assimp.assimp/code/ColladaLoader.cpp

/*
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/** @file Implementation of the Collada loader */


#ifndef ASSIMP_BUILD_NO_COLLADA_IMPORTER

#include "ColladaLoader.h"
#include <assimp/anim.h>
#include <assimp/scene.h>
#include <assimp/DefaultLogger.hpp>
#include <assimp/Importer.hpp>
#include "ColladaParser.h"

#include "fast_atof.h"
#include "ParsingUtils.h"
#include "SkeletonMeshBuilder.h"
#include "Defines.h"

#include "time.h"
#include "math.h"
#include <algorithm>
#include <cstdint>
#include <numeric>
#include "Defines.h"


using namespace Assimp;
using namespace Assimp::Formatter;

static const aiImporterDesc desc = {
    "Collada Importer",
    "",
    "",
    "http://collada.org",
    aiImporterFlags_SupportTextFlavour,
    1,
    3,
    1,
    5,
    "dae"
};

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
ColladaLoader::ColladaLoader()
    : mFileName()
	, mMeshIndexByID()
	, mMaterialIndexByName()
	, mMeshes()
	, newMats()
	, mCameras()
	, mLights()
	, mTextures()
	, mAnims()
	, noSkeletonMesh( false )
    , ignoreUpDirection(false)
    , mNodeNameCounter( 0 )
{}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well
ColladaLoader::~ColladaLoader()
{}

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file.
bool ColladaLoader::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool checkSig) const
{
    // check file extension
    std::string extension = GetExtension(pFile);

    if( extension == "dae")
        return true;

    // XML - too generic, we need to open the file and search for typical keywords
    if( extension == "xml" || !extension.length() || checkSig)  {
        /*  If CanRead() is called in order to check whether we
         *  support a specific file extension in general pIOHandler
         *  might be NULL and it's our duty to return true here.
         */
        if (!pIOHandler)return true;
        const char* tokens[] = {"collada"};
        return SearchFileHeaderForToken(pIOHandler,pFile,tokens,1);
    }
    return false;
}

// ------------------------------------------------------------------------------------------------
void ColladaLoader::SetupProperties(const Importer* pImp)
{
    noSkeletonMesh = pImp->GetPropertyInteger(AI_CONFIG_IMPORT_NO_SKELETON_MESHES,0) != 0;
    ignoreUpDirection = pImp->GetPropertyInteger(AI_CONFIG_IMPORT_COLLADA_IGNORE_UP_DIRECTION,0) != 0;
}


// ------------------------------------------------------------------------------------------------
// Get file extension list
const aiImporterDesc* ColladaLoader::GetInfo () const
{
    return &desc;
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure.
void ColladaLoader::InternReadFile( const std::string& pFile, aiScene* pScene, IOSystem* pIOHandler)
{
    mFileName = pFile;

    // clean all member arrays - just for safety, it should work even if we did not
    mMeshIndexByID.clear();
    mMaterialIndexByName.clear();
    mMeshes.clear();
    newMats.clear();
    mLights.clear();
    mCameras.clear();
    mTextures.clear();
    mAnims.clear();

    // parse the input file
    ColladaParser parser( pIOHandler, pFile);

    if( !parser.mRootNode)
        throw DeadlyImportError( "Collada: File came out empty. Something is wrong here.");

    // reserve some storage to avoid unnecessary reallocs
    newMats.reserve(parser.mMaterialLibrary.size()*2);
    mMeshes.reserve(parser.mMeshLibrary.size()*2);

    mCameras.reserve(parser.mCameraLibrary.size());
    mLights.reserve(parser.mLightLibrary.size());

    // create the materials first, for the meshes to find
    BuildMaterials( parser, pScene);

    // build the node hierarchy from it
    pScene->mRootNode = BuildHierarchy( parser, parser.mRootNode);

    // ... then fill the materials with the now adjusted settings
    FillMaterials(parser, pScene);

