] = nullptr;
+        }
+        b = true;
+        delete node;
+    }
+    else
+    {
+        AI_RC_UNMASK(node->mNumMeshes);
+        childsOfParent.push_back(node);
+
+        if (b)
+        {
+            // reallocate the array of our children here
+            node->mNumChildren = (unsigned int)mine.size();
+            aiNode** const children = new aiNode*[mine.size()];
+            aiNode** ptr = children;
+
+            for (std::list<aiNode*>::iterator it = mine.begin(), end = mine.end();
+                 it != end; ++it)
+            {
+                *ptr++ = *it;
+            }
+            delete[] node->mChildren;
+            node->mChildren = children;
+            return false;
+        }
+    }
+    return b;
+}
+#endif
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void RemoveVCProcess::Execute(aiScene *pScene) {
+    ASSIMP_LOG_DEBUG("RemoveVCProcess begin");
+    bool bHas = false; //,bMasked = false;
+
+    mScene = pScene;
+
+    // handle animations
+    if (configDeleteFlags & aiComponent_ANIMATIONS) {
+
+        bHas = true;
+        ArrayDelete(pScene->mAnimations, pScene->mNumAnimations);
+    }
+
+    // handle textures
+    if (configDeleteFlags & aiComponent_TEXTURES) {
+        bHas = true;
+        ArrayDelete(pScene->mTextures, pScene->mNumTextures);
+    }
+
+    // handle materials
+    if (configDeleteFlags & aiComponent_MATERIALS && pScene->mNumMaterials) {
+        bHas = true;
+        for (unsigned int i = 1; i < pScene->mNumMaterials; ++i)
+            delete pScene->mMaterials[i];
+
+        pScene->mNumMaterials = 1;
+        aiMaterial *helper = (aiMaterial *)pScene->mMaterials[0];
+        ai_assert(nullptr != helper);
+        helper->Clear();
+
+        // gray
+        aiColor3D clr(0.6f, 0.6f, 0.6f);
+        helper->AddProperty(&clr, 1, AI_MATKEY_COLOR_DIFFUSE);
+
+        // add a small ambient color value
+        clr = aiColor3D(0.05f, 0.05f, 0.05f);
+        helper->AddProperty(&clr, 1, AI_MATKEY_COLOR_AMBIENT);
+
+        aiString s;
+        s.Set("Dummy_MaterialsRemoved");
+        helper->AddProperty(&s, AI_MATKEY_NAME);
+    }
+
+    // handle light sources
+    if (configDeleteFlags & aiComponent_LIGHTS) {
+        bHas = true;
+        ArrayDelete(pScene->mLights, pScene->mNumLights);
+    }
+
+    // handle camneras
+    if (configDeleteFlags & aiComponent_CAMERAS) {
+        bHas = true;
+        ArrayDelete(pScene->mCameras, pScene->mNumCameras);
+    }
+
+    // handle meshes
+    if (configDeleteFlags & aiComponent_MESHES) {
+        bHas = true;
+        ArrayDelete(pScene->mMeshes, pScene->mNumMeshes);
+    } else {
+        for (unsigned int a = 0; a < pScene->mNumMeshes; a++) {
+            if (ProcessMesh(pScene->mMeshes[a]))
+                bHas = true;
+        }
+    }
+
+    // now check whether the result is still a full scene
+    if (!pScene->mNumMeshes || !pScene->mNumMaterials) {
+        pScene->mFlags |= AI_SCENE_FLAGS_INCOMPLETE;
+        ASSIMP_LOG_DEBUG("Setting AI_SCENE_FLAGS_INCOMPLETE flag");
+
+        // If we have no meshes anymore we should also clear another flag ...
+        if (!pScene->mNumMeshes)
+            pScene->mFlags &= ~AI_SCENE_FLAGS_NON_VERBOSE_FORMAT;
+    }
+
+    if (bHas) {
+        ASSIMP_LOG_INFO("RemoveVCProcess finished. Data structure cleanup has been done.");
+    } else {
+        ASSIMP_LOG_DEBUG("RemoveVCProcess finished. Nothing to be done ...");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Setup configuration properties for the step
+void RemoveVCProcess::SetupProperties(const Importer *pImp) {
+    configDeleteFlags = pImp->GetPropertyInteger(AI_CONFIG_PP_RVC_FLAGS, 0x0);
+    if (!configDeleteFlags) {
+        ASSIMP_LOG_WARN("RemoveVCProcess: AI_CONFIG_PP_RVC_FLAGS is zero.");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+bool RemoveVCProcess::ProcessMesh(aiMesh *pMesh) {
+    bool ret = false;
+
+    // if all materials have been deleted let the material
+    // index of the mesh point to the created default material
+    if (configDeleteFlags & aiComponent_MATERIALS)
+        pMesh->mMaterialIndex = 0;
+
+    // handle normals
+    if (configDeleteFlags & aiComponent_NORMALS && pMesh->mNormals) {
+        delete[] pMesh->mNormals;
+        pMesh->mNormals = nullptr;
+        ret = true;
+    }
+
+    // handle tangents and bitangents
+    if (configDeleteFlags & aiComponent_TANGENTS_AND_BITANGENTS && pMesh->mTangents) {
+        delete[] pMesh->mTangents;
+        pMesh->mTangents = nullptr;
+
+        delete[] pMesh->mBitangents;
+        pMesh->mBitangents = nullptr;
+        ret = true;
+    }
+
+    // handle texture coordinates
+    bool b = (0 != (configDeleteFlags & aiComponent_TEXCOORDS));
+    for (unsigned int i = 0, real = 0; real < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++real) {
+        if (!pMesh->mTextureCoords[i]) break;
+        if (configDeleteFlags & aiComponent_TEXCOORDSn(real) || b) {
+            delete[] pMesh->mTextureCoords[i];
+            pMesh->mTextureCoords[i] = nullptr;
+            ret = true;
+
+            if (!b) {
+                // collapse the rest of the array
+                for (unsigned int a = i + 1; a < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++a)
+                    pMesh->mTextureCoords[a - 1] = pMesh->mTextureCoords[a];
+
+                pMesh->mTextureCoords[AI_MAX_NUMBER_OF_TEXTURECOORDS - 1] = nullptr;
+                continue;
+            }
+        }
+        ++i;
+    }
+
+    // handle vertex colors
+    b = (0 != (configDeleteFlags & aiComponent_COLORS));
+    for (unsigned int i = 0, real = 0; real < AI_MAX_NUMBER_OF_COLOR_SETS; ++real) {
+        if (!pMesh->mColors[i]) break;
+        if (configDeleteFlags & aiComponent_COLORSn(i) || b) {
+            delete[] pMesh->mColors[i];
+            pMesh->mColors[i] = nullptr;
+            ret = true;
+
+            if (!b) {
+                // collapse the rest of the array
+                for (unsigned int a = i + 1; a < AI_MAX_NUMBER_OF_COLOR_SETS; ++a)
+                    pMesh->mColors[a - 1] = pMesh->mColors[a];
+
+                pMesh->mColors[AI_MAX_NUMBER_OF_COLOR_SETS - 1] = nullptr;
+                continue;
+            }
+        }
+        ++i;
+    }
+
+    // handle bones
+    if (configDeleteFlags & aiComponent_BONEWEIGHTS && pMesh->mBones) {
+        ArrayDelete(pMesh->mBones, pMesh->mNumBones);
+        ret = true;
+    }
+    return ret;
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/RemoveVCProcess.h b/src/mesh/assimp-master/code/PostProcessing/RemoveVCProcess.h
new file mode 100644
index 0000000..cf10868
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/RemoveVCProcess.h
@@ -0,0 +1,124 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file Defines a post processing step to remove specific parts of the scene */
+#ifndef AI_REMOVEVCPROCESS_H_INCLUDED
+#define AI_REMOVEVCPROCESS_H_INCLUDED
+
+#include "Common/BaseProcess.h"
+
+#include <assimp/mesh.h>
+
+class RemoveVCProcessTest;
+
+namespace Assimp {
+
+// ---------------------------------------------------------------------------
+/** RemoveVCProcess: Class to exclude specific parts of the data structure
+ *  from further processing by removing them,
+*/
+class ASSIMP_API RemoveVCProcess : public BaseProcess {
+public:
+    /// The default class constructor.
+    RemoveVCProcess();
+
+    /// The class destructor.
+    ~RemoveVCProcess();
+
+    // -------------------------------------------------------------------
+    /** Returns whether the processing step is present in the given flag field.
+    * @param pFlags The processing flags the importer was called with. A bitwise
+    *   combination of #aiPostProcessSteps.
+    * @return true if the process is present in this flag fields, false if not.
+    */
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    /** Executes the post processing step on the given imported data.
+    * At the moment a process is not supposed to fail.
+    * @param pScene The imported data to work at.
+    */
+    void Execute( aiScene* pScene);
+
+    // -------------------------------------------------------------------
+    /** Called prior to ExecuteOnScene().
+    * The function is a request to the process to update its configuration
+    * basing on the Importer's configuration property list.
+    */
+    virtual void SetupProperties(const Importer* pImp);
+
+    // -------------------------------------------------------------------
+    /** Manually setup the configuration flags for the step
+     *
+     *  @param Bitwise combination of the #aiComponent enumerated values.
+    */
+    void SetDeleteFlags(unsigned int f)
+    {
+        configDeleteFlags = f;
+    }
+
+    // -------------------------------------------------------------------
+    /** Query the current configuration.
+    */
+    unsigned int GetDeleteFlags() const
+    {
+        return configDeleteFlags;
+    }
+
+private:
+
+    bool ProcessMesh (aiMesh* pcMesh);
+
+    /** Configuration flag
+     */
+    unsigned int configDeleteFlags;
+
+    /** The scene we're working with
+     */
+    aiScene* mScene;
+};
+
+// ---------------------------------------------------------------------------
+
+} // end of namespace Assimp
+
+#endif // !!AI_REMOVEVCPROCESS_H_INCLUDED
diff --git a/src/mesh/assimp-master/code/PostProcessing/ScaleProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/ScaleProcess.cpp
new file mode 100644
index 0000000..0090f8d
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/ScaleProcess.cpp
@@ -0,0 +1,208 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+#include "ScaleProcess.h"
+
+#include <assimp/scene.h>
+#include <assimp/postprocess.h>
+#include <assimp/BaseImporter.h>
+
+namespace Assimp {
+
+ScaleProcess::ScaleProcess()
+: BaseProcess()
+, mScale( AI_CONFIG_GLOBAL_SCALE_FACTOR_DEFAULT ) {
+}
+
+ScaleProcess::~ScaleProcess() {
+    // empty
+}
+
+void ScaleProcess::setScale( ai_real scale ) {
+    mScale = scale;
+}
+
+ai_real ScaleProcess::getScale() const {
+    return mScale;
+}
+
+bool ScaleProcess::IsActive( unsigned int pFlags ) const {
+    return ( pFlags & aiProcess_GlobalScale ) != 0;
+}
+
+void ScaleProcess::SetupProperties( const Importer* pImp ) {
+    // User scaling
+    mScale = pImp->GetPropertyFloat( AI_CONFIG_GLOBAL_SCALE_FACTOR_KEY, 1.0f );
+
+    // File scaling * Application Scaling
+    float importerScale = pImp->GetPropertyFloat( AI_CONFIG_APP_SCALE_KEY, 1.0f );
+
+    // apply scale to the scale
+    // helps prevent bugs with backward compatibility for anyone using normal scaling.
+    mScale *= importerScale;
+}
+
+void ScaleProcess::Execute( aiScene* pScene ) {
+    if(mScale == 1.0f)  {
+        return; // nothing to scale
+    }
+
+    ai_assert( mScale != 0 );
+    ai_assert( nullptr != pScene );
+    ai_assert( nullptr != pScene->mRootNode );
+
+    if ( nullptr == pScene ) {
+        return;
+    }
+
+    if ( nullptr == pScene->mRootNode ) {
+        return;
+    }
+
+    // Process animations and update position transform to new unit system
+    for( unsigned int animationID = 0; animationID < pScene->mNumAnimations; animationID++ )
+    {
+        aiAnimation* animation = pScene->mAnimations[animationID];
+
+        for( unsigned int animationChannel = 0; animationChannel < animation->mNumChannels; animationChannel++)
+        {
+            aiNodeAnim* anim = animation->mChannels[animationChannel];
+
+            for( unsigned int posKey = 0; posKey < anim->mNumPositionKeys; posKey++)
+            {
+                aiVectorKey& vectorKey = anim->mPositionKeys[posKey];
+                vectorKey.mValue *= mScale;
+            }
+        }
+    }
+
+    for( unsigned int meshID = 0; meshID < pScene->mNumMeshes; meshID++)
+    {
+        aiMesh *mesh = pScene->mMeshes[meshID];
+
+        // Reconstruct mesh vertices to the new unit system
+        for( unsigned int vertexID = 0; vertexID < mesh->mNumVertices; vertexID++)
+        {
+            aiVector3D& vertex = mesh->mVertices[vertexID];
+            vertex *= mScale;
+        }
+
+
+        // bone placement / scaling
+        for( unsigned int boneID = 0; boneID < mesh->mNumBones; boneID++)
+        {
+            // Reconstruct matrix by transform rather than by scale
+            // This prevent scale values being changed which can
+            // be meaningful in some cases
+            // like when you want the modeller to see 1:1 compatibility.
+            aiBone* bone = mesh->mBones[boneID];
+
+            aiVector3D pos, scale;
+            aiQuaternion rotation;
+
+            bone->mOffsetMatrix.Decompose( scale, rotation, pos);
+
+            aiMatrix4x4 translation;
+            aiMatrix4x4::Translation( pos * mScale, translation );
+
+            aiMatrix4x4 scaling;
+            aiMatrix4x4::Scaling( aiVector3D(scale), scaling );
+
+            aiMatrix4x4 RotMatrix = aiMatrix4x4 (rotation.GetMatrix());
+
+            bone->mOffsetMatrix = translation * RotMatrix * scaling;
+        }
+
+
+        // animation mesh processing
+        // convert by position rather than scale.
+        for( unsigned int animMeshID = 0; animMeshID < mesh->mNumAnimMeshes; animMeshID++)
+        {
+            aiAnimMesh * animMesh = mesh->mAnimMeshes[animMeshID];
+
+            for( unsigned int vertexID = 0; vertexID < animMesh->mNumVertices; vertexID++)
+            {
+                aiVector3D& vertex = animMesh->mVertices[vertexID];
+                vertex *= mScale;
+            }
+        }
+    }
+
+    traverseNodes( pScene->mRootNode );
+}
+
+void ScaleProcess::traverseNodes( aiNode *node, unsigned int nested_node_id ) {
+    applyScaling( node );
+
+    for( size_t i = 0; i < node->mNumChildren; i++)
+    {
+        // recurse into the tree until we are done!
+        traverseNodes( node->mChildren[i], nested_node_id+1 );
+    }
+}
+
+void ScaleProcess::applyScaling( aiNode *currentNode ) {
+    if ( nullptr != currentNode ) {
+        // Reconstruct matrix by transform rather than by scale
+        // This prevent scale values being changed which can
+        // be meaningful in some cases
+        // like when you want the modeller to
+        // see 1:1 compatibility.
+
+        aiVector3D pos, scale;
+        aiQuaternion rotation;
+        currentNode->mTransformation.Decompose( scale, rotation, pos);
+
+        aiMatrix4x4 translation;
+        aiMatrix4x4::Translation( pos * mScale, translation );
+
+        aiMatrix4x4 scaling;
+
+        // note: we do not use mScale here, this is on purpose.
+        aiMatrix4x4::Scaling( scale, scaling );
+
+        aiMatrix4x4 RotMatrix = aiMatrix4x4 (rotation.GetMatrix());
+
+        currentNode->mTransformation = translation * RotMatrix * scaling;
+    }
+}
+
+} // Namespace Assimp
diff --git a/src/mesh/assimp-master/code/PostProcessing/ScaleProcess.h b/src/mesh/assimp-master/code/PostProcessing/ScaleProcess.h
new file mode 100644
index 0000000..b6eb75d
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/ScaleProcess.h
@@ -0,0 +1,97 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+#ifndef SCALE_PROCESS_H_
+#define SCALE_PROCESS_H_
+
+#include "Common/BaseProcess.h"
+
+struct aiNode;
+
+#if (!defined AI_CONFIG_GLOBAL_SCALE_FACTOR_DEFAULT)
+#   define AI_CONFIG_GLOBAL_SCALE_FACTOR_DEFAULT  1.0f
+#endif // !! AI_DEBONE_THRESHOLD
+
+namespace Assimp {
+
+// ---------------------------------------------------------------------------
+/** ScaleProcess: Class to rescale the whole model.
+ * Now rescales animations, bones, and blend shapes properly.
+ * Please note this will not write to 'scale' transform it will rewrite mesh
+ * and matrixes so that your scale values
+ * from your model package are preserved, so this is completely intentional
+ * bugs should be reported as soon as they are found.
+*/
+class ASSIMP_API ScaleProcess : public BaseProcess {
+public:
+    /// The default class constructor.
+    ScaleProcess();
+
+    /// The class destructor.
+    virtual ~ScaleProcess();
+
+    /// Will set the scale manually.
+    void setScale( ai_real scale );
+
+    /// Returns the current scaling value.
+    ai_real getScale() const;
+
+    /// Overwritten, @see BaseProcess
+    virtual bool IsActive( unsigned int pFlags ) const;
+
+    /// Overwritten, @see BaseProcess
+    virtual void SetupProperties( const Importer* pImp );
+
+    /// Overwritten, @see BaseProcess
+    virtual void Execute( aiScene* pScene );
+
+private:
+    void traverseNodes( aiNode *currentNode, unsigned int nested_node_id = 0 );
+    void applyScaling( aiNode *currentNode );
+
+private:
+    ai_real mScale;
+};
+
+} // Namespace Assimp
+
+
+#endif // SCALE_PROCESS_H_
diff --git a/src/mesh/assimp-master/code/PostProcessing/SortByPTypeProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/SortByPTypeProcess.cpp
new file mode 100644
index 0000000..c926809
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/SortByPTypeProcess.cpp
@@ -0,0 +1,439 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file Implementation of the DeterminePTypeHelperProcess and
+ *  SortByPTypeProcess post-process steps.
