add assimp submodule

1 files changed, 1976 insertions, 0 deletions

diff --git a/src/mesh/assimp-master/code/AssetLib/MDL/MDLLoader.cpp b/src/mesh/assimp-master/code/AssetLib/MDL/MDLLoader.cpp
new file mode 100644
index 0000000..1e90c8e
--- /dev/null
+++ b/src/mesh/assimp-master/code/AssetLib/MDL/MDLLoader.cpp
@@ -0,0 +1,1976 @@
+/*
+---------------------------------------------------------------------------
+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 MDLLoader.cpp
+ *  @brief Implementation of the main parts of the MDL importer class
+ *  *TODO* Cleanup and further testing of some parts necessary
+ */
+
+// internal headers
+
+#ifndef ASSIMP_BUILD_NO_MDL_IMPORTER
+
+#include "AssetLib/MDL/MDLLoader.h"
+#include "AssetLib/MD2/MD2FileData.h"
+#include "AssetLib/MDL/HalfLife/HL1MDLLoader.h"
+#include "AssetLib/MDL/MDLDefaultColorMap.h"
+
+#include <assimp/StringUtils.h>
+#include <assimp/importerdesc.h>
+#include <assimp/qnan.h>
+#include <assimp/scene.h>
+#include <assimp/DefaultLogger.hpp>
+#include <assimp/IOSystem.hpp>
+#include <assimp/Importer.hpp>
+
+#include <memory>
+
+using namespace Assimp;
+
+static const aiImporterDesc desc = {
+    "Quake Mesh / 3D GameStudio Mesh Importer",
+    "",
+    "",
+    "",
+    aiImporterFlags_SupportBinaryFlavour,
+    0,
+    0,
+    7,
+    0,
+    "mdl"
+};
+
+// ------------------------------------------------------------------------------------------------
+// Ugly stuff ... nevermind
+#define _AI_MDL7_ACCESS(_data, _index, _limit, _type) \
+    (*((const _type *)(((const char *)_data) + _index * _limit)))
+
+#define _AI_MDL7_ACCESS_PTR(_data, _index, _limit, _type) \
+    ((BE_NCONST _type *)(((const char *)_data) + _index * _limit))
+
+#define _AI_MDL7_ACCESS_VERT(_data, _index, _limit) \
+    _AI_MDL7_ACCESS(_data, _index, _limit, MDL::Vertex_MDL7)
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+MDLImporter::MDLImporter() :
+        configFrameID(), mBuffer(), iGSFileVersion(), mIOHandler(nullptr), pScene(), iFileSize() {
+    // empty
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+MDLImporter::~MDLImporter() {
+    // empty
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the class can handle the format of the given file.
+bool MDLImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
+    static const uint32_t tokens[] = {
+        AI_MDL_MAGIC_NUMBER_LE_HL2a,
+        AI_MDL_MAGIC_NUMBER_LE_HL2b,
+        AI_MDL_MAGIC_NUMBER_LE_GS7,
+        AI_MDL_MAGIC_NUMBER_LE_GS5b,
+        AI_MDL_MAGIC_NUMBER_LE_GS5a,
+        AI_MDL_MAGIC_NUMBER_LE_GS4,
+        AI_MDL_MAGIC_NUMBER_LE_GS3,
+        AI_MDL_MAGIC_NUMBER_LE
+    };
+    return CheckMagicToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
+}
+
+// ------------------------------------------------------------------------------------------------
+// Setup configuration properties
+void MDLImporter::SetupProperties(const Importer *pImp) {
+    configFrameID = pImp->GetPropertyInteger(AI_CONFIG_IMPORT_MDL_KEYFRAME, -1);
+
+    // The
+    // AI_CONFIG_IMPORT_MDL_KEYFRAME option overrides the
+    // AI_CONFIG_IMPORT_GLOBAL_KEYFRAME option.
+    if (static_cast<unsigned int>(-1) == configFrameID) {
+        configFrameID = pImp->GetPropertyInteger(AI_CONFIG_IMPORT_GLOBAL_KEYFRAME, 0);
+    }
+
+    // AI_CONFIG_IMPORT_MDL_COLORMAP - palette file
+    configPalette = pImp->GetPropertyString(AI_CONFIG_IMPORT_MDL_COLORMAP, "colormap.lmp");
+
+    // Read configuration specific to MDL (Half-Life 1).
+    mHL1ImportSettings.read_animations = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_ANIMATIONS, true);
+    if (mHL1ImportSettings.read_animations) {
+        mHL1ImportSettings.read_animation_events = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_ANIMATION_EVENTS, true);
+        mHL1ImportSettings.read_blend_controllers = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_BLEND_CONTROLLERS, true);
+        mHL1ImportSettings.read_sequence_transitions = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_SEQUENCE_TRANSITIONS, true);
+    }
+    mHL1ImportSettings.read_attachments = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_ATTACHMENTS, true);
+    mHL1ImportSettings.read_bone_controllers = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_BONE_CONTROLLERS, true);
+    mHL1ImportSettings.read_hitboxes = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_HITBOXES, true);
+    mHL1ImportSettings.read_misc_global_info = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_MISC_GLOBAL_INFO, true);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Get a list of all supported extensions
+const aiImporterDesc *MDLImporter::GetInfo() const {
+    return &desc;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Imports the given file into the given scene structure.
+void MDLImporter::InternReadFile(const std::string &pFile,
+        aiScene *_pScene, IOSystem *pIOHandler) {
+    pScene = _pScene;
+    mIOHandler = pIOHandler;
+    std::unique_ptr<IOStream> file(pIOHandler->Open(pFile));
+
+    // Check whether we can read from the file
+    if (file.get() == nullptr) {
+        throw DeadlyImportError("Failed to open MDL file ", pFile, ".");
+    }
+
+    // This should work for all other types of MDL files, too ...
+    // the HL1 sequence group header is one of the smallest, afaik
+    iFileSize = (unsigned int)file->FileSize();
+    if (iFileSize < sizeof(MDL::HalfLife::SequenceHeader_HL1)) {
+        throw DeadlyImportError("MDL File is too small.");
+    }
+
+    // delete the file buffer and cleanup.
+    auto DeleteBufferAndCleanup = [&]() {
+        if (mBuffer) {
+            delete[] mBuffer;
+            mBuffer = nullptr;
+        }
+        AI_DEBUG_INVALIDATE_PTR(mIOHandler);
+        AI_DEBUG_INVALIDATE_PTR(pScene);
+    };
+
+    try {
+        // Allocate storage and copy the contents of the file to a memory buffer
+        mBuffer = new unsigned char[iFileSize + 1];
+        file->Read((void *)mBuffer, 1, iFileSize);
+
+        // Append a binary zero to the end of the buffer.
+        // this is just for safety that string parsing routines
+        // find the end of the buffer ...
+        mBuffer[iFileSize] = '\0';
+        const uint32_t iMagicWord = *((uint32_t *)mBuffer);
+
+        // Determine the file subtype and call the appropriate member function
+        bool is_half_life = false;
+
+        // Original Quake1 format
+        if (AI_MDL_MAGIC_NUMBER_BE == iMagicWord || AI_MDL_MAGIC_NUMBER_LE == iMagicWord) {
+            ASSIMP_LOG_DEBUG("MDL subtype: Quake 1, magic word is IDPO");
+            iGSFileVersion = 0;
+            InternReadFile_Quake1();
+        }
+        // GameStudio A<old> MDL2 format - used by some test models that come with 3DGS
+        else if (AI_MDL_MAGIC_NUMBER_BE_GS3 == iMagicWord || AI_MDL_MAGIC_NUMBER_LE_GS3 == iMagicWord) {
+            ASSIMP_LOG_DEBUG("MDL subtype: 3D GameStudio A2, magic word is MDL2");
+            iGSFileVersion = 2;
+            InternReadFile_Quake1();
+        }
+        // GameStudio A4 MDL3 format
+        else if (AI_MDL_MAGIC_NUMBER_BE_GS4 == iMagicWord || AI_MDL_MAGIC_NUMBER_LE_GS4 == iMagicWord) {
+            ASSIMP_LOG_DEBUG("MDL subtype: 3D GameStudio A4, magic word is MDL3");
+            iGSFileVersion = 3;
+            InternReadFile_3DGS_MDL345();
+        }
+        // GameStudio A5+ MDL4 format
+        else if (AI_MDL_MAGIC_NUMBER_BE_GS5a == iMagicWord || AI_MDL_MAGIC_NUMBER_LE_GS5a == iMagicWord) {
+            ASSIMP_LOG_DEBUG("MDL subtype: 3D GameStudio A4, magic word is MDL4");
+            iGSFileVersion = 4;
+            InternReadFile_3DGS_MDL345();
+        }
+        // GameStudio A5+ MDL5 format
+        else if (AI_MDL_MAGIC_NUMBER_BE_GS5b == iMagicWord || AI_MDL_MAGIC_NUMBER_LE_GS5b == iMagicWord) {
+            ASSIMP_LOG_DEBUG("MDL subtype: 3D GameStudio A5, magic word is MDL5");
+            iGSFileVersion = 5;
+            InternReadFile_3DGS_MDL345();
+        }
+        // GameStudio A7 MDL7 format
+        else if (AI_MDL_MAGIC_NUMBER_BE_GS7 == iMagicWord || AI_MDL_MAGIC_NUMBER_LE_GS7 == iMagicWord) {
+            ASSIMP_LOG_DEBUG("MDL subtype: 3D GameStudio A7, magic word is MDL7");
+            iGSFileVersion = 7;
+            InternReadFile_3DGS_MDL7();
+        }
+        // IDST/IDSQ Format (CS:S/HL^2, etc ...)