        // Apply unitsize scale calculation
        pScene->mRootNode->mTransformation *= aiMatrix4x4(parser.mUnitSize, 0,  0,  0,
                                                          0,  parser.mUnitSize,  0,  0,
                                                          0,  0,  parser.mUnitSize,  0,
                                                          0,  0,  0,  1);
        if( !ignoreUpDirection ) {
        // Convert to Y_UP, if different orientation
        if( parser.mUpDirection == ColladaParser::UP_X)
            pScene->mRootNode->mTransformation *= aiMatrix4x4(
                 0, -1,  0,  0,
                 1,  0,  0,  0,
                 0,  0,  1,  0,
                 0,  0,  0,  1);
        else if( parser.mUpDirection == ColladaParser::UP_Z)
            pScene->mRootNode->mTransformation *= aiMatrix4x4(
                 1,  0,  0,  0,
                 0,  0,  1,  0,
                 0, -1,  0,  0,
                 0,  0,  0,  1);
        }
    // store all meshes
    StoreSceneMeshes( pScene);

    // store all materials
    StoreSceneMaterials( pScene);

    // store all lights
    StoreSceneLights( pScene);

    // store all cameras
    StoreSceneCameras( pScene);

    // store all animations
    StoreAnimations( pScene, parser);


    // If no meshes have been loaded, it's probably just an animated skeleton.
    if (!pScene->mNumMeshes) {

        if (!noSkeletonMesh) {
            SkeletonMeshBuilder hero(pScene);
        }
        pScene->mFlags |= AI_SCENE_FLAGS_INCOMPLETE;
    }
}

// ------------------------------------------------------------------------------------------------
// Recursively constructs a scene node for the given parser node and returns it.
aiNode* ColladaLoader::BuildHierarchy( const ColladaParser& pParser, const Collada::Node* pNode)
{
    // create a node for it
    aiNode* node = new aiNode();

    // find a name for the new node. It's more complicated than you might think
    node->mName.Set( FindNameForNode( pNode));

    // calculate the transformation matrix for it
    node->mTransformation = pParser.CalculateResultTransform( pNode->mTransforms);

    // now resolve node instances
    std::vector<const Collada::Node*> instances;
    ResolveNodeInstances(pParser,pNode,instances);

    // add children. first the *real* ones
    node->mNumChildren = static_cast<unsigned int>(pNode->mChildren.size()+instances.size());
    node->mChildren = new aiNode*[node->mNumChildren];

    for( size_t a = 0; a < pNode->mChildren.size(); a++)
    {
        node->mChildren[a] = BuildHierarchy( pParser, pNode->mChildren[a]);
        node->mChildren[a]->mParent = node;
    }

    // ... and finally the resolved node instances
    for( size_t a = 0; a < instances.size(); a++)
    {
        node->mChildren[pNode->mChildren.size() + a] = BuildHierarchy( pParser, instances[a]);
        node->mChildren[pNode->mChildren.size() + a]->mParent = node;
    }

    // construct meshes
    BuildMeshesForNode( pParser, pNode, node);

    // construct cameras
    BuildCamerasForNode(pParser, pNode, node);

    // construct lights
    BuildLightsForNode(pParser, pNode, node);
    return node;
}

// ------------------------------------------------------------------------------------------------
// Resolve node instances
void ColladaLoader::ResolveNodeInstances( const ColladaParser& pParser, const Collada::Node* pNode,
    std::vector<const Collada::Node*>& resolved)
{
    // reserve enough storage
    resolved.reserve(pNode->mNodeInstances.size());

    // ... and iterate through all nodes to be instanced as children of pNode
    for (const auto &nodeInst: pNode->mNodeInstances)
    {
        // find the corresponding node in the library
        const ColladaParser::NodeLibrary::const_iterator itt = pParser.mNodeLibrary.find(nodeInst.mNode);
        const Collada::Node* nd = itt == pParser.mNodeLibrary.end() ? NULL : (*itt).second;