+*/
+
+// internal headers
+#include "SortByPTypeProcess.h"
+#include "ProcessHelper.h"
+#include <assimp/Exceptional.h>
+
+using namespace Assimp;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+SortByPTypeProcess::SortByPTypeProcess() :
+        mConfigRemoveMeshes(0) {
+    // empty
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+SortByPTypeProcess::~SortByPTypeProcess() {
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool SortByPTypeProcess::IsActive(unsigned int pFlags) const {
+    return (pFlags & aiProcess_SortByPType) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+void SortByPTypeProcess::SetupProperties(const Importer *pImp) {
+    mConfigRemoveMeshes = pImp->GetPropertyInteger(AI_CONFIG_PP_SBP_REMOVE, 0);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Update changed meshes in all nodes
+void UpdateNodes(const std::vector<unsigned int> &replaceMeshIndex, aiNode *node) {
+    if (node->mNumMeshes) {
+        unsigned int newSize = 0;
+        for (unsigned int m = 0; m < node->mNumMeshes; ++m) {
+            unsigned int add = node->mMeshes[m] << 2;
+            for (unsigned int i = 0; i < 4; ++i) {
+                if (UINT_MAX != replaceMeshIndex[add + i]) ++newSize;
+            }
+        }
+        if (!newSize) {
+            delete[] node->mMeshes;
+            node->mNumMeshes = 0;
+            node->mMeshes = nullptr;
+        } else {
+            // Try to reuse the old array if possible
+            unsigned int *newMeshes = (newSize > node->mNumMeshes ? new unsigned int[newSize] : node->mMeshes);
+
+            for (unsigned int m = 0; m < node->mNumMeshes; ++m) {
+                unsigned int add = node->mMeshes[m] << 2;
+                for (unsigned int i = 0; i < 4; ++i) {
+                    if (UINT_MAX != replaceMeshIndex[add + i])
+                        *newMeshes++ = replaceMeshIndex[add + i];
+                }
+            }
+            if (newSize > node->mNumMeshes)
+                delete[] node->mMeshes;
+
+            node->mMeshes = newMeshes - (node->mNumMeshes = newSize);
+        }
+    }
+
+    // call all subnodes recursively
+    for (unsigned int m = 0; m < node->mNumChildren; ++m)
+        UpdateNodes(replaceMeshIndex, node->mChildren[m]);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void SortByPTypeProcess::Execute(aiScene *pScene) {
+    if (0 == pScene->mNumMeshes) {
+        ASSIMP_LOG_DEBUG("SortByPTypeProcess skipped, there are no meshes");
+        return;
+    }
+
+    ASSIMP_LOG_DEBUG("SortByPTypeProcess begin");
+
+    unsigned int aiNumMeshesPerPType[4] = { 0, 0, 0, 0 };
+
+    std::vector<aiMesh *> outMeshes;
+    outMeshes.reserve(static_cast<size_t>(pScene->mNumMeshes) << 1u);
+
+    bool bAnyChanges = false;
+
+    std::vector<unsigned int> replaceMeshIndex(pScene->mNumMeshes * 4, UINT_MAX);
+    std::vector<unsigned int>::iterator meshIdx = replaceMeshIndex.begin();
+    for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
+        aiMesh *const mesh = pScene->mMeshes[i];
+        if (mesh->mPrimitiveTypes == 0) {
+            throw DeadlyImportError("Mesh with invalid primitive type: ", mesh->mName.C_Str());
+        }
+
+        // if there's just one primitive type in the mesh there's nothing to do for us
+        unsigned int num = 0;
+        if (mesh->mPrimitiveTypes & aiPrimitiveType_POINT) {
+            ++aiNumMeshesPerPType[0];
+            ++num;
+        }
+        if (mesh->mPrimitiveTypes & aiPrimitiveType_LINE) {
+            ++aiNumMeshesPerPType[1];
+            ++num;
+        }
+        if (mesh->mPrimitiveTypes & aiPrimitiveType_TRIANGLE) {
+            ++aiNumMeshesPerPType[2];
+            ++num;
+        }
+        if (mesh->mPrimitiveTypes & aiPrimitiveType_POLYGON) {
+            ++aiNumMeshesPerPType[3];
+            ++num;
+        }
+
+        if (1 == num) {
+            if (!(mConfigRemoveMeshes & mesh->mPrimitiveTypes)) {
+                *meshIdx = static_cast<unsigned int>(outMeshes.size());
+                outMeshes.push_back(mesh);
+            } else {
+                delete mesh;
+                pScene->mMeshes[i] = nullptr;
+                bAnyChanges = true;
+            }
+
+            meshIdx += 4;
+            continue;
+        }
+        bAnyChanges = true;
+
+        // reuse our current mesh arrays for the submesh
+        // with the largest number of primitives
+        unsigned int aiNumPerPType[4] = { 0, 0, 0, 0 };
+        aiFace *pFirstFace = mesh->mFaces;
+        aiFace *const pLastFace = pFirstFace + mesh->mNumFaces;
+
+        unsigned int numPolyVerts = 0;
+        for (; pFirstFace != pLastFace; ++pFirstFace) {
+            if (pFirstFace->mNumIndices <= 3)
+                ++aiNumPerPType[pFirstFace->mNumIndices - 1];
+            else {
+                ++aiNumPerPType[3];
+                numPolyVerts += pFirstFace->mNumIndices;
+            }
+        }
+
+        VertexWeightTable *avw = ComputeVertexBoneWeightTable(mesh);
+        for (unsigned int real = 0; real < 4; ++real, ++meshIdx) {
+            if (!aiNumPerPType[real] || mConfigRemoveMeshes & (1u << real)) {
+                continue;
+            }
+
+            *meshIdx = (unsigned int)outMeshes.size();
+            outMeshes.push_back(new aiMesh());
+            aiMesh *out = outMeshes.back();
+
+            // the name carries the adjacency information between the meshes
+            out->mName = mesh->mName;
+
+            // copy data members
+            out->mPrimitiveTypes = 1u << real;
+            out->mMaterialIndex = mesh->mMaterialIndex;
+
+            // allocate output storage
+            out->mNumFaces = aiNumPerPType[real];
+            aiFace *outFaces = out->mFaces = new aiFace[out->mNumFaces];
+
+            out->mNumVertices = (3 == real ? numPolyVerts : out->mNumFaces * (real + 1));
+
+            aiVector3D *vert(nullptr), *nor(nullptr), *tan(nullptr), *bit(nullptr);
+            aiVector3D *uv[AI_MAX_NUMBER_OF_TEXTURECOORDS];
+            aiColor4D *cols[AI_MAX_NUMBER_OF_COLOR_SETS];
+
+            if (mesh->mVertices) {
+                vert = out->mVertices = new aiVector3D[out->mNumVertices];
+            }
+
+            if (mesh->mNormals) {
+                nor = out->mNormals = new aiVector3D[out->mNumVertices];
+            }
+
+            if (mesh->mTangents) {
+                tan = out->mTangents = new aiVector3D[out->mNumVertices];
+                bit = out->mBitangents = new aiVector3D[out->mNumVertices];
+            }
+
+            for (unsigned int j = 0; j < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++j) {
+                uv[j] = nullptr;
+                if (mesh->mTextureCoords[j]) {
+                    uv[j] = out->mTextureCoords[j] = new aiVector3D[out->mNumVertices];
+                }
+
+                out->mNumUVComponents[j] = mesh->mNumUVComponents[j];
+            }
+
+            for (unsigned int j = 0; j < AI_MAX_NUMBER_OF_COLOR_SETS; ++j) {
+                cols[j] = nullptr;
+                if (mesh->mColors[j]) {
+                    cols[j] = out->mColors[j] = new aiColor4D[out->mNumVertices];
+                }
+            }
+
+            if (mesh->mNumAnimMeshes > 0 && mesh->mAnimMeshes) {
+                out->mNumAnimMeshes = mesh->mNumAnimMeshes;
+                out->mAnimMeshes = new aiAnimMesh *[out->mNumAnimMeshes];
+            }
+
+            for (unsigned int j = 0; j < mesh->mNumAnimMeshes; ++j) {
+                aiAnimMesh *animMesh = mesh->mAnimMeshes[j];
+                aiAnimMesh *outAnimMesh = out->mAnimMeshes[j] = new aiAnimMesh;
+                outAnimMesh->mNumVertices = out->mNumVertices;
+                if (animMesh->mVertices)
+                    outAnimMesh->mVertices = new aiVector3D[out->mNumVertices];
+                else
+                    outAnimMesh->mVertices = nullptr;
+                if (animMesh->mNormals)
+                    outAnimMesh->mNormals = new aiVector3D[out->mNumVertices];
+                else
+                    outAnimMesh->mNormals = nullptr;
+                if (animMesh->mTangents)
+                    outAnimMesh->mTangents = new aiVector3D[out->mNumVertices];
+                else
+                    outAnimMesh->mTangents = nullptr;
+                if (animMesh->mBitangents)
+                    outAnimMesh->mBitangents = new aiVector3D[out->mNumVertices];
+                else
+                    outAnimMesh->mBitangents = nullptr;
+                for (int jj = 0; jj < AI_MAX_NUMBER_OF_COLOR_SETS; ++jj) {
+                    if (animMesh->mColors[jj])
+                        outAnimMesh->mColors[jj] = new aiColor4D[out->mNumVertices];
+                    else
+                        outAnimMesh->mColors[jj] = nullptr;
+                }
+                for (int jj = 0; jj < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++jj) {
+                    if (animMesh->mTextureCoords[jj])
+                        outAnimMesh->mTextureCoords[jj] = new aiVector3D[out->mNumVertices];
+                    else
+                        outAnimMesh->mTextureCoords[jj] = nullptr;
+                }
+            }
+
+            typedef std::vector<aiVertexWeight> TempBoneInfo;
+            std::vector<TempBoneInfo> tempBones(mesh->mNumBones);
+
+            // try to guess how much storage we'll need
+            for (unsigned int q = 0; q < mesh->mNumBones; ++q) {
+                tempBones[q].reserve(mesh->mBones[q]->mNumWeights / (num - 1));
+            }
+
+            unsigned int outIdx = 0;
+            unsigned int amIdx = 0; // AnimMesh index
+            for (unsigned int m = 0; m < mesh->mNumFaces; ++m) {
+                aiFace &in = mesh->mFaces[m];
+                if ((real == 3 && in.mNumIndices <= 3) || (real != 3 && in.mNumIndices != real + 1)) {
+                    continue;
+                }
+
+                outFaces->mNumIndices = in.mNumIndices;
+                outFaces->mIndices = in.mIndices;
+
+                for (unsigned int q = 0; q < in.mNumIndices; ++q) {
+                    unsigned int idx = in.mIndices[q];
+
+                    // process all bones of this index
+                    if (avw) {
+                        VertexWeightTable &tbl = avw[idx];
+                        for (VertexWeightTable::const_iterator it = tbl.begin(), end = tbl.end();
+                                it != end; ++it) {
+                            tempBones[(*it).first].push_back(aiVertexWeight(outIdx, (*it).second));
+                        }
+                    }
+
+                    if (vert) {
+                        *vert++ = mesh->mVertices[idx];
+                        //mesh->mVertices[idx].x = get_qnan();
+                    }
+                    if (nor) *nor++ = mesh->mNormals[idx];
+                    if (tan) {
+                        *tan++ = mesh->mTangents[idx];
+                        *bit++ = mesh->mBitangents[idx];
+                    }
+
+                    for (unsigned int pp = 0; pp < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++pp) {
+                        if (!uv[pp]) break;
+                        *uv[pp]++ = mesh->mTextureCoords[pp][idx];
+                    }
+
+                    for (unsigned int pp = 0; pp < AI_MAX_NUMBER_OF_COLOR_SETS; ++pp) {
+                        if (!cols[pp]) break;
+                        *cols[pp]++ = mesh->mColors[pp][idx];
+                    }
+
+                    unsigned int pp = 0;
+                    for (; pp < mesh->mNumAnimMeshes; ++pp) {
+                        aiAnimMesh *animMesh = mesh->mAnimMeshes[pp];
+                        aiAnimMesh *outAnimMesh = out->mAnimMeshes[pp];
+                        if (animMesh->mVertices)
+                            outAnimMesh->mVertices[amIdx] = animMesh->mVertices[idx];
+                        if (animMesh->mNormals)
+                            outAnimMesh->mNormals[amIdx] = animMesh->mNormals[idx];
+                        if (animMesh->mTangents)
+                            outAnimMesh->mTangents[amIdx] = animMesh->mTangents[idx];
+                        if (animMesh->mBitangents)
+                            outAnimMesh->mBitangents[amIdx] = animMesh->mBitangents[idx];
+                        for (int jj = 0; jj < AI_MAX_NUMBER_OF_COLOR_SETS; ++jj) {
+                            if (animMesh->mColors[jj])
+                                outAnimMesh->mColors[jj][amIdx] = animMesh->mColors[jj][idx];
+                        }
+                        for (int jj = 0; jj < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++jj) {
+                            if (animMesh->mTextureCoords[jj])
+                                outAnimMesh->mTextureCoords[jj][amIdx] = animMesh->mTextureCoords[jj][idx];
+                        }
+                    }
+                    if (pp == mesh->mNumAnimMeshes)
+                        amIdx++;
+
+                    in.mIndices[q] = outIdx++;
+                }
+
+                in.mIndices = nullptr;
+                ++outFaces;
+            }
+            ai_assert(outFaces == out->mFaces + out->mNumFaces);
+
+            // now generate output bones
+            for (unsigned int q = 0; q < mesh->mNumBones; ++q) {
+                if (!tempBones[q].empty()) {
+                    ++out->mNumBones;
+                }
+            }
+
+            if (out->mNumBones) {
+                out->mBones = new aiBone *[out->mNumBones];
+                for (unsigned int q = 0, boneIdx = 0; q < mesh->mNumBones; ++q) {
+                    TempBoneInfo &in = tempBones[q];
+                    if (in.empty()) {
+                        continue;
+                    }
+
+                    aiBone *srcBone = mesh->mBones[q];
+                    aiBone *bone = out->mBones[boneIdx] = new aiBone();
+
+                    bone->mName = srcBone->mName;
+                    bone->mOffsetMatrix = srcBone->mOffsetMatrix;
+
+                    bone->mNumWeights = (unsigned int)in.size();
+                    bone->mWeights = new aiVertexWeight[bone->mNumWeights];
+
+                    ::memcpy(bone->mWeights, &in[0], bone->mNumWeights * sizeof(aiVertexWeight));
+
+                    ++boneIdx;
+                }
+            }
+        }
+
+        // delete the per-vertex bone weights table
+        delete[] avw;
+
+        // delete the input mesh
+        delete mesh;
+
+        // avoid invalid pointer
+        pScene->mMeshes[i] = nullptr;
+    }
+
+    if (outMeshes.empty()) {
+        // This should not occur
+        throw DeadlyImportError("No meshes remaining");
+    }
+
+    // If we added at least one mesh process all nodes in the node
+    // graph and update their respective mesh indices.
+    if (bAnyChanges) {
+        UpdateNodes(replaceMeshIndex, pScene->mRootNode);
+    }
+
+    if (outMeshes.size() != pScene->mNumMeshes) {
+        delete[] pScene->mMeshes;
+        pScene->mNumMeshes = (unsigned int)outMeshes.size();
+        pScene->mMeshes = new aiMesh *[pScene->mNumMeshes];
+    }
+    ::memcpy(pScene->mMeshes, &outMeshes[0], pScene->mNumMeshes * sizeof(void *));
+
+    if (!DefaultLogger::isNullLogger()) {
+        char buffer[1024];
+        ::ai_snprintf(buffer, 1024, "Points: %u%s, Lines: %u%s, Triangles: %u%s, Polygons: %u%s (Meshes, X = removed)",
+                aiNumMeshesPerPType[0], ((mConfigRemoveMeshes & aiPrimitiveType_POINT) ? "X" : ""),
+                aiNumMeshesPerPType[1], ((mConfigRemoveMeshes & aiPrimitiveType_LINE) ? "X" : ""),
+                aiNumMeshesPerPType[2], ((mConfigRemoveMeshes & aiPrimitiveType_TRIANGLE) ? "X" : ""),
+                aiNumMeshesPerPType[3], ((mConfigRemoveMeshes & aiPrimitiveType_POLYGON) ? "X" : ""));
+        ASSIMP_LOG_INFO(buffer);
+        ASSIMP_LOG_DEBUG("SortByPTypeProcess finished");
+    }
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/SortByPTypeProcess.h b/src/mesh/assimp-master/code/PostProcessing/SortByPTypeProcess.h
new file mode 100644
index 0000000..e30342a
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/SortByPTypeProcess.h
@@ -0,0 +1,82 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file Defines a post processing step to sort meshes by the types
+    of primitives they contain */
+#ifndef AI_SORTBYPTYPEPROCESS_H_INC
+#define AI_SORTBYPTYPEPROCESS_H_INC
+
+#include "Common/BaseProcess.h"
+#include <assimp/mesh.h>
+
+class SortByPTypeProcessTest;
+
+namespace Assimp    {
+
+
+// ---------------------------------------------------------------------------
+/** SortByPTypeProcess: Sorts meshes by the types of primitives they contain.
+ *  A mesh with 5 lines, 3 points and 145 triangles would be split in 3
+ * submeshes.
+*/
+class ASSIMP_API SortByPTypeProcess : public BaseProcess {
+public:
+    SortByPTypeProcess();
+    ~SortByPTypeProcess();
+
+    // -------------------------------------------------------------------
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    void Execute( aiScene* pScene);
+
+    // -------------------------------------------------------------------
+    void SetupProperties(const Importer* pImp);
+
+private:
+    int mConfigRemoveMeshes;
+};
+
+
+} // end of namespace Assimp
+
+#endif // !!AI_SORTBYPTYPEPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/SplitByBoneCountProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/SplitByBoneCountProcess.cpp
new file mode 100644
index 0000000..ace62ae
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/SplitByBoneCountProcess.cpp
@@ -0,0 +1,480 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+
+/// @file SplitByBoneCountProcess.cpp
+/// Implementation of the SplitByBoneCount postprocessing step
+
+// internal headers of the post-processing framework
+#include "SplitByBoneCountProcess.h"
+#include <assimp/postprocess.h>
+#include <assimp/DefaultLogger.hpp>
+
+#include <limits>
+#include <assimp/TinyFormatter.h>
+#include <assimp/Exceptional.h>
+#include <set>
+
+using namespace Assimp;
+using namespace Assimp::Formatter;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor
+SplitByBoneCountProcess::SplitByBoneCountProcess()
+{
+    // set default, might be overridden by importer config
+    mMaxBoneCount = AI_SBBC_DEFAULT_MAX_BONES;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor
+SplitByBoneCountProcess::~SplitByBoneCountProcess()
+{
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag.
+bool SplitByBoneCountProcess::IsActive( unsigned int pFlags) const
+{
+    return !!(pFlags & aiProcess_SplitByBoneCount);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Updates internal properties
+void SplitByBoneCountProcess::SetupProperties(const Importer* pImp)
+{
+    mMaxBoneCount = pImp->GetPropertyInteger(AI_CONFIG_PP_SBBC_MAX_BONES,AI_SBBC_DEFAULT_MAX_BONES);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void SplitByBoneCountProcess::Execute( aiScene* pScene)
+{
+    ASSIMP_LOG_DEBUG("SplitByBoneCountProcess begin");
+
+    // early out
+    bool isNecessary = false;
+    for( unsigned int a = 0; a < pScene->mNumMeshes; ++a)
+        if( pScene->mMeshes[a]->mNumBones > mMaxBoneCount )
+        {
+            isNecessary = true;
+            break;
+        }
+
+    if( !isNecessary )
+    {
+        ASSIMP_LOG_DEBUG("SplitByBoneCountProcess early-out: no meshes with more than ", mMaxBoneCount, " bones." );
+        return;
+    }
+
+    // we need to do something. Let's go.
+    mSubMeshIndices.clear();
+    mSubMeshIndices.resize( pScene->mNumMeshes);
+
+    // build a new array of meshes for the scene
+    std::vector<aiMesh*> meshes;
+
+    for( unsigned int a = 0; a < pScene->mNumMeshes; ++a)
+    {
+        aiMesh* srcMesh = pScene->mMeshes[a];
+
+        std::vector<aiMesh*> newMeshes;
+        SplitMesh( pScene->mMeshes[a], newMeshes);
+
+        // mesh was split
+        if( !newMeshes.empty() )
+        {
+            // store new meshes and indices of the new meshes
+            for( unsigned int b = 0; b < newMeshes.size(); ++b)
+            {
+                mSubMeshIndices[a].push_back( static_cast<unsigned int>(meshes.size()));
+                meshes.push_back( newMeshes[b]);
+            }
+
+            // and destroy the source mesh. It should be completely contained inside the new submeshes
+            delete srcMesh;
+        }
+        else
+        {
+            // Mesh is kept unchanged - store it's new place in the mesh array
+            mSubMeshIndices[a].push_back( static_cast<unsigned int>(meshes.size()));
+            meshes.push_back( srcMesh);
+        }
+    }
+
+    // rebuild the scene's mesh array
+    pScene->mNumMeshes = static_cast<unsigned int>(meshes.size());
+    delete [] pScene->mMeshes;
+    pScene->mMeshes = new aiMesh*[pScene->mNumMeshes];
+    std::copy( meshes.begin(), meshes.end(), pScene->mMeshes);
+
+    // recurse through all nodes and translate the node's mesh indices to fit the new mesh array
+    UpdateNode( pScene->mRootNode);
+
+    ASSIMP_LOG_DEBUG( "SplitByBoneCountProcess end: split ", mSubMeshIndices.size(), " meshes into ", meshes.size(), " submeshes." );
+}
+
+// ------------------------------------------------------------------------------------------------
+// Splits the given mesh by bone count.
+void SplitByBoneCountProcess::SplitMesh( const aiMesh* pMesh, std::vector<aiMesh*>& poNewMeshes) const
+{
+    // skip if not necessary
+    if( pMesh->mNumBones <= mMaxBoneCount )
+    {
+        return;
+    }
+
+    // necessary optimisation: build a list of all affecting bones for each vertex
+    // TODO: (thom) maybe add a custom allocator here to avoid allocating tens of thousands of small arrays
+    typedef std::pair<unsigned int, float> BoneWeight;
+    std::vector< std::vector<BoneWeight> > vertexBones( pMesh->mNumVertices);
+    for( unsigned int a = 0; a < pMesh->mNumBones; ++a)
+    {
+        const aiBone* bone = pMesh->mBones[a];
+        for( unsigned int b = 0; b < bone->mNumWeights; ++b)
+        {
+          if (bone->mWeights[b].mWeight > 0.0f)
+          {
+            int vertexId = bone->mWeights[b].mVertexId;
+            vertexBones[vertexId].push_back( BoneWeight( a, bone->mWeights[b].mWeight));
+            if (vertexBones[vertexId].size() > mMaxBoneCount)
+            {
+              throw DeadlyImportError("SplitByBoneCountProcess: Single face requires more bones than specified max bone count!");
+            }
+          }
+        }
+    }
+
+    unsigned int numFacesHandled = 0;
+    std::vector<bool> isFaceHandled( pMesh->mNumFaces, false);
+    while( numFacesHandled < pMesh->mNumFaces )
+    {
+        // which bones are used in the current submesh
+        unsigned int numBones = 0;
+        std::vector<bool> isBoneUsed( pMesh->mNumBones, false);
+        // indices of the faces which are going to go into this submesh
+        std::vector<unsigned int> subMeshFaces;
+        subMeshFaces.reserve( pMesh->mNumFaces);
+        // accumulated vertex count of all the faces in this submesh
+        unsigned int numSubMeshVertices = 0;
+
+        // add faces to the new submesh as long as all bones affecting the faces' vertices fit in the limit
+        for( unsigned int a = 0; a < pMesh->mNumFaces; ++a)
+        {
+            // skip if the face is already stored in a submesh
+            if( isFaceHandled[a] )
+            {
+                continue;
+            }
+            // a small local set of new bones for the current face. State of all used bones for that face
+            // can only be updated AFTER the face is completely analysed. Thanks to imre for the fix.
