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diff --git a/libs/assimp/tools/assimp_view/SceneAnimator.cpp b/libs/assimp/tools/assimp_view/SceneAnimator.cpp
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+/*
+---------------------------------------------------------------------------
+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 SceneAnimator.cpp
+ *  @brief Implementation of the utility class SceneAnimator
+ */
+
+#include "assimp_view.h"
+
+using namespace AssimpView;
+
+const aiMatrix4x4 IdentityMatrix;
+
+// ------------------------------------------------------------------------------------------------
+// Constructor for a given scene.
+SceneAnimator::SceneAnimator(const aiScene *pScene, size_t pAnimIndex) :
+        mScene(pScene),
+        mCurrentAnimIndex(-1),
+        mAnimEvaluator(nullptr),
+        mRootNode(nullptr) {
+    // build the nodes-for-bones table
+    for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
+        const aiMesh *mesh = pScene->mMeshes[i];
+        for (unsigned int n = 0; n < mesh->mNumBones; ++n) {
+            const aiBone *bone = mesh->mBones[n];
+
+            mBoneNodesByName[bone->mName.data] = pScene->mRootNode->FindNode(bone->mName);
+        }
+    }
+
+    // changing the current animation also creates the node tree for this animation
+    SetAnimIndex(pAnimIndex);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor
+SceneAnimator::~SceneAnimator() {
+    delete mRootNode;
+    delete mAnimEvaluator;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Sets the animation to use for playback.
+void SceneAnimator::SetAnimIndex(size_t pAnimIndex) {
+    // no change
+    if (pAnimIndex == static_cast<unsigned int>(mCurrentAnimIndex)) {
+        return;
+    }
+
+    // kill data of the previous anim
+    delete mRootNode;
+    mRootNode = nullptr;
+    delete mAnimEvaluator;
+    mAnimEvaluator = nullptr;
+    mNodesByName.clear();
+
+    mCurrentAnimIndex = static_cast<int>(pAnimIndex);
+
+    // create the internal node tree. Do this even in case of invalid animation index
+    // so that the transformation matrices are properly set up to mimic the current scene
+    mRootNode = CreateNodeTree(mScene->mRootNode, nullptr);
+
+    // invalid anim index
+    if (static_cast<unsigned int>(mCurrentAnimIndex) >= mScene->mNumAnimations) {
+        return;
+    }
+
+    // create an evaluator for this animation
+    mAnimEvaluator = new AnimEvaluator(mScene->mAnimations[mCurrentAnimIndex]);
+}
+
+// ------------------------------------------------------------------------------------------------
+// Calculates the node transformations for the scene.
+void SceneAnimator::Calculate(double pTime) {
+    // invalid anim
+    if (!mAnimEvaluator) {
+        return;
+    }
+
+    // calculate current local transformations
+    mAnimEvaluator->Evaluate(pTime);
+
+    // and update all node transformations with the results
+    UpdateTransforms(mRootNode, mAnimEvaluator->GetTransformations());
+}
+
+// ------------------------------------------------------------------------------------------------
+// Retrieves the most recent local transformation matrix for the given node.
+const aiMatrix4x4 &SceneAnimator::GetLocalTransform(const aiNode *node) const {
+    NodeMap::const_iterator it = mNodesByName.find(node);
+    if (it == mNodesByName.end()) {
+        return IdentityMatrix;
+    }
+
+    return it->second->mLocalTransform;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Retrieves the most recent global transformation matrix for the given node.
+const aiMatrix4x4 &SceneAnimator::GetGlobalTransform(const aiNode *node) const {
+    NodeMap::const_iterator it = mNodesByName.find(node);
+    if (it == mNodesByName.end()) {
+        return IdentityMatrix;
+    }
+
+    return it->second->mGlobalTransform;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Calculates the bone matrices for the given mesh.