        // FIX for http://sourceforge.net/tracker/?func=detail&aid=3054873&group_id=226462&atid=1067632
        // need to check for both name and ID to catch all. To avoid breaking valid files,
        // the workaround is only enabled when the first attempt to resolve the node has failed.
        if (!nd) {
            nd = FindNode(pParser.mRootNode, nodeInst.mNode);
        }
        if (!nd)
            DefaultLogger::get()->error("Collada: Unable to resolve reference to instanced node " + nodeInst.mNode);

        else {
            //  attach this node to the list of children
            resolved.push_back(nd);
        }
    }
}

// ------------------------------------------------------------------------------------------------
// Resolve UV channels
void ColladaLoader::ApplyVertexToEffectSemanticMapping(Collada::Sampler& sampler,
     const Collada::SemanticMappingTable& table)
{
    std::map<std::string, Collada::InputSemanticMapEntry>::const_iterator it = table.mMap.find(sampler.mUVChannel);
    if (it != table.mMap.end()) {
        if (it->second.mType != Collada::IT_Texcoord)
            DefaultLogger::get()->error("Collada: Unexpected effect input mapping");

        sampler.mUVId = it->second.mSet;
    }
}

// ------------------------------------------------------------------------------------------------
// Builds lights for the given node and references them
void ColladaLoader::BuildLightsForNode( const ColladaParser& pParser, const Collada::Node* pNode, aiNode* pTarget)
{
    for( const Collada::LightInstance& lid : pNode->mLights)
    {
        // find the referred light
        ColladaParser::LightLibrary::const_iterator srcLightIt = pParser.mLightLibrary.find( lid.mLight);
        if( srcLightIt == pParser.mLightLibrary.end())
        {
            DefaultLogger::get()->warn("Collada: Unable to find light for ID \"" + lid.mLight + "\". Skipping.");
            continue;
        }
        const Collada::Light* srcLight = &srcLightIt->second;

        // now fill our ai data structure
        aiLight* out = new aiLight();
        out->mName = pTarget->mName;
        out->mType = (aiLightSourceType)srcLight->mType;

        // collada lights point in -Z by default, rest is specified in node transform
        out->mDirection = aiVector3D(0.f,0.f,-1.f);

        out->mAttenuationConstant = srcLight->mAttConstant;
        out->mAttenuationLinear = srcLight->mAttLinear;
        out->mAttenuationQuadratic = srcLight->mAttQuadratic;

        out->mColorDiffuse = out->mColorSpecular = out->mColorAmbient = srcLight->mColor*srcLight->mIntensity;
        if (out->mType == aiLightSource_AMBIENT) {
            out->mColorDiffuse = out->mColorSpecular = aiColor3D(0, 0, 0);
            out->mColorAmbient = srcLight->mColor*srcLight->mIntensity;
        }
        else {
            // collada doesn't differentiate between these color types
            out->mColorDiffuse = out->mColorSpecular = srcLight->mColor*srcLight->mIntensity;
            out->mColorAmbient = aiColor3D(0, 0, 0);
        }

        // convert falloff angle and falloff exponent in our representation, if given
        if (out->mType == aiLightSource_SPOT) {

            out->mAngleInnerCone = AI_DEG_TO_RAD( srcLight->mFalloffAngle );

            // ... some extension magic.
            if (srcLight->mOuterAngle >= ASSIMP_COLLADA_LIGHT_ANGLE_NOT_SET*(1-1e-6f))
            {
                // ... some deprecation magic.
                if (srcLight->mPenumbraAngle >= ASSIMP_COLLADA_LIGHT_ANGLE_NOT_SET*(1-1e-6f))
                {
                    // Need to rely on falloff_exponent. I don't know how to interpret it, so I need to guess ....
                    // epsilon chosen to be 0.1
                    out->mAngleOuterCone = std::acos(std::pow(0.1f,1.f/srcLight->mFalloffExponent))+
                            out->mAngleInnerCone;
                }
                else {
                    out->mAngleOuterCone = out->mAngleInnerCone + AI_DEG_TO_RAD(  srcLight->mPenumbraAngle );
                    if (out->mAngleOuterCone < out->mAngleInnerCone)
                        std::swap(out->mAngleInnerCone,out->mAngleOuterCone);
                }
            }
            else out->mAngleOuterCone = AI_DEG_TO_RAD(  srcLight->mOuterAngle );
        }