+        else if (AI_MDL_MAGIC_NUMBER_BE_HL2a == iMagicWord || AI_MDL_MAGIC_NUMBER_LE_HL2a == iMagicWord ||
+                 AI_MDL_MAGIC_NUMBER_BE_HL2b == iMagicWord || AI_MDL_MAGIC_NUMBER_LE_HL2b == iMagicWord) {
+            iGSFileVersion = 0;
+            is_half_life = true;
+
+            HalfLife::HalfLifeMDLBaseHeader *pHeader = (HalfLife::HalfLifeMDLBaseHeader *)mBuffer;
+            if (pHeader->version == AI_MDL_HL1_VERSION) {
+                ASSIMP_LOG_DEBUG("MDL subtype: Half-Life 1/Goldsrc Engine, magic word is IDST/IDSQ");
+                InternReadFile_HL1(pFile, iMagicWord);
+            } else {
+                ASSIMP_LOG_DEBUG("MDL subtype: Source(tm) Engine, magic word is IDST/IDSQ");
+                InternReadFile_HL2();
+            }
+        } else {
+            // print the magic word to the log file
+            throw DeadlyImportError("Unknown MDL subformat ", pFile,
+                                    ". Magic word (", ai_str_toprintable((const char *)&iMagicWord, sizeof(iMagicWord)), ") is not known");
+        }
+
+        if (is_half_life){
+            // Now rotate the whole scene 90 degrees around the z and x axes to convert to internal coordinate system
+            pScene->mRootNode->mTransformation = aiMatrix4x4(
+                    0.f, -1.f, 0.f, 0.f,
+                    0.f, 0.f, 1.f, 0.f,
+                    -1.f, 0.f, 0.f, 0.f,
+                    0.f, 0.f, 0.f, 1.f);
+        }
+        else {
+            // Now rotate the whole scene 90 degrees around the x axis to convert to internal coordinate system
+            pScene->mRootNode->mTransformation = aiMatrix4x4(1.f, 0.f, 0.f, 0.f,
+                    0.f, 0.f, 1.f, 0.f, 0.f, -1.f, 0.f, 0.f, 0.f, 0.f, 0.f, 1.f);
+        }
+
+        DeleteBufferAndCleanup();
+    } catch (...) {
+        DeleteBufferAndCleanup();
+        throw;
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Check whether we're still inside the valid file range
+void MDLImporter::SizeCheck(const void *szPos) {
+    if (!szPos || (const unsigned char *)szPos > this->mBuffer + this->iFileSize) {
+        throw DeadlyImportError("Invalid MDL file. The file is too small "
+                                "or contains invalid data.");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Just for debugging purposes
+void MDLImporter::SizeCheck(const void *szPos, const char *szFile, unsigned int iLine) {
+    ai_assert(nullptr != szFile);
+    if (!szPos || (const unsigned char *)szPos > mBuffer + iFileSize) {
+        // remove a directory if there is one
+        const char *szFilePtr = ::strrchr(szFile, '\\');
+        if (!szFilePtr) {
+            szFilePtr = ::strrchr(szFile, '/');
+            if (nullptr == szFilePtr) {
+                szFilePtr = szFile;
+            }
+        }
+        if (szFilePtr) {
+            ++szFilePtr;
+        }
+
+        char szBuffer[1024];
+        ::sprintf(szBuffer, "Invalid MDL file. The file is too small "
+                            "or contains invalid data (File: %s Line: %u)",
+                szFilePtr, iLine);
+
+        throw DeadlyImportError(szBuffer);
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Validate a quake file header
+void MDLImporter::ValidateHeader_Quake1(const MDL::Header *pcHeader) {
+    // some values may not be nullptr
+    if (!pcHeader->num_frames)
+        throw DeadlyImportError("[Quake 1 MDL] There are no frames in the file");
+
+    if (!pcHeader->num_verts)
+        throw DeadlyImportError("[Quake 1 MDL] There are no vertices in the file");
+
+    if (!pcHeader->num_tris)
+        throw DeadlyImportError("[Quake 1 MDL] There are no triangles in the file");
+
+    // check whether the maxima are exceeded ...however, this applies for Quake 1 MDLs only
+    if (!this->iGSFileVersion) {
+        if (pcHeader->num_verts > AI_MDL_MAX_VERTS)
+            ASSIMP_LOG_WARN("Quake 1 MDL model has more than AI_MDL_MAX_VERTS vertices");
+
+        if (pcHeader->num_tris > AI_MDL_MAX_TRIANGLES)
+            ASSIMP_LOG_WARN("Quake 1 MDL model has more than AI_MDL_MAX_TRIANGLES triangles");
+
+        if (pcHeader->num_frames > AI_MDL_MAX_FRAMES)
+            ASSIMP_LOG_WARN("Quake 1 MDL model has more than AI_MDL_MAX_FRAMES frames");
+
+        // (this does not apply for 3DGS MDLs)
+        if (!this->iGSFileVersion && pcHeader->version != AI_MDL_VERSION)
+            ASSIMP_LOG_WARN("Quake 1 MDL model has an unknown version: AI_MDL_VERSION (=6) is "
+                            "the expected file format version");
+        if (pcHeader->num_skins && (!pcHeader->skinwidth || !pcHeader->skinheight))
+            ASSIMP_LOG_WARN("Skin width or height are 0");
+    }
+}
+
+#ifdef AI_BUILD_BIG_ENDIAN
+// ------------------------------------------------------------------------------------------------
+void FlipQuakeHeader(BE_NCONST MDL::Header *pcHeader) {
+    AI_SWAP4(pcHeader->ident);
+    AI_SWAP4(pcHeader->version);
+    AI_SWAP4(pcHeader->boundingradius);
+    AI_SWAP4(pcHeader->flags);
+    AI_SWAP4(pcHeader->num_frames);
+    AI_SWAP4(pcHeader->num_skins);
+    AI_SWAP4(pcHeader->num_tris);
+    AI_SWAP4(pcHeader->num_verts);
+    for (unsigned int i = 0; i < 3; ++i) {
+        AI_SWAP4(pcHeader->scale[i]);
+        AI_SWAP4(pcHeader->translate[i]);
+    }
+    AI_SWAP4(pcHeader->size);
+    AI_SWAP4(pcHeader->skinheight);
+    AI_SWAP4(pcHeader->skinwidth);
+    AI_SWAP4(pcHeader->synctype);
+}
+#endif
+
+// ------------------------------------------------------------------------------------------------
+// Read a Quake 1 file
+void MDLImporter::InternReadFile_Quake1() {
+    ai_assert(nullptr != pScene);
+
+    BE_NCONST MDL::Header *pcHeader = (BE_NCONST MDL::Header *)this->mBuffer;
+
+#ifdef AI_BUILD_BIG_ENDIAN
+    FlipQuakeHeader(pcHeader);
+#endif
+
+    ValidateHeader_Quake1(pcHeader);
+
+    // current cursor position in the file
+    const unsigned char *szCurrent = (const unsigned char *)(pcHeader + 1);
+
+    // need to read all textures
+    for (unsigned int i = 0; i < (unsigned int)pcHeader->num_skins; ++i) {
+        union {
+            BE_NCONST MDL::Skin *pcSkin;
+            BE_NCONST MDL::GroupSkin *pcGroupSkin;
+        };
+        if (szCurrent + sizeof(MDL::Skin) > this->mBuffer + this->iFileSize) {
+            throw DeadlyImportError("[Quake 1 MDL] Unexpected EOF");
+        }
+        pcSkin = (BE_NCONST MDL::Skin *)szCurrent;
+
+        AI_SWAP4(pcSkin->group);
+
+        // Quake 1 group-skins
+        if (1 == pcSkin->group) {
+            AI_SWAP4(pcGroupSkin->nb);
+
+            // need to skip multiple images
+            const unsigned int iNumImages = (unsigned int)pcGroupSkin->nb;
+            szCurrent += sizeof(uint32_t) * 2;
+
+            if (0 != iNumImages) {
+                if (!i) {
+                    // however, create only one output image (the first)
+                    this->CreateTextureARGB8_3DGS_MDL3(szCurrent + iNumImages * sizeof(float));
+                }
+                // go to the end of the skin section / the beginning of the next skin
+                szCurrent += pcHeader->skinheight * pcHeader->skinwidth +
+                             sizeof(float) * iNumImages;
+            }
+        } else {
+            szCurrent += sizeof(uint32_t);
+            unsigned int iSkip = i ? UINT_MAX : 0;
+            CreateTexture_3DGS_MDL4(szCurrent, pcSkin->group, &iSkip);
+            szCurrent += iSkip;
+        }
+    }
+    // get a pointer to the texture coordinates
+    BE_NCONST MDL::TexCoord *pcTexCoords = (BE_NCONST MDL::TexCoord *)szCurrent;
+    szCurrent += sizeof(MDL::TexCoord) * pcHeader->num_verts;
+
+    // get a pointer to the triangles
+    BE_NCONST MDL::Triangle *pcTriangles = (BE_NCONST MDL::Triangle *)szCurrent;
+    szCurrent += sizeof(MDL::Triangle) * pcHeader->num_tris;
+    VALIDATE_FILE_SIZE(szCurrent);
+
+    // now get a pointer to the first frame in the file
+    BE_NCONST MDL::Frame *pcFrames = (BE_NCONST MDL::Frame *)szCurrent;
+    MDL::SimpleFrame *pcFirstFrame;
+
+    if (0 == pcFrames->type) {
+        // get address of single frame
+        pcFirstFrame = (MDL::SimpleFrame *)&pcFrames->frame;
+    } else {
+        // get the first frame in the group
+        BE_NCONST MDL::GroupFrame *pcFrames2 = (BE_NCONST MDL::GroupFrame *)szCurrent;
+        pcFirstFrame = (MDL::SimpleFrame *)( szCurrent + sizeof(MDL::GroupFrame::type) + sizeof(MDL::GroupFrame::numframes)
+        + sizeof(MDL::GroupFrame::min) + sizeof(MDL::GroupFrame::max) + sizeof(*MDL::GroupFrame::times) * pcFrames2->numframes );
+    }
+    BE_NCONST MDL::Vertex *pcVertices = (BE_NCONST MDL::Vertex *)((pcFirstFrame->name) + sizeof(pcFirstFrame->name));
+    VALIDATE_FILE_SIZE((const unsigned char *)(pcVertices + pcHeader->num_verts));
+
+#ifdef AI_BUILD_BIG_ENDIAN
+    for (int i = 0; i < pcHeader->num_verts; ++i) {
+        AI_SWAP4(pcTexCoords[i].onseam);
+        AI_SWAP4(pcTexCoords[i].s);
+        AI_SWAP4(pcTexCoords[i].t);
+    }
+
+    for (int i = 0; i < pcHeader->num_tris; ++i) {
+        AI_SWAP4(pcTriangles[i].facesfront);
+        AI_SWAP4(pcTriangles[i].vertex[0]);
+        AI_SWAP4(pcTriangles[i].vertex[1]);
+        AI_SWAP4(pcTriangles[i].vertex[2]);
+    }
+#endif
+
+    // setup materials
+    SetupMaterialProperties_3DGS_MDL5_Quake1();
+
+    // allocate enough storage to hold all vertices and triangles
+    aiMesh *pcMesh = new aiMesh();
+
+    pcMesh->mPrimitiveTypes = aiPrimitiveType_TRIANGLE;
+    pcMesh->mNumVertices = pcHeader->num_tris * 3;
+    pcMesh->mNumFaces = pcHeader->num_tris;
+    pcMesh->mVertices = new aiVector3D[pcMesh->mNumVertices];
+    pcMesh->mTextureCoords[0] = new aiVector3D[pcMesh->mNumVertices];
+    pcMesh->mFaces = new aiFace[pcMesh->mNumFaces];
+    pcMesh->mNormals = new aiVector3D[pcMesh->mNumVertices];
+    pcMesh->mNumUVComponents[0] = 2;
+
+    // there won't be more than one mesh inside the file
+    pScene->mRootNode = new aiNode();
+    pScene->mRootNode->mNumMeshes = 1;
+    pScene->mRootNode->mMeshes = new unsigned int[1];
+    pScene->mRootNode->mMeshes[0] = 0;
+    pScene->mNumMeshes = 1;
+    pScene->mMeshes = new aiMesh *[1];
+    pScene->mMeshes[0] = pcMesh;
+
+    // now iterate through all triangles
+    unsigned int iCurrent = 0;
+    for (unsigned int i = 0; i < (unsigned int)pcHeader->num_tris; ++i) {
+        pcMesh->mFaces[i].mIndices = new unsigned int[3];
+        pcMesh->mFaces[i].mNumIndices = 3;
+
+        unsigned int iTemp = iCurrent;
+        for (unsigned int c = 0; c < 3; ++c, ++iCurrent) {
+            pcMesh->mFaces[i].mIndices[c] = iCurrent;
+
+            // read vertices
+            unsigned int iIndex = pcTriangles->vertex[c];
+            if (iIndex >= (unsigned int)pcHeader->num_verts) {
+                iIndex = pcHeader->num_verts - 1;
+                ASSIMP_LOG_WARN("Index overflow in Q1-MDL vertex list.");
+            }
+
+            aiVector3D &vec = pcMesh->mVertices[iCurrent];
+            vec.x = (float)pcVertices[iIndex].v[0] * pcHeader->scale[0];
+            vec.x += pcHeader->translate[0];
+
+            vec.y = (float)pcVertices[iIndex].v[1] * pcHeader->scale[1];
+            vec.y += pcHeader->translate[1];
+            //vec.y *= -1.0f;
+
+            vec.z = (float)pcVertices[iIndex].v[2] * pcHeader->scale[2];
+            vec.z += pcHeader->translate[2];
+
+            // read the normal vector from the precalculated normal table
+            MD2::LookupNormalIndex(pcVertices[iIndex].normalIndex, pcMesh->mNormals[iCurrent]);
+            //pcMesh->mNormals[iCurrent].y *= -1.0f;
+
+            // read texture coordinates
+            float s = (float)pcTexCoords[iIndex].s;
+            float t = (float)pcTexCoords[iIndex].t;
+
+            // translate texture coordinates
+            if (0 == pcTriangles->facesfront && 0 != pcTexCoords[iIndex].onseam) {
+                s += pcHeader->skinwidth * 0.5f;
+            }
+
+            // Scale s and t to range from 0.0 to 1.0
+            pcMesh->mTextureCoords[0][iCurrent].x = (s + 0.5f) / pcHeader->skinwidth;
+            pcMesh->mTextureCoords[0][iCurrent].y = 1.0f - (t + 0.5f) / pcHeader->skinheight;
+        }
+        pcMesh->mFaces[i].mIndices[0] = iTemp + 2;
+        pcMesh->mFaces[i].mIndices[1] = iTemp + 1;
+        pcMesh->mFaces[i].mIndices[2] = iTemp + 0;
+        pcTriangles++;
+    }
+    return;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Setup material properties for Quake and older GameStudio files
+void MDLImporter::SetupMaterialProperties_3DGS_MDL5_Quake1() {
+    const MDL::Header *const pcHeader = (const MDL::Header *)this->mBuffer;
+
+    // allocate ONE material
+    pScene->mMaterials = new aiMaterial *[1];
+    pScene->mMaterials[0] = new aiMaterial();
+    pScene->mNumMaterials = 1;
+
+    // setup the material's properties
+    const int iMode = (int)aiShadingMode_Gouraud;
+    aiMaterial *const pcHelper = (aiMaterial *)pScene->mMaterials[0];
+    pcHelper->AddProperty<int>(&iMode, 1, AI_MATKEY_SHADING_MODEL);
+
+    aiColor4D clr;
+    if (0 != pcHeader->num_skins && pScene->mNumTextures) {
+        // can we replace the texture with a single color?