+const std::vector<aiMatrix4x4> &SceneAnimator::GetBoneMatrices(const aiNode *pNode, size_t pMeshIndex /* = 0 */) {
+    ai_assert(pMeshIndex < pNode->mNumMeshes);
+    size_t meshIndex = pNode->mMeshes[pMeshIndex];
+    ai_assert(meshIndex < mScene->mNumMeshes);
+    const aiMesh *mesh = mScene->mMeshes[meshIndex];
+
+    // resize array and initialize it with identity matrices
+    mTransforms.resize(mesh->mNumBones, aiMatrix4x4());
+
+    // calculate the mesh's inverse global transform
+    aiMatrix4x4 globalInverseMeshTransform = GetGlobalTransform(pNode);
+    globalInverseMeshTransform.Inverse();
+
+    // Bone matrices transform from mesh coordinates in bind pose to mesh coordinates in skinned pose
+    // Therefore the formula is offsetMatrix * currentGlobalTransform * inverseCurrentMeshTransform
+    for (size_t a = 0; a < mesh->mNumBones; ++a) {
+        const aiBone *bone = mesh->mBones[a];
+        const aiMatrix4x4 &currentGlobalTransform = GetGlobalTransform(mBoneNodesByName[bone->mName.data]);
+        mTransforms[a] = globalInverseMeshTransform * currentGlobalTransform * bone->mOffsetMatrix;
+    }
+
+    // and return the result
+    return mTransforms;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Recursively creates an internal node structure matching the current scene and animation.
+SceneAnimNode *SceneAnimator::CreateNodeTree(aiNode *pNode, SceneAnimNode *pParent) {
+    // create a node
+    SceneAnimNode *internalNode = new SceneAnimNode(pNode->mName.data);
+    internalNode->mParent = pParent;
+    mNodesByName[pNode] = internalNode;
+
+    // copy its transformation
+    internalNode->mLocalTransform = pNode->mTransformation;
+    CalculateGlobalTransform(internalNode);
+
+    // find the index of the animation track affecting this node, if any
+    if (static_cast<unsigned int>(mCurrentAnimIndex) < mScene->mNumAnimations) {
+        internalNode->mChannelIndex = -1;
+        const aiAnimation *currentAnim = mScene->mAnimations[mCurrentAnimIndex];
+        for (unsigned int a = 0; a < currentAnim->mNumChannels; a++) {
+            if (currentAnim->mChannels[a]->mNodeName.data == internalNode->mName) {
+                internalNode->mChannelIndex = a;
+                break;
+            }
+        }
+    }
+
+    // continue for all child nodes and assign the created internal nodes as our children
+    for (unsigned int a = 0; a < pNode->mNumChildren; ++a) {
+        SceneAnimNode *childNode = CreateNodeTree(pNode->mChildren[a], internalNode);
+        internalNode->mChildren.push_back(childNode);
+    }
+
+    return internalNode;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Recursively updates the internal node transformations from the given matrix array
+void SceneAnimator::UpdateTransforms(SceneAnimNode *pNode, const std::vector<aiMatrix4x4> &pTransforms) {
+    // update node local transform
+    if (pNode->mChannelIndex != -1) {
+        ai_assert(static_cast<unsigned int>(pNode->mChannelIndex) < pTransforms.size());
+        pNode->mLocalTransform = pTransforms[pNode->mChannelIndex];
+    }
+
+    // update global transform as well
+    CalculateGlobalTransform(pNode);
+
+    // continue for all children
+    for (std::vector<SceneAnimNode *>::iterator it = pNode->mChildren.begin(); it != pNode->mChildren.end(); ++it) {
+        UpdateTransforms(*it, pTransforms);
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Calculates the global transformation matrix for the given internal node
+void SceneAnimator::CalculateGlobalTransform(SceneAnimNode *pInternalNode) {
+    // concatenate all parent transforms to get the global transform for this node
+    pInternalNode->mGlobalTransform = pInternalNode->mLocalTransform;
+    SceneAnimNode *node = pInternalNode->mParent;
+    while (node) {
+        pInternalNode->mGlobalTransform = node->mLocalTransform * pInternalNode->mGlobalTransform;
+        node = node->mParent;
+    }
+}