        // add to light list
        mLights.push_back(out);
    }
}

// ------------------------------------------------------------------------------------------------
// Builds cameras for the given node and references them
void ColladaLoader::BuildCamerasForNode( const ColladaParser& pParser, const Collada::Node* pNode, aiNode* pTarget)
{
    for( const Collada::CameraInstance& cid : pNode->mCameras)
    {
        // find the referred light
        ColladaParser::CameraLibrary::const_iterator srcCameraIt = pParser.mCameraLibrary.find( cid.mCamera);
        if( srcCameraIt == pParser.mCameraLibrary.end())
        {
            DefaultLogger::get()->warn("Collada: Unable to find camera for ID \"" + cid.mCamera + "\". Skipping.");
            continue;
        }
        const Collada::Camera* srcCamera = &srcCameraIt->second;

        // orthographic cameras not yet supported in Assimp
        if (srcCamera->mOrtho) {
            DefaultLogger::get()->warn("Collada: Orthographic cameras are not supported.");
        }

        // now fill our ai data structure
        aiCamera* out = new aiCamera();
        out->mName = pTarget->mName;

        // collada cameras point in -Z by default, rest is specified in node transform
        out->mLookAt = aiVector3D(0.f,0.f,-1.f);

        // near/far z is already ok
        out->mClipPlaneFar = srcCamera->mZFar;
        out->mClipPlaneNear = srcCamera->mZNear;

        // ... but for the rest some values are optional
        // and we need to compute the others in any combination.
         if (srcCamera->mAspect != 10e10f)
            out->mAspect = srcCamera->mAspect;

        if (srcCamera->mHorFov != 10e10f) {
            out->mHorizontalFOV = srcCamera->mHorFov;

            if (srcCamera->mVerFov != 10e10f && srcCamera->mAspect == 10e10f) {
                out->mAspect = std::tan(AI_DEG_TO_RAD(srcCamera->mHorFov)) /
                    std::tan(AI_DEG_TO_RAD(srcCamera->mVerFov));
            }
        }
        else if (srcCamera->mAspect != 10e10f && srcCamera->mVerFov != 10e10f)  {
            out->mHorizontalFOV = 2.0f * AI_RAD_TO_DEG(std::atan(srcCamera->mAspect *
                std::tan(AI_DEG_TO_RAD(srcCamera->mVerFov) * 0.5f)));
        }

        // Collada uses degrees, we use radians
        out->mHorizontalFOV = AI_DEG_TO_RAD(out->mHorizontalFOV);

        // add to camera list
        mCameras.push_back(out);
    }
}

// ------------------------------------------------------------------------------------------------
// Builds meshes for the given node and references them
void ColladaLoader::BuildMeshesForNode( const ColladaParser& pParser, const Collada::Node* pNode, aiNode* pTarget)
{
    // accumulated mesh references by this node
    std::vector<size_t> newMeshRefs;
    newMeshRefs.reserve(pNode->mMeshes.size());

    // add a mesh for each subgroup in each collada mesh
    for( const Collada::MeshInstance& mid : pNode->mMeshes)
    {
        const Collada::Mesh* srcMesh = NULL;
        const Collada::Controller* srcController = NULL;