+        clr = this->ReplaceTextureWithColor(pScene->mTextures[0]);
+        if (is_not_qnan(clr.r)) {
+            delete pScene->mTextures[0];
+            delete[] pScene->mTextures;
+
+            pScene->mTextures = nullptr;
+            pScene->mNumTextures = 0;
+        } else {
+            clr.b = clr.a = clr.g = clr.r = 1.0f;
+            aiString szString;
+            ::memcpy(szString.data, AI_MAKE_EMBEDDED_TEXNAME(0), 3);
+            szString.length = 2;
+            pcHelper->AddProperty(&szString, AI_MATKEY_TEXTURE_DIFFUSE(0));
+        }
+    }
+
+    pcHelper->AddProperty<aiColor4D>(&clr, 1, AI_MATKEY_COLOR_DIFFUSE);
+    pcHelper->AddProperty<aiColor4D>(&clr, 1, AI_MATKEY_COLOR_SPECULAR);
+
+    clr.r *= 0.05f;
+    clr.g *= 0.05f;
+    clr.b *= 0.05f;
+    clr.a = 1.0f;
+    pcHelper->AddProperty<aiColor4D>(&clr, 1, AI_MATKEY_COLOR_AMBIENT);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Read a MDL 3,4,5 file
+void MDLImporter::InternReadFile_3DGS_MDL345() {
+    ai_assert(nullptr != pScene);
+
+    // the header of MDL 3/4/5 is nearly identical to the original Quake1 header
+    BE_NCONST MDL::Header *pcHeader = (BE_NCONST MDL::Header *)this->mBuffer;
+#ifdef AI_BUILD_BIG_ENDIAN
+    FlipQuakeHeader(pcHeader);
+#endif
+    ValidateHeader_Quake1(pcHeader);
+
+    // current cursor position in the file
+    const unsigned char *szCurrent = (const unsigned char *)(pcHeader + 1);
+    const unsigned char *szEnd = mBuffer + iFileSize;
+
+    // need to read all textures
+    for (unsigned int i = 0; i < (unsigned int)pcHeader->num_skins; ++i) {
+        if (szCurrent + sizeof(uint32_t) > szEnd) {
+            throw DeadlyImportError("Texture data past end of file.");
+        }
+        BE_NCONST MDL::Skin *pcSkin;
+        pcSkin = (BE_NCONST MDL::Skin *)szCurrent;
+        AI_SWAP4(pcSkin->group);
+        // create one output image
+        unsigned int iSkip = i ? UINT_MAX : 0;
+        if (5 <= iGSFileVersion) {
+            // MDL5 format could contain MIPmaps
+            CreateTexture_3DGS_MDL5((unsigned char *)pcSkin + sizeof(uint32_t),
+                    pcSkin->group, &iSkip);
+        } else {
+            CreateTexture_3DGS_MDL4((unsigned char *)pcSkin + sizeof(uint32_t),
+                    pcSkin->group, &iSkip);
+        }
+        // need to skip one image
+        szCurrent += iSkip + sizeof(uint32_t);
+    }
+    // get a pointer to the texture coordinates
+    BE_NCONST MDL::TexCoord_MDL3 *pcTexCoords = (BE_NCONST MDL::TexCoord_MDL3 *)szCurrent;
+    szCurrent += sizeof(MDL::TexCoord_MDL3) * pcHeader->synctype;
+
+    // NOTE: for MDLn formats "synctype" corresponds to the number of UV coords
+
+    // get a pointer to the triangles
+    BE_NCONST MDL::Triangle_MDL3 *pcTriangles = (BE_NCONST MDL::Triangle_MDL3 *)szCurrent;
+    szCurrent += sizeof(MDL::Triangle_MDL3) * pcHeader->num_tris;
+
+#ifdef AI_BUILD_BIG_ENDIAN
+
+    for (int i = 0; i < pcHeader->synctype; ++i) {
+        AI_SWAP2(pcTexCoords[i].u);
+        AI_SWAP2(pcTexCoords[i].v);
+    }
+
+    for (int i = 0; i < pcHeader->num_tris; ++i) {
+        AI_SWAP2(pcTriangles[i].index_xyz[0]);
+        AI_SWAP2(pcTriangles[i].index_xyz[1]);
+        AI_SWAP2(pcTriangles[i].index_xyz[2]);
+        AI_SWAP2(pcTriangles[i].index_uv[0]);
+        AI_SWAP2(pcTriangles[i].index_uv[1]);
+        AI_SWAP2(pcTriangles[i].index_uv[2]);
+    }
+
+#endif
+
+    VALIDATE_FILE_SIZE(szCurrent);
+
+    // setup materials
+    SetupMaterialProperties_3DGS_MDL5_Quake1();
+
+    // allocate enough storage to hold all vertices and triangles
+    aiMesh *pcMesh = new aiMesh();
+    pcMesh->mPrimitiveTypes = aiPrimitiveType_TRIANGLE;
+
+    pcMesh->mNumVertices = pcHeader->num_tris * 3;
+    pcMesh->mNumFaces = pcHeader->num_tris;
+    pcMesh->mFaces = new aiFace[pcMesh->mNumFaces];
+
+    // there won't be more than one mesh inside the file
+    pScene->mRootNode = new aiNode();
+    pScene->mRootNode->mNumMeshes = 1;
+    pScene->mRootNode->mMeshes = new unsigned int[1];
+    pScene->mRootNode->mMeshes[0] = 0;
+    pScene->mNumMeshes = 1;
+    pScene->mMeshes = new aiMesh *[1];
+    pScene->mMeshes[0] = pcMesh;
+
+    // allocate output storage
+    pcMesh->mNumVertices = (unsigned int)pcHeader->num_tris * 3;
+    pcMesh->mVertices = new aiVector3D[pcMesh->mNumVertices];
+    pcMesh->mNormals = new aiVector3D[pcMesh->mNumVertices];
+
+    if (pcHeader->synctype) {
+        pcMesh->mTextureCoords[0] = new aiVector3D[pcMesh->mNumVertices];
+        pcMesh->mNumUVComponents[0] = 2;
+    }
+
+    // now get a pointer to the first frame in the file
+    BE_NCONST MDL::Frame *pcFrames = (BE_NCONST MDL::Frame *)szCurrent;
+    AI_SWAP4(pcFrames->type);
+
+    // byte packed vertices
+    // FIXME: these two snippets below are almost identical ... join them?
+    /////////////////////////////////////////////////////////////////////////////////////
+    if (0 == pcFrames->type || 3 >= this->iGSFileVersion) {
+
+        const MDL::SimpleFrame *pcFirstFrame = (const MDL::SimpleFrame *)(szCurrent + sizeof(uint32_t));
+        const MDL::Vertex *pcVertices = (const MDL::Vertex *)((pcFirstFrame->name) + sizeof(pcFirstFrame->name));
+
+        VALIDATE_FILE_SIZE(pcVertices + pcHeader->num_verts);
+
+        // now iterate through all triangles
+        unsigned int iCurrent = 0;
+        for (unsigned int i = 0; i < (unsigned int)pcHeader->num_tris; ++i) {
+            pcMesh->mFaces[i].mIndices = new unsigned int[3];
+            pcMesh->mFaces[i].mNumIndices = 3;
+
+            unsigned int iTemp = iCurrent;
+            for (unsigned int c = 0; c < 3; ++c, ++iCurrent) {
+                // read vertices
+                unsigned int iIndex = pcTriangles->index_xyz[c];
+                if (iIndex >= (unsigned int)pcHeader->num_verts) {
+                    iIndex = pcHeader->num_verts - 1;
+                    ASSIMP_LOG_WARN("Index overflow in MDLn vertex list");
+                }
+
+                aiVector3D &vec = pcMesh->mVertices[iCurrent];
+                vec.x = (float)pcVertices[iIndex].v[0] * pcHeader->scale[0];
+                vec.x += pcHeader->translate[0];
+
+                vec.y = (float)pcVertices[iIndex].v[1] * pcHeader->scale[1];
+                vec.y += pcHeader->translate[1];
+                // vec.y *= -1.0f;
+
+                vec.z = (float)pcVertices[iIndex].v[2] * pcHeader->scale[2];
+                vec.z += pcHeader->translate[2];
+
+                // read the normal vector from the precalculated normal table
+                MD2::LookupNormalIndex(pcVertices[iIndex].normalIndex, pcMesh->mNormals[iCurrent]);
+                // pcMesh->mNormals[iCurrent].y *= -1.0f;
+
+                // read texture coordinates
+                if (pcHeader->synctype) {
+                    ImportUVCoordinate_3DGS_MDL345(pcMesh->mTextureCoords[0][iCurrent],
+                            pcTexCoords, pcTriangles->index_uv[c]);
+                }
+            }
+            pcMesh->mFaces[i].mIndices[0] = iTemp + 2;
+            pcMesh->mFaces[i].mIndices[1] = iTemp + 1;
+            pcMesh->mFaces[i].mIndices[2] = iTemp + 0;
+            pcTriangles++;
+        }
+
+    }
+    // short packed vertices
+    /////////////////////////////////////////////////////////////////////////////////////
+    else {
+        // now get a pointer to the first frame in the file
+        const MDL::SimpleFrame_MDLn_SP *pcFirstFrame = (const MDL::SimpleFrame_MDLn_SP *)(szCurrent + sizeof(uint32_t));
+
+        // get a pointer to the vertices
+        const MDL::Vertex_MDL4 *pcVertices = (const MDL::Vertex_MDL4 *)((pcFirstFrame->name) +
+                                                                        sizeof(pcFirstFrame->name));
+
+        VALIDATE_FILE_SIZE(pcVertices + pcHeader->num_verts);
+
+        // now iterate through all triangles
+        unsigned int iCurrent = 0;
+        for (unsigned int i = 0; i < (unsigned int)pcHeader->num_tris; ++i) {
+            pcMesh->mFaces[i].mIndices = new unsigned int[3];
+            pcMesh->mFaces[i].mNumIndices = 3;
+
+            unsigned int iTemp = iCurrent;
+            for (unsigned int c = 0; c < 3; ++c, ++iCurrent) {
+                // read vertices
+                unsigned int iIndex = pcTriangles->index_xyz[c];
+                if (iIndex >= (unsigned int)pcHeader->num_verts) {
+                    iIndex = pcHeader->num_verts - 1;
+                    ASSIMP_LOG_WARN("Index overflow in MDLn vertex list");
+                }
+
+                aiVector3D &vec = pcMesh->mVertices[iCurrent];
+                vec.x = (float)pcVertices[iIndex].v[0] * pcHeader->scale[0];
+                vec.x += pcHeader->translate[0];
+
+                vec.y = (float)pcVertices[iIndex].v[1] * pcHeader->scale[1];
+                vec.y += pcHeader->translate[1];
+                // vec.y *= -1.0f;
+
+                vec.z = (float)pcVertices[iIndex].v[2] * pcHeader->scale[2];
+                vec.z += pcHeader->translate[2];
+
+                // read the normal vector from the precalculated normal table
+                MD2::LookupNormalIndex(pcVertices[iIndex].normalIndex, pcMesh->mNormals[iCurrent]);
+                // pcMesh->mNormals[iCurrent].y *= -1.0f;
+
+                // read texture coordinates
+                if (pcHeader->synctype) {