+            std::set<unsigned int> newBonesAtCurrentFace;
+
+            const aiFace& face = pMesh->mFaces[a];
+            // check every vertex if its bones would still fit into the current submesh
+            for( unsigned int b = 0; b < face.mNumIndices; ++b )
+            {
+              const std::vector<BoneWeight>& vb = vertexBones[face.mIndices[b]];
+              for( unsigned int c = 0; c < vb.size(); ++c)
+              {
+                unsigned int boneIndex = vb[c].first;
+                if( !isBoneUsed[boneIndex] )
+                {
+                  newBonesAtCurrentFace.insert(boneIndex);
+                }
+              }
+            }
+
+            // leave out the face if the new bones required for this face don't fit the bone count limit anymore
+            if( numBones + newBonesAtCurrentFace.size() > mMaxBoneCount )
+            {
+                continue;
+            }
+
+            // mark all new bones as necessary
+            for (std::set<unsigned int>::iterator it = newBonesAtCurrentFace.begin(); it != newBonesAtCurrentFace.end(); ++it)
+            {
+              if (!isBoneUsed[*it])
+              {
+                isBoneUsed[*it] = true;
+                numBones++;
+              }
+            }
+
+            // store the face index and the vertex count
+            subMeshFaces.push_back( a);
+            numSubMeshVertices += face.mNumIndices;
+
+            // remember that this face is handled
+            isFaceHandled[a] = true;
+            numFacesHandled++;
+        }
+
+        // create a new mesh to hold this subset of the source mesh
+        aiMesh* newMesh = new aiMesh;
+        if( pMesh->mName.length > 0 )
+        {
+            newMesh->mName.Set( format() << pMesh->mName.data << "_sub" << poNewMeshes.size());
+        }
+        newMesh->mMaterialIndex = pMesh->mMaterialIndex;
+        newMesh->mPrimitiveTypes = pMesh->mPrimitiveTypes;
+        poNewMeshes.push_back( newMesh);
+
+        // create all the arrays for this mesh if the old mesh contained them
+        newMesh->mNumVertices = numSubMeshVertices;
+        newMesh->mNumFaces = static_cast<unsigned int>(subMeshFaces.size());
+        newMesh->mVertices = new aiVector3D[newMesh->mNumVertices];
+        if( pMesh->HasNormals() )
+        {
+            newMesh->mNormals = new aiVector3D[newMesh->mNumVertices];
+        }
+        if( pMesh->HasTangentsAndBitangents() )
+        {
+            newMesh->mTangents = new aiVector3D[newMesh->mNumVertices];
+            newMesh->mBitangents = new aiVector3D[newMesh->mNumVertices];
+        }
+        for( unsigned int a = 0; a < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++a )
+        {
+            if( pMesh->HasTextureCoords( a) )
+            {
+                newMesh->mTextureCoords[a] = new aiVector3D[newMesh->mNumVertices];
+            }
+            newMesh->mNumUVComponents[a] = pMesh->mNumUVComponents[a];
+        }
+        for( unsigned int a = 0; a < AI_MAX_NUMBER_OF_COLOR_SETS; ++a )
+        {
+            if( pMesh->HasVertexColors( a) )
+            {
+                newMesh->mColors[a] = new aiColor4D[newMesh->mNumVertices];
+            }
+        }
+
+        // and copy over the data, generating faces with linear indices along the way
+        newMesh->mFaces = new aiFace[subMeshFaces.size()];
+        unsigned int nvi = 0; // next vertex index
+        std::vector<unsigned int> previousVertexIndices( numSubMeshVertices, std::numeric_limits<unsigned int>::max()); // per new vertex: its index in the source mesh
+        for( unsigned int a = 0; a < subMeshFaces.size(); ++a )
+        {
+            const aiFace& srcFace = pMesh->mFaces[subMeshFaces[a]];
+            aiFace& dstFace = newMesh->mFaces[a];
+            dstFace.mNumIndices = srcFace.mNumIndices;
+            dstFace.mIndices = new unsigned int[dstFace.mNumIndices];
+
+            // accumulate linearly all the vertices of the source face
+            for( unsigned int b = 0; b < dstFace.mNumIndices; ++b )
+            {
+                unsigned int srcIndex = srcFace.mIndices[b];
+                dstFace.mIndices[b] = nvi;
+                previousVertexIndices[nvi] = srcIndex;
+
+                newMesh->mVertices[nvi] = pMesh->mVertices[srcIndex];
+                if( pMesh->HasNormals() )
+                {
+                    newMesh->mNormals[nvi] = pMesh->mNormals[srcIndex];
+                }
+                if( pMesh->HasTangentsAndBitangents() )
+                {
+                    newMesh->mTangents[nvi] = pMesh->mTangents[srcIndex];
+                    newMesh->mBitangents[nvi] = pMesh->mBitangents[srcIndex];
+                }
+                for( unsigned int c = 0; c < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++c )
+                {
+                    if( pMesh->HasTextureCoords( c) )
+                    {
+                        newMesh->mTextureCoords[c][nvi] = pMesh->mTextureCoords[c][srcIndex];
+                    }
+                }
+                for( unsigned int c = 0; c < AI_MAX_NUMBER_OF_COLOR_SETS; ++c )
+                {
+                    if( pMesh->HasVertexColors( c) )
+                    {
+                        newMesh->mColors[c][nvi] = pMesh->mColors[c][srcIndex];
+                    }
+                }
+
+                nvi++;
+            }
+        }
+
+        ai_assert( nvi == numSubMeshVertices );
+
+        // Create the bones for the new submesh: first create the bone array
+        newMesh->mNumBones = 0;
+        newMesh->mBones = new aiBone*[numBones];
+
+        std::vector<unsigned int> mappedBoneIndex( pMesh->mNumBones, std::numeric_limits<unsigned int>::max());
+        for( unsigned int a = 0; a < pMesh->mNumBones; ++a )
+        {
+            if( !isBoneUsed[a] )
+            {
+                continue;
+            }
+
+            // create the new bone
+            const aiBone* srcBone = pMesh->mBones[a];
+            aiBone* dstBone = new aiBone;
+            mappedBoneIndex[a] = newMesh->mNumBones;
+            newMesh->mBones[newMesh->mNumBones++] = dstBone;
+            dstBone->mName = srcBone->mName;
+            dstBone->mOffsetMatrix = srcBone->mOffsetMatrix;
+            dstBone->mNumWeights = 0;
+        }
+
+        ai_assert( newMesh->mNumBones == numBones );
+
+        // iterate over all new vertices and count which bones affected its old vertex in the source mesh
+        for( unsigned int a = 0; a < numSubMeshVertices; ++a )
+        {
+            unsigned int oldIndex = previousVertexIndices[a];
+            const std::vector<BoneWeight>& bonesOnThisVertex = vertexBones[oldIndex];
+
+            for( unsigned int b = 0; b < bonesOnThisVertex.size(); ++b )
+            {
+                unsigned int newBoneIndex = mappedBoneIndex[ bonesOnThisVertex[b].first ];
+                if( newBoneIndex != std::numeric_limits<unsigned int>::max() )
+                {
+                    newMesh->mBones[newBoneIndex]->mNumWeights++;
+                }
+            }
+        }
+
+        // allocate all bone weight arrays accordingly
+        for( unsigned int a = 0; a < newMesh->mNumBones; ++a )
+        {
+            aiBone* bone = newMesh->mBones[a];
+            ai_assert( bone->mNumWeights > 0 );
+            bone->mWeights = new aiVertexWeight[bone->mNumWeights];
+            bone->mNumWeights = 0; // for counting up in the next step
+        }
+
+        // now copy all the bone vertex weights for all the vertices which made it into the new submesh
+        for( unsigned int a = 0; a < numSubMeshVertices; ++a)
+        {
+            // find the source vertex for it in the source mesh
+            unsigned int previousIndex = previousVertexIndices[a];
+            // these bones were affecting it
+            const std::vector<BoneWeight>& bonesOnThisVertex = vertexBones[previousIndex];
+            // all of the bones affecting it should be present in the new submesh, or else
+            // the face it comprises shouldn't be present
+            for( unsigned int b = 0; b < bonesOnThisVertex.size(); ++b)
+            {
+                unsigned int newBoneIndex = mappedBoneIndex[ bonesOnThisVertex[b].first ];
+                ai_assert( newBoneIndex != std::numeric_limits<unsigned int>::max() );
+                aiVertexWeight* dstWeight = newMesh->mBones[newBoneIndex]->mWeights + newMesh->mBones[newBoneIndex]->mNumWeights;
+                newMesh->mBones[newBoneIndex]->mNumWeights++;
+
+                dstWeight->mVertexId = a;
+                dstWeight->mWeight = bonesOnThisVertex[b].second;
+            }
+        }
+
+        // ... and copy all the morph targets for all the vertices which made it into the new submesh
+        if (pMesh->mNumAnimMeshes > 0) {
+            newMesh->mNumAnimMeshes = pMesh->mNumAnimMeshes;
+            newMesh->mAnimMeshes = new aiAnimMesh*[newMesh->mNumAnimMeshes];
+
+            for (unsigned int morphIdx = 0; morphIdx < newMesh->mNumAnimMeshes; ++morphIdx) {
+                aiAnimMesh* origTarget = pMesh->mAnimMeshes[morphIdx];
+                aiAnimMesh* newTarget = new aiAnimMesh;
+                newTarget->mName = origTarget->mName;
+                newTarget->mWeight = origTarget->mWeight;
+                newTarget->mNumVertices = numSubMeshVertices;
+                newTarget->mVertices = new aiVector3D[numSubMeshVertices];
+                newMesh->mAnimMeshes[morphIdx] = newTarget;
+
+                if (origTarget->HasNormals()) {
+                    newTarget->mNormals = new aiVector3D[numSubMeshVertices];
+                }
+
+                if (origTarget->HasTangentsAndBitangents()) {
+                    newTarget->mTangents = new aiVector3D[numSubMeshVertices];
+                    newTarget->mBitangents = new aiVector3D[numSubMeshVertices];
+                }
+
+                for( unsigned int vi = 0; vi < numSubMeshVertices; ++vi) {
+                    // find the source vertex for it in the source mesh
+                    unsigned int previousIndex = previousVertexIndices[vi];
+                    newTarget->mVertices[vi] = origTarget->mVertices[previousIndex];
+
+                    if (newTarget->HasNormals()) {
+                        newTarget->mNormals[vi] = origTarget->mNormals[previousIndex];
+                    }
+                    if (newTarget->HasTangentsAndBitangents()) {
+                        newTarget->mTangents[vi] = origTarget->mTangents[previousIndex];
+                        newTarget->mBitangents[vi] = origTarget->mBitangents[previousIndex];
+                    }
+                }
+            }
+        }
+
+        // I have the strange feeling that this will break apart at some point in time...
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Recursively updates the node's mesh list to account for the changed mesh list
+void SplitByBoneCountProcess::UpdateNode( aiNode* pNode) const
+{
+    // rebuild the node's mesh index list
+    if( pNode->mNumMeshes > 0 )
+    {
+        std::vector<unsigned int> newMeshList;
+        for( unsigned int a = 0; a < pNode->mNumMeshes; ++a)
+        {
+            unsigned int srcIndex = pNode->mMeshes[a];
+            const std::vector<unsigned int>& replaceMeshes = mSubMeshIndices[srcIndex];
+            newMeshList.insert( newMeshList.end(), replaceMeshes.begin(), replaceMeshes.end());
+        }
+
+        delete [] pNode->mMeshes;
+        pNode->mNumMeshes = static_cast<unsigned int>(newMeshList.size());
+        pNode->mMeshes = new unsigned int[pNode->mNumMeshes];
+        std::copy( newMeshList.begin(), newMeshList.end(), pNode->mMeshes);
+    }
+
+    // do that also recursively for all children
+    for( unsigned int a = 0; a < pNode->mNumChildren; ++a )
+    {
+        UpdateNode( pNode->mChildren[a]);
+    }
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/SplitByBoneCountProcess.h b/src/mesh/assimp-master/code/PostProcessing/SplitByBoneCountProcess.h
new file mode 100644
index 0000000..938b00c
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/SplitByBoneCountProcess.h
@@ -0,0 +1,111 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/// @file SplitByBoneCountProcess.h
+/// Defines a post processing step to split meshes with many bones into submeshes
+#ifndef AI_SPLITBYBONECOUNTPROCESS_H_INC
+#define AI_SPLITBYBONECOUNTPROCESS_H_INC
+
+#include <vector>
+#include "Common/BaseProcess.h"
+
+#include <assimp/mesh.h>
+#include <assimp/scene.h>
+
+namespace Assimp
+{
+
+
+/** Postprocessing filter to split meshes with many bones into submeshes
+ * so that each submesh has a certain max bone count.
+ *
+ * Applied BEFORE the JoinVertices-Step occurs.
+ * Returns NON-UNIQUE vertices, splits by bone count.
+*/
+class SplitByBoneCountProcess : public BaseProcess
+{
+public:
+
+    SplitByBoneCountProcess();
+    ~SplitByBoneCountProcess();
+
+public:
+    /** Returns whether the processing step is present in the given flag.
+    * @param pFlags The processing flags the importer was called with. A
+    *   bitwise combination of #aiPostProcessSteps.
+    * @return true if the process is present in this flag fields,
+    *   false if not.
+    */
+    bool IsActive( unsigned int pFlags) const;
+
+    /** Called prior to ExecuteOnScene().
+    * The function is a request to the process to update its configuration
+    * basing on the Importer's configuration property list.
+    */
+    virtual void SetupProperties(const Importer* pImp);
+
+protected:
+    /** Executes the post processing step on the given imported data.
+    * At the moment a process is not supposed to fail.
+    * @param pScene The imported data to work at.
+    */
+    void Execute( aiScene* pScene);
+
+    /// Splits the given mesh by bone count.
+    /// @param pMesh the Mesh to split. Is not changed at all, but might be superfluous in case it was split.
+    /// @param poNewMeshes Array of submeshes created in the process. Empty if splitting was not necessary.
+    void SplitMesh( const aiMesh* pMesh, std::vector<aiMesh*>& poNewMeshes) const;
+
+    /// Recursively updates the node's mesh list to account for the changed mesh list
+    void UpdateNode( aiNode* pNode) const;
+
+public:
+    /// Max bone count. Splitting occurs if a mesh has more than that number of bones.
+    size_t mMaxBoneCount;
+
+    /// Per mesh index: Array of indices of the new submeshes.
+    std::vector< std::vector<unsigned int> > mSubMeshIndices;
+};
+
+} // end of namespace Assimp
+
+#endif // !!AI_SPLITBYBONECOUNTPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/SplitLargeMeshes.cpp b/src/mesh/assimp-master/code/PostProcessing/SplitLargeMeshes.cpp
new file mode 100644
index 0000000..508a826
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/SplitLargeMeshes.cpp
@@ -0,0 +1,624 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/**
+ *  @file Implementation of the SplitLargeMeshes postprocessing step
+ */
+
+// internal headers of the post-processing framework
+#include "SplitLargeMeshes.h"
+#include "ProcessHelper.h"
+
+using namespace Assimp;
+
+// ------------------------------------------------------------------------------------------------
+SplitLargeMeshesProcess_Triangle::SplitLargeMeshesProcess_Triangle() {
+    LIMIT = AI_SLM_DEFAULT_MAX_TRIANGLES;
+}
+
+// ------------------------------------------------------------------------------------------------
+SplitLargeMeshesProcess_Triangle::~SplitLargeMeshesProcess_Triangle() {
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool SplitLargeMeshesProcess_Triangle::IsActive( unsigned int pFlags) const {
+    return (pFlags & aiProcess_SplitLargeMeshes) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void SplitLargeMeshesProcess_Triangle::Execute( aiScene* pScene) {
+    if (0xffffffff == this->LIMIT || nullptr == pScene ) {
+        return;
+    }
+
+    ASSIMP_LOG_DEBUG("SplitLargeMeshesProcess_Triangle begin");
+    std::vector<std::pair<aiMesh*, unsigned int> > avList;
+
+    for( unsigned int a = 0; a < pScene->mNumMeshes; ++a) {
+        this->SplitMesh(a, pScene->mMeshes[a],avList);
+    }
+
+    if (avList.size() != pScene->mNumMeshes) {
+        // it seems something has been split. rebuild the mesh list
+        delete[] pScene->mMeshes;
+        pScene->mNumMeshes = (unsigned int)avList.size();
+        pScene->mMeshes = new aiMesh*[avList.size()];
+
+        for (unsigned int i = 0; i < avList.size();++i) {
+            pScene->mMeshes[i] = avList[i].first;
+        }
+
+        // now we need to update all nodes
+        this->UpdateNode(pScene->mRootNode,avList);
+        ASSIMP_LOG_INFO("SplitLargeMeshesProcess_Triangle finished. Meshes have been split");
+    } else {
+        ASSIMP_LOG_DEBUG("SplitLargeMeshesProcess_Triangle finished. There was nothing to do");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Setup properties
+void SplitLargeMeshesProcess_Triangle::SetupProperties( const Importer* pImp) {
+    // get the current value of the split property
+    this->LIMIT = pImp->GetPropertyInteger(AI_CONFIG_PP_SLM_TRIANGLE_LIMIT,AI_SLM_DEFAULT_MAX_TRIANGLES);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Update a node after some meshes have been split
+void SplitLargeMeshesProcess_Triangle::UpdateNode(aiNode* pcNode,
+        const std::vector<std::pair<aiMesh*, unsigned int> >& avList) {
+    // for every index in out list build a new entry
+    std::vector<unsigned int> aiEntries;
+    aiEntries.reserve(pcNode->mNumMeshes + 1);
+    for (unsigned int i = 0; i < pcNode->mNumMeshes;++i) {
+        for (unsigned int a = 0; a < avList.size();++a) {
+            if (avList[a].second == pcNode->mMeshes[i]) {
+                aiEntries.push_back(a);
+            }
+        }
+    }
+
+    // now build the new list
+    delete[] pcNode->mMeshes;
+    pcNode->mNumMeshes = (unsigned int)aiEntries.size();
+    pcNode->mMeshes = new unsigned int[pcNode->mNumMeshes];
+
+    for (unsigned int b = 0; b < pcNode->mNumMeshes;++b) {
+        pcNode->mMeshes[b] = aiEntries[b];
+    }
+
+    // recursively update all other nodes
+    for (unsigned int i = 0; i < pcNode->mNumChildren;++i) {
+        UpdateNode ( pcNode->mChildren[i], avList );
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void SplitLargeMeshesProcess_Triangle::SplitMesh(
+        unsigned int a,
+        aiMesh* pMesh,
+        std::vector<std::pair<aiMesh*, unsigned int> >& avList) {
+    if (pMesh->mNumFaces > SplitLargeMeshesProcess_Triangle::LIMIT) {
+        ASSIMP_LOG_INFO("Mesh exceeds the triangle limit. It will be split ...");
+
+        // we need to split this mesh into sub meshes
+        // determine the size of a submesh
+        const unsigned int iSubMeshes = (pMesh->mNumFaces / LIMIT) + 1;
+
+        const unsigned int iOutFaceNum = pMesh->mNumFaces / iSubMeshes;
+        const unsigned int iOutVertexNum = iOutFaceNum * 3;
+
+        // now generate all submeshes
+        for (unsigned int i = 0; i < iSubMeshes;++i) {
+            aiMesh* pcMesh          = new aiMesh;
+            pcMesh->mNumFaces       = iOutFaceNum;
+            pcMesh->mMaterialIndex  = pMesh->mMaterialIndex;
+
+            // the name carries the adjacency information between the meshes
+            pcMesh->mName = pMesh->mName;
+
+            if (i == iSubMeshes-1) {
+                pcMesh->mNumFaces = iOutFaceNum + (
+                    pMesh->mNumFaces - iOutFaceNum * iSubMeshes);
+            }
+            // copy the list of faces
+            pcMesh->mFaces = new aiFace[pcMesh->mNumFaces];
+
+            const unsigned int iBase = iOutFaceNum * i;
+
+            // get the total number of indices
+            unsigned int iCnt = 0;
+            for (unsigned int p = iBase; p < pcMesh->mNumFaces + iBase;++p) {
+                iCnt += pMesh->mFaces[p].mNumIndices;
+            }
+            pcMesh->mNumVertices = iCnt;
+
+            // allocate storage
+            if (pMesh->mVertices != nullptr) {
+                pcMesh->mVertices = new aiVector3D[iCnt];
+            }
+
+            if (pMesh->HasNormals()) {
+                pcMesh->mNormals = new aiVector3D[iCnt];
+            }
+
+            if (pMesh->HasTangentsAndBitangents()) {
+                pcMesh->mTangents = new aiVector3D[iCnt];
+                pcMesh->mBitangents = new aiVector3D[iCnt];
+            }
+
+            // texture coordinates
+            for (unsigned int c = 0;  c < AI_MAX_NUMBER_OF_TEXTURECOORDS;++c) {
+                pcMesh->mNumUVComponents[c] = pMesh->mNumUVComponents[c];
+                if (pMesh->HasTextureCoords( c)) {
+                    pcMesh->mTextureCoords[c] = new aiVector3D[iCnt];
+                }
+            }
+
+            // vertex colors
+            for (unsigned int c = 0;  c < AI_MAX_NUMBER_OF_COLOR_SETS;++c) {
+                if (pMesh->HasVertexColors( c)) {
+                    pcMesh->mColors[c] = new aiColor4D[iCnt];
+                }
+            }
+
+            if (pMesh->HasBones()) {
+                // assume the number of bones won't change in most cases
+                pcMesh->mBones = new aiBone*[pMesh->mNumBones];
+
+                // iterate through all bones of the mesh and find those which
+                // need to be copied to the split mesh
+                std::vector<aiVertexWeight> avTempWeights;
+                for (unsigned int p = 0; p < pcMesh->mNumBones;++p) {
+                    aiBone* const bone = pcMesh->mBones[p];
+                    avTempWeights.clear();
+                    avTempWeights.reserve(bone->mNumWeights / iSubMeshes);
+
+                    for (unsigned int q = 0; q < bone->mNumWeights;++q) {
+                        aiVertexWeight& weight = bone->mWeights[q];
+                        if(weight.mVertexId >= iBase && weight.mVertexId < iBase + iOutVertexNum) {
+                            avTempWeights.push_back(weight);
+                            weight = avTempWeights.back();
+                            weight.mVertexId -= iBase;
+                        }
+                    }
+
+                    if (!avTempWeights.empty()) {
+                        // we'll need this bone. Copy it ...
+                        aiBone* pc = new aiBone();
+                        pcMesh->mBones[pcMesh->mNumBones++] = pc;
+                        pc->mName = aiString(bone->mName);
+                        pc->mNumWeights = (unsigned int)avTempWeights.size();
+                        pc->mOffsetMatrix = bone->mOffsetMatrix;
+
+                        // no need to reallocate the array for the last submesh.