        // find the referred mesh
        ColladaParser::MeshLibrary::const_iterator srcMeshIt = pParser.mMeshLibrary.find( mid.mMeshOrController);
        if( srcMeshIt == pParser.mMeshLibrary.end())
        {
            // if not found in the mesh-library, it might also be a controller referring to a mesh
            ColladaParser::ControllerLibrary::const_iterator srcContrIt = pParser.mControllerLibrary.find( mid.mMeshOrController);
            if( srcContrIt != pParser.mControllerLibrary.end())
            {
                srcController = &srcContrIt->second;
                srcMeshIt = pParser.mMeshLibrary.find( srcController->mMeshId);
                if( srcMeshIt != pParser.mMeshLibrary.end())
                    srcMesh = srcMeshIt->second;
            }

            if( !srcMesh)
            {
                DefaultLogger::get()->warn( format() << "Collada: Unable to find geometry for ID \"" << mid.mMeshOrController << "\". Skipping." );
                continue;
            }
        } else
        {
            // ID found in the mesh library -> direct reference to an unskinned mesh
            srcMesh = srcMeshIt->second;
        }

        // build a mesh for each of its subgroups
        size_t vertexStart = 0, faceStart = 0;
        for( size_t sm = 0; sm < srcMesh->mSubMeshes.size(); ++sm)
        {
            const Collada::SubMesh& submesh = srcMesh->mSubMeshes[sm];
            if( submesh.mNumFaces == 0)
                continue;

            // find material assigned to this submesh
            std::string meshMaterial;
            std::map<std::string, Collada::SemanticMappingTable >::const_iterator meshMatIt = mid.mMaterials.find( submesh.mMaterial);

            const Collada::SemanticMappingTable* table = NULL;
            if( meshMatIt != mid.mMaterials.end())
            {
                table = &meshMatIt->second;
                meshMaterial = table->mMatName;
            }
            else
            {
                DefaultLogger::get()->warn( format() << "Collada: No material specified for subgroup <" << submesh.mMaterial << "> in geometry <" << mid.mMeshOrController << ">." );
                if( !mid.mMaterials.empty() )
                    meshMaterial = mid.mMaterials.begin()->second.mMatName;
            }

            // OK ... here the *real* fun starts ... we have the vertex-input-to-effect-semantic-table
            // given. The only mapping stuff which we do actually support is the UV channel.
            std::map<std::string, size_t>::const_iterator matIt = mMaterialIndexByName.find( meshMaterial);
            unsigned int matIdx;
            if( matIt != mMaterialIndexByName.end())
                matIdx = static_cast<unsigned int>(matIt->second);
            else
                matIdx = 0;

            if (table && !table->mMap.empty() ) {
                std::pair<Collada::Effect*, aiMaterial*>&  mat = newMats[matIdx];

                // Iterate through all texture channels assigned to the effect and
                // check whether we have mapping information for it.
                ApplyVertexToEffectSemanticMapping(mat.first->mTexDiffuse,    *table);
                ApplyVertexToEffectSemanticMapping(mat.first->mTexAmbient,    *table);
                ApplyVertexToEffectSemanticMapping(mat.first->mTexSpecular,   *table);
                ApplyVertexToEffectSemanticMapping(mat.first->mTexEmissive,   *table);
                ApplyVertexToEffectSemanticMapping(mat.first->mTexTransparent,*table);
                ApplyVertexToEffectSemanticMapping(mat.first->mTexBump,       *table);
            }

            // built lookup index of the Mesh-Submesh-Material combination
            ColladaMeshIndex index( mid.mMeshOrController, sm, meshMaterial);

            // if we already have the mesh at the library, just add its index to the node's array
            std::map<ColladaMeshIndex, size_t>::const_iterator dstMeshIt = mMeshIndexByID.find( index);
            if( dstMeshIt != mMeshIndexByID.end())  {
                newMeshRefs.push_back( dstMeshIt->second);
            }
            else
            {
                // else we have to add the mesh to the collection and store its newly assigned index at the node
                aiMesh* dstMesh = CreateMesh( pParser, srcMesh, submesh, srcController, vertexStart, faceStart);

                // store the mesh, and store its new index in the node
                newMeshRefs.push_back( mMeshes.size());
                mMeshIndexByID[index] = mMeshes.size();
                mMeshes.push_back( dstMesh);
                vertexStart += dstMesh->mNumVertices; faceStart += submesh.mNumFaces;