+                    ImportUVCoordinate_3DGS_MDL345(pcMesh->mTextureCoords[0][iCurrent],
+                            pcTexCoords, pcTriangles->index_uv[c]);
+                }
+            }
+            pcMesh->mFaces[i].mIndices[0] = iTemp + 2;
+            pcMesh->mFaces[i].mIndices[1] = iTemp + 1;
+            pcMesh->mFaces[i].mIndices[2] = iTemp + 0;
+            pcTriangles++;
+        }
+    }
+
+    // For MDL5 we will need to build valid texture coordinates
+    // basing upon the file loaded (only support one file as skin)
+    if (0x5 == iGSFileVersion)
+        CalculateUVCoordinates_MDL5();
+    return;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Get a single UV coordinate for Quake and older GameStudio files
+void MDLImporter::ImportUVCoordinate_3DGS_MDL345(
+        aiVector3D &vOut,
+        const MDL::TexCoord_MDL3 *pcSrc,
+        unsigned int iIndex) {
+    ai_assert(nullptr != pcSrc);
+    const MDL::Header *const pcHeader = (const MDL::Header *)this->mBuffer;
+
+    // validate UV indices
+    if (iIndex >= (unsigned int)pcHeader->synctype) {
+        iIndex = pcHeader->synctype - 1;
+        ASSIMP_LOG_WARN("Index overflow in MDLn UV coord list");
+    }
+
+    float s = (float)pcSrc[iIndex].u;
+    float t = (float)pcSrc[iIndex].v;
+
+    // Scale s and t to range from 0.0 to 1.0
+    if (0x5 != iGSFileVersion) {
+        s = (s + 0.5f) / pcHeader->skinwidth;
+        t = 1.0f - (t + 0.5f) / pcHeader->skinheight;
+    }
+
+    vOut.x = s;
+    vOut.y = t;
+    vOut.z = 0.0f;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Compute UV coordinates for a MDL5 file
+void MDLImporter::CalculateUVCoordinates_MDL5() {
+    const MDL::Header *const pcHeader = (const MDL::Header *)this->mBuffer;
+    if (pcHeader->num_skins && this->pScene->mNumTextures) {
+        const aiTexture *pcTex = this->pScene->mTextures[0];
+
+        // if the file is loaded in DDS format: get the size of the
+        // texture from the header of the DDS file
+        // skip three DWORDs and read first height, then the width
+        unsigned int iWidth, iHeight;
+        if (!pcTex->mHeight) {
+            const uint32_t *piPtr = (uint32_t *)pcTex->pcData;
+
+            piPtr += 3;
+            iHeight = (unsigned int)*piPtr++;
+            iWidth = (unsigned int)*piPtr;
+            if (!iHeight || !iWidth) {
+                ASSIMP_LOG_WARN("Either the width or the height of the "
+                                "embedded DDS texture is zero. Unable to compute final texture "
+                                "coordinates. The texture coordinates remain in their original "
+                                "0-x/0-y (x,y = texture size) range.");
+                iWidth = 1;
+                iHeight = 1;
+            }
+        } else {
+            iWidth = pcTex->mWidth;
+            iHeight = pcTex->mHeight;
+        }
+
+        if (1 != iWidth || 1 != iHeight) {
+            const float fWidth = (float)iWidth;
+            const float fHeight = (float)iHeight;
+            aiMesh *pcMesh = this->pScene->mMeshes[0];
+            for (unsigned int i = 0; i < pcMesh->mNumVertices; ++i) {
+                pcMesh->mTextureCoords[0][i].x /= fWidth;
+                pcMesh->mTextureCoords[0][i].y /= fHeight;
+                pcMesh->mTextureCoords[0][i].y = 1.0f - pcMesh->mTextureCoords[0][i].y; // DX to OGL
+            }
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Validate the header of a MDL7 file
+void MDLImporter::ValidateHeader_3DGS_MDL7(const MDL::Header_MDL7 *pcHeader) {
+    ai_assert(nullptr != pcHeader);
+
+    // There are some fixed sizes ...
+    if (sizeof(MDL::ColorValue_MDL7) != pcHeader->colorvalue_stc_size) {
+        throw DeadlyImportError(
+                "[3DGS MDL7] sizeof(MDL::ColorValue_MDL7) != pcHeader->colorvalue_stc_size");
+    }
+    if (sizeof(MDL::TexCoord_MDL7) != pcHeader->skinpoint_stc_size) {
+        throw DeadlyImportError(
+                "[3DGS MDL7] sizeof(MDL::TexCoord_MDL7) != pcHeader->skinpoint_stc_size");
+    }
+    if (sizeof(MDL::Skin_MDL7) != pcHeader->skin_stc_size) {
+        throw DeadlyImportError(
+                "sizeof(MDL::Skin_MDL7) != pcHeader->skin_stc_size");
+    }
+
+    // if there are no groups ... how should we load such a file?
+    if (!pcHeader->groups_num) {
+        throw DeadlyImportError("[3DGS MDL7] No frames found");
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// resolve bone animation matrices
+void MDLImporter::CalcAbsBoneMatrices_3DGS_MDL7(MDL::IntBone_MDL7 **apcOutBones) {
+    const MDL::Header_MDL7 *pcHeader = (const MDL::Header_MDL7 *)this->mBuffer;
+    const MDL::Bone_MDL7 *pcBones = (const MDL::Bone_MDL7 *)(pcHeader + 1);
+    ai_assert(nullptr != apcOutBones);
+
+    // first find the bone that has NO parent, calculate the
+    // animation matrix for it, then go on and search for the next parent
+    // index (0) and so on until we can't find a new node.
+    uint16_t iParent = 0xffff;
+    uint32_t iIterations = 0;
+    while (iIterations++ < pcHeader->bones_num) {
+        for (uint32_t iBone = 0; iBone < pcHeader->bones_num; ++iBone) {
+            BE_NCONST MDL::Bone_MDL7 *pcBone = _AI_MDL7_ACCESS_PTR(pcBones, iBone,
+                    pcHeader->bone_stc_size, MDL::Bone_MDL7);
+
+            AI_SWAP2(pcBone->parent_index);
+            AI_SWAP4(pcBone->x);
+            AI_SWAP4(pcBone->y);
+            AI_SWAP4(pcBone->z);
+
+            if (iParent == pcBone->parent_index) {
+                // MDL7 readme
+                ////////////////////////////////////////////////////////////////
+                /*
+                The animation matrix is then calculated the following way:
+
+                vector3 bPos = <absolute bone position>
+                matrix44 laM;   // local animation matrix
+                sphrvector key_rotate = <bone rotation>
+
+                matrix44 m1,m2;
+                create_trans_matrix(m1, -bPos.x, -bPos.y, -bPos.z);
+                create_trans_matrix(m2, -bPos.x, -bPos.y, -bPos.z);
+
+                create_rotation_matrix(laM,key_rotate);
+
+                laM = sm1 * laM;
+                laM = laM * sm2;
+                */
+                /////////////////////////////////////////////////////////////////
+
+                MDL::IntBone_MDL7 *const pcOutBone = apcOutBones[iBone];
+
+                // store the parent index of the bone
+                pcOutBone->iParent = pcBone->parent_index;
+                if (0xffff != iParent) {
+                    const MDL::IntBone_MDL7 *pcParentBone = apcOutBones[iParent];
+                    pcOutBone->mOffsetMatrix.a4 = -pcParentBone->vPosition.x;
+                    pcOutBone->mOffsetMatrix.b4 = -pcParentBone->vPosition.y;
+                    pcOutBone->mOffsetMatrix.c4 = -pcParentBone->vPosition.z;
+                }
+                pcOutBone->vPosition.x = pcBone->x;
+                pcOutBone->vPosition.y = pcBone->y;
+                pcOutBone->vPosition.z = pcBone->z;
+                pcOutBone->mOffsetMatrix.a4 -= pcBone->x;
+                pcOutBone->mOffsetMatrix.b4 -= pcBone->y;
+                pcOutBone->mOffsetMatrix.c4 -= pcBone->z;
+
+                if (AI_MDL7_BONE_STRUCT_SIZE__NAME_IS_NOT_THERE == pcHeader->bone_stc_size) {
+                    // no real name for our poor bone is specified :-(
+                    pcOutBone->mName.length = ai_snprintf(pcOutBone->mName.data, MAXLEN,
+                            "UnnamedBone_%i", iBone);
+                } else {
+                    // Make sure we won't run over the buffer's end if there is no
+                    // terminal 0 character (however the documentation says there
+                    // should be one)
+                    uint32_t iMaxLen = pcHeader->bone_stc_size - 16;
+                    for (uint32_t qq = 0; qq < iMaxLen; ++qq) {
+                        if (!pcBone->name[qq]) {
+                            iMaxLen = qq;
+                            break;
+                        }
+                    }
+
+                    // store the name of the bone
+                    pcOutBone->mName.length = (size_t)iMaxLen;
+                    ::memcpy(pcOutBone->mName.data, pcBone->name, pcOutBone->mName.length);
+                    pcOutBone->mName.data[pcOutBone->mName.length] = '\0';
+                }
+            }
+        }
+        ++iParent;
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// read bones from a MDL7 file
+MDL::IntBone_MDL7 **MDLImporter::LoadBones_3DGS_MDL7() {
+    const MDL::Header_MDL7 *pcHeader = (const MDL::Header_MDL7 *)this->mBuffer;
+    if (pcHeader->bones_num) {
+        // validate the size of the bone data structure in the file
+        if (AI_MDL7_BONE_STRUCT_SIZE__NAME_IS_20_CHARS != pcHeader->bone_stc_size &&
+                AI_MDL7_BONE_STRUCT_SIZE__NAME_IS_32_CHARS != pcHeader->bone_stc_size &&
+                AI_MDL7_BONE_STRUCT_SIZE__NAME_IS_NOT_THERE != pcHeader->bone_stc_size) {
+            ASSIMP_LOG_WARN("Unknown size of bone data structure");
+            return nullptr;
+        }
+
+        MDL::IntBone_MDL7 **apcBonesOut = new MDL::IntBone_MDL7 *[pcHeader->bones_num];
+        for (uint32_t crank = 0; crank < pcHeader->bones_num; ++crank)
+            apcBonesOut[crank] = new MDL::IntBone_MDL7();
+
+        // and calculate absolute bone offset matrices ...