+                        // Here we can reuse the (large) source array, although
+                        // we'll waste some memory
+                        if (iSubMeshes-1 == i) {
+                            pc->mWeights = bone->mWeights;
+                            bone->mWeights = nullptr;
+                        } else {
+                            pc->mWeights = new aiVertexWeight[pc->mNumWeights];
+                        }
+
+                        // copy the weights
+                        ::memcpy(pc->mWeights,&avTempWeights[0],sizeof(aiVertexWeight)*pc->mNumWeights);
+                    }
+                }
+            }
+
+            // (we will also need to copy the array of indices)
+            unsigned int iCurrent = 0;
+            for (unsigned int p = 0; p < pcMesh->mNumFaces;++p) {
+                pcMesh->mFaces[p].mNumIndices = 3;
+                // allocate a new array
+                const unsigned int iTemp = p + iBase;
+                const unsigned int iNumIndices = pMesh->mFaces[iTemp].mNumIndices;
+
+                // setup face type and number of indices
+                pcMesh->mFaces[p].mNumIndices = iNumIndices;
+                unsigned int* pi = pMesh->mFaces[iTemp].mIndices;
+                unsigned int* piOut = pcMesh->mFaces[p].mIndices = new unsigned int[iNumIndices];
+
+                // need to update the output primitive types
+                switch (iNumIndices) {
+                case 1:
+                    pcMesh->mPrimitiveTypes |= aiPrimitiveType_POINT;
+                    break;
+                case 2:
+                    pcMesh->mPrimitiveTypes |= aiPrimitiveType_LINE;
+                    break;
+                case 3:
+                    pcMesh->mPrimitiveTypes |= aiPrimitiveType_TRIANGLE;
+                    break;
+                default:
+                    pcMesh->mPrimitiveTypes |= aiPrimitiveType_POLYGON;
+                }
+
+                // and copy the contents of the old array, offset by current base
+                for (unsigned int v = 0; v < iNumIndices;++v) {
+                    unsigned int iIndex = pi[v];
+                    unsigned int iIndexOut = iCurrent++;
+                    piOut[v] = iIndexOut;
+
+                    // copy positions
+                    if (pMesh->mVertices != nullptr) {
+                        pcMesh->mVertices[iIndexOut] = pMesh->mVertices[iIndex];
+                    }
+
+                    // copy normals
+                    if (pMesh->HasNormals()) {
+                        pcMesh->mNormals[iIndexOut] = pMesh->mNormals[iIndex];
+                    }
+
+                    // copy tangents/bitangents
+                    if (pMesh->HasTangentsAndBitangents()) {
+                        pcMesh->mTangents[iIndexOut] = pMesh->mTangents[iIndex];
+                        pcMesh->mBitangents[iIndexOut] = pMesh->mBitangents[iIndex];
+                    }
+
+                    // texture coordinates
+                    for (unsigned int c = 0;  c < AI_MAX_NUMBER_OF_TEXTURECOORDS;++c) {
+                        if (pMesh->HasTextureCoords( c ) ) {
+                            pcMesh->mTextureCoords[c][iIndexOut] = pMesh->mTextureCoords[c][iIndex];
+                        }
+                    }
+                    // vertex colors
+                    for (unsigned int c = 0;  c < AI_MAX_NUMBER_OF_COLOR_SETS;++c) {
+                        if (pMesh->HasVertexColors( c)) {
+                            pcMesh->mColors[c][iIndexOut] = pMesh->mColors[c][iIndex];
+                        }
+                    }
+                }
+            }
+
+            // add the newly created mesh to the list
+            avList.push_back(std::pair<aiMesh*, unsigned int>(pcMesh,a));
+        }
+
+        // now delete the old mesh data
+        delete pMesh;
+    } else {
+        avList.push_back(std::pair<aiMesh*, unsigned int>(pMesh,a));
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+SplitLargeMeshesProcess_Vertex::SplitLargeMeshesProcess_Vertex() {
+    LIMIT = AI_SLM_DEFAULT_MAX_VERTICES;
+}
+
+// ------------------------------------------------------------------------------------------------
+SplitLargeMeshesProcess_Vertex::~SplitLargeMeshesProcess_Vertex() {
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool SplitLargeMeshesProcess_Vertex::IsActive( unsigned int pFlags) const {
+    return (pFlags & aiProcess_SplitLargeMeshes) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void SplitLargeMeshesProcess_Vertex::Execute( aiScene* pScene) {
+    if (0xffffffff == this->LIMIT || nullptr == pScene ) {
+        return;
+    }
+
+    ASSIMP_LOG_DEBUG("SplitLargeMeshesProcess_Vertex begin");
+
+    std::vector<std::pair<aiMesh*, unsigned int> > avList;
+
+    //Check for point cloud first,
+    //Do not process point cloud, splitMesh works only with faces data
+    for (unsigned int a = 0; a < pScene->mNumMeshes; a++) {
+        if ( pScene->mMeshes[a]->mPrimitiveTypes == aiPrimitiveType_POINT ) {
+            return;
+        }
+    }
+
+    for( unsigned int a = 0; a < pScene->mNumMeshes; ++a ) {
+        this->SplitMesh(a, pScene->mMeshes[a], avList);
+    }
+
+    if (avList.size() != pScene->mNumMeshes) {
+        // it seems something has been split. rebuild the mesh list
+        delete[] pScene->mMeshes;
+        pScene->mNumMeshes = (unsigned int)avList.size();
+        pScene->mMeshes = new aiMesh*[avList.size()];
+
+        for (unsigned int i = 0; i < avList.size();++i) {
+            pScene->mMeshes[i] = avList[i].first;
+        }
+
+        // now we need to update all nodes
+        SplitLargeMeshesProcess_Triangle::UpdateNode(pScene->mRootNode,avList);
+        ASSIMP_LOG_INFO("SplitLargeMeshesProcess_Vertex finished. Meshes have been split");
+    } else {
+        ASSIMP_LOG_DEBUG("SplitLargeMeshesProcess_Vertex finished. There was nothing to do");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Setup properties
+void SplitLargeMeshesProcess_Vertex::SetupProperties( const Importer* pImp) {
+    this->LIMIT = pImp->GetPropertyInteger(AI_CONFIG_PP_SLM_VERTEX_LIMIT,AI_SLM_DEFAULT_MAX_VERTICES);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void SplitLargeMeshesProcess_Vertex::SplitMesh(
+        unsigned int a,
+        aiMesh* pMesh,
+        std::vector<std::pair<aiMesh*, unsigned int> >& avList) {
+    if (pMesh->mNumVertices > SplitLargeMeshesProcess_Vertex::LIMIT) {
+        typedef std::vector< std::pair<unsigned int,float> > VertexWeightTable;
+
+        // build a per-vertex weight list if necessary
+        VertexWeightTable* avPerVertexWeights = ComputeVertexBoneWeightTable(pMesh);
+
+        // we need to split this mesh into sub meshes
+        // determine the estimated size of a submesh
+        // (this could be too large. Max waste is a single digit percentage)
+        const unsigned int iSubMeshes = (pMesh->mNumVertices / SplitLargeMeshesProcess_Vertex::LIMIT) + 1;
+
+        // create a std::vector<unsigned int> to indicate which vertices
+        // have already been copied
+        std::vector<unsigned int> avWasCopied;
+        avWasCopied.resize(pMesh->mNumVertices,0xFFFFFFFF);
+
+        // try to find a good estimate for the number of output faces
+        // per mesh. Add 12.5% as buffer
+        unsigned int iEstimatedSize = pMesh->mNumFaces / iSubMeshes;
+        iEstimatedSize += iEstimatedSize >> 3;
+
+        // now generate all submeshes
+        unsigned int iBase( 0 );
+        while (true) {
+            const unsigned int iOutVertexNum = SplitLargeMeshesProcess_Vertex::LIMIT;
+            aiMesh* pcMesh          = new aiMesh;
+            pcMesh->mNumVertices    = 0;
+            pcMesh->mMaterialIndex  = pMesh->mMaterialIndex;
+
+            // the name carries the adjacency information between the meshes
+            pcMesh->mName = pMesh->mName;
+
+            typedef std::vector<aiVertexWeight> BoneWeightList;
+            if (pMesh->HasBones()) {
+                pcMesh->mBones = new aiBone*[pMesh->mNumBones];
+                ::memset(pcMesh->mBones,0,sizeof(void*)*pMesh->mNumBones);
+            }
+
+            // clear the temporary helper array
+            if (iBase) {
+                // we can't use memset here we unsigned int needn' be 32 bits
+                for (auto &elem : avWasCopied) {
+                    elem = 0xffffffff;
+                }
+            }
+
+            // output vectors
+            std::vector<aiFace> vFaces;
+
+            // reserve enough storage for most cases
+            if (pMesh->HasPositions()) {
+                pcMesh->mVertices = new aiVector3D[iOutVertexNum];
+            }
+            if (pMesh->HasNormals()) {
+                pcMesh->mNormals = new aiVector3D[iOutVertexNum];
+            }
+            if (pMesh->HasTangentsAndBitangents()) {
+                pcMesh->mTangents = new aiVector3D[iOutVertexNum];
+                pcMesh->mBitangents = new aiVector3D[iOutVertexNum];
+            }
+            for (unsigned int c = 0; pMesh->HasVertexColors(c);++c) {
+                pcMesh->mColors[c] = new aiColor4D[iOutVertexNum];
+            }
+            for (unsigned int c = 0; pMesh->HasTextureCoords(c);++c) {
+                pcMesh->mNumUVComponents[c] = pMesh->mNumUVComponents[c];
+                pcMesh->mTextureCoords[c] = new aiVector3D[iOutVertexNum];
+            }
+            vFaces.reserve(iEstimatedSize);
+
+            // (we will also need to copy the array of indices)
+            while (iBase < pMesh->mNumFaces) {
+                // allocate a new array
+                const unsigned int iNumIndices = pMesh->mFaces[iBase].mNumIndices;
+
+                // doesn't catch degenerates but is quite fast
+                unsigned int iNeed = 0;
+                for (unsigned int v = 0; v < iNumIndices;++v) {
+                    unsigned int iIndex = pMesh->mFaces[iBase].mIndices[v];
+
+                    // check whether we do already have this vertex
+                    if (0xFFFFFFFF == avWasCopied[iIndex]) {
+                        iNeed++;
+                    }
+                }
+                if (pcMesh->mNumVertices + iNeed > iOutVertexNum) {
+                    // don't use this face
+                    break;
+                }
+
+                vFaces.push_back(aiFace());
+                aiFace& rFace = vFaces.back();
+
+                // setup face type and number of indices
+                rFace.mNumIndices = iNumIndices;
+                rFace.mIndices = new unsigned int[iNumIndices];
+
+                // need to update the output primitive types
+                switch (rFace.mNumIndices) {
+                case 1:
+                    pcMesh->mPrimitiveTypes |= aiPrimitiveType_POINT;
+                    break;
+                case 2:
+                    pcMesh->mPrimitiveTypes |= aiPrimitiveType_LINE;
+                    break;
+                case 3:
+                    pcMesh->mPrimitiveTypes |= aiPrimitiveType_TRIANGLE;
+                    break;
+                default:
+                    pcMesh->mPrimitiveTypes |= aiPrimitiveType_POLYGON;
+                }
+
+                // and copy the contents of the old array, offset by current base
+                for (unsigned int v = 0; v < iNumIndices;++v) {
+                    unsigned int iIndex = pMesh->mFaces[iBase].mIndices[v];
+
+                    // check whether we do already have this vertex
+                    if (0xFFFFFFFF != avWasCopied[iIndex]) {
+                        rFace.mIndices[v] = avWasCopied[iIndex];
+                        continue;
+                    }
+
+                    // copy positions
+                    pcMesh->mVertices[pcMesh->mNumVertices] = (pMesh->mVertices[iIndex]);
+
+                    // copy normals
+                    if (pMesh->HasNormals()) {
+                        pcMesh->mNormals[pcMesh->mNumVertices] = (pMesh->mNormals[iIndex]);
+                    }
+
+                    // copy tangents/bitangents
+                    if (pMesh->HasTangentsAndBitangents()) {
+                        pcMesh->mTangents[pcMesh->mNumVertices] = (pMesh->mTangents[iIndex]);
+                        pcMesh->mBitangents[pcMesh->mNumVertices] = (pMesh->mBitangents[iIndex]);
+                    }
+
+                    // texture coordinates
+                    for (unsigned int c = 0;  c < AI_MAX_NUMBER_OF_TEXTURECOORDS;++c) {
+                        if (pMesh->HasTextureCoords( c)) {
+                            pcMesh->mTextureCoords[c][pcMesh->mNumVertices] = pMesh->mTextureCoords[c][iIndex];
+                        }
+                    }
+                    // vertex colors
+                    for (unsigned int c = 0;  c < AI_MAX_NUMBER_OF_COLOR_SETS;++c) {
+                        if (pMesh->HasVertexColors( c)) {
+                            pcMesh->mColors[c][pcMesh->mNumVertices] = pMesh->mColors[c][iIndex];
+                        }
+                    }
+                    // check whether we have bone weights assigned to this vertex
+                    rFace.mIndices[v] = pcMesh->mNumVertices;
+                    if (avPerVertexWeights) {
+                        VertexWeightTable& table = avPerVertexWeights[ pcMesh->mNumVertices ];
+                        if( !table.empty() ) {
+                            for (VertexWeightTable::const_iterator iter =  table.begin();
+                                    iter != table.end();++iter) {
+                                // allocate the bone weight array if necessary
+                                BoneWeightList* pcWeightList = (BoneWeightList*)pcMesh->mBones[(*iter).first];
+                                if (nullptr == pcWeightList) {
+                                    pcMesh->mBones[(*iter).first] = (aiBone*)(pcWeightList = new BoneWeightList());
+                                }
+                                pcWeightList->push_back(aiVertexWeight(pcMesh->mNumVertices,(*iter).second));
+                            }
+                        }
+                    }
+
+                    avWasCopied[iIndex] = pcMesh->mNumVertices;
+                    pcMesh->mNumVertices++;
+                }
+                ++iBase;
+                if(pcMesh->mNumVertices == iOutVertexNum) {
+                    // break here. The face is only added if it was complete
+                    break;
+                }
+            }
+
+            // check which bones we'll need to create for this submesh
+            if (pMesh->HasBones()) {
+                aiBone** ppCurrent = pcMesh->mBones;
+                for (unsigned int k = 0; k < pMesh->mNumBones;++k) {
+                    // check whether the bone is existing
+                    BoneWeightList* pcWeightList;
+                    pcWeightList = (BoneWeightList *)pcMesh->mBones[k];
+                    if (nullptr != pcWeightList) {
+                        aiBone *pcOldBone = pMesh->mBones[k];
+                        aiBone* pcOut( nullptr );
+                        *ppCurrent++ = pcOut = new aiBone();
+                        pcOut->mName = aiString(pcOldBone->mName);
+                        pcOut->mOffsetMatrix = pcOldBone->mOffsetMatrix;
+                        pcOut->mNumWeights = (unsigned int)pcWeightList->size();
+                        pcOut->mWeights = new aiVertexWeight[pcOut->mNumWeights];
+
+                        // copy the vertex weights
+                        ::memcpy(pcOut->mWeights,&pcWeightList->operator[](0),
+                            pcOut->mNumWeights * sizeof(aiVertexWeight));
+
+                        // delete the temporary bone weight list
+                        delete pcWeightList;
+                        pcMesh->mNumBones++;
+                    }
+                }
+            }
+
+            // copy the face list to the mesh
+            pcMesh->mFaces = new aiFace[vFaces.size()];
+            pcMesh->mNumFaces = (unsigned int)vFaces.size();
+
+            for (unsigned int p = 0; p < pcMesh->mNumFaces;++p) {
+                pcMesh->mFaces[p] = vFaces[p];
+            }
+
+            // add the newly created mesh to the list
+            avList.push_back(std::pair<aiMesh*, unsigned int>(pcMesh,a));
+
+            if (iBase == pMesh->mNumFaces) {
+                // have all faces ... finish the outer loop, too
+                break;
+            }
+        }
+
+        // delete the per-vertex weight list again
+        delete[] avPerVertexWeights;
+
+        // now delete the old mesh data
+        delete pMesh;
+        return;
+    }
+    avList.push_back(std::pair<aiMesh*, unsigned int>(pMesh,a));
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/SplitLargeMeshes.h b/src/mesh/assimp-master/code/PostProcessing/SplitLargeMeshes.h
new file mode 100644
index 0000000..e5a8d4c
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/SplitLargeMeshes.h
@@ -0,0 +1,209 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file Defines a post processing step to split large meshes into sub-meshes
+ */
+#ifndef AI_SPLITLARGEMESHES_H_INC
+#define AI_SPLITLARGEMESHES_H_INC
+
+#include <vector>
+#include "Common/BaseProcess.h"
+
+#include <assimp/mesh.h>
+#include <assimp/scene.h>
+
+// Forward declarations
+class SplitLargeMeshesTest;
+
+namespace Assimp {
+
+class SplitLargeMeshesProcess_Triangle;
+class SplitLargeMeshesProcess_Vertex;
+
+// NOTE: If you change these limits, don't forget to change the
+// corresponding values in all Assimp ports
+
+// **********************************************************
+// Java: ConfigProperty.java,
+//  ConfigProperty.DEFAULT_VERTEX_SPLIT_LIMIT
+//  ConfigProperty.DEFAULT_TRIANGLE_SPLIT_LIMIT
+// **********************************************************
+
+// default limit for vertices
+#if (!defined AI_SLM_DEFAULT_MAX_VERTICES)
+#   define AI_SLM_DEFAULT_MAX_VERTICES      1000000
+#endif
+
+// default limit for triangles
+#if (!defined AI_SLM_DEFAULT_MAX_TRIANGLES)
+#   define AI_SLM_DEFAULT_MAX_TRIANGLES     1000000
+#endif
+
+// ---------------------------------------------------------------------------
+/** Post-processing filter to split large meshes into sub-meshes
+ *
+ * Applied BEFORE the JoinVertices-Step occurs.
+ * Returns NON-UNIQUE vertices, splits by triangle number.
+*/
+class ASSIMP_API SplitLargeMeshesProcess_Triangle : public BaseProcess
+{
+    friend class SplitLargeMeshesProcess_Vertex;
+
+public:
+
+    SplitLargeMeshesProcess_Triangle();
+    ~SplitLargeMeshesProcess_Triangle();
+
+public:
+    // -------------------------------------------------------------------
+    /** Returns whether the processing step is present in the given flag.
+    * @param pFlags The processing flags the importer was called with. A
+    *   bitwise combination of #aiPostProcessSteps.
+    * @return true if the process is present in this flag fields,
+    *   false if not.
+    */
+    bool IsActive( unsigned int pFlags) const;
+
+
+    // -------------------------------------------------------------------
+    /** Called prior to ExecuteOnScene().
+    * The function is a request to the process to update its configuration
+    * basing on the Importer's configuration property list.
+    */
+    virtual void SetupProperties(const Importer* pImp);
+
+
+    //! Set the split limit - needed for unit testing
+    inline void SetLimit(unsigned int l)
+        {LIMIT = l;}
+
+    //! Get the split limit
+    inline unsigned int GetLimit() const
+        {return LIMIT;}
+
+public:
+
+    // -------------------------------------------------------------------
+    /** Executes the post processing step on the given imported data.
+    * At the moment a process is not supposed to fail.
+    * @param pScene The imported data to work at.
+    */
+    void Execute( aiScene* pScene);
+
+    // -------------------------------------------------------------------
+    //! Apply the algorithm to a given mesh
+    void SplitMesh (unsigned int a, aiMesh* pcMesh,
+        std::vector<std::pair<aiMesh*, unsigned int> >& avList);
+
+    // -------------------------------------------------------------------
+    //! Update a node in the asset after a few of its meshes
+    //! have been split
+    static void UpdateNode(aiNode* pcNode,
+        const std::vector<std::pair<aiMesh*, unsigned int> >& avList);
+
+public:
+    //! Triangle limit
+    unsigned int LIMIT;
+};
+
+
+// ---------------------------------------------------------------------------
+/** Post-processing filter to split large meshes into sub-meshes
+ *
+ * Applied AFTER the JoinVertices-Step occurs.
+ * Returns UNIQUE vertices, splits by vertex number.
+*/
+class ASSIMP_API SplitLargeMeshesProcess_Vertex : public BaseProcess
+{
+public:
+
+    SplitLargeMeshesProcess_Vertex();
+    ~SplitLargeMeshesProcess_Vertex();
+
+public:
+    // -------------------------------------------------------------------
+    /** Returns whether the processing step is present in the given flag field.
+    * @param pFlags The processing flags the importer was called with. A bitwise
+    *   combination of #aiPostProcessSteps.
+    * @return true if the process is present in this flag fields, false if not.
+    */
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    /** Called prior to ExecuteOnScene().
+    * The function is a request to the process to update its configuration
+    * basing on the Importer's configuration property list.
+    */
+    virtual void SetupProperties(const Importer* pImp);
+
+
+    //! Set the split limit - needed for unit testing
+    inline void SetLimit(unsigned int l)
+        {LIMIT = l;}
+
+    //! Get the split limit
+    inline unsigned int GetLimit() const
+        {return LIMIT;}
+
+public:
+
+    // -------------------------------------------------------------------
+    /** Executes the post processing step on the given imported data.
+    * At the moment a process is not supposed to fail.
+    * @param pScene The imported data to work at.
+    */
+    void Execute( aiScene* pScene);
+
+    // -------------------------------------------------------------------
+    //! Apply the algorithm to a given mesh
+    void SplitMesh (unsigned int a, aiMesh* pcMesh,
+        std::vector<std::pair<aiMesh*, unsigned int> >& avList);
+
+    // NOTE: Reuse SplitLargeMeshesProcess_Triangle::UpdateNode()
+
+public:
+    //! Triangle limit
+    unsigned int LIMIT;
+};
+
+} // end of namespace Assimp
+
+#endif // !!AI_SPLITLARGEMESHES_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/TextureTransform.cpp b/src/mesh/assimp-master/code/PostProcessing/TextureTransform.cpp
new file mode 100644
index 0000000..653506e
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/TextureTransform.cpp
@@ -0,0 +1,567 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file A helper class that processes texture transformations */
+
+
+
+#include <assimp/Importer.hpp>
+#include <assimp/postprocess.h>
+#include <assimp/DefaultLogger.hpp>
+#include <assimp/scene.h>
+
+#include "TextureTransform.h"
+#include <assimp/StringUtils.h>
+
+using namespace Assimp;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+TextureTransformStep::TextureTransformStep() :
+    configFlags()
+{
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+TextureTransformStep::~TextureTransformStep()
+{
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool TextureTransformStep::IsActive( unsigned int pFlags) const
+{
+    return  (pFlags & aiProcess_TransformUVCoords) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Setup properties
+void TextureTransformStep::SetupProperties(const Importer* pImp)
+{
+    configFlags = pImp->GetPropertyInteger(AI_CONFIG_PP_TUV_EVALUATE,AI_UVTRAFO_ALL);
+}
+
+// ------------------------------------------------------------------------------------------------
+void TextureTransformStep::PreProcessUVTransform(STransformVecInfo& info)
+{
+    /*  This function tries to simplify the input UV transformation.
+     *  That's very important as it allows us to reduce the number
+     *  of output UV channels. The order in which the transformations
+     *  are applied is - as always - scaling, rotation, translation.
+     */
+
+	int rounded;
+	char szTemp[512];
+
+    /* Optimize the rotation angle. That's slightly difficult as
+     * we have an inprecise floating-point number (when comparing
+     * UV transformations we'll take that into account by using
+     * an epsilon of 5 degrees). If there is a rotation value, we can't
+     * perform any further optimizations.
+     */
+    if (info.mRotation)
+    {
+        float out = info.mRotation;
+        rounded = static_cast<int>((info.mRotation / static_cast<float>(AI_MATH_TWO_PI)));
+        if (rounded)
+        {
+            out -= rounded * static_cast<float>(AI_MATH_PI);
+            ASSIMP_LOG_INFO("Texture coordinate rotation ", info.mRotation, " can be simplified to ", out);
+        }
+
+        // Next step - convert negative rotation angles to positives
+        if (out < 0.f)
+            out = (float)AI_MATH_TWO_PI * 2 + out;
+
+        info.mRotation = out;
+        return;
+    }
+
+
+    /* Optimize UV translation in the U direction. To determine whether
+     * or not we can optimize we need to look at the requested mapping
+     * type (e.g. if mirroring is active there IS a difference between
+     * offset 2 and 3)
+     */
+    rounded = (int)info.mTranslation.x;
+    if (rounded) {
+        float out = 0.0f;
+        szTemp[0] = 0;
+        if (aiTextureMapMode_Wrap == info.mapU) {
+            // Wrap - simple take the fraction of the field
+            out = info.mTranslation.x-(float)rounded;
+			ai_snprintf(szTemp, 512, "[w] UV U offset %f can be simplified to %f", info.mTranslation.x, out);
+        }
+        else if (aiTextureMapMode_Mirror == info.mapU && 1 != rounded)  {
+            // Mirror
+            if (rounded % 2)
+                rounded--;
+            out = info.mTranslation.x-(float)rounded;
+
+            ai_snprintf(szTemp,512,"[m/d] UV U offset %f can be simplified to %f",info.mTranslation.x,out);
+        }
+        else if (aiTextureMapMode_Clamp == info.mapU || aiTextureMapMode_Decal == info.mapU)    {
+            // Clamp - translations beyond 1,1 are senseless
+            ai_snprintf(szTemp,512,"[c] UV U offset %f can be clamped to 1.0f",info.mTranslation.x);
+
+            out = 1.f;
+        }
+        if (szTemp[0])      {
+            ASSIMP_LOG_INFO(szTemp);
+            info.mTranslation.x = out;
+        }
+    }
+
+    /* Optimize UV translation in the V direction. To determine whether
+     * or not we can optimize we need to look at the requested mapping
+     * type (e.g. if mirroring is active there IS a difference between
+     * offset 2 and 3)
+     */
+    rounded = (int)info.mTranslation.y;
+    if (rounded) {
+        float out = 0.0f;
+        szTemp[0] = 0;
+        if (aiTextureMapMode_Wrap == info.mapV) {
+            // Wrap - simple take the fraction of the field
+            out = info.mTranslation.y-(float)rounded;
+            ::ai_snprintf(szTemp,512,"[w] UV V offset %f can be simplified to %f",info.mTranslation.y,out);
+        }
+        else if (aiTextureMapMode_Mirror == info.mapV  && 1 != rounded) {
+            // Mirror
+            if (rounded % 2)
+                rounded--;
+            out = info.mTranslation.x-(float)rounded;
+
+            ::ai_snprintf(szTemp,512,"[m/d] UV V offset %f can be simplified to %f",info.mTranslation.y,out);
+        }
+        else if (aiTextureMapMode_Clamp == info.mapV || aiTextureMapMode_Decal == info.mapV)    {
+            // Clamp - translations beyond 1,1 are senseless
+            ::ai_snprintf(szTemp,512,"[c] UV V offset %f can be clamped to 1.0f",info.mTranslation.y);
+
+            out = 1.f;
+        }
+        if (szTemp[0])  {
+            ASSIMP_LOG_INFO(szTemp);
+            info.mTranslation.y = out;
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+void UpdateUVIndex(const std::list<TTUpdateInfo>& l, unsigned int n)
+{
+    // Don't set if == 0 && wasn't set before
+    for (std::list<TTUpdateInfo>::const_iterator it = l.begin();it != l.end(); ++it) {
+        const TTUpdateInfo& info = *it;
+
+        if (info.directShortcut)
+            *info.directShortcut = n;
+        else if (!n)
+        {
+            info.mat->AddProperty<int>((int*)&n,1,AI_MATKEY_UVWSRC(info.semantic,info.index));
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+inline const char* MappingModeToChar(aiTextureMapMode map)
+{
+    if (aiTextureMapMode_Wrap == map)
+        return "-w";
+
+    if (aiTextureMapMode_Mirror == map)
+        return "-m";
+
+    return "-c";
+}
+
+// ------------------------------------------------------------------------------------------------
+void TextureTransformStep::Execute( aiScene* pScene)
+{
+    ASSIMP_LOG_DEBUG("TransformUVCoordsProcess begin");
+
+
+    /*  We build a per-mesh list of texture transformations we'll need
+     *  to apply. To achieve this, we iterate through all materials,
+     *  find all textures and get their transformations and UV indices.