                // assign the material index
                dstMesh->mMaterialIndex = matIdx;
                if(dstMesh->mName.length == 0)
                {
                    dstMesh->mName = mid.mMeshOrController;
                }
      }
        }
    }

    // now place all mesh references we gathered in the target node
    pTarget->mNumMeshes = static_cast<unsigned int>(newMeshRefs.size());
    if( newMeshRefs.size())
    {
        struct UIntTypeConverter
        {
            unsigned int operator()(const size_t& v) const
            {
                return static_cast<unsigned int>(v);
            }
        };

        pTarget->mMeshes = new unsigned int[pTarget->mNumMeshes];
        std::transform( newMeshRefs.begin(), newMeshRefs.end(), pTarget->mMeshes, UIntTypeConverter());
    }
}

// ------------------------------------------------------------------------------------------------
// Creates a mesh for the given ColladaMesh face subset and returns the newly created mesh
aiMesh* ColladaLoader::CreateMesh( const ColladaParser& pParser, const Collada::Mesh* pSrcMesh, const Collada::SubMesh& pSubMesh,
    const Collada::Controller* pSrcController, size_t pStartVertex, size_t pStartFace)
{
    aiMesh* dstMesh = new aiMesh;

    dstMesh->mName = pSrcMesh->mName;

    // count the vertices addressed by its faces
    const size_t numVertices = std::accumulate( pSrcMesh->mFaceSize.begin() + pStartFace,
        pSrcMesh->mFaceSize.begin() + pStartFace + pSubMesh.mNumFaces, size_t(0));

    // copy positions
    dstMesh->mNumVertices = static_cast<unsigned int>(numVertices);
    dstMesh->mVertices = new aiVector3D[numVertices];
    std::copy( pSrcMesh->mPositions.begin() + pStartVertex, pSrcMesh->mPositions.begin() +
        pStartVertex + numVertices, dstMesh->mVertices);

    // normals, if given. HACK: (thom) Due to the glorious Collada spec we never
    // know if we have the same number of normals as there are positions. So we
    // also ignore any vertex attribute if it has a different count
    if( pSrcMesh->mNormals.size() >= pStartVertex + numVertices)
    {
        dstMesh->mNormals = new aiVector3D[numVertices];
        std::copy( pSrcMesh->mNormals.begin() + pStartVertex, pSrcMesh->mNormals.begin() +
            pStartVertex + numVertices, dstMesh->mNormals);
    }

    // tangents, if given.
    if( pSrcMesh->mTangents.size() >= pStartVertex + numVertices)
    {
        dstMesh->mTangents = new aiVector3D[numVertices];
        std::copy( pSrcMesh->mTangents.begin() + pStartVertex, pSrcMesh->mTangents.begin() +
            pStartVertex + numVertices, dstMesh->mTangents);
    }

    // bitangents, if given.
    if( pSrcMesh->mBitangents.size() >= pStartVertex + numVertices)
    {
        dstMesh->mBitangents = new aiVector3D[numVertices];
        std::copy( pSrcMesh->mBitangents.begin() + pStartVertex, pSrcMesh->mBitangents.begin() +
            pStartVertex + numVertices, dstMesh->mBitangents);
    }

    // same for texturecoords, as many as we have
    // empty slots are not allowed, need to pack and adjust UV indexes accordingly
    for( size_t a = 0, real = 0; a < AI_MAX_NUMBER_OF_TEXTURECOORDS; a++)
    {
        if( pSrcMesh->mTexCoords[a].size() >= pStartVertex + numVertices)
        {
            dstMesh->mTextureCoords[real] = new aiVector3D[numVertices];
            for( size_t b = 0; b < numVertices; ++b)
                dstMesh->mTextureCoords[real][b] = pSrcMesh->mTexCoords[a][pStartVertex+b];

            dstMesh->mNumUVComponents[real] = pSrcMesh->mNumUVComponents[a];
            ++real;
        }
    }