+        CalcAbsBoneMatrices_3DGS_MDL7(apcBonesOut);
+        return apcBonesOut;
+    }
+    return nullptr;
+}
+
+// ------------------------------------------------------------------------------------------------
+// read faces from a MDL7 file
+void MDLImporter::ReadFaces_3DGS_MDL7(const MDL::IntGroupInfo_MDL7 &groupInfo,
+        MDL::IntGroupData_MDL7 &groupData) {
+    const MDL::Header_MDL7 *pcHeader = (const MDL::Header_MDL7 *)this->mBuffer;
+    MDL::Triangle_MDL7 *pcGroupTris = groupInfo.pcGroupTris;
+
+    // iterate through all triangles and build valid display lists
+    unsigned int iOutIndex = 0;
+    for (unsigned int iTriangle = 0; iTriangle < (unsigned int)groupInfo.pcGroup->numtris; ++iTriangle) {
+        AI_SWAP2(pcGroupTris->v_index[0]);
+        AI_SWAP2(pcGroupTris->v_index[1]);
+        AI_SWAP2(pcGroupTris->v_index[2]);
+
+        // iterate through all indices of the current triangle
+        for (unsigned int c = 0; c < 3; ++c, ++iOutIndex) {
+
+            // validate the vertex index
+            unsigned int iIndex = pcGroupTris->v_index[c];
+            if (iIndex > (unsigned int)groupInfo.pcGroup->numverts) {
+                // (we might need to read this section a second time - to process frame vertices correctly)
+                pcGroupTris->v_index[c] = (uint16_t)(iIndex = groupInfo.pcGroup->numverts - 1);
+                ASSIMP_LOG_WARN("Index overflow in MDL7 vertex list");
+            }
+
+            // write the output face index
+            groupData.pcFaces[iTriangle].mIndices[2 - c] = iOutIndex;
+
+            aiVector3D &vPosition = groupData.vPositions[iOutIndex];
+            vPosition.x = _AI_MDL7_ACCESS_VERT(groupInfo.pcGroupVerts, iIndex, pcHeader->mainvertex_stc_size).x;
+            vPosition.y = _AI_MDL7_ACCESS_VERT(groupInfo.pcGroupVerts, iIndex, pcHeader->mainvertex_stc_size).y;
+            vPosition.z = _AI_MDL7_ACCESS_VERT(groupInfo.pcGroupVerts, iIndex, pcHeader->mainvertex_stc_size).z;
+
+            // if we have bones, save the index
+            if (!groupData.aiBones.empty()) {
+                groupData.aiBones[iOutIndex] = _AI_MDL7_ACCESS_VERT(groupInfo.pcGroupVerts,
+                        iIndex, pcHeader->mainvertex_stc_size)
+                                                       .vertindex;
+            }
+
+            // now read the normal vector
+            if (AI_MDL7_FRAMEVERTEX030305_STCSIZE <= pcHeader->mainvertex_stc_size) {
+                // read the full normal vector
+                aiVector3D &vNormal = groupData.vNormals[iOutIndex];
+                vNormal.x = _AI_MDL7_ACCESS_VERT(groupInfo.pcGroupVerts, iIndex, pcHeader->mainvertex_stc_size).norm[0];
+                AI_SWAP4(vNormal.x);
+                vNormal.y = _AI_MDL7_ACCESS_VERT(groupInfo.pcGroupVerts, iIndex, pcHeader->mainvertex_stc_size).norm[1];
+                AI_SWAP4(vNormal.y);
+                vNormal.z = _AI_MDL7_ACCESS_VERT(groupInfo.pcGroupVerts, iIndex, pcHeader->mainvertex_stc_size).norm[2];
+                AI_SWAP4(vNormal.z);
+            } else if (AI_MDL7_FRAMEVERTEX120503_STCSIZE <= pcHeader->mainvertex_stc_size) {
+                // read the normal vector from Quake2's smart table
+                aiVector3D &vNormal = groupData.vNormals[iOutIndex];
+                MD2::LookupNormalIndex(_AI_MDL7_ACCESS_VERT(groupInfo.pcGroupVerts, iIndex,
+                                               pcHeader->mainvertex_stc_size)
+                                               .norm162index,
+                        vNormal);
+            }
+            // validate and process the first uv coordinate set
+            if (pcHeader->triangle_stc_size >= AI_MDL7_TRIANGLE_STD_SIZE_ONE_UV) {
+
+                if (groupInfo.pcGroup->num_stpts) {
+                    AI_SWAP2(pcGroupTris->skinsets[0].st_index[0]);
+                    AI_SWAP2(pcGroupTris->skinsets[0].st_index[1]);
+                    AI_SWAP2(pcGroupTris->skinsets[0].st_index[2]);
+
+                    iIndex = pcGroupTris->skinsets[0].st_index[c];
+                    if (iIndex > (unsigned int)groupInfo.pcGroup->num_stpts) {
+                        iIndex = groupInfo.pcGroup->num_stpts - 1;
+                        ASSIMP_LOG_WARN("Index overflow in MDL7 UV coordinate list (#1)");
+                    }
+
+                    float u = groupInfo.pcGroupUVs[iIndex].u;
+                    float v = 1.0f - groupInfo.pcGroupUVs[iIndex].v; // DX to OGL
+
+                    groupData.vTextureCoords1[iOutIndex].x = u;
+                    groupData.vTextureCoords1[iOutIndex].y = v;
+                }
+                // assign the material index, but only if it is existing
+                if (pcHeader->triangle_stc_size >= AI_MDL7_TRIANGLE_STD_SIZE_ONE_UV_WITH_MATINDEX) {
+                    AI_SWAP4(pcGroupTris->skinsets[0].material);
+                    groupData.pcFaces[iTriangle].iMatIndex[0] = pcGroupTris->skinsets[0].material;
+                }
+            }
+            // validate and process the second uv coordinate set
+            if (pcHeader->triangle_stc_size >= AI_MDL7_TRIANGLE_STD_SIZE_TWO_UV) {
+
+                if (groupInfo.pcGroup->num_stpts) {
+                    AI_SWAP2(pcGroupTris->skinsets[1].st_index[0]);
+                    AI_SWAP2(pcGroupTris->skinsets[1].st_index[1]);
+                    AI_SWAP2(pcGroupTris->skinsets[1].st_index[2]);
+                    AI_SWAP4(pcGroupTris->skinsets[1].material);
+
+                    iIndex = pcGroupTris->skinsets[1].st_index[c];
+                    if (iIndex > (unsigned int)groupInfo.pcGroup->num_stpts) {
+                        iIndex = groupInfo.pcGroup->num_stpts - 1;
+                        ASSIMP_LOG_WARN("Index overflow in MDL7 UV coordinate list (#2)");
+                    }
+
+                    float u = groupInfo.pcGroupUVs[iIndex].u;
+                    float v = 1.0f - groupInfo.pcGroupUVs[iIndex].v;
+
+                    groupData.vTextureCoords2[iOutIndex].x = u;
+                    groupData.vTextureCoords2[iOutIndex].y = v; // DX to OGL
+
+                    // check whether we do really need the second texture
+                    // coordinate set ... wastes memory and loading time
+                    if (0 != iIndex && (u != groupData.vTextureCoords1[iOutIndex].x ||
+                                               v != groupData.vTextureCoords1[iOutIndex].y))
+                        groupData.bNeed2UV = true;
+
+                    // if the material differs, we need a second skin, too
+                    if (pcGroupTris->skinsets[1].material != pcGroupTris->skinsets[0].material)
+                        groupData.bNeed2UV = true;
+                }
+                // assign the material index
+                groupData.pcFaces[iTriangle].iMatIndex[1] = pcGroupTris->skinsets[1].material;
+            }
+        }
+        // get the next triangle in the list
+        pcGroupTris = (MDL::Triangle_MDL7 *)((const char *)pcGroupTris + pcHeader->triangle_stc_size);
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// handle frames in a MDL7 file
+bool MDLImporter::ProcessFrames_3DGS_MDL7(const MDL::IntGroupInfo_MDL7 &groupInfo,
+        MDL::IntGroupData_MDL7 &groupData,
+        MDL::IntSharedData_MDL7 &shared,
+        const unsigned char *szCurrent,
+        const unsigned char **szCurrentOut) {
+    ai_assert(nullptr != szCurrent);
+    ai_assert(nullptr != szCurrentOut);
+
+    const MDL::Header_MDL7 *pcHeader = (const MDL::Header_MDL7 *)mBuffer;
+
+    // if we have no bones we can simply skip all frames,
+    // otherwise we'll need to process them.
+    // FIX: If we need another frame than the first we must apply frame vertex replacements ...
+    for (unsigned int iFrame = 0; iFrame < (unsigned int)groupInfo.pcGroup->numframes; ++iFrame) {
+        MDL::IntFrameInfo_MDL7 frame((BE_NCONST MDL::Frame_MDL7 *)szCurrent, iFrame);
+
+        AI_SWAP4(frame.pcFrame->vertices_count);
+        AI_SWAP4(frame.pcFrame->transmatrix_count);
+
+        const unsigned int iAdd = pcHeader->frame_stc_size +
+                                  frame.pcFrame->vertices_count * pcHeader->framevertex_stc_size +
+                                  frame.pcFrame->transmatrix_count * pcHeader->bonetrans_stc_size;
+
+        if (((const char *)szCurrent - (const char *)pcHeader) + iAdd > (unsigned int)pcHeader->data_size) {
+            ASSIMP_LOG_WARN("Index overflow in frame area. "
+                            "Ignoring all frames and all further mesh groups, too.");
+
+            // don't parse more groups if we can't even read one
+            // FIXME: sometimes this seems to occur even for valid files ...
+            *szCurrentOut = szCurrent;
+            return false;
+        }
+        // our output frame?
+        if (configFrameID == iFrame) {
+            BE_NCONST MDL::Vertex_MDL7 *pcFrameVertices = (BE_NCONST MDL::Vertex_MDL7 *)(szCurrent + pcHeader->frame_stc_size);
+
+            for (unsigned int qq = 0; qq < frame.pcFrame->vertices_count; ++qq) {
+                // I assume this are simple replacements for normal vertices, the bone index serving
+                // as the index of the vertex to be replaced.
+                uint16_t iIndex = _AI_MDL7_ACCESS(pcFrameVertices, qq, pcHeader->framevertex_stc_size, MDL::Vertex_MDL7).vertindex;
+                AI_SWAP2(iIndex);
+                if (iIndex >= groupInfo.pcGroup->numverts) {
+                    ASSIMP_LOG_WARN("Invalid vertex index in frame vertex section");
+                    continue;
+                }
+
+                aiVector3D vPosition, vNormal;
+
+                vPosition.x = _AI_MDL7_ACCESS_VERT(pcFrameVertices, qq, pcHeader->framevertex_stc_size).x;
+                AI_SWAP4(vPosition.x);
+                vPosition.y = _AI_MDL7_ACCESS_VERT(pcFrameVertices, qq, pcHeader->framevertex_stc_size).y;
+                AI_SWAP4(vPosition.y);
+                vPosition.z = _AI_MDL7_ACCESS_VERT(pcFrameVertices, qq, pcHeader->framevertex_stc_size).z;
+                AI_SWAP4(vPosition.z);
+
+                // now read the normal vector
+                if (AI_MDL7_FRAMEVERTEX030305_STCSIZE <= pcHeader->mainvertex_stc_size) {
+                    // read the full normal vector
+                    vNormal.x = _AI_MDL7_ACCESS_VERT(pcFrameVertices, qq, pcHeader->framevertex_stc_size).norm[0];
+                    AI_SWAP4(vNormal.x);
+                    vNormal.y = _AI_MDL7_ACCESS_VERT(pcFrameVertices, qq, pcHeader->framevertex_stc_size).norm[1];
+                    AI_SWAP4(vNormal.y);
+                    vNormal.z = _AI_MDL7_ACCESS_VERT(pcFrameVertices, qq, pcHeader->framevertex_stc_size).norm[2];
+                    AI_SWAP4(vNormal.z);
+                } else if (AI_MDL7_FRAMEVERTEX120503_STCSIZE <= pcHeader->mainvertex_stc_size) {
+                    // read the normal vector from Quake2's smart table
+                    MD2::LookupNormalIndex(_AI_MDL7_ACCESS_VERT(pcFrameVertices, qq,
+                                                   pcHeader->framevertex_stc_size)
+                                                   .norm162index,
+                            vNormal);
+                }
+
+                // FIXME: O(n^2) at the moment ...
+                BE_NCONST MDL::Triangle_MDL7 *pcGroupTris = groupInfo.pcGroupTris;
+                unsigned int iOutIndex = 0;
+                for (unsigned int iTriangle = 0; iTriangle < (unsigned int)groupInfo.pcGroup->numtris; ++iTriangle) {
+                    // iterate through all indices of the current triangle
+                    for (unsigned int c = 0; c < 3; ++c, ++iOutIndex) {
+                        // replace the vertex with the new data
+                        const unsigned int iCurIndex = pcGroupTris->v_index[c];
+                        if (iCurIndex == iIndex) {
+                            groupData.vPositions[iOutIndex] = vPosition;
+                            groupData.vNormals[iOutIndex] = vNormal;
+                        }
+                    }
+                    // get the next triangle in the list
+                    pcGroupTris = (BE_NCONST MDL::Triangle_MDL7 *)((const char *)
+                                                                           pcGroupTris +
+                                                                   pcHeader->triangle_stc_size);
+                }
+            }
+        }
+        // parse bone trafo matrix keys (only if there are bones ...)
+        if (shared.apcOutBones) {
+            ParseBoneTrafoKeys_3DGS_MDL7(groupInfo, frame, shared);
+        }
+        szCurrent += iAdd;
+    }
+    *szCurrentOut = szCurrent;
+    return true;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Sort faces by material, handle multiple UVs correctly
+void MDLImporter::SortByMaterials_3DGS_MDL7(
+        const MDL::IntGroupInfo_MDL7 &groupInfo,
+        MDL::IntGroupData_MDL7 &groupData,
+        MDL::IntSplitGroupData_MDL7 &splitGroupData) {
+    const unsigned int iNumMaterials = (unsigned int)splitGroupData.shared.pcMats.size();
+    if (!groupData.bNeed2UV) {
+        // if we don't need a second set of texture coordinates there is no reason to keep it in memory ...