+     *  Then we search for all meshes using this material.
+     */
+    typedef std::list<STransformVecInfo> MeshTrafoList;
+    std::vector<MeshTrafoList> meshLists(pScene->mNumMeshes);
+
+    for (unsigned int i = 0; i < pScene->mNumMaterials;++i) {
+
+        aiMaterial* mat = pScene->mMaterials[i];
+        for (unsigned int a = 0; a < mat->mNumProperties;++a)   {
+
+            aiMaterialProperty* prop = mat->mProperties[a];
+            if (!::strcmp( prop->mKey.data, "$tex.file"))   {
+                STransformVecInfo info;
+
+                // Setup a shortcut structure to allow for a fast updating
+                // of the UV index later
+                TTUpdateInfo update;
+                update.mat = (aiMaterial*) mat;
+                update.semantic = prop->mSemantic;
+                update.index = prop->mIndex;
+
+                // Get textured properties and transform
+                for (unsigned int a2 = 0; a2 < mat->mNumProperties;++a2)  {
+                    aiMaterialProperty* prop2 = mat->mProperties[a2];
+                    if (prop2->mSemantic != prop->mSemantic || prop2->mIndex != prop->mIndex) {
+                        continue;
+                    }
+
+                    if ( !::strcmp( prop2->mKey.data, "$tex.uvwsrc")) {
+                        info.uvIndex = *((int*)prop2->mData);
+
+                        // Store a direct pointer for later use
+                        update.directShortcut = (unsigned int*) prop2->mData;
+                    }
+
+                    else if ( !::strcmp( prop2->mKey.data, "$tex.mapmodeu")) {
+                        info.mapU = *((aiTextureMapMode*)prop2->mData);
+                    }
+                    else if ( !::strcmp( prop2->mKey.data, "$tex.mapmodev")) {
+                        info.mapV = *((aiTextureMapMode*)prop2->mData);
+                    }
+                    else if ( !::strcmp( prop2->mKey.data, "$tex.uvtrafo"))  {
+                        // ValidateDS should check this
+                        ai_assert(prop2->mDataLength >= 20);
+                        ::memcpy(&info.mTranslation.x,prop2->mData,sizeof(float)*5);
+
+                        // Directly remove this property from the list
+                        mat->mNumProperties--;
+                        for (unsigned int a3 = a2; a3 < mat->mNumProperties;++a3) {
+                            mat->mProperties[a3] = mat->mProperties[a3+1];
+                        }
+
+                        delete prop2;
+
+                        // Warn: could be an underflow, but this does not invoke undefined behaviour
+                        --a2;
+                    }
+                }
+
+                // Find out which transformations are to be evaluated
+                if (!(configFlags & AI_UVTRAFO_ROTATION)) {
+                    info.mRotation = 0.f;
+                }
+                if (!(configFlags & AI_UVTRAFO_SCALING)) {
+                    info.mScaling = aiVector2D(1.f,1.f);
+                }
+                if (!(configFlags & AI_UVTRAFO_TRANSLATION)) {
+                    info.mTranslation = aiVector2D(0.f,0.f);
+                }
+
+                // Do some preprocessing
+                PreProcessUVTransform(info);
+                info.uvIndex = std::min(info.uvIndex,AI_MAX_NUMBER_OF_TEXTURECOORDS -1u);
+
+                // Find out whether this material is used by more than
+                // one mesh. This will make our task much, much more difficult!
+                unsigned int cnt = 0;
+                for (unsigned int n = 0; n < pScene->mNumMeshes;++n)    {
+                    if (pScene->mMeshes[n]->mMaterialIndex == i)
+                        ++cnt;
+                }
+
+                if (!cnt)
+                    continue;
+                else if (1 != cnt)  {
+                    // This material is referenced by more than one mesh!
+                    // So we need to make sure the UV index for the texture
+                    // is identical for each of it ...
+                    info.lockedPos = AI_TT_UV_IDX_LOCK_TBD;
+                }
+
+                // Get all corresponding meshes
+                for (unsigned int n = 0; n < pScene->mNumMeshes;++n)    {
+                    aiMesh* mesh = pScene->mMeshes[n];
+                    if (mesh->mMaterialIndex != i || !mesh->mTextureCoords[0])
+                        continue;
+
+                    unsigned int uv = info.uvIndex;
+                    if (!mesh->mTextureCoords[uv])  {
+                        // If the requested UV index is not available, take the first one instead.
+                        uv = 0;
+                    }
+
+                    if (mesh->mNumUVComponents[info.uvIndex] >= 3){
+                        ASSIMP_LOG_WARN("UV transformations on 3D mapping channels are not supported");
+                        continue;
+                    }
+
+                    MeshTrafoList::iterator it;
+
+                    // Check whether we have this transform setup already
+                    for (it = meshLists[n].begin();it != meshLists[n].end(); ++it)  {
+
+                        if ((*it) == info && (*it).uvIndex == uv)   {
+                            (*it).updateList.push_back(update);
+                            break;
+                        }
+                    }
+
+                    if (it == meshLists[n].end())   {
+                        meshLists[n].push_back(info);
+                        meshLists[n].back().uvIndex = uv;
+                        meshLists[n].back().updateList.push_back(update);
+                    }
+                }
+            }
+        }
+    }
+
+    char buffer[1024]; // should be sufficiently large
+    unsigned int outChannels = 0, inChannels = 0, transformedChannels = 0;
+
+    // Now process all meshes. Important: we don't remove unreferenced UV channels.
+    // This is a job for the RemoveUnreferencedData-Step.
+    for (unsigned int q = 0; q < pScene->mNumMeshes;++q)    {
+
+        aiMesh* mesh = pScene->mMeshes[q];
+        MeshTrafoList& trafo =  meshLists[q];
+
+        inChannels += mesh->GetNumUVChannels();
+
+        if (!mesh->mTextureCoords[0] || trafo.empty() ||  (trafo.size() == 1 && trafo.begin()->IsUntransformed())) {
+            outChannels += mesh->GetNumUVChannels();
+            continue;
+        }
+
+        // Move untransformed UV channels to the first position in the list ....
+        // except if we need a new locked index which should be as small as possible
+        bool veto = false, need = false;
+        unsigned int cnt = 0;
+        unsigned int untransformed = 0;
+
+        MeshTrafoList::iterator it,it2;
+        for (it = trafo.begin();it != trafo.end(); ++it,++cnt)  {
+
+            if (!(*it).IsUntransformed()) {
+                need = true;
+            }
+
+            if ((*it).lockedPos == AI_TT_UV_IDX_LOCK_TBD)   {
+                // Lock this index and make sure it won't be changed
+                (*it).lockedPos = cnt;
+                veto = true;
+                continue;
+            }
+
+            if (!veto && it != trafo.begin() && (*it).IsUntransformed())    {
+                for (it2 = trafo.begin();it2 != it; ++it2) {
+                    if (!(*it2).IsUntransformed())
+                        break;
+                }
+                trafo.insert(it2,*it);
+                trafo.erase(it);
+                break;
+            }
+        }
+        if (!need)
+            continue;
+
+        // Find all that are not at their 'locked' position and move them to it.
+        // Conflicts are possible but quite unlikely.
+        cnt = 0;
+        for (it = trafo.begin();it != trafo.end(); ++it,++cnt) {
+            if ((*it).lockedPos != AI_TT_UV_IDX_LOCK_NONE && (*it).lockedPos != cnt) {
+                it2 = trafo.begin();unsigned int t = 0;
+                while (t != (*it).lockedPos)
+                    ++it2;
+
+                if ((*it2).lockedPos != AI_TT_UV_IDX_LOCK_NONE) {
+                    ASSIMP_LOG_ERROR("Channel mismatch, can't compute all transformations properly [design bug]");
+                    continue;
+                }
+
+                std::swap(*it2,*it);
+                if ((*it).lockedPos == untransformed)
+                    untransformed = cnt;
+            }
+        }
+
+        // ... and add dummies for all unreferenced channels
+        // at the end of the list
+        bool ref[AI_MAX_NUMBER_OF_TEXTURECOORDS];
+        for (unsigned int n = 0; n < AI_MAX_NUMBER_OF_TEXTURECOORDS;++n)
+            ref[n] = !mesh->mTextureCoords[n];
+
+        for (it = trafo.begin();it != trafo.end(); ++it)
+            ref[(*it).uvIndex] = true;
+
+        for (unsigned int n = 0; n < AI_MAX_NUMBER_OF_TEXTURECOORDS;++n) {
+            if (ref[n])
+                continue;
+            trafo.push_back(STransformVecInfo());
+            trafo.back().uvIndex = n;
+        }
+
+        // Then check whether this list breaks the channel limit.
+        // The unimportant ones are at the end of the list, so
+        // it shouldn't be too worse if we remove them.
+        unsigned int size = (unsigned int)trafo.size();
+        if (size > AI_MAX_NUMBER_OF_TEXTURECOORDS) {
+
+            if (!DefaultLogger::isNullLogger()) {
+                ASSIMP_LOG_ERROR(static_cast<unsigned int>(trafo.size()), " UV channels required but just ",
+                    AI_MAX_NUMBER_OF_TEXTURECOORDS, " available");
+            }
+            size = AI_MAX_NUMBER_OF_TEXTURECOORDS;
+        }
+
+
+        aiVector3D* old[AI_MAX_NUMBER_OF_TEXTURECOORDS];
+        for (unsigned int n = 0; n < AI_MAX_NUMBER_OF_TEXTURECOORDS;++n)
+            old[n] = mesh->mTextureCoords[n];
+
+        // Now continue and generate the output channels. Channels
+        // that we're not going to need later can be overridden.
+        it = trafo.begin();
+        for (unsigned int n = 0; n < trafo.size();++n,++it) {
+
+            if (n >= size)  {
+                // Try to use an untransformed channel for all channels we threw over board
+                UpdateUVIndex((*it).updateList,untransformed);
+                continue;
+            }
+
+            outChannels++;
+
+            // Write to the log
+            if (!DefaultLogger::isNullLogger()) {
+                ::ai_snprintf(buffer,1024,"Mesh %u, channel %u: t(%.3f,%.3f), s(%.3f,%.3f), r(%.3f), %s%s",
+                    q,n,
+                    (*it).mTranslation.x,
+                    (*it).mTranslation.y,
+                    (*it).mScaling.x,
+                    (*it).mScaling.y,
+                    AI_RAD_TO_DEG( (*it).mRotation),
+                    MappingModeToChar ((*it).mapU),
+                    MappingModeToChar ((*it).mapV));
+
+                ASSIMP_LOG_INFO(buffer);
+            }
+
+            // Check whether we need a new buffer here
+            if (mesh->mTextureCoords[n])    {
+
+                it2 = it;++it2;
+                for (unsigned int m = n+1; m < size;++m, ++it2) {
+
+                    if ((*it2).uvIndex == n){
+                        it2 = trafo.begin();
+                        break;
+                    }
+                }
+                if (it2 == trafo.begin()){
+                    mesh->mTextureCoords[n] = new aiVector3D[mesh->mNumVertices];
+                }
+            }
+            else mesh->mTextureCoords[n] = new aiVector3D[mesh->mNumVertices];
+
+            aiVector3D* src = old[(*it).uvIndex];
+            aiVector3D* dest, *end;
+            dest = mesh->mTextureCoords[n];
+
+            ai_assert(nullptr != src);
+
+            // Copy the data to the destination array
+            if (dest != src)
+                ::memcpy(dest,src,sizeof(aiVector3D)*mesh->mNumVertices);
+
+            end = dest + mesh->mNumVertices;
+
+            // Build a transformation matrix and transform all UV coords with it
+            if (!(*it).IsUntransformed()) {
+                const aiVector2D& trl = (*it).mTranslation;
+                const aiVector2D& scl = (*it).mScaling;
+
+                // fixme: simplify ..
+                ++transformedChannels;
+                aiMatrix3x3 matrix;
+
+                aiMatrix3x3 m2,m3,m4,m5;
+
+                m4.a1 = scl.x;
+                m4.b2 = scl.y;
+
+                m2.a3 = m2.b3 = 0.5f;
+                m3.a3 = m3.b3 = -0.5f;
+
+                if ((*it).mRotation > AI_TT_ROTATION_EPSILON )
+                    aiMatrix3x3::RotationZ((*it).mRotation,matrix);
+
+                m5.a3 += trl.x; m5.b3 += trl.y;
+                matrix = m2 * m4 * matrix * m3 * m5;
+
+                for (src = dest; src != end; ++src) { /* manual homogeneous divide */
+                    src->z = 1.f;
+                    *src = matrix * *src;
+                    src->x /= src->z;
+                    src->y /= src->z;
+                    src->z = 0.f;
+                }
+            }
+
+            // Update all UV indices
+            UpdateUVIndex((*it).updateList,n);
+        }
+    }
+
+    // Print some detailed statistics into the log
+    if (!DefaultLogger::isNullLogger()) {
+
+        if (transformedChannels)    {
+            ASSIMP_LOG_INFO("TransformUVCoordsProcess end: ", outChannels, " output channels (in: ", inChannels, ", modified: ", transformedChannels,")");
+        } else {
+            ASSIMP_LOG_DEBUG("TransformUVCoordsProcess finished");
+        }
+    }
+}
+
+
diff --git a/src/mesh/assimp-master/code/PostProcessing/TextureTransform.h b/src/mesh/assimp-master/code/PostProcessing/TextureTransform.h
new file mode 100644
index 0000000..c1cccf8
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/TextureTransform.h
@@ -0,0 +1,232 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file Definition of a helper step that processes texture transformations */
+#ifndef AI_TEXTURE_TRANSFORM_H_INCLUDED
+#define AI_TEXTURE_TRANSFORM_H_INCLUDED
+
+#include <assimp/BaseImporter.h>
+#include "Common/BaseProcess.h"
+
+#include <assimp/material.h>
+#include <list>
+
+struct aiNode;
+struct aiMaterial;
+
+namespace Assimp    {
+
+#define AI_TT_UV_IDX_LOCK_TBD   0xffffffff
+#define AI_TT_UV_IDX_LOCK_NONE  0xeeeeeeee
+
+
+#define AI_TT_ROTATION_EPSILON  ((float)AI_DEG_TO_RAD(0.5))
+
+// ---------------------------------------------------------------------------
+/** Small helper structure representing a shortcut into the material list
+ *  to be able to update some values quickly.
+*/
+struct TTUpdateInfo {
+    TTUpdateInfo() AI_NO_EXCEPT
+    : directShortcut(nullptr)
+    , mat(nullptr)
+    , semantic(0)
+    , index(0) {
+        // empty
+    }
+
+    //! Direct shortcut, if available
+    unsigned int* directShortcut;
+
+    //! Material
+    aiMaterial *mat;
+
+    //! Texture type and index
+    unsigned int semantic, index;
+};
+
+
+// ---------------------------------------------------------------------------
+/** Helper class representing texture coordinate transformations
+*/
+struct STransformVecInfo : public aiUVTransform {
+    STransformVecInfo() AI_NO_EXCEPT
+    : uvIndex(0)
+    , mapU(aiTextureMapMode_Wrap)
+    , mapV(aiTextureMapMode_Wrap)
+    , lockedPos(AI_TT_UV_IDX_LOCK_NONE) {
+        // empty
+    }
+
+    //! Source texture coordinate index
+    unsigned int uvIndex;
+
+    //! Texture mapping mode in the u, v direction
+    aiTextureMapMode mapU,mapV;
+
+    //! Locked destination UV index
+    //! AI_TT_UV_IDX_LOCK_TBD - to be determined
+    //! AI_TT_UV_IDX_LOCK_NONE - none (default)
+    unsigned int lockedPos;
+
+    //! Update info - shortcuts into all materials
+    //! that are referencing this transform setup
+    std::list<TTUpdateInfo> updateList;
+
+
+    // -------------------------------------------------------------------
+    /** Compare two transform setups
+    */
+    inline bool operator== (const STransformVecInfo& other) const
+    {
+        // We use a small epsilon here
+        const static float epsilon = 0.05f;
+
+        if (std::fabs( mTranslation.x - other.mTranslation.x ) > epsilon ||
+            std::fabs( mTranslation.y - other.mTranslation.y ) > epsilon)
+        {
+            return false;
+        }
+
+        if (std::fabs( mScaling.x - other.mScaling.x ) > epsilon ||
+            std::fabs( mScaling.y - other.mScaling.y ) > epsilon)
+        {
+            return false;
+        }
+
+        if (std::fabs( mRotation - other.mRotation) > epsilon)
+        {
+            return false;
+        }
+        return true;
+    }
+
+    inline bool operator!= (const STransformVecInfo& other) const
+    {
+            return !(*this == other);
+    }
+
+
+    // -------------------------------------------------------------------
+    /** Returns whether this is an untransformed texture coordinate set
+    */
+    inline bool IsUntransformed() const
+    {
+        return (1.0f == mScaling.x && 1.f == mScaling.y &&
+            !mTranslation.x && !mTranslation.y &&
+            mRotation < AI_TT_ROTATION_EPSILON);
+    }
+
+    // -------------------------------------------------------------------
+    /** Build a 3x3 matrix from the transformations
+    */
+    inline void GetMatrix(aiMatrix3x3& mOut)
+    {
+        mOut = aiMatrix3x3();
+
+        if (1.0f != mScaling.x || 1.0f != mScaling.y)
+        {
+            aiMatrix3x3 mScale;
+            mScale.a1 = mScaling.x;
+            mScale.b2 = mScaling.y;
+            mOut = mScale;
+        }
+        if (mRotation)
+        {
+            aiMatrix3x3 mRot;
+            mRot.a1 = mRot.b2 = std::cos(mRotation);
+            mRot.a2 = mRot.b1 = std::sin(mRotation);
+            mRot.a2 = -mRot.a2;
+            mOut *= mRot;
+        }
+        if (mTranslation.x || mTranslation.y)
+        {
+            aiMatrix3x3 mTrans;
+            mTrans.a3 = mTranslation.x;
+            mTrans.b3 = mTranslation.y;
+            mOut *= mTrans;
+        }
+    }
+};
+
+
+// ---------------------------------------------------------------------------
+/** Helper step to compute final UV coordinate sets if there are scalings
+ *  or rotations in the original data read from the file.
+*/
+class TextureTransformStep : public BaseProcess
+{
+public:
+
+    TextureTransformStep();
+    ~TextureTransformStep();
+
+public:
+
+    // -------------------------------------------------------------------
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    void Execute( aiScene* pScene);
+
+    // -------------------------------------------------------------------
+    void SetupProperties(const Importer* pImp);
+
+
+protected:
+
+
+    // -------------------------------------------------------------------
+    /** Preprocess a specific UV transformation setup
+     *
+     *  @param info Transformation setup to be preprocessed.
+    */
+    void PreProcessUVTransform(STransformVecInfo& info);
+
+private:
+
+    unsigned int configFlags;
+};
+
+}
+
+#endif //! AI_TEXTURE_TRANSFORM_H_INCLUDED
diff --git a/src/mesh/assimp-master/code/PostProcessing/TriangulateProcess.cpp b/src/mesh/assimp-master/code/PostProcessing/TriangulateProcess.cpp
new file mode 100644
index 0000000..a18bf1c
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/TriangulateProcess.cpp
@@ -0,0 +1,628 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file  TriangulateProcess.cpp
+ *  @brief Implementation of the post processing step to split up
+ *    all faces with more than three indices into triangles.
+ *
+ *
+ *  The triangulation algorithm will handle concave or convex polygons.
+ *  Self-intersecting or non-planar polygons are not rejected, but
+ *  they're probably not triangulated correctly.
+ *
+ * DEBUG SWITCHES - do not enable any of them in release builds:
+ *
+ * AI_BUILD_TRIANGULATE_COLOR_FACE_WINDING
+ *   - generates vertex colors to represent the face winding order.
+ *     the first vertex of a polygon becomes red, the last blue.
+ * AI_BUILD_TRIANGULATE_DEBUG_POLYS
+ *   - dump all polygons and their triangulation sequences to
+ *     a file
+ */
+#ifndef ASSIMP_BUILD_NO_TRIANGULATE_PROCESS
+
+#include "PostProcessing/TriangulateProcess.h"
+#include "PostProcessing/ProcessHelper.h"
+#include "Common/PolyTools.h"
+
+#include <memory>
+#include <cstdint>
+
+//#define AI_BUILD_TRIANGULATE_COLOR_FACE_WINDING
+//#define AI_BUILD_TRIANGULATE_DEBUG_POLYS
+
+#define POLY_GRID_Y 40
+#define POLY_GRID_X 70
+#define POLY_GRID_XPAD 20
+#define POLY_OUTPUT_FILE "assimp_polygons_debug.txt"
+
+using namespace Assimp;
+
+namespace {
+
+    /**
+     * @brief Helper struct used to simplify NGON encoding functions.
+     */
+    struct NGONEncoder {
+        NGONEncoder() : mLastNGONFirstIndex((unsigned int)-1) {}
+
+        /**
+         * @brief Encode the current triangle, and make sure it is recognized as a triangle.