    // same for vertex colors, as many as we have. again the same packing to avoid empty slots
    for( size_t a = 0, real = 0; a < AI_MAX_NUMBER_OF_COLOR_SETS; a++)
    {
        if( pSrcMesh->mColors[a].size() >= pStartVertex + numVertices)
        {
            dstMesh->mColors[real] = new aiColor4D[numVertices];
            std::copy( pSrcMesh->mColors[a].begin() + pStartVertex, pSrcMesh->mColors[a].begin() + pStartVertex + numVertices,dstMesh->mColors[real]);
            ++real;
        }
    }

    // create faces. Due to the fact that each face uses unique vertices, we can simply count up on each vertex
    size_t vertex = 0;
    dstMesh->mNumFaces = static_cast<unsigned int>(pSubMesh.mNumFaces);
    dstMesh->mFaces = new aiFace[dstMesh->mNumFaces];
    for( size_t a = 0; a < dstMesh->mNumFaces; ++a)
    {
        size_t s = pSrcMesh->mFaceSize[ pStartFace + a];
        aiFace& face = dstMesh->mFaces[a];
        face.mNumIndices = static_cast<unsigned int>(s);
        face.mIndices = new unsigned int[s];
        for( size_t b = 0; b < s; ++b)
            face.mIndices[b] = static_cast<unsigned int>(vertex++);
    }

    // create bones if given
    if( pSrcController)
    {
        // refuse if the vertex count does not match
//      if( pSrcController->mWeightCounts.size() != dstMesh->mNumVertices)
//          throw DeadlyImportError( "Joint Controller vertex count does not match mesh vertex count");

        // resolve references - joint names
        const Collada::Accessor& jointNamesAcc = pParser.ResolveLibraryReference( pParser.mAccessorLibrary, pSrcController->mJointNameSource);
        const Collada::Data& jointNames = pParser.ResolveLibraryReference( pParser.mDataLibrary, jointNamesAcc.mSource);
        // joint offset matrices
        const Collada::Accessor& jointMatrixAcc = pParser.ResolveLibraryReference( pParser.mAccessorLibrary, pSrcController->mJointOffsetMatrixSource);
        const Collada::Data& jointMatrices = pParser.ResolveLibraryReference( pParser.mDataLibrary, jointMatrixAcc.mSource);
        // joint vertex_weight name list - should refer to the same list as the joint names above. If not, report and reconsider
        const Collada::Accessor& weightNamesAcc = pParser.ResolveLibraryReference( pParser.mAccessorLibrary, pSrcController->mWeightInputJoints.mAccessor);
        if( &weightNamesAcc != &jointNamesAcc)
            throw DeadlyImportError( "Temporary implementational laziness. If you read this, please report to the author.");
        // vertex weights
        const Collada::Accessor& weightsAcc = pParser.ResolveLibraryReference( pParser.mAccessorLibrary, pSrcController->mWeightInputWeights.mAccessor);
        const Collada::Data& weights = pParser.ResolveLibraryReference( pParser.mDataLibrary, weightsAcc.mSource);

        if( !jointNames.mIsStringArray || jointMatrices.mIsStringArray || weights.mIsStringArray)
            throw DeadlyImportError( "Data type mismatch while resolving mesh joints");
        // sanity check: we rely on the vertex weights always coming as pairs of BoneIndex-WeightIndex
        if( pSrcController->mWeightInputJoints.mOffset != 0 || pSrcController->mWeightInputWeights.mOffset != 1)
            throw DeadlyImportError( "Unsupported vertex_weight addressing scheme. ");

        // create containers to collect the weights for each bone
        size_t numBones = jointNames.mStrings.size();
        std::vector<std::vector<aiVertexWeight> > dstBones( numBones);