+        groupData.vTextureCoords2.clear();
+
+        // allocate the array
+        splitGroupData.aiSplit = new std::vector<unsigned int> *[iNumMaterials];
+
+        for (unsigned int m = 0; m < iNumMaterials; ++m)
+            splitGroupData.aiSplit[m] = new std::vector<unsigned int>();
+
+        // iterate through all faces and sort by material
+        for (unsigned int iFace = 0; iFace < (unsigned int)groupInfo.pcGroup->numtris; ++iFace) {
+            // check range
+            if (groupData.pcFaces[iFace].iMatIndex[0] >= iNumMaterials) {
+                // use the last material instead
+                splitGroupData.aiSplit[iNumMaterials - 1]->push_back(iFace);
+
+                // sometimes MED writes -1, but normally only if there is only
+                // one skin assigned. No warning in this case
+                if (0xFFFFFFFF != groupData.pcFaces[iFace].iMatIndex[0])
+                    ASSIMP_LOG_WARN("Index overflow in MDL7 material list [#0]");
+            } else
+                splitGroupData.aiSplit[groupData.pcFaces[iFace].iMatIndex[0]]->push_back(iFace);
+        }
+    } else {
+        // we need to build combined materials for each combination of
+        std::vector<MDL::IntMaterial_MDL7> avMats;
+        avMats.reserve(iNumMaterials * 2);
+
+        // fixme: why on the heap?
+        std::vector<std::vector<unsigned int> *> aiTempSplit(iNumMaterials * 2);
+        for (unsigned int m = 0; m < iNumMaterials; ++m)
+            aiTempSplit[m] = new std::vector<unsigned int>();
+
+        // iterate through all faces and sort by material
+        for (unsigned int iFace = 0; iFace < (unsigned int)groupInfo.pcGroup->numtris; ++iFace) {
+            // check range
+            unsigned int iMatIndex = groupData.pcFaces[iFace].iMatIndex[0];
+            if (iMatIndex >= iNumMaterials) {
+                // sometimes MED writes -1, but normally only if there is only
+                // one skin assigned. No warning in this case
+                if (UINT_MAX != iMatIndex)
+                    ASSIMP_LOG_WARN("Index overflow in MDL7 material list [#1]");
+                iMatIndex = iNumMaterials - 1;
+            }
+            unsigned int iMatIndex2 = groupData.pcFaces[iFace].iMatIndex[1];
+
+            unsigned int iNum = iMatIndex;
+            if (UINT_MAX != iMatIndex2 && iMatIndex != iMatIndex2) {
+                if (iMatIndex2 >= iNumMaterials) {
+                    // sometimes MED writes -1, but normally only if there is only
+                    // one skin assigned. No warning in this case
+                    ASSIMP_LOG_WARN("Index overflow in MDL7 material list [#2]");
+                    iMatIndex2 = iNumMaterials - 1;
+                }
+
+                // do a slow search in the list ...
+                iNum = 0;
+                bool bFound = false;
+                for (std::vector<MDL::IntMaterial_MDL7>::iterator i = avMats.begin(); i != avMats.end(); ++i, ++iNum) {
+                    if ((*i).iOldMatIndices[0] == iMatIndex && (*i).iOldMatIndices[1] == iMatIndex2) {
+                        // reuse this material
+                        bFound = true;
+                        break;
+                    }
+                }
+                if (!bFound) {
+                    //  build a new material ...
+                    MDL::IntMaterial_MDL7 sHelper;
+                    sHelper.pcMat = new aiMaterial();
+                    sHelper.iOldMatIndices[0] = iMatIndex;
+                    sHelper.iOldMatIndices[1] = iMatIndex2;
+                    JoinSkins_3DGS_MDL7(splitGroupData.shared.pcMats[iMatIndex],
+                            splitGroupData.shared.pcMats[iMatIndex2], sHelper.pcMat);
+
+                    // and add it to the list
+                    avMats.push_back(sHelper);
+                    iNum = (unsigned int)avMats.size() - 1;
+                }
+                // adjust the size of the file array
+                if (iNum == aiTempSplit.size()) {
+                    aiTempSplit.push_back(new std::vector<unsigned int>());
+                }
+            }
+            aiTempSplit[iNum]->push_back(iFace);
+        }
+
+        // now add the newly created materials to the old list
+        if (0 == groupInfo.iIndex) {
+            splitGroupData.shared.pcMats.resize(avMats.size());
+            for (unsigned int o = 0; o < avMats.size(); ++o)
+                splitGroupData.shared.pcMats[o] = avMats[o].pcMat;
+        } else {
+            // This might result in redundant materials ...
+            splitGroupData.shared.pcMats.resize(iNumMaterials + avMats.size());
+            for (unsigned int o = iNumMaterials; o < avMats.size(); ++o)
+                splitGroupData.shared.pcMats[o] = avMats[o].pcMat;
+        }
+
+        // and build the final face-to-material array
+        splitGroupData.aiSplit = new std::vector<unsigned int> *[aiTempSplit.size()];
+        for (unsigned int m = 0; m < iNumMaterials; ++m)
+            splitGroupData.aiSplit[m] = aiTempSplit[m];
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Read a MDL7 file
+void MDLImporter::InternReadFile_3DGS_MDL7() {
+    ai_assert(nullptr != pScene);
+
+    MDL::IntSharedData_MDL7 sharedData;
+
+    // current cursor position in the file
+    BE_NCONST MDL::Header_MDL7 *pcHeader = (BE_NCONST MDL::Header_MDL7 *)this->mBuffer;
+    const unsigned char *szCurrent = (const unsigned char *)(pcHeader + 1);
+
+    AI_SWAP4(pcHeader->version);
+    AI_SWAP4(pcHeader->bones_num);
+    AI_SWAP4(pcHeader->groups_num);
+    AI_SWAP4(pcHeader->data_size);
+    AI_SWAP4(pcHeader->entlump_size);
+    AI_SWAP4(pcHeader->medlump_size);
+    AI_SWAP2(pcHeader->bone_stc_size);
+    AI_SWAP2(pcHeader->skin_stc_size);
+    AI_SWAP2(pcHeader->colorvalue_stc_size);
+    AI_SWAP2(pcHeader->material_stc_size);
+    AI_SWAP2(pcHeader->skinpoint_stc_size);
+    AI_SWAP2(pcHeader->triangle_stc_size);
+    AI_SWAP2(pcHeader->mainvertex_stc_size);
+    AI_SWAP2(pcHeader->framevertex_stc_size);
+    AI_SWAP2(pcHeader->bonetrans_stc_size);
+    AI_SWAP2(pcHeader->frame_stc_size);
+
+    // validate the header of the file. There are some structure
+    // sizes that are expected by the loader to be constant
+    this->ValidateHeader_3DGS_MDL7(pcHeader);
+
+    // load all bones (they are shared by all groups, so
+    // we'll need to add them to all groups/meshes later)
+    // apcBonesOut is a list of all bones or nullptr if they could not been loaded
+    szCurrent += pcHeader->bones_num * pcHeader->bone_stc_size;
+    sharedData.apcOutBones = this->LoadBones_3DGS_MDL7();
+
+    // vector to held all created meshes
+    std::vector<aiMesh *> *avOutList;
+
+    // 3 meshes per group - that should be OK for most models
+    avOutList = new std::vector<aiMesh *>[pcHeader->groups_num];
+    for (uint32_t i = 0; i < pcHeader->groups_num; ++i)
+        avOutList[i].reserve(3);
+
+    // buffer to held the names of all groups in the file
+    const size_t buffersize(AI_MDL7_MAX_GROUPNAMESIZE * pcHeader->groups_num);
+    char *aszGroupNameBuffer = new char[buffersize];
+
+    // read all groups
+    for (unsigned int iGroup = 0; iGroup < (unsigned int)pcHeader->groups_num; ++iGroup) {
+        MDL::IntGroupInfo_MDL7 groupInfo((BE_NCONST MDL::Group_MDL7 *)szCurrent, iGroup);
+        szCurrent = (const unsigned char *)(groupInfo.pcGroup + 1);
+
+        VALIDATE_FILE_SIZE(szCurrent);
+
+        AI_SWAP4(groupInfo.pcGroup->groupdata_size);
+        AI_SWAP4(groupInfo.pcGroup->numskins);
+        AI_SWAP4(groupInfo.pcGroup->num_stpts);
+        AI_SWAP4(groupInfo.pcGroup->numtris);
+        AI_SWAP4(groupInfo.pcGroup->numverts);
+        AI_SWAP4(groupInfo.pcGroup->numframes);
+
+        if (1 != groupInfo.pcGroup->typ) {
+            // Not a triangle-based mesh
+            ASSIMP_LOG_WARN("[3DGS MDL7] Not a triangle mesh group. Continuing happily");
+        }
+
+        // store the name of the group
+        const unsigned int ofs = iGroup * AI_MDL7_MAX_GROUPNAMESIZE;
+        ::memcpy(&aszGroupNameBuffer[ofs],
+                groupInfo.pcGroup->name, AI_MDL7_MAX_GROUPNAMESIZE);
+
+        // make sure '\0' is at the end
+        aszGroupNameBuffer[ofs + AI_MDL7_MAX_GROUPNAMESIZE - 1] = '\0';
+
+        // read all skins
+        sharedData.pcMats.reserve(sharedData.pcMats.size() + groupInfo.pcGroup->numskins);
+        sharedData.abNeedMaterials.resize(sharedData.abNeedMaterials.size() +
+                                                  groupInfo.pcGroup->numskins,
+                false);
+
+        for (unsigned int iSkin = 0; iSkin < (unsigned int)groupInfo.pcGroup->numskins; ++iSkin) {
+            ParseSkinLump_3DGS_MDL7(szCurrent, &szCurrent, sharedData.pcMats);
+        }
+        // if we have absolutely no skin loaded we need to generate a default material
+        if (sharedData.pcMats.empty()) {
+            const int iMode = (int)aiShadingMode_Gouraud;
+            sharedData.pcMats.push_back(new aiMaterial());
+            aiMaterial *pcHelper = (aiMaterial *)sharedData.pcMats[0];
+            pcHelper->AddProperty<int>(&iMode, 1, AI_MATKEY_SHADING_MODEL);
+
+            aiColor3D clr;
+            clr.b = clr.g = clr.r = 0.6f;
+            pcHelper->AddProperty<aiColor3D>(&clr, 1, AI_MATKEY_COLOR_DIFFUSE);
+            pcHelper->AddProperty<aiColor3D>(&clr, 1, AI_MATKEY_COLOR_SPECULAR);
+
+            clr.b = clr.g = clr.r = 0.05f;
+            pcHelper->AddProperty<aiColor3D>(&clr, 1, AI_MATKEY_COLOR_AMBIENT);
+
+            aiString szName;
+            szName.Set(AI_DEFAULT_MATERIAL_NAME);
+            pcHelper->AddProperty(&szName, AI_MATKEY_NAME);
+
+            sharedData.abNeedMaterials.resize(1, false);
+        }
+
+        // now get a pointer to all texture coords in the group
+        groupInfo.pcGroupUVs = (BE_NCONST MDL::TexCoord_MDL7 *)szCurrent;
+        for (int i = 0; i < groupInfo.pcGroup->num_stpts; ++i) {
+            AI_SWAP4(groupInfo.pcGroupUVs[i].u);
+            AI_SWAP4(groupInfo.pcGroupUVs[i].v);
+        }
+        szCurrent += pcHeader->skinpoint_stc_size * groupInfo.pcGroup->num_stpts;
+
+        // now get a pointer to all triangle in the group
+        groupInfo.pcGroupTris = (Triangle_MDL7 *)szCurrent;
+        szCurrent += pcHeader->triangle_stc_size * groupInfo.pcGroup->numtris;
+
+        // now get a pointer to all vertices in the group
+        groupInfo.pcGroupVerts = (BE_NCONST MDL::Vertex_MDL7 *)szCurrent;
+        for (int i = 0; i < groupInfo.pcGroup->numverts; ++i) {
+            AI_SWAP4(groupInfo.pcGroupVerts[i].x);
+            AI_SWAP4(groupInfo.pcGroupVerts[i].y);
+            AI_SWAP4(groupInfo.pcGroupVerts[i].z);