+         *
+         * This method will rotate indices in tri if needed in order to avoid tri to be considered
+         * part of the previous ngon. This method is to be used whenever you want to emit a real triangle,
+         * and make sure it is seen as a triangle.
+         *
+         * @param tri Triangle to encode.
+         */
+        void ngonEncodeTriangle(aiFace * tri) {
+            ai_assert(tri->mNumIndices == 3);
+
+            // Rotate indices in new triangle to avoid ngon encoding false ngons
+            // Otherwise, the new triangle would be considered part of the previous NGON.
+            if (isConsideredSameAsLastNgon(tri)) {
+                std::swap(tri->mIndices[0], tri->mIndices[2]);
+                std::swap(tri->mIndices[1], tri->mIndices[2]);
+            }
+
+            mLastNGONFirstIndex = tri->mIndices[0];
+        }
+
+        /**
+         * @brief Encode a quad (2 triangles) in ngon encoding, and make sure they are seen as a single ngon.
+         *
+         * @param tri1 First quad triangle
+         * @param tri2 Second quad triangle
+         *
+         * @pre Triangles must be properly fanned from the most appropriate vertex.
+         */
+        void ngonEncodeQuad(aiFace *tri1, aiFace *tri2) {
+            ai_assert(tri1->mNumIndices == 3);
+            ai_assert(tri2->mNumIndices == 3);
+            ai_assert(tri1->mIndices[0] == tri2->mIndices[0]);
+
+            // If the selected fanning vertex is the same as the previously
+            // emitted ngon, we use the opposite vertex which also happens to work
+            // for tri-fanning a concave quad.
+            // ref: https://github.com/assimp/assimp/pull/3695#issuecomment-805999760
+            if (isConsideredSameAsLastNgon(tri1)) {
+                // Right-rotate indices for tri1 (index 2 becomes the new fanning vertex)
+                std::swap(tri1->mIndices[0], tri1->mIndices[2]);
+                std::swap(tri1->mIndices[1], tri1->mIndices[2]);
+
+                // Left-rotate indices for tri2 (index 2 becomes the new fanning vertex)
+                std::swap(tri2->mIndices[1], tri2->mIndices[2]);
+                std::swap(tri2->mIndices[0], tri2->mIndices[2]);
+
+                ai_assert(tri1->mIndices[0] == tri2->mIndices[0]);
+            }
+
+            mLastNGONFirstIndex = tri1->mIndices[0];
+        }
+
+        /**
+         * @brief Check whether this triangle would be considered part of the lastly emitted ngon or not.
+         *
+         * @param tri Current triangle.
+         * @return true If used as is, this triangle will be part of last ngon.
+         * @return false If used as is, this triangle is not considered part of the last ngon.
+         */
+        bool isConsideredSameAsLastNgon(const aiFace * tri) const {
+            ai_assert(tri->mNumIndices == 3);
+            return tri->mIndices[0] == mLastNGONFirstIndex;
+        }
+
+    private:
+        unsigned int mLastNGONFirstIndex;
+    };
+
+}
+
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+TriangulateProcess::TriangulateProcess()
+{
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+TriangulateProcess::~TriangulateProcess()
+{
+    // nothing to do here
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool TriangulateProcess::IsActive( unsigned int pFlags) const
+{
+    return (pFlags & aiProcess_Triangulate) != 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void TriangulateProcess::Execute( aiScene* pScene)
+{
+    ASSIMP_LOG_DEBUG("TriangulateProcess begin");
+
+    bool bHas = false;
+    for( unsigned int a = 0; a < pScene->mNumMeshes; a++)
+    {
+        if (pScene->mMeshes[ a ]) {
+            if ( TriangulateMesh( pScene->mMeshes[ a ] ) ) {
+                bHas = true;
+            }
+        }
+    }
+    if ( bHas ) {
+        ASSIMP_LOG_INFO( "TriangulateProcess finished. All polygons have been triangulated." );
+    } else {
+        ASSIMP_LOG_DEBUG( "TriangulateProcess finished. There was nothing to be done." );
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Triangulates the given mesh.
+bool TriangulateProcess::TriangulateMesh( aiMesh* pMesh)
+{
+    // Now we have aiMesh::mPrimitiveTypes, so this is only here for test cases
+    if (!pMesh->mPrimitiveTypes)    {
+        bool bNeed = false;
+
+        for( unsigned int a = 0; a < pMesh->mNumFaces; a++) {
+            const aiFace& face = pMesh->mFaces[a];
+
+            if( face.mNumIndices != 3)  {
+                bNeed = true;
+            }
+        }
+        if (!bNeed)
+            return false;
+    }
+    else if (!(pMesh->mPrimitiveTypes & aiPrimitiveType_POLYGON)) {
+        return false;
+    }
+
+    // Find out how many output faces we'll get
+    uint32_t numOut = 0, max_out = 0;
+    bool get_normals = true;
+    for( unsigned int a = 0; a < pMesh->mNumFaces; a++) {
+        aiFace& face = pMesh->mFaces[a];
+        if (face.mNumIndices <= 4) {
+            get_normals = false;
+        }
+        if( face.mNumIndices <= 3) {
+            numOut++;
+
+        }
+        else {
+            numOut += face.mNumIndices-2;
+            max_out = std::max(max_out,face.mNumIndices);
+        }
+    }
+
+    // Just another check whether aiMesh::mPrimitiveTypes is correct
+    ai_assert(numOut != pMesh->mNumFaces);
+
+    aiVector3D *nor_out = nullptr;
+
+    // if we don't have normals yet, but expect them to be a cheap side
+    // product of triangulation anyway, allocate storage for them.
+    if (!pMesh->mNormals && get_normals) {
+        // XXX need a mechanism to inform the GenVertexNormals process to treat these normals as preprocessed per-face normals
+    //  nor_out = pMesh->mNormals = new aiVector3D[pMesh->mNumVertices];
+    }
+
+    // the output mesh will contain triangles, but no polys anymore
+    pMesh->mPrimitiveTypes |= aiPrimitiveType_TRIANGLE;
+    pMesh->mPrimitiveTypes &= ~aiPrimitiveType_POLYGON;
+
+    // The mesh becomes NGON encoded now, during the triangulation process.
+    pMesh->mPrimitiveTypes |= aiPrimitiveType_NGONEncodingFlag;
+
+    aiFace* out = new aiFace[numOut](), *curOut = out;
+    std::vector<aiVector3D> temp_verts3d(max_out+2); /* temporary storage for vertices */
+    std::vector<aiVector2D> temp_verts(max_out+2);
+
+    NGONEncoder ngonEncoder;
+
+    // Apply vertex colors to represent the face winding?
+#ifdef AI_BUILD_TRIANGULATE_COLOR_FACE_WINDING
+    if (!pMesh->mColors[0])
+        pMesh->mColors[0] = new aiColor4D[pMesh->mNumVertices];
+    else
+        new(pMesh->mColors[0]) aiColor4D[pMesh->mNumVertices];
+
+    aiColor4D* clr = pMesh->mColors[0];
+#endif
+
+#ifdef AI_BUILD_TRIANGULATE_DEBUG_POLYS
+    FILE* fout = fopen(POLY_OUTPUT_FILE,"a");
+#endif
+
+    const aiVector3D* verts = pMesh->mVertices;
+
+    // use std::unique_ptr to avoid slow std::vector<bool> specialiations
+    std::unique_ptr<bool[]> done(new bool[max_out]);
+    for( unsigned int a = 0; a < pMesh->mNumFaces; a++) {
+        aiFace& face = pMesh->mFaces[a];
+
+        unsigned int* idx = face.mIndices;
+        int num = (int)face.mNumIndices, ear = 0, tmp, prev = num-1, next = 0, max = num;
+
+        // Apply vertex colors to represent the face winding?
+#ifdef AI_BUILD_TRIANGULATE_COLOR_FACE_WINDING
+        for (unsigned int i = 0; i < face.mNumIndices; ++i) {
+            aiColor4D& c = clr[idx[i]];
+            c.r = (i+1) / (float)max;
+            c.b = 1.f - c.r;
+        }
+#endif
+
+        aiFace* const last_face = curOut;
+
+        // if it's a simple point,line or triangle: just copy it
+        if( face.mNumIndices <= 3)
+        {
+            aiFace& nface = *curOut++;
+            nface.mNumIndices = face.mNumIndices;
+            nface.mIndices    = face.mIndices;
+            face.mIndices = nullptr;
+
+            // points and lines don't require ngon encoding (and are not supported either!)
+            if (nface.mNumIndices == 3) ngonEncoder.ngonEncodeTriangle(&nface);
+
+            continue;
+        }
+        // optimized code for quadrilaterals
+        else if ( face.mNumIndices == 4) {
+
+            // quads can have at maximum one concave vertex. Determine
+            // this vertex (if it exists) and start tri-fanning from
+            // it.
+            unsigned int start_vertex = 0;
+            for (unsigned int i = 0; i < 4; ++i) {
+                const aiVector3D& v0 = verts[face.mIndices[(i+3) % 4]];
+                const aiVector3D& v1 = verts[face.mIndices[(i+2) % 4]];
+                const aiVector3D& v2 = verts[face.mIndices[(i+1) % 4]];
+
+                const aiVector3D& v = verts[face.mIndices[i]];
+
+                aiVector3D left = (v0-v);
+                aiVector3D diag = (v1-v);
+                aiVector3D right = (v2-v);
+
+                left.Normalize();
+                diag.Normalize();
+                right.Normalize();
+
+                const float angle = std::acos(left*diag) + std::acos(right*diag);
+                if (angle > AI_MATH_PI_F) {
+                    // this is the concave point
+                    start_vertex = i;
+                    break;
+                }
+            }
+
+            const unsigned int temp[] = {face.mIndices[0], face.mIndices[1], face.mIndices[2], face.mIndices[3]};
+
+            aiFace& nface = *curOut++;
+            nface.mNumIndices = 3;
+            nface.mIndices = face.mIndices;
+
+            nface.mIndices[0] = temp[start_vertex];
+            nface.mIndices[1] = temp[(start_vertex + 1) % 4];
+            nface.mIndices[2] = temp[(start_vertex + 2) % 4];
+
+            aiFace& sface = *curOut++;
+            sface.mNumIndices = 3;
+            sface.mIndices = new unsigned int[3];
+
+            sface.mIndices[0] = temp[start_vertex];
+            sface.mIndices[1] = temp[(start_vertex + 2) % 4];
+            sface.mIndices[2] = temp[(start_vertex + 3) % 4];
+
+            // prevent double deletion of the indices field
+            face.mIndices = nullptr;
+
+            ngonEncoder.ngonEncodeQuad(&nface, &sface);
+
+            continue;
+        }
+        else
+        {
+            // A polygon with more than 3 vertices can be either concave or convex.
+            // Usually everything we're getting is convex and we could easily
+            // triangulate by tri-fanning. However, LightWave is probably the only
+            // modeling suite to make extensive use of highly concave, monster polygons ...
+            // so we need to apply the full 'ear cutting' algorithm to get it right.
+
+            // REQUIREMENT: polygon is expected to be simple and *nearly* planar.
+            // We project it onto a plane to get a 2d triangle.
+
+            // Collect all vertices of of the polygon.
+            for (tmp = 0; tmp < max; ++tmp) {
+                temp_verts3d[tmp] = verts[idx[tmp]];
+            }
+
+            // Get newell normal of the polygon. Store it for future use if it's a polygon-only mesh
+            aiVector3D n;
+            NewellNormal<3,3,3>(n,max,&temp_verts3d.front().x,&temp_verts3d.front().y,&temp_verts3d.front().z);
+            if (nor_out) {
+                 for (tmp = 0; tmp < max; ++tmp)
+                     nor_out[idx[tmp]] = n;
+            }
+
+            // Select largest normal coordinate to ignore for projection
+            const float ax = (n.x>0 ? n.x : -n.x);
+            const float ay = (n.y>0 ? n.y : -n.y);
+            const float az = (n.z>0 ? n.z : -n.z);
+
+            unsigned int ac = 0, bc = 1; /* no z coord. projection to xy */
+            float inv = n.z;
+            if (ax > ay) {
+                if (ax > az) { /* no x coord. projection to yz */
+                    ac = 1; bc = 2;
+                    inv = n.x;
+                }
+            }
+            else if (ay > az) { /* no y coord. projection to zy */
+                ac = 2; bc = 0;
+                inv = n.y;
+            }
+
+            // Swap projection axes to take the negated projection vector into account
+            if (inv < 0.f) {
+                std::swap(ac,bc);
+            }
+
+            for (tmp =0; tmp < max; ++tmp) {
+                temp_verts[tmp].x = verts[idx[tmp]][ac];
+                temp_verts[tmp].y = verts[idx[tmp]][bc];
+                done[tmp] = false;
+            }
+
+#ifdef AI_BUILD_TRIANGULATE_DEBUG_POLYS
+            // plot the plane onto which we mapped the polygon to a 2D ASCII pic
+            aiVector2D bmin,bmax;
+            ArrayBounds(&temp_verts[0],max,bmin,bmax);
+
+            char grid[POLY_GRID_Y][POLY_GRID_X+POLY_GRID_XPAD];
+            std::fill_n((char*)grid,POLY_GRID_Y*(POLY_GRID_X+POLY_GRID_XPAD),' ');
+
+            for (int i =0; i < max; ++i) {
+                const aiVector2D& v = (temp_verts[i] - bmin) / (bmax-bmin);
+                const size_t x = static_cast<size_t>(v.x*(POLY_GRID_X-1)), y = static_cast<size_t>(v.y*(POLY_GRID_Y-1));
+                char* loc = grid[y]+x;
+                if (grid[y][x] != ' ') {
+                    for(;*loc != ' '; ++loc);
+                    *loc++ = '_';
+                }
+                *(loc+::ai_snprintf(loc, POLY_GRID_XPAD,"%i",i)) = ' ';
+            }
+
+
+            for(size_t y = 0; y < POLY_GRID_Y; ++y) {
+                grid[y][POLY_GRID_X+POLY_GRID_XPAD-1] = '\0';
+                fprintf(fout,"%s\n",grid[y]);
+            }
+
+            fprintf(fout,"\ntriangulation sequence: ");
+#endif
+
+            //
+            // FIXME: currently this is the slow O(kn) variant with a worst case
+            // complexity of O(n^2) (I think). Can be done in O(n).
+            while (num > 3) {
+
+                // Find the next ear of the polygon
+                int num_found = 0;
+                for (ear = next;;prev = ear,ear = next) {
+
+                    // break after we looped two times without a positive match
+                    for (next=ear+1;done[(next>=max?next=0:next)];++next);
+                    if (next < ear) {
+                        if (++num_found == 2) {
+                            break;
+                        }
+                    }
+                    const aiVector2D* pnt1 = &temp_verts[ear],
+                        *pnt0 = &temp_verts[prev],
+                        *pnt2 = &temp_verts[next];
+
+                    // Must be a convex point. Assuming ccw winding, it must be on the right of the line between p-1 and p+1.
+                    if (OnLeftSideOfLine2D(*pnt0,*pnt2,*pnt1)) {
+                        continue;
+                    }
+
+                    // and no other point may be contained in this triangle
+                    for ( tmp = 0; tmp < max; ++tmp) {
+
+                        // We need to compare the actual values because it's possible that multiple indexes in
+                        // the polygon are referring to the same position. concave_polygon.obj is a sample
+                        //
+                        // FIXME: Use 'epsiloned' comparisons instead? Due to numeric inaccuracies in
+                        // PointInTriangle() I'm guessing that it's actually possible to construct
+                        // input data that would cause us to end up with no ears. The problem is,
+                        // which epsilon? If we chose a too large value, we'd get wrong results
+                        const aiVector2D& vtmp = temp_verts[tmp];
+                        if ( vtmp != *pnt1 && vtmp != *pnt2 && vtmp != *pnt0 && PointInTriangle2D(*pnt0,*pnt1,*pnt2,vtmp)) {
+                            break;
+                        }
+                    }
+                    if (tmp != max) {
+                        continue;
+                    }
+
+                    // this vertex is an ear
+                    break;
+                }
+                if (num_found == 2) {
+
+                    // Due to the 'two ear theorem', every simple polygon with more than three points must
+                    // have 2 'ears'. Here's definitely something wrong ... but we don't give up yet.
+                    //
+
+                    // Instead we're continuing with the standard tri-fanning algorithm which we'd
+                    // use if we had only convex polygons. That's life.
+                    ASSIMP_LOG_ERROR("Failed to triangulate polygon (no ear found). Probably not a simple polygon?");
+
+#ifdef AI_BUILD_TRIANGULATE_DEBUG_POLYS
+                    fprintf(fout,"critical error here, no ear found! ");
+#endif
+                    num = 0;
+                    break;
+
+                    /*curOut -= (max-num); // undo all previous work
+                    for (tmp = 0; tmp < max-2; ++tmp) {
+                        aiFace& nface = *curOut++;
+
+                        nface.mNumIndices = 3;
+                        if (!nface.mIndices)
+                            nface.mIndices = new unsigned int[3];
+
+                        nface.mIndices[0] = 0;
+                        nface.mIndices[1] = tmp+1;
+                        nface.mIndices[2] = tmp+2;
+
+                    }
+                    num = 0;
+                    break;*/
+                }
+
+                aiFace& nface = *curOut++;
+                nface.mNumIndices = 3;
+
+                if (!nface.mIndices) {
+                    nface.mIndices = new unsigned int[3];
+                }
+
+                // setup indices for the new triangle ...
+                nface.mIndices[0] = prev;
+                nface.mIndices[1] = ear;
+                nface.mIndices[2] = next;
+
+                // exclude the ear from most further processing
+                done[ear] = true;
+                --num;
+            }
+            if (num > 0) {
+                // We have three indices forming the last 'ear' remaining. Collect them.
+                aiFace& nface = *curOut++;
+                nface.mNumIndices = 3;
+                if (!nface.mIndices) {
+                    nface.mIndices = new unsigned int[3];
+                }
+
+                for (tmp = 0; done[tmp]; ++tmp);
+                nface.mIndices[0] = tmp;
+
+                for (++tmp; done[tmp]; ++tmp);
+                nface.mIndices[1] = tmp;
+
+                for (++tmp; done[tmp]; ++tmp);
+                nface.mIndices[2] = tmp;
+
+            }
+        }
+
+#ifdef AI_BUILD_TRIANGULATE_DEBUG_POLYS
+
+        for(aiFace* f = last_face; f != curOut; ++f) {
+            unsigned int* i = f->mIndices;
+            fprintf(fout," (%i %i %i)",i[0],i[1],i[2]);
+        }
+
+        fprintf(fout,"\n*********************************************************************\n");
+        fflush(fout);
+
+#endif
+
+        for(aiFace* f = last_face; f != curOut; ) {
+            unsigned int* i = f->mIndices;
+
+            //  drop dumb 0-area triangles - deactivated for now:
+            //FindDegenerates post processing step can do the same thing
+            //if (std::fabs(GetArea2D(temp_verts[i[0]],temp_verts[i[1]],temp_verts[i[2]])) < 1e-5f) {
+            //    ASSIMP_LOG_VERBOSE_DEBUG("Dropping triangle with area 0");
+            //    --curOut;
+
+            //    delete[] f->mIndices;
+            //    f->mIndices = nullptr;
+
+            //    for(aiFace* ff = f; ff != curOut; ++ff) {
+            //        ff->mNumIndices = (ff+1)->mNumIndices;
+            //        ff->mIndices = (ff+1)->mIndices;
+            //        (ff+1)->mIndices = nullptr;
+            //    }
+            //    continue;
+            //}
+
+            i[0] = idx[i[0]];
+            i[1] = idx[i[1]];
+            i[2] = idx[i[2]];
+
+            // IMPROVEMENT: Polygons are not supported yet by this ngon encoding + triangulation step.
+            //              So we encode polygons as regular triangles. No way to reconstruct the original
+            //              polygon in this case.
+            ngonEncoder.ngonEncodeTriangle(f);
+            ++f;
+        }
+
+        delete[] face.mIndices;
+        face.mIndices = nullptr;
+    }
+
+#ifdef AI_BUILD_TRIANGULATE_DEBUG_POLYS
+    fclose(fout);
+#endif
+
+    // kill the old faces
+    delete [] pMesh->mFaces;
+
+    // ... and store the new ones
+    pMesh->mFaces    = out;
+    pMesh->mNumFaces = (unsigned int)(curOut-out); /* not necessarily equal to numOut */
+    return true;
+}
+
+#endif // !! ASSIMP_BUILD_NO_TRIANGULATE_PROCESS
diff --git a/src/mesh/assimp-master/code/PostProcessing/TriangulateProcess.h b/src/mesh/assimp-master/code/PostProcessing/TriangulateProcess.h
new file mode 100644
index 0000000..ed5f4a5
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/TriangulateProcess.h
@@ -0,0 +1,91 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file Defines a post processing step to triangulate all faces
+          with more than three vertices.
+ */
+#ifndef AI_TRIANGULATEPROCESS_H_INC
+#define AI_TRIANGULATEPROCESS_H_INC
+
+#include "Common/BaseProcess.h"
+
+struct aiMesh;
+
+class TriangulateProcessTest;
+
+namespace Assimp {
+
+// ---------------------------------------------------------------------------
+/** The TriangulateProcess splits up all faces with more than three indices
+ * into triangles. You usually want this to happen because the graphics cards
+ * need their data as triangles.
+ */
+class ASSIMP_API TriangulateProcess : public BaseProcess {
+public:
+    TriangulateProcess();
+    ~TriangulateProcess();
+
+    // -------------------------------------------------------------------
+    /** Returns whether the processing step is present in the given flag field.
+     * @param pFlags The processing flags the importer was called with. A bitwise
+     *   combination of #aiPostProcessSteps.
+     * @return true if the process is present in this flag fields, false if not.
+    */
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    /** Executes the post processing step on the given imported data.
+    * At the moment a process is not supposed to fail.
+    * @param pScene The imported data to work at.
+    */
+    void Execute( aiScene* pScene);
+
+    // -------------------------------------------------------------------
+    /** Triangulates the given mesh.
+     * @param pMesh The mesh to triangulate.
+     */
+    bool TriangulateMesh( aiMesh* pMesh);
+};
+
+} // end of namespace Assimp
+
+#endif // AI_TRIANGULATEPROCESS_H_INC
diff --git a/src/mesh/assimp-master/code/PostProcessing/ValidateDataStructure.cpp b/src/mesh/assimp-master/code/PostProcessing/ValidateDataStructure.cpp
new file mode 100644
index 0000000..e99f6a6
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/ValidateDataStructure.cpp
@@ -0,0 +1,942 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file  ValidateDataStructure.cpp
+ *  @brief Implementation of the post processing step to validate
+ *    the data structure returned by Assimp.