        // build a temporary array of pointers to the start of each vertex's weights
        typedef std::vector< std::pair<size_t, size_t> > IndexPairVector;
        std::vector<IndexPairVector::const_iterator> weightStartPerVertex;
        weightStartPerVertex.resize(pSrcController->mWeightCounts.size(),pSrcController->mWeights.end());

        IndexPairVector::const_iterator pit = pSrcController->mWeights.begin();
        for( size_t a = 0; a < pSrcController->mWeightCounts.size(); ++a)
        {
            weightStartPerVertex[a] = pit;
            pit += pSrcController->mWeightCounts[a];
        }

        // now for each vertex put the corresponding vertex weights into each bone's weight collection
        for( size_t a = pStartVertex; a < pStartVertex + numVertices; ++a)
        {
            // which position index was responsible for this vertex? that's also the index by which
            // the controller assigns the vertex weights
            size_t orgIndex = pSrcMesh->mFacePosIndices[a];
            // find the vertex weights for this vertex
            IndexPairVector::const_iterator iit = weightStartPerVertex[orgIndex];
            size_t pairCount = pSrcController->mWeightCounts[orgIndex];

            for( size_t b = 0; b < pairCount; ++b, ++iit)
            {
                size_t jointIndex = iit->first;
                size_t vertexIndex = iit->second;

                ai_real weight = ReadFloat( weightsAcc, weights, vertexIndex, 0);

                // one day I gonna kill that XSI Collada exporter
                if( weight > 0.0f)
                {
                    aiVertexWeight w;
                    w.mVertexId = static_cast<unsigned int>(a - pStartVertex);
                    w.mWeight = weight;
                    dstBones[jointIndex].push_back( w);
                }
            }
        }

        // count the number of bones which influence vertices of the current submesh
        size_t numRemainingBones = 0;
        for( std::vector<std::vector<aiVertexWeight> >::const_iterator it = dstBones.begin(); it != dstBones.end(); ++it)
            if( it->size() > 0)
                numRemainingBones++;

        // create bone array and copy bone weights one by one
        dstMesh->mNumBones = static_cast<unsigned int>(numRemainingBones);
        dstMesh->mBones = new aiBone*[numRemainingBones];
        size_t boneCount = 0;
        for( size_t a = 0; a < numBones; ++a)
        {
            // omit bones without weights
            if( dstBones[a].size() == 0)
                continue;

            // create bone with its weights
            aiBone* bone = new aiBone;
            bone->mName = ReadString( jointNamesAcc, jointNames, a);
            bone->mOffsetMatrix.a1 = ReadFloat( jointMatrixAcc, jointMatrices, a, 0);
            bone->mOffsetMatrix.a2 = ReadFloat( jointMatrixAcc, jointMatrices, a, 1);
            bone->mOffsetMatrix.a3 = ReadFloat( jointMatrixAcc, jointMatrices, a, 2);
            bone->mOffsetMatrix.a4 = ReadFloat( jointMatrixAcc, jointMatrices, a, 3);
            bone->mOffsetMatrix.b1 = ReadFloat( jointMatrixAcc, jointMatrices, a, 4);
            bone->mOffsetMatrix.b2 = ReadFloat( jointMatrixAcc, jointMatrices, a, 5);
            bone->mOffsetMatrix.b3 = ReadFloat( jointMatrixAcc, jointMatrices, a, 6);
            bone->mOffsetMatrix.b4 = ReadFloat( jointMatrixAcc, jointMatrices, a, 7);
            bone->mOffsetMatrix.c1 = ReadFloat( jointMatrixAcc, jointMatrices, a, 8);
            bone->mOffsetMatrix.c2 = ReadFloat( jointMatrixAcc, jointMatrices, a, 9);
            bone->mOffsetMatrix.c3 = ReadFloat( jointMatrixAcc, jointMatrices, a, 10);
            bone->mOffsetMatrix.c4 = ReadFloat( jointMatrixAcc, jointMatrices, a, 11);
            bone->mNumWeights = static_cast<unsigned int>(dstBones[a].size());
            bone->mWeights = new aiVertexWeight[