+
+            AI_SWAP2(groupInfo.pcGroupVerts[i].vertindex);
+            //We can not swap the normal information now as we don't know which of the two kinds it is
+        }
+        szCurrent += pcHeader->mainvertex_stc_size * groupInfo.pcGroup->numverts;
+        VALIDATE_FILE_SIZE(szCurrent);
+
+        MDL::IntSplitGroupData_MDL7 splitGroupData(sharedData, avOutList[iGroup]);
+        MDL::IntGroupData_MDL7 groupData;
+        if (groupInfo.pcGroup->numtris && groupInfo.pcGroup->numverts) {
+            // build output vectors
+            const unsigned int iNumVertices = groupInfo.pcGroup->numtris * 3;
+            groupData.vPositions.resize(iNumVertices);
+            groupData.vNormals.resize(iNumVertices);
+
+            if (sharedData.apcOutBones) groupData.aiBones.resize(iNumVertices, UINT_MAX);
+
+            // it is also possible that there are 0 UV coordinate sets
+            if (groupInfo.pcGroup->num_stpts) {
+                groupData.vTextureCoords1.resize(iNumVertices, aiVector3D());
+
+                // check whether the triangle data structure is large enough
+                // to contain a second UV coordinate set
+                if (pcHeader->triangle_stc_size >= AI_MDL7_TRIANGLE_STD_SIZE_TWO_UV) {
+                    groupData.vTextureCoords2.resize(iNumVertices, aiVector3D());
+                    groupData.bNeed2UV = true;
+                }
+            }
+            groupData.pcFaces.resize(groupInfo.pcGroup->numtris);
+
+            // read all faces into the preallocated arrays
+            ReadFaces_3DGS_MDL7(groupInfo, groupData);
+
+            // sort by materials
+            SortByMaterials_3DGS_MDL7(groupInfo, groupData,
+                    splitGroupData);
+
+            for (unsigned int qq = 0; qq < sharedData.pcMats.size(); ++qq) {
+                if (!splitGroupData.aiSplit[qq]->empty())
+                    sharedData.abNeedMaterials[qq] = true;
+            }
+        } else
+            ASSIMP_LOG_WARN("[3DGS MDL7] Mesh group consists of 0 "
+                            "vertices or faces. It will be skipped.");
+
+        // process all frames and generate output meshes
+        ProcessFrames_3DGS_MDL7(groupInfo, groupData, sharedData, szCurrent, &szCurrent);
+        GenerateOutputMeshes_3DGS_MDL7(groupData, splitGroupData);
+    }
+
+    // generate a nodegraph and subnodes for each group
+    pScene->mRootNode = new aiNode();
+
+    // now we need to build a final mesh list
+    for (uint32_t i = 0; i < pcHeader->groups_num; ++i)
+        pScene->mNumMeshes += (unsigned int)avOutList[i].size();
+
+    pScene->mMeshes = new aiMesh *[pScene->mNumMeshes];
+    {
+        unsigned int p = 0, q = 0;
+        for (uint32_t i = 0; i < pcHeader->groups_num; ++i) {
+            for (unsigned int a = 0; a < avOutList[i].size(); ++a) {
+                pScene->mMeshes[p++] = avOutList[i][a];
+            }
+            if (!avOutList[i].empty()) ++pScene->mRootNode->mNumChildren;
+        }
+        // we will later need an extra node to serve as parent for all bones
+        if (sharedData.apcOutBones) ++pScene->mRootNode->mNumChildren;
+        this->pScene->mRootNode->mChildren = new aiNode *[pScene->mRootNode->mNumChildren];
+        p = 0;
+        for (uint32_t i = 0; i < pcHeader->groups_num; ++i) {
+            if (avOutList[i].empty()) continue;
+
+            aiNode *const pcNode = pScene->mRootNode->mChildren[p] = new aiNode();
+            pcNode->mNumMeshes = (unsigned int)avOutList[i].size();
+            pcNode->mMeshes = new unsigned int[pcNode->mNumMeshes];
+            pcNode->mParent = this->pScene->mRootNode;
+            for (unsigned int a = 0; a < pcNode->mNumMeshes; ++a)
+                pcNode->mMeshes[a] = q + a;
+            q += (unsigned int)avOutList[i].size();
+
+            // setup the name of the node
+            char *const szBuffer = &aszGroupNameBuffer[i * AI_MDL7_MAX_GROUPNAMESIZE];
+            if ('\0' == *szBuffer) {
+                const size_t maxSize(buffersize - (i * AI_MDL7_MAX_GROUPNAMESIZE));
+                pcNode->mName.length = ai_snprintf(szBuffer, maxSize, "Group_%u", p);
+            } else {
+                pcNode->mName.length = (ai_uint32)::strlen(szBuffer);
+            }
+            ::strncpy(pcNode->mName.data, szBuffer, MAXLEN - 1);
+            ++p;
+        }
+    }
+
+    // if there is only one root node with a single child we can optimize it a bit ...
+    if (1 == pScene->mRootNode->mNumChildren && !sharedData.apcOutBones) {
+        aiNode *pcOldRoot = this->pScene->mRootNode;
+        pScene->mRootNode = pcOldRoot->mChildren[0];
+        pcOldRoot->mChildren[0] = nullptr;
+        delete pcOldRoot;
+        pScene->mRootNode->mParent = nullptr;
+    } else
+        pScene->mRootNode->mName.Set("<mesh_root>");
+
+    delete[] avOutList;
+    delete[] aszGroupNameBuffer;
+    AI_DEBUG_INVALIDATE_PTR(avOutList);
+    AI_DEBUG_INVALIDATE_PTR(aszGroupNameBuffer);
+
+    // build a final material list.
+    CopyMaterials_3DGS_MDL7(sharedData);
+    HandleMaterialReferences_3DGS_MDL7();
+
+    // generate output bone animations and add all bones to the scenegraph
+    if (sharedData.apcOutBones) {
+        // this step adds empty dummy bones to the nodegraph
+        // insert another dummy node to avoid name conflicts
+        aiNode *const pc = pScene->mRootNode->mChildren[pScene->mRootNode->mNumChildren - 1] = new aiNode();
+
+        pc->mName.Set("<skeleton_root>");
+
+        // add bones to the nodegraph
+        AddBonesToNodeGraph_3DGS_MDL7((const Assimp::MDL::IntBone_MDL7 **)
+                                              sharedData.apcOutBones,
+                pc, 0xffff);
+
+        // this steps build a valid output animation
+        BuildOutputAnims_3DGS_MDL7((const Assimp::MDL::IntBone_MDL7 **)
+                                           sharedData.apcOutBones);
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Copy materials
+void MDLImporter::CopyMaterials_3DGS_MDL7(MDL::IntSharedData_MDL7 &shared) {
+    pScene->mNumMaterials = (unsigned int)shared.pcMats.size();
+    pScene->mMaterials = new aiMaterial *[pScene->mNumMaterials];
+    for (unsigned int i = 0; i < pScene->mNumMaterials; ++i)
+        pScene->mMaterials[i] = shared.pcMats[i];
+}
+
+// ------------------------------------------------------------------------------------------------
+// Process material references
+void MDLImporter::HandleMaterialReferences_3DGS_MDL7() {
+    // search for referrer materials
+    for (unsigned int i = 0; i < pScene->mNumMaterials; ++i) {
+        int iIndex = 0;
+        if (AI_SUCCESS == aiGetMaterialInteger(pScene->mMaterials[i], AI_MDL7_REFERRER_MATERIAL, &iIndex)) {
+            for (unsigned int a = 0; a < pScene->mNumMeshes; ++a) {
+                aiMesh *const pcMesh = pScene->mMeshes[a];
+                if (i == pcMesh->mMaterialIndex) {
+                    pcMesh->mMaterialIndex = iIndex;
+                }
+            }
+            // collapse the rest of the array
+            delete pScene->mMaterials[i];
+            for (unsigned int pp = i; pp < pScene->mNumMaterials - 1; ++pp) {
+
+                pScene->mMaterials[pp] = pScene->mMaterials[pp + 1];
+                for (unsigned int a = 0; a < pScene->mNumMeshes; ++a) {
+                    aiMesh *const pcMesh = pScene->mMeshes[a];
+                    if (pcMesh->mMaterialIndex > i) --pcMesh->mMaterialIndex;
+                }
+            }
+            --pScene->mNumMaterials;
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Read bone transformation keys
+void MDLImporter::ParseBoneTrafoKeys_3DGS_MDL7(
+        const MDL::IntGroupInfo_MDL7 &groupInfo,
+        IntFrameInfo_MDL7 &frame,
+        MDL::IntSharedData_MDL7 &shared) {
+    const MDL::Header_MDL7 *const pcHeader = (const MDL::Header_MDL7 *)this->mBuffer;
+
+    // only the first group contains bone animation keys
+    if (frame.pcFrame->transmatrix_count) {
+        if (!groupInfo.iIndex) {
+            // skip all frames vertices. We can't support them
+            const MDL::BoneTransform_MDL7 *pcBoneTransforms = (const MDL::BoneTransform_MDL7 *)(((const char *)frame.pcFrame) + pcHeader->frame_stc_size +
+                                                                                                frame.pcFrame->vertices_count * pcHeader->framevertex_stc_size);
+
+            // read all transformation matrices
+            for (unsigned int iTrafo = 0; iTrafo < frame.pcFrame->transmatrix_count; ++iTrafo) {
+                if (pcBoneTransforms->bone_index >= pcHeader->bones_num) {
+                    ASSIMP_LOG_WARN("Index overflow in frame area. "
+                                    "Unable to parse this bone transformation");
+                } else {
+                    AddAnimationBoneTrafoKey_3DGS_MDL7(frame.iIndex,
+                            pcBoneTransforms, shared.apcOutBones);
+                }
+                pcBoneTransforms = (const MDL::BoneTransform_MDL7 *)((const char *)pcBoneTransforms + pcHeader->bonetrans_stc_size);
+            }
+        } else {
+            ASSIMP_LOG_WARN("Ignoring animation keyframes in groups != 0");
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Attach bones to the output nodegraph
+void MDLImporter::AddBonesToNodeGraph_3DGS_MDL7(const MDL::IntBone_MDL7 **apcBones,
+        aiNode *pcParent, uint16_t iParentIndex) {
+    ai_assert(nullptr != apcBones);
+    ai_assert(nullptr != pcParent);
+
+    // get a pointer to the header ...
+    const MDL::Header_MDL7 *const pcHeader = (const MDL::Header_MDL7 *)this->mBuffer;
+
+    const MDL::IntBone_MDL7 **apcBones2 = apcBones;
+    for (uint32_t i = 0; i < pcHeader->bones_num; ++i) {
+
+        const MDL::IntBone_MDL7 *const pcBone = *apcBones2++;
+        if (pcBone->iParent == iParentIndex) {
+            ++pcParent->mNumChildren;
+        }
+    }
+    pcParent->mChildren = new aiNode *[pcParent->mNumChildren];
+    unsigned int qq = 0;
+    for (uint32_t i = 0; i < pcHeader->bones_num; ++i) {
+
+        const MDL::IntBone_MDL7 *const pcBone = *apcBones++;
+        if (pcBone->iParent != iParentIndex) continue;
+
+        aiNode *pcNode = pcParent->mChildren[qq++] = new aiNode();
+        pcNode->mName = aiString(pcBone->mName);
+
+        AddBonesToNodeGraph_3DGS_MDL7(apcBones, pcNode, (uint16_t)i);
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Build output animations
+void MDLImporter::BuildOutputAnims_3DGS_MDL7(
+        const MDL::IntBone_MDL7 **apcBonesOut) {
+    ai_assert(nullptr != apcBonesOut);
+    const MDL::Header_MDL7 *const pcHeader = (const MDL::Header_MDL7 *)mBuffer;
+
+    // one animation ...