+ */
+
+// internal headers
+#include "ValidateDataStructure.h"
+#include "ProcessHelper.h"
+#include <assimp/BaseImporter.h>
+#include <assimp/fast_atof.h>
+#include <memory>
+
+// CRT headers
+#include <stdarg.h>
+
+using namespace Assimp;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+ValidateDSProcess::ValidateDSProcess() :
+        mScene() {}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+ValidateDSProcess::~ValidateDSProcess() {}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the processing step is present in the given flag field.
+bool ValidateDSProcess::IsActive(unsigned int pFlags) const {
+    return (pFlags & aiProcess_ValidateDataStructure) != 0;
+}
+// ------------------------------------------------------------------------------------------------
+AI_WONT_RETURN void ValidateDSProcess::ReportError(const char *msg, ...) {
+    ai_assert(nullptr != msg);
+
+    va_list args;
+    va_start(args, msg);
+
+    char szBuffer[3000];
+    const int iLen = vsprintf(szBuffer, msg, args);
+    ai_assert(iLen > 0);
+
+    va_end(args);
+
+    throw DeadlyImportError("Validation failed: ", std::string(szBuffer, iLen));
+}
+// ------------------------------------------------------------------------------------------------
+void ValidateDSProcess::ReportWarning(const char *msg, ...) {
+    ai_assert(nullptr != msg);
+
+    va_list args;
+    va_start(args, msg);
+
+    char szBuffer[3000];
+    const int iLen = vsprintf(szBuffer, msg, args);
+    ai_assert(iLen > 0);
+
+    va_end(args);
+    ASSIMP_LOG_WARN("Validation warning: ", std::string(szBuffer, iLen));
+}
+
+// ------------------------------------------------------------------------------------------------
+inline int HasNameMatch(const aiString &in, aiNode *node) {
+    int result = (node->mName == in ? 1 : 0);
+    for (unsigned int i = 0; i < node->mNumChildren; ++i) {
+        result += HasNameMatch(in, node->mChildren[i]);
+    }
+    return result;
+}
+
+// ------------------------------------------------------------------------------------------------
+template <typename T>
+inline void ValidateDSProcess::DoValidation(T **parray, unsigned int size, const char *firstName, const char *secondName) {
+    // validate all entries
+    if (size) {
+        if (!parray) {
+            ReportError("aiScene::%s is nullptr (aiScene::%s is %i)",
+                    firstName, secondName, size);
+        }
+        for (unsigned int i = 0; i < size; ++i) {
+            if (!parray[i]) {
+                ReportError("aiScene::%s[%i] is nullptr (aiScene::%s is %i)",
+                        firstName, i, secondName, size);
+            }
+            Validate(parray[i]);
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+template <typename T>
+inline void ValidateDSProcess::DoValidationEx(T **parray, unsigned int size,
+        const char *firstName, const char *secondName) {
+    // validate all entries
+    if (size) {
+        if (!parray) {
+            ReportError("aiScene::%s is nullptr (aiScene::%s is %i)",
+                    firstName, secondName, size);
+        }
+        for (unsigned int i = 0; i < size; ++i) {
+            if (!parray[i]) {
+                ReportError("aiScene::%s[%u] is nullptr (aiScene::%s is %u)",
+                        firstName, i, secondName, size);
+            }
+            Validate(parray[i]);
+
+            // check whether there are duplicate names
+            for (unsigned int a = i + 1; a < size; ++a) {
+                if (parray[i]->mName == parray[a]->mName) {
+                    ReportError("aiScene::%s[%u] has the same name as "
+                                "aiScene::%s[%u]",
+                            firstName, i, secondName, a);
+                }
+            }
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+template <typename T>
+inline void ValidateDSProcess::DoValidationWithNameCheck(T **array, unsigned int size, const char *firstName,
+        const char *secondName) {
+    // validate all entries
+    DoValidationEx(array, size, firstName, secondName);
+
+    for (unsigned int i = 0; i < size; ++i) {
+        int res = HasNameMatch(array[i]->mName, mScene->mRootNode);
+        if (0 == res) {
+            const std::string name = static_cast<char *>(array[i]->mName.data);
+            ReportError("aiScene::%s[%i] has no corresponding node in the scene graph (%s)",
+                    firstName, i, name.c_str());
+        } else if (1 != res) {
+            const std::string name = static_cast<char *>(array[i]->mName.data);
+            ReportError("aiScene::%s[%i]: there are more than one nodes with %s as name",
+                    firstName, i, name.c_str());
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Executes the post processing step on the given imported data.
+void ValidateDSProcess::Execute(aiScene *pScene) {
+    mScene = pScene;
+    ASSIMP_LOG_DEBUG("ValidateDataStructureProcess begin");
+
+    // validate the node graph of the scene
+    Validate(pScene->mRootNode);
+
+    // validate all meshes
+    if (pScene->mNumMeshes) {
+        DoValidation(pScene->mMeshes, pScene->mNumMeshes, "mMeshes", "mNumMeshes");
+    } else if (!(mScene->mFlags & AI_SCENE_FLAGS_INCOMPLETE)) {
+        ReportError("aiScene::mNumMeshes is 0. At least one mesh must be there");
+    } else if (pScene->mMeshes) {
+        ReportError("aiScene::mMeshes is non-null although there are no meshes");
+    }
+
+    // validate all animations
+    if (pScene->mNumAnimations) {
+        DoValidation(pScene->mAnimations, pScene->mNumAnimations,
+                "mAnimations", "mNumAnimations");
+    } else if (pScene->mAnimations) {
+        ReportError("aiScene::mAnimations is non-null although there are no animations");
+    }
+
+    // validate all cameras
+    if (pScene->mNumCameras) {
+        DoValidationWithNameCheck(pScene->mCameras, pScene->mNumCameras,
+                "mCameras", "mNumCameras");
+    } else if (pScene->mCameras) {
+        ReportError("aiScene::mCameras is non-null although there are no cameras");
+    }
+
+    // validate all lights
+    if (pScene->mNumLights) {
+        DoValidationWithNameCheck(pScene->mLights, pScene->mNumLights,
+                "mLights", "mNumLights");
+    } else if (pScene->mLights) {
+        ReportError("aiScene::mLights is non-null although there are no lights");
+    }
+
+    // validate all textures
+    if (pScene->mNumTextures) {
+        DoValidation(pScene->mTextures, pScene->mNumTextures,
+                "mTextures", "mNumTextures");
+    } else if (pScene->mTextures) {
+        ReportError("aiScene::mTextures is non-null although there are no textures");
+    }
+
+    // validate all materials
+    if (pScene->mNumMaterials) {
+        DoValidation(pScene->mMaterials, pScene->mNumMaterials, "mMaterials", "mNumMaterials");
+    }
+#if 0
+    // NOTE: ScenePreprocessor generates a default material if none is there
+    else if (!(mScene->mFlags & AI_SCENE_FLAGS_INCOMPLETE)) {
+        ReportError("aiScene::mNumMaterials is 0. At least one material must be there");
+    }
+#endif
+    else if (pScene->mMaterials) {
+        ReportError("aiScene::mMaterials is non-null although there are no materials");
+    }
+
+    //  if (!has)ReportError("The aiScene data structure is empty");
+    ASSIMP_LOG_DEBUG("ValidateDataStructureProcess end");
+}
+
+// ------------------------------------------------------------------------------------------------
+void ValidateDSProcess::Validate(const aiLight *pLight) {
+    if (pLight->mType == aiLightSource_UNDEFINED)
+        ReportWarning("aiLight::mType is aiLightSource_UNDEFINED");
+
+    if (!pLight->mAttenuationConstant &&
+            !pLight->mAttenuationLinear &&
+            !pLight->mAttenuationQuadratic) {
+        ReportWarning("aiLight::mAttenuationXXX - all are zero");
+    }
+
+    if (pLight->mAngleInnerCone > pLight->mAngleOuterCone)
+        ReportError("aiLight::mAngleInnerCone is larger than aiLight::mAngleOuterCone");
+
+    if (pLight->mColorDiffuse.IsBlack() && pLight->mColorAmbient.IsBlack() && pLight->mColorSpecular.IsBlack()) {
+        ReportWarning("aiLight::mColorXXX - all are black and won't have any influence");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+void ValidateDSProcess::Validate(const aiCamera *pCamera) {
+    if (pCamera->mClipPlaneFar <= pCamera->mClipPlaneNear)
+        ReportError("aiCamera::mClipPlaneFar must be >= aiCamera::mClipPlaneNear");
+
+    // FIX: there are many 3ds files with invalid FOVs. No reason to
+    // reject them at all ... a warning is appropriate.
+    if (!pCamera->mHorizontalFOV || pCamera->mHorizontalFOV >= (float)AI_MATH_PI)
+        ReportWarning("%f is not a valid value for aiCamera::mHorizontalFOV", pCamera->mHorizontalFOV);
+}
+
+// ------------------------------------------------------------------------------------------------
+void ValidateDSProcess::Validate(const aiMesh *pMesh) {
+    // validate the material index of the mesh
+    if (mScene->mNumMaterials && pMesh->mMaterialIndex >= mScene->mNumMaterials) {
+        ReportError("aiMesh::mMaterialIndex is invalid (value: %i maximum: %i)",
+                pMesh->mMaterialIndex, mScene->mNumMaterials - 1);
+    }
+
+    Validate(&pMesh->mName);
+
+    for (unsigned int i = 0; i < pMesh->mNumFaces; ++i) {
+        aiFace &face = pMesh->mFaces[i];
+
+        if (pMesh->mPrimitiveTypes) {
+            switch (face.mNumIndices) {
+            case 0:
+                ReportError("aiMesh::mFaces[%i].mNumIndices is 0", i);
+                break;
+            case 1:
+                if (0 == (pMesh->mPrimitiveTypes & aiPrimitiveType_POINT)) {
+                    ReportError("aiMesh::mFaces[%i] is a POINT but aiMesh::mPrimitiveTypes "
+                                "does not report the POINT flag",
+                            i);
+                }
+                break;
+            case 2:
+                if (0 == (pMesh->mPrimitiveTypes & aiPrimitiveType_LINE)) {
+                    ReportError("aiMesh::mFaces[%i] is a LINE but aiMesh::mPrimitiveTypes "
+                                "does not report the LINE flag",
+                            i);
+                }
+                break;
+            case 3:
+                if (0 == (pMesh->mPrimitiveTypes & aiPrimitiveType_TRIANGLE)) {
+                    ReportError("aiMesh::mFaces[%i] is a TRIANGLE but aiMesh::mPrimitiveTypes "
+                                "does not report the TRIANGLE flag",
+                            i);
+                }
+                break;
+            default:
+                if (0 == (pMesh->mPrimitiveTypes & aiPrimitiveType_POLYGON)) {
+                    this->ReportError("aiMesh::mFaces[%i] is a POLYGON but aiMesh::mPrimitiveTypes "
+                                      "does not report the POLYGON flag",
+                            i);
+                }
+                break;
+            };
+        }
+
+        if (!face.mIndices)
+            ReportError("aiMesh::mFaces[%i].mIndices is nullptr", i);
+    }
+
+    // positions must always be there ...
+    if (!pMesh->mNumVertices || (!pMesh->mVertices && !mScene->mFlags)) {
+        ReportError("The mesh %s contains no vertices", pMesh->mName.C_Str());
+    }
+
+    if (pMesh->mNumVertices > AI_MAX_VERTICES) {
+        ReportError("Mesh has too many vertices: %u, but the limit is %u", pMesh->mNumVertices, AI_MAX_VERTICES);
+    }
+    if (pMesh->mNumFaces > AI_MAX_FACES) {
+        ReportError("Mesh has too many faces: %u, but the limit is %u", pMesh->mNumFaces, AI_MAX_FACES);
+    }
+
+    // if tangents are there there must also be bitangent vectors ...
+    if ((pMesh->mTangents != nullptr) != (pMesh->mBitangents != nullptr)) {
+        ReportError("If there are tangents, bitangent vectors must be present as well");
+    }
+
+    // faces, too
+    if (!pMesh->mNumFaces || (!pMesh->mFaces && !mScene->mFlags)) {
+        ReportError("Mesh %s contains no faces", pMesh->mName.C_Str());
+    }
+
+    // now check whether the face indexing layout is correct:
+    // unique vertices, pseudo-indexed.
+    std::vector<bool> abRefList;
+    abRefList.resize(pMesh->mNumVertices, false);
+    for (unsigned int i = 0; i < pMesh->mNumFaces; ++i) {
+        aiFace &face = pMesh->mFaces[i];
+        if (face.mNumIndices > AI_MAX_FACE_INDICES) {
+            ReportError("Face %u has too many faces: %u, but the limit is %u", i, face.mNumIndices, AI_MAX_FACE_INDICES);
+        }
+
+        for (unsigned int a = 0; a < face.mNumIndices; ++a) {
+            if (face.mIndices[a] >= pMesh->mNumVertices) {
+                ReportError("aiMesh::mFaces[%i]::mIndices[%i] is out of range", i, a);
+            }
+            // the MSB flag is temporarily used by the extra verbose
+            // mode to tell us that the JoinVerticesProcess might have
+            // been executed already.
+            /*if ( !(this->mScene->mFlags & AI_SCENE_FLAGS_NON_VERBOSE_FORMAT ) && !(this->mScene->mFlags & AI_SCENE_FLAGS_ALLOW_SHARED) &&
+				abRefList[face.mIndices[a]])
+            {
+                ReportError("aiMesh::mVertices[%i] is referenced twice - second "
+                    "time by aiMesh::mFaces[%i]::mIndices[%i]",face.mIndices[a],i,a);
+            }*/
+            abRefList[face.mIndices[a]] = true;
+        }
+    }
+
+    // check whether there are vertices that aren't referenced by a face
+    bool b = false;
+    for (unsigned int i = 0; i < pMesh->mNumVertices; ++i) {
+        if (!abRefList[i]) b = true;
+    }
+    abRefList.clear();
+    if (b) {
+        ReportWarning("There are unreferenced vertices");
+    }
+
+    // texture channel 2 may not be set if channel 1 is zero ...
+    {
+        unsigned int i = 0;
+        for (; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++i) {
+            if (!pMesh->HasTextureCoords(i)) break;
+        }
+        for (; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++i)
+            if (pMesh->HasTextureCoords(i)) {
+                ReportError("Texture coordinate channel %i exists "
+                            "although the previous channel was nullptr.",
+                        i);
+            }
+    }
+    // the same for the vertex colors
+    {
+        unsigned int i = 0;
+        for (; i < AI_MAX_NUMBER_OF_COLOR_SETS; ++i) {
+            if (!pMesh->HasVertexColors(i)) break;
+        }
+        for (; i < AI_MAX_NUMBER_OF_COLOR_SETS; ++i)
+            if (pMesh->HasVertexColors(i)) {
+                ReportError("Vertex color channel %i is exists "
+                            "although the previous channel was nullptr.",
+                        i);
+            }
+    }
+
+    // now validate all bones
+    if (pMesh->mNumBones) {
+        if (!pMesh->mBones) {
+            ReportError("aiMesh::mBones is nullptr (aiMesh::mNumBones is %i)",
+                    pMesh->mNumBones);
+        }
+        std::unique_ptr<float[]> afSum(nullptr);
+        if (pMesh->mNumVertices) {
+            afSum.reset(new float[pMesh->mNumVertices]);
+            for (unsigned int i = 0; i < pMesh->mNumVertices; ++i)
+                afSum[i] = 0.0f;
+        }
+
+        // check whether there are duplicate bone names
+        for (unsigned int i = 0; i < pMesh->mNumBones; ++i) {
+            const aiBone *bone = pMesh->mBones[i];
+            if (bone->mNumWeights > AI_MAX_BONE_WEIGHTS) {
+                ReportError("Bone %u has too many weights: %u, but the limit is %u", i, bone->mNumWeights, AI_MAX_BONE_WEIGHTS);
+            }
+
+            if (!pMesh->mBones[i]) {
+                ReportError("aiMesh::mBones[%i] is nullptr (aiMesh::mNumBones is %i)",
+                        i, pMesh->mNumBones);
+            }
+            Validate(pMesh, pMesh->mBones[i], afSum.get());
+
+            for (unsigned int a = i + 1; a < pMesh->mNumBones; ++a) {
+                if (pMesh->mBones[i]->mName == pMesh->mBones[a]->mName) {
+                    const char *name = "unknown";
+                    if (nullptr != pMesh->mBones[i]->mName.C_Str()) {
+                        name = pMesh->mBones[i]->mName.C_Str();
+                    }
+                    ReportError("aiMesh::mBones[%i], name = \"%s\" has the same name as "
+                                "aiMesh::mBones[%i]",
+                            i, name, a);
+                }
+            }
+        }
+        // check whether all bone weights for a vertex sum to 1.0 ...
+        for (unsigned int i = 0; i < pMesh->mNumVertices; ++i) {
+            if (afSum[i] && (afSum[i] <= 0.94 || afSum[i] >= 1.05)) {
+                ReportWarning("aiMesh::mVertices[%i]: bone weight sum != 1.0 (sum is %f)", i, afSum[i]);
+            }
+        }
+    } else if (pMesh->mBones) {
+        ReportError("aiMesh::mBones is non-null although there are no bones");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+void ValidateDSProcess::Validate(const aiMesh *pMesh, const aiBone *pBone, float *afSum) {
+    this->Validate(&pBone->mName);
+
+    if (!pBone->mNumWeights) {
+        //ReportError("aiBone::mNumWeights is zero");
+    }
+
+    // check whether all vertices affected by this bone are valid
+    for (unsigned int i = 0; i < pBone->mNumWeights; ++i) {
+        if (pBone->mWeights[i].mVertexId >= pMesh->mNumVertices) {
+            ReportError("aiBone::mWeights[%i].mVertexId is out of range", i);
+        } else if (!pBone->mWeights[i].mWeight || pBone->mWeights[i].mWeight > 1.0f) {
+            ReportWarning("aiBone::mWeights[%i].mWeight has an invalid value", i);
+        }
+        afSum[pBone->mWeights[i].mVertexId] += pBone->mWeights[i].mWeight;
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+void ValidateDSProcess::Validate(const aiAnimation *pAnimation) {
+    Validate(&pAnimation->mName);
+
+    // validate all animations
+    if (pAnimation->mNumChannels || pAnimation->mNumMorphMeshChannels) {
+        if (!pAnimation->mChannels && pAnimation->mNumChannels) {
+            ReportError("aiAnimation::mChannels is nullptr (aiAnimation::mNumChannels is %i)",
+                    pAnimation->mNumChannels);
+        }
+        if (!pAnimation->mMorphMeshChannels && pAnimation->mNumMorphMeshChannels) {
+            ReportError("aiAnimation::mMorphMeshChannels is nullptr (aiAnimation::mNumMorphMeshChannels is %i)",
+                    pAnimation->mNumMorphMeshChannels);
+        }
+        for (unsigned int i = 0; i < pAnimation->mNumChannels; ++i) {
+            if (!pAnimation->mChannels[i]) {
+                ReportError("aiAnimation::mChannels[%i] is nullptr (aiAnimation::mNumChannels is %i)",
+                        i, pAnimation->mNumChannels);
+            }
+            Validate(pAnimation, pAnimation->mChannels[i]);
+        }
+        for (unsigned int i = 0; i < pAnimation->mNumMorphMeshChannels; ++i) {
+            if (!pAnimation->mMorphMeshChannels[i]) {
+                ReportError("aiAnimation::mMorphMeshChannels[%i] is nullptr (aiAnimation::mNumMorphMeshChannels is %i)",
+                        i, pAnimation->mNumMorphMeshChannels);
+            }
+            Validate(pAnimation, pAnimation->mMorphMeshChannels[i]);
+        }
+    } else {
+        ReportError("aiAnimation::mNumChannels is 0. At least one node animation channel must be there.");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+void ValidateDSProcess::SearchForInvalidTextures(const aiMaterial *pMaterial,
+        aiTextureType type) {
+    const char *szType = TextureTypeToString(type);
+
+    // ****************************************************************************
+    // Search all keys of the material ...
+    // textures must be specified with ascending indices
+    // (e.g. diffuse #2 may not be specified if diffuse #1 is not there ...)
+    // ****************************************************************************
+
+    int iNumIndices = 0;
+    int iIndex = -1;
+    for (unsigned int i = 0; i < pMaterial->mNumProperties; ++i) {
+        aiMaterialProperty *prop = pMaterial->mProperties[i];
+        ai_assert(nullptr != prop);
+        if (!::strcmp(prop->mKey.data, "$tex.file") && prop->mSemantic == static_cast<unsigned int>(type)) {
+            iIndex = std::max(iIndex, (int)prop->mIndex);
+            ++iNumIndices;
+
+            if (aiPTI_String != prop->mType) {
+                ReportError("Material property %s is expected to be a string", prop->mKey.data);
+            }
+        }
+    }
+    if (iIndex + 1 != iNumIndices) {
+        ReportError("%s #%i is set, but there are only %i %s textures",
+                szType, iIndex, iNumIndices, szType);
+    }
+    if (!iNumIndices) {
+        return;
+    }
+    std::vector<aiTextureMapping> mappings(iNumIndices);
+
+    // Now check whether all UV indices are valid ...
+    bool bNoSpecified = true;
+    for (unsigned int i = 0; i < pMaterial->mNumProperties; ++i) {
+        aiMaterialProperty *prop = pMaterial->mProperties[i];
+        if (static_cast<aiTextureType>(prop->mSemantic) != type) {
+            continue;
+        }
+
+        if ((int)prop->mIndex >= iNumIndices) {
+            ReportError("Found texture property with index %i, although there "
+                        "are only %i textures of type %s",
+                    prop->mIndex, iNumIndices, szType);
+        }
+
+        if (!::strcmp(prop->mKey.data, "$tex.mapping")) {
+            if (aiPTI_Integer != prop->mType || prop->mDataLength < sizeof(aiTextureMapping)) {
+                ReportError("Material property %s%i is expected to be an integer (size is %i)",
+                        prop->mKey.data, prop->mIndex, prop->mDataLength);
+            }
+            mappings[prop->mIndex] = *((aiTextureMapping *)prop->mData);
+        } else if (!::strcmp(prop->mKey.data, "$tex.uvtrafo")) {
+            if (aiPTI_Float != prop->mType || prop->mDataLength < sizeof(aiUVTransform)) {
+                ReportError("Material property %s%i is expected to be 5 floats large (size is %i)",
+                        prop->mKey.data, prop->mIndex, prop->mDataLength);
+            }
+            //mappings[prop->mIndex] = ((aiUVTransform*)prop->mData);
+        } else if (!::strcmp(prop->mKey.data, "$tex.uvwsrc")) {
+            if (aiPTI_Integer != prop->mType || sizeof(int) > prop->mDataLength) {
+                ReportError("Material property %s%i is expected to be an integer (size is %i)",
+                        prop->mKey.data, prop->mIndex, prop->mDataLength);
+            }
+            bNoSpecified = false;
+
+            // Ignore UV indices for texture channels that are not there ...