+    aiAnimation *pcAnim = new aiAnimation();
+    for (uint32_t i = 0; i < pcHeader->bones_num; ++i) {
+        if (!apcBonesOut[i]->pkeyPositions.empty()) {
+
+            // get the last frame ... (needn't be equal to pcHeader->frames_num)
+            for (size_t qq = 0; qq < apcBonesOut[i]->pkeyPositions.size(); ++qq) {
+                pcAnim->mDuration = std::max(pcAnim->mDuration, (double)
+                                                                        apcBonesOut[i]
+                                                                                ->pkeyPositions[qq]
+                                                                                .mTime);
+            }
+            ++pcAnim->mNumChannels;
+        }
+    }
+    if (pcAnim->mDuration) {
+        pcAnim->mChannels = new aiNodeAnim *[pcAnim->mNumChannels];
+
+        unsigned int iCnt = 0;
+        for (uint32_t i = 0; i < pcHeader->bones_num; ++i) {
+            if (!apcBonesOut[i]->pkeyPositions.empty()) {
+                const MDL::IntBone_MDL7 *const intBone = apcBonesOut[i];
+
+                aiNodeAnim *const pcNodeAnim = pcAnim->mChannels[iCnt++] = new aiNodeAnim();
+                pcNodeAnim->mNodeName = aiString(intBone->mName);
+
+                // allocate enough storage for all keys
+                pcNodeAnim->mNumPositionKeys = (unsigned int)intBone->pkeyPositions.size();
+                pcNodeAnim->mNumScalingKeys = (unsigned int)intBone->pkeyPositions.size();
+                pcNodeAnim->mNumRotationKeys = (unsigned int)intBone->pkeyPositions.size();
+
+                pcNodeAnim->mPositionKeys = new aiVectorKey[pcNodeAnim->mNumPositionKeys];
+                pcNodeAnim->mScalingKeys = new aiVectorKey[pcNodeAnim->mNumPositionKeys];
+                pcNodeAnim->mRotationKeys = new aiQuatKey[pcNodeAnim->mNumPositionKeys];
+
+                // copy all keys
+                for (unsigned int qq = 0; qq < pcNodeAnim->mNumPositionKeys; ++qq) {
+                    pcNodeAnim->mPositionKeys[qq] = intBone->pkeyPositions[qq];
+                    pcNodeAnim->mScalingKeys[qq] = intBone->pkeyScalings[qq];
+                    pcNodeAnim->mRotationKeys[qq] = intBone->pkeyRotations[qq];
+                }
+            }
+        }
+
+        // store the output animation
+        pScene->mNumAnimations = 1;
+        pScene->mAnimations = new aiAnimation *[1];
+        pScene->mAnimations[0] = pcAnim;
+    } else
+        delete pcAnim;
+}
+
+// ------------------------------------------------------------------------------------------------
+void MDLImporter::AddAnimationBoneTrafoKey_3DGS_MDL7(unsigned int iTrafo,
+        const MDL::BoneTransform_MDL7 *pcBoneTransforms,
+        MDL::IntBone_MDL7 **apcBonesOut) {
+    ai_assert(nullptr != pcBoneTransforms);
+    ai_assert(nullptr != apcBonesOut);
+
+    // first .. get the transformation matrix
+    aiMatrix4x4 mTransform;
+    mTransform.a1 = pcBoneTransforms->m[0];
+    mTransform.b1 = pcBoneTransforms->m[1];
+    mTransform.c1 = pcBoneTransforms->m[2];
+    mTransform.d1 = pcBoneTransforms->m[3];
+
+    mTransform.a2 = pcBoneTransforms->m[4];
+    mTransform.b2 = pcBoneTransforms->m[5];
+    mTransform.c2 = pcBoneTransforms->m[6];
+    mTransform.d2 = pcBoneTransforms->m[7];
+
+    mTransform.a3 = pcBoneTransforms->m[8];
+    mTransform.b3 = pcBoneTransforms->m[9];
+    mTransform.c3 = pcBoneTransforms->m[10];
+    mTransform.d3 = pcBoneTransforms->m[11];
+
+    // now decompose the transformation matrix into separate
+    // scaling, rotation and translation
+    aiVectorKey vScaling, vPosition;
+    aiQuatKey qRotation;
+
+    // FIXME: Decompose will assert in debug builds if the matrix is invalid ...
+    mTransform.Decompose(vScaling.mValue, qRotation.mValue, vPosition.mValue);
+
+    // now generate keys
+    vScaling.mTime = qRotation.mTime = vPosition.mTime = (double)iTrafo;
+
+    // add the keys to the bone
+    MDL::IntBone_MDL7 *const pcBoneOut = apcBonesOut[pcBoneTransforms->bone_index];
+    pcBoneOut->pkeyPositions.push_back(vPosition);
+    pcBoneOut->pkeyScalings.push_back(vScaling);
+    pcBoneOut->pkeyRotations.push_back(qRotation);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Construct output meshes
+void MDLImporter::GenerateOutputMeshes_3DGS_MDL7(
+        MDL::IntGroupData_MDL7 &groupData,
+        MDL::IntSplitGroupData_MDL7 &splitGroupData) {
+    const MDL::IntSharedData_MDL7 &shared = splitGroupData.shared;
+
+    // get a pointer to the header ...
+    const MDL::Header_MDL7 *const pcHeader = (const MDL::Header_MDL7 *)this->mBuffer;
+    const unsigned int iNumOutBones = pcHeader->bones_num;
+
+    for (std::vector<aiMaterial *>::size_type i = 0; i < shared.pcMats.size(); ++i) {
+        if (!splitGroupData.aiSplit[i]->empty()) {
+
+            // allocate the output mesh
+            aiMesh *pcMesh = new aiMesh();
+
+            pcMesh->mPrimitiveTypes = aiPrimitiveType_TRIANGLE;
+            pcMesh->mMaterialIndex = (unsigned int)i;
+
+            // allocate output storage
+            pcMesh->mNumFaces = (unsigned int)splitGroupData.aiSplit[i]->size();
+            pcMesh->mFaces = new aiFace[pcMesh->mNumFaces];
+
+            pcMesh->mNumVertices = pcMesh->mNumFaces * 3;
+            pcMesh->mVertices = new aiVector3D[pcMesh->mNumVertices];
+            pcMesh->mNormals = new aiVector3D[pcMesh->mNumVertices];
+
+            if (!groupData.vTextureCoords1.empty()) {
+                pcMesh->mNumUVComponents[0] = 2;
+                pcMesh->mTextureCoords[0] = new aiVector3D[pcMesh->mNumVertices];
+                if (!groupData.vTextureCoords2.empty()) {
+                    pcMesh->mNumUVComponents[1] = 2;
+                    pcMesh->mTextureCoords[1] = new aiVector3D[pcMesh->mNumVertices];
+                }
+            }
+
+            // iterate through all faces and build an unique set of vertices
+            unsigned int iCurrent = 0;
+            for (unsigned int iFace = 0; iFace < pcMesh->mNumFaces; ++iFace) {
+                pcMesh->mFaces[iFace].mNumIndices = 3;
+                pcMesh->mFaces[iFace].mIndices = new unsigned int[3];
+
+                unsigned int iSrcFace = splitGroupData.aiSplit[i]->operator[](iFace);
+                const MDL::IntFace_MDL7 &oldFace = groupData.pcFaces[iSrcFace];
+
+                // iterate through all face indices
+                for (unsigned int c = 0; c < 3; ++c) {
+                    const uint32_t iIndex = oldFace.mIndices[c];
+                    pcMesh->mVertices[iCurrent] = groupData.vPositions[iIndex];
+                    pcMesh->mNormals[iCurrent] = groupData.vNormals[iIndex];
+
+                    if (!groupData.vTextureCoords1.empty()) {
+
+                        pcMesh->mTextureCoords[0][iCurrent] = groupData.vTextureCoords1[iIndex];
+                        if (!groupData.vTextureCoords2.empty()) {
+                            pcMesh->mTextureCoords[1][iCurrent] = groupData.vTextureCoords2[iIndex];
+                        }
+                    }
+                    pcMesh->mFaces[iFace].mIndices[c] = iCurrent++;
+                }
+            }
+
+            // if we have bones in the mesh we'll need to generate
+            // proper vertex weights for them
+            if (!groupData.aiBones.empty()) {
+                std::vector<std::vector<unsigned int>> aaiVWeightList;
+                aaiVWeightList.resize(iNumOutBones);
+
+                int iCurrentWeight = 0;
+                for (unsigned int iFace = 0; iFace < pcMesh->mNumFaces; ++iFace) {
+                    unsigned int iSrcFace = splitGroupData.aiSplit[i]->operator[](iFace);
+                    const MDL::IntFace_MDL7 &oldFace = groupData.pcFaces[iSrcFace];
+
+                    // iterate through all face indices
+                    for (unsigned int c = 0; c < 3; ++c) {
+                        unsigned int iBone = groupData.aiBones[oldFace.mIndices[c]];
+                        if (UINT_MAX != iBone) {
+                            if (iBone >= iNumOutBones) {
+                                ASSIMP_LOG_ERROR("Bone index overflow. "
+                                                 "The bone index of a vertex exceeds the allowed range. ");
+                                iBone = iNumOutBones - 1;
+                            }
+                            aaiVWeightList[iBone].push_back(iCurrentWeight);
+                        }
+                        ++iCurrentWeight;
+                    }
+                }
+                // now check which bones are required ...
+                for (std::vector<std::vector<unsigned int>>::const_iterator k = aaiVWeightList.begin(); k != aaiVWeightList.end(); ++k) {
+                    if (!(*k).empty()) {
+                        ++pcMesh->mNumBones;
+                    }
+                }
+                pcMesh->mBones = new aiBone *[pcMesh->mNumBones];
+                iCurrent = 0;
+                for (std::vector<std::vector<unsigned int>>::const_iterator k = aaiVWeightList.begin(); k != aaiVWeightList.end(); ++k, ++iCurrent) {
+                    if ((*k).empty())
+                        continue;
+
+                    // seems we'll need this node
+                    aiBone *pcBone = pcMesh->mBones[iCurrent] = new aiBone();
+                    pcBone->mName = aiString(shared.apcOutBones[iCurrent]->mName);
+                    pcBone->mOffsetMatrix = shared.apcOutBones[iCurrent]->mOffsetMatrix;
+
+                    // setup vertex weights
+                    pcBone->mNumWeights = (unsigned int)(*k).size();
+                    pcBone->mWeights = new aiVertexWeight[pcBone->mNumWeights];
+
+                    for (unsigned int weight = 0; weight < pcBone->mNumWeights; ++weight) {
+                        pcBone->mWeights[weight].mVertexId = (*k)[weight];
+                        pcBone->mWeights[weight].mWeight = 1.0f;
+                    }
+                }
+            }
+            // add the mesh to the list of output meshes
+            splitGroupData.avOutList.push_back(pcMesh);
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Join to materials
+void MDLImporter::JoinSkins_3DGS_MDL7(
+        aiMaterial *pcMat1,
+        aiMaterial *pcMat2,
+        aiMaterial *pcMatOut) {
+    ai_assert(nullptr != pcMat1);
+    ai_assert(nullptr != pcMat2);
+    ai_assert(nullptr != pcMatOut);
+
+    // first create a full copy of the first skin property set
+    // and assign it to the output material
+    aiMaterial::CopyPropertyList(pcMatOut, pcMat1);
+
+    int iVal = 0;
+    pcMatOut->AddProperty<int>(&iVal, 1, AI_MATKEY_UVWSRC_DIFFUSE(0));
+
+    // then extract the diffuse texture from the second skin,
+    // setup 1 as UV source and we have it
+    aiString sString;
+    if (AI_SUCCESS == aiGetMaterialString(pcMat2, AI_MATKEY_TEXTURE_DIFFUSE(0), &sString)) {
+        iVal = 1;
+        pcMatOut->AddProperty<int>(&iVal, 1, AI_MATKEY_UVWSRC_DIFFUSE(1));
+        pcMatOut->AddProperty(&sString, AI_MATKEY_TEXTURE_DIFFUSE(1));
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Read a Half-life 1 MDL
+void MDLImporter::InternReadFile_HL1(const std::string &pFile, const uint32_t iMagicWord) {
+    // We can't correctly load an MDL from a MDL "sequence" file.
+    if (iMagicWord == AI_MDL_MAGIC_NUMBER_BE_HL2b || iMagicWord == AI_MDL_MAGIC_NUMBER_LE_HL2b)
+        throw DeadlyImportError("Impossible to properly load a model from an MDL sequence file.");
+
+    // Read the MDL file.
+    HalfLife::HL1MDLLoader loader(
+            pScene,
+            mIOHandler,
+            mBuffer,
+            pFile,
+            mHL1ImportSettings);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Read a half-life 2 MDL
+void MDLImporter::InternReadFile_HL2() {
+    //const MDL::Header_HL2* pcHeader = (const MDL::Header_HL2*)this->mBuffer;
+    throw DeadlyImportError("HL2 MDLs are not implemented");
+}
+
+#endif // !! ASSIMP_BUILD_NO_MDL_IMPORTER