+
+            // Get the value
+            iIndex = *((unsigned int *)prop->mData);
+
+            // Check whether there is a mesh using this material
+            // which has not enough UV channels ...
+            for (unsigned int a = 0; a < mScene->mNumMeshes; ++a) {
+                aiMesh *mesh = this->mScene->mMeshes[a];
+                if (mesh->mMaterialIndex == (unsigned int)i) {
+                    int iChannels = 0;
+                    while (mesh->HasTextureCoords(iChannels))
+                        ++iChannels;
+                    if (iIndex >= iChannels) {
+                        ReportWarning("Invalid UV index: %i (key %s). Mesh %i has only %i UV channels",
+                                iIndex, prop->mKey.data, a, iChannels);
+                    }
+                }
+            }
+        }
+    }
+    if (bNoSpecified) {
+        // Assume that all textures are using the first UV channel
+        for (unsigned int a = 0; a < mScene->mNumMeshes; ++a) {
+            aiMesh *mesh = mScene->mMeshes[a];
+            if (mesh->mMaterialIndex == (unsigned int)iIndex && mappings[0] == aiTextureMapping_UV) {
+                if (!mesh->mTextureCoords[0]) {
+                    // This is a special case ... it could be that the
+                    // original mesh format intended the use of a special
+                    // mapping here.
+                    ReportWarning("UV-mapped texture, but there are no UV coords");
+                }
+            }
+        }
+    }
+}
+// ------------------------------------------------------------------------------------------------
+void ValidateDSProcess::Validate(const aiMaterial *pMaterial) {
+    // check whether there are material keys that are obviously not legal
+    for (unsigned int i = 0; i < pMaterial->mNumProperties; ++i) {
+        const aiMaterialProperty *prop = pMaterial->mProperties[i];
+        if (!prop) {
+            ReportError("aiMaterial::mProperties[%i] is nullptr (aiMaterial::mNumProperties is %i)",
+                    i, pMaterial->mNumProperties);
+        }
+        if (!prop->mDataLength || !prop->mData) {
+            ReportError("aiMaterial::mProperties[%i].mDataLength or "
+                        "aiMaterial::mProperties[%i].mData is 0",
+                    i, i);
+        }
+        // check all predefined types
+        if (aiPTI_String == prop->mType) {
+            // FIX: strings are now stored in a less expensive way, but we can't use the
+            // validation routine for 'normal' aiStrings
+            if (prop->mDataLength < 5 || prop->mDataLength < 4 + (*reinterpret_cast<uint32_t *>(prop->mData)) + 1) {
+                ReportError("aiMaterial::mProperties[%i].mDataLength is "
+                            "too small to contain a string (%i, needed: %i)",
+                        i, prop->mDataLength, static_cast<int>(sizeof(aiString)));
+            }
+            if (prop->mData[prop->mDataLength - 1]) {
+                ReportError("Missing null-terminator in string material property");
+            }
+            //  Validate((const aiString*)prop->mData);
+        } else if (aiPTI_Float == prop->mType) {
+            if (prop->mDataLength < sizeof(float)) {
+                ReportError("aiMaterial::mProperties[%i].mDataLength is "
+                            "too small to contain a float (%i, needed: %i)",
+                        i, prop->mDataLength, static_cast<int>(sizeof(float)));
+            }
+        } else if (aiPTI_Integer == prop->mType) {
+            if (prop->mDataLength < sizeof(int)) {
+                ReportError("aiMaterial::mProperties[%i].mDataLength is "
+                            "too small to contain an integer (%i, needed: %i)",
+                        i, prop->mDataLength, static_cast<int>(sizeof(int)));
+            }
+        }
+        // TODO: check whether there is a key with an unknown name ...
+    }
+
+    // make some more specific tests
+    ai_real fTemp;
+    int iShading;
+    if (AI_SUCCESS == aiGetMaterialInteger(pMaterial, AI_MATKEY_SHADING_MODEL, &iShading)) {
+        switch ((aiShadingMode)iShading) {
+        case aiShadingMode_Blinn:
+        case aiShadingMode_CookTorrance:
+        case aiShadingMode_Phong:
+
+            if (AI_SUCCESS != aiGetMaterialFloat(pMaterial, AI_MATKEY_SHININESS, &fTemp)) {
+                ReportWarning("A specular shading model is specified but there is no "
+                              "AI_MATKEY_SHININESS key");
+            }
+            if (AI_SUCCESS == aiGetMaterialFloat(pMaterial, AI_MATKEY_SHININESS_STRENGTH, &fTemp) && !fTemp) {
+                ReportWarning("A specular shading model is specified but the value of the "
+                              "AI_MATKEY_SHININESS_STRENGTH key is 0.0");
+            }
+            break;
+        default:
+            break;
+        }
+    }
+
+    if (AI_SUCCESS == aiGetMaterialFloat(pMaterial, AI_MATKEY_OPACITY, &fTemp) && (!fTemp || fTemp > 1.01)) {
+        ReportWarning("Invalid opacity value (must be 0 < opacity < 1.0)");
+    }
+
+    // Check whether there are invalid texture keys
+    // TODO: that's a relict of the past, where texture type and index were baked
+    // into the material string ... we could do that in one single pass.
+    SearchForInvalidTextures(pMaterial, aiTextureType_DIFFUSE);
+    SearchForInvalidTextures(pMaterial, aiTextureType_SPECULAR);
+    SearchForInvalidTextures(pMaterial, aiTextureType_AMBIENT);
+    SearchForInvalidTextures(pMaterial, aiTextureType_EMISSIVE);
+    SearchForInvalidTextures(pMaterial, aiTextureType_OPACITY);
+    SearchForInvalidTextures(pMaterial, aiTextureType_SHININESS);
+    SearchForInvalidTextures(pMaterial, aiTextureType_HEIGHT);
+    SearchForInvalidTextures(pMaterial, aiTextureType_NORMALS);
+    SearchForInvalidTextures(pMaterial, aiTextureType_DISPLACEMENT);
+    SearchForInvalidTextures(pMaterial, aiTextureType_LIGHTMAP);
+    SearchForInvalidTextures(pMaterial, aiTextureType_REFLECTION);
+    SearchForInvalidTextures(pMaterial, aiTextureType_BASE_COLOR);
+    SearchForInvalidTextures(pMaterial, aiTextureType_NORMAL_CAMERA);
+    SearchForInvalidTextures(pMaterial, aiTextureType_EMISSION_COLOR);
+    SearchForInvalidTextures(pMaterial, aiTextureType_METALNESS);
+    SearchForInvalidTextures(pMaterial, aiTextureType_DIFFUSE_ROUGHNESS);
+    SearchForInvalidTextures(pMaterial, aiTextureType_AMBIENT_OCCLUSION);
+}
+
+// ------------------------------------------------------------------------------------------------
+void ValidateDSProcess::Validate(const aiTexture *pTexture) {
+    // the data section may NEVER be nullptr
+    if (nullptr == pTexture->pcData) {
+        ReportError("aiTexture::pcData is nullptr");
+    }
+    if (pTexture->mHeight) {
+        if (!pTexture->mWidth) {
+            ReportError("aiTexture::mWidth is zero (aiTexture::mHeight is %i, uncompressed texture)",
+                    pTexture->mHeight);
+        }
+    } else {
+        if (!pTexture->mWidth) {
+            ReportError("aiTexture::mWidth is zero (compressed texture)");
+        }
+        if ('\0' != pTexture->achFormatHint[HINTMAXTEXTURELEN - 1]) {
+            ReportWarning("aiTexture::achFormatHint must be zero-terminated");
+        } else if ('.' == pTexture->achFormatHint[0]) {
+            ReportWarning("aiTexture::achFormatHint should contain a file extension "
+                          "without a leading dot (format hint: %s).",
+                    pTexture->achFormatHint);
+        }
+    }
+
+    const char *sz = pTexture->achFormatHint;
+    if ((sz[0] >= 'A' && sz[0] <= 'Z') ||
+            (sz[1] >= 'A' && sz[1] <= 'Z') ||
+            (sz[2] >= 'A' && sz[2] <= 'Z') ||
+            (sz[3] >= 'A' && sz[3] <= 'Z')) {
+        ReportError("aiTexture::achFormatHint contains non-lowercase letters");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+void ValidateDSProcess::Validate(const aiAnimation *pAnimation,
+        const aiNodeAnim *pNodeAnim) {
+    Validate(&pNodeAnim->mNodeName);
+
+    if (!pNodeAnim->mNumPositionKeys && !pNodeAnim->mScalingKeys && !pNodeAnim->mNumRotationKeys) {
+        ReportError("Empty node animation channel");
+    }
+    // otherwise check whether one of the keys exceeds the total duration of the animation
+    if (pNodeAnim->mNumPositionKeys) {
+        if (!pNodeAnim->mPositionKeys) {
+            ReportError("aiNodeAnim::mPositionKeys is nullptr (aiNodeAnim::mNumPositionKeys is %i)",
+                    pNodeAnim->mNumPositionKeys);
+        }
+        double dLast = -10e10;
+        for (unsigned int i = 0; i < pNodeAnim->mNumPositionKeys; ++i) {
+            // ScenePreprocessor will compute the duration if still the default value
+            // (Aramis) Add small epsilon, comparison tended to fail if max_time == duration,
+            //  seems to be due the compilers register usage/width.
+            if (pAnimation->mDuration > 0. && pNodeAnim->mPositionKeys[i].mTime > pAnimation->mDuration + 0.001) {
+                ReportError("aiNodeAnim::mPositionKeys[%i].mTime (%.5f) is larger "
+                            "than aiAnimation::mDuration (which is %.5f)",
+                        i,
+                        (float)pNodeAnim->mPositionKeys[i].mTime,
+                        (float)pAnimation->mDuration);
+            }
+            if (i && pNodeAnim->mPositionKeys[i].mTime <= dLast) {
+                ReportWarning("aiNodeAnim::mPositionKeys[%i].mTime (%.5f) is smaller "
+                              "than aiAnimation::mPositionKeys[%i] (which is %.5f)",
+                        i,
+                        (float)pNodeAnim->mPositionKeys[i].mTime,
+                        i - 1, (float)dLast);
+            }
+            dLast = pNodeAnim->mPositionKeys[i].mTime;
+        }
+    }
+    // rotation keys
+    if (pNodeAnim->mNumRotationKeys) {
+        if (!pNodeAnim->mRotationKeys) {
+            ReportError("aiNodeAnim::mRotationKeys is nullptr (aiNodeAnim::mNumRotationKeys is %i)",
+                    pNodeAnim->mNumRotationKeys);
+        }
+        double dLast = -10e10;
+        for (unsigned int i = 0; i < pNodeAnim->mNumRotationKeys; ++i) {
+            if (pAnimation->mDuration > 0. && pNodeAnim->mRotationKeys[i].mTime > pAnimation->mDuration + 0.001) {
+                ReportError("aiNodeAnim::mRotationKeys[%i].mTime (%.5f) is larger "
+                            "than aiAnimation::mDuration (which is %.5f)",
+                        i,
+                        (float)pNodeAnim->mRotationKeys[i].mTime,
+                        (float)pAnimation->mDuration);
+            }
+            if (i && pNodeAnim->mRotationKeys[i].mTime <= dLast) {
+                ReportWarning("aiNodeAnim::mRotationKeys[%i].mTime (%.5f) is smaller "
+                              "than aiAnimation::mRotationKeys[%i] (which is %.5f)",
+                        i,
+                        (float)pNodeAnim->mRotationKeys[i].mTime,
+                        i - 1, (float)dLast);
+            }
+            dLast = pNodeAnim->mRotationKeys[i].mTime;
+        }
+    }
+    // scaling keys
+    if (pNodeAnim->mNumScalingKeys) {
+        if (!pNodeAnim->mScalingKeys) {
+            ReportError("aiNodeAnim::mScalingKeys is nullptr (aiNodeAnim::mNumScalingKeys is %i)",
+                    pNodeAnim->mNumScalingKeys);
+        }
+        double dLast = -10e10;
+        for (unsigned int i = 0; i < pNodeAnim->mNumScalingKeys; ++i) {
+            if (pAnimation->mDuration > 0. && pNodeAnim->mScalingKeys[i].mTime > pAnimation->mDuration + 0.001) {
+                ReportError("aiNodeAnim::mScalingKeys[%i].mTime (%.5f) is larger "
+                            "than aiAnimation::mDuration (which is %.5f)",
+                        i,
+                        (float)pNodeAnim->mScalingKeys[i].mTime,
+                        (float)pAnimation->mDuration);
+            }
+            if (i && pNodeAnim->mScalingKeys[i].mTime <= dLast) {
+                ReportWarning("aiNodeAnim::mScalingKeys[%i].mTime (%.5f) is smaller "
+                              "than aiAnimation::mScalingKeys[%i] (which is %.5f)",
+                        i,
+                        (float)pNodeAnim->mScalingKeys[i].mTime,
+                        i - 1, (float)dLast);
+            }
+            dLast = pNodeAnim->mScalingKeys[i].mTime;
+        }
+    }
+
+    if (!pNodeAnim->mNumScalingKeys && !pNodeAnim->mNumRotationKeys &&
+            !pNodeAnim->mNumPositionKeys) {
+        ReportError("A node animation channel must have at least one subtrack");
+    }
+}
+
+void ValidateDSProcess::Validate(const aiAnimation *pAnimation,
+        const aiMeshMorphAnim *pMeshMorphAnim) {
+    Validate(&pMeshMorphAnim->mName);
+
+    if (!pMeshMorphAnim->mNumKeys) {
+        ReportWarning("Empty mesh morph animation channel");
+        return;
+    }
+
+    // otherwise check whether one of the keys exceeds the total duration of the animation
+    if (pMeshMorphAnim->mNumKeys) {
+        if (!pMeshMorphAnim->mKeys) {
+            ReportError("aiMeshMorphAnim::mKeys is nullptr (aiMeshMorphAnim::mNumKeys is %i)",
+                    pMeshMorphAnim->mNumKeys);
+        }
+        double dLast = -10e10;
+        for (unsigned int i = 0; i < pMeshMorphAnim->mNumKeys; ++i) {
+            // ScenePreprocessor will compute the duration if still the default value
+            // (Aramis) Add small epsilon, comparison tended to fail if max_time == duration,
+            //  seems to be due the compilers register usage/width.
+            if (pAnimation->mDuration > 0. && pMeshMorphAnim->mKeys[i].mTime > pAnimation->mDuration + 0.001) {
+                ReportError("aiMeshMorphAnim::mKeys[%i].mTime (%.5f) is larger "
+                            "than aiAnimation::mDuration (which is %.5f)",
+                        i,
+                        (float)pMeshMorphAnim->mKeys[i].mTime,
+                        (float)pAnimation->mDuration);
+            }
+            if (i && pMeshMorphAnim->mKeys[i].mTime <= dLast) {
+                ReportWarning("aiMeshMorphAnim::mKeys[%i].mTime (%.5f) is smaller "
+                              "than aiMeshMorphAnim::mKeys[%i] (which is %.5f)",
+                        i,
+                        (float)pMeshMorphAnim->mKeys[i].mTime,
+                        i - 1, (float)dLast);
+            }
+            dLast = pMeshMorphAnim->mKeys[i].mTime;
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+void ValidateDSProcess::Validate(const aiNode *pNode) {
+    if (!pNode) {
+        ReportError("A node of the scene-graph is nullptr");
+    }
+    // Validate node name string first so that it's safe to use in below expressions
+    this->Validate(&pNode->mName);
+    const char *nodeName = (&pNode->mName)->C_Str();
+    if (pNode != mScene->mRootNode && !pNode->mParent) {
+        ReportError("Non-root node %s lacks a valid parent (aiNode::mParent is nullptr) ", nodeName);
+    }
+
+    // validate all meshes
+    if (pNode->mNumMeshes) {
+        if (!pNode->mMeshes) {
+            ReportError("aiNode::mMeshes is nullptr for node %s (aiNode::mNumMeshes is %i)",
+                    nodeName, pNode->mNumMeshes);
+        }
+        std::vector<bool> abHadMesh;
+        abHadMesh.resize(mScene->mNumMeshes, false);
+        for (unsigned int i = 0; i < pNode->mNumMeshes; ++i) {
+            if (pNode->mMeshes[i] >= mScene->mNumMeshes) {
+                ReportError("aiNode::mMeshes[%i] is out of range for node %s (maximum is %i)",
+                        pNode->mMeshes[i], nodeName, mScene->mNumMeshes - 1);
+            }
+            if (abHadMesh[pNode->mMeshes[i]]) {
+                ReportError("aiNode::mMeshes[%i] is already referenced by this node %s (value: %i)",
+                        i, nodeName, pNode->mMeshes[i]);
+            }
+            abHadMesh[pNode->mMeshes[i]] = true;
+        }
+    }
+    if (pNode->mNumChildren) {
+        if (!pNode->mChildren) {
+            ReportError("aiNode::mChildren is nullptr for node %s (aiNode::mNumChildren is %i)",
+                    nodeName, pNode->mNumChildren);
+        }
+        for (unsigned int i = 0; i < pNode->mNumChildren; ++i) {
+            Validate(pNode->mChildren[i]);
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+void ValidateDSProcess::Validate(const aiString *pString) {
+    if (pString->length > MAXLEN) {
+        ReportError("aiString::length is too large (%u, maximum is %lu)",
+                pString->length, MAXLEN);
+    }
+    const char *sz = pString->data;
+    while (true) {
+        if ('\0' == *sz) {
+            if (pString->length != (unsigned int)(sz - pString->data)) {
+                ReportError("aiString::data is invalid: the terminal zero is at a wrong offset");
+            }
+            break;
+        } else if (sz >= &pString->data[MAXLEN]) {
+            ReportError("aiString::data is invalid. There is no terminal character");
+        }
+        ++sz;
+    }
+}
diff --git a/src/mesh/assimp-master/code/PostProcessing/ValidateDataStructure.h b/src/mesh/assimp-master/code/PostProcessing/ValidateDataStructure.h
new file mode 100644
index 0000000..077a47b
--- /dev/null
+++ b/src/mesh/assimp-master/code/PostProcessing/ValidateDataStructure.h
@@ -0,0 +1,197 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file Defines a (dummy) post processing step to validate the loader's
+ * output data structure (for debugging)
+ */
+#ifndef AI_VALIDATEPROCESS_H_INC
+#define AI_VALIDATEPROCESS_H_INC
+
+#include <assimp/types.h>
+#include <assimp/material.h>
+
+#include "Common/BaseProcess.h"
+
+struct aiBone;
+struct aiMesh;
+struct aiAnimation;
+struct aiNodeAnim;
+struct aiMeshMorphAnim;
+struct aiTexture;
+struct aiMaterial;
+struct aiNode;
+struct aiString;
+struct aiCamera;
+struct aiLight;
+
+namespace Assimp    {
+
+// --------------------------------------------------------------------------------------
+/** Validates the whole ASSIMP scene data structure for correctness.
+ *  ImportErrorException is thrown of the scene is corrupt.*/
+// --------------------------------------------------------------------------------------
+class ValidateDSProcess : public BaseProcess
+{
+public:
+
+    ValidateDSProcess();
+    ~ValidateDSProcess();
+
+public:
+    // -------------------------------------------------------------------
+    bool IsActive( unsigned int pFlags) const;
+
+    // -------------------------------------------------------------------
+    void Execute( aiScene* pScene);
+
+protected:
+
+    // -------------------------------------------------------------------
+    /** Report a validation error. This will throw an exception,
+     *  control won't return.
+     * @param msg Format string for sprintf().*/
+    AI_WONT_RETURN void ReportError(const char* msg,...) AI_WONT_RETURN_SUFFIX;
+
+
+    // -------------------------------------------------------------------
+    /** Report a validation warning. This won't throw an exception,
+     *  control will return to the caller.
+     * @param msg Format string for sprintf().*/
+    void ReportWarning(const char* msg,...);
+
+
+    // -------------------------------------------------------------------
+    /** Validates a mesh
+     * @param pMesh Input mesh*/
+    void Validate( const aiMesh* pMesh);
+
+    // -------------------------------------------------------------------
+    /** Validates a bone
+     * @param pMesh Input mesh
+     * @param pBone Input bone*/
+    void Validate( const aiMesh* pMesh,const aiBone* pBone,float* afSum);
+
+    // -------------------------------------------------------------------
+    /** Validates an animation
+     * @param pAnimation Input animation*/
+    void Validate( const aiAnimation* pAnimation);
+
+    // -------------------------------------------------------------------
+    /** Validates a material
+     * @param pMaterial Input material*/
+    void Validate( const aiMaterial* pMaterial);
+
+    // -------------------------------------------------------------------
+    /** Search the material data structure for invalid or corrupt
+     *  texture keys.
+     * @param pMaterial Input material
+     * @param type Type of the texture*/
+    void SearchForInvalidTextures(const aiMaterial* pMaterial,
+        aiTextureType type);
+
+    // -------------------------------------------------------------------
+    /** Validates a texture
+     * @param pTexture Input texture*/
+    void Validate( const aiTexture* pTexture);
+
+    // -------------------------------------------------------------------
+    /** Validates a light source
+     * @param pLight Input light
+     */
+    void Validate( const aiLight* pLight);
+
+    // -------------------------------------------------------------------
+    /** Validates a camera
+     * @param pCamera Input camera*/
+    void Validate( const aiCamera* pCamera);
+
+    // -------------------------------------------------------------------
+    /** Validates a bone animation channel
+     * @param pAnimation Animation channel.
+     * @param pBoneAnim Input bone animation */
+    void Validate( const aiAnimation* pAnimation,
+        const aiNodeAnim* pBoneAnim);
+
+    /** Validates a mesh morph animation channel.
+     * @param pAnimation Input animation.
+     * @param pMeshMorphAnim Mesh morph animation channel.
+     * */
+    void Validate( const aiAnimation* pAnimation,
+        const aiMeshMorphAnim* pMeshMorphAnim);
+
+    // -------------------------------------------------------------------
+    /** Validates a node and all of its subnodes
+     * @param Node Input node*/
+    void Validate( const aiNode* pNode);
+
+    // -------------------------------------------------------------------
+    /** Validates a string
+     * @param pString Input string*/
+    void Validate( const aiString* pString);
+
+private:
+
+    // template to validate one of the aiScene::mXXX arrays
+    template <typename T>
+    inline void DoValidation(T** array, unsigned int size,
+        const char* firstName, const char* secondName);
+
+    // extended version: checks whether T::mName occurs twice
+    template <typename T>
+    inline void DoValidationEx(T** array, unsigned int size,
+        const char* firstName, const char* secondName);
+
+    // extension to the first template which does also search
+    // the nodegraph for an item with the same name
+    template <typename T>
+    inline void DoValidationWithNameCheck(T** array, unsigned int size,
+        const char* firstName, const char* secondName);
+
+    aiScene* mScene;
+};
+
+
+
+
+} // end of namespace Assimp
+
+#endif // AI_VALIDATEPROCESS_H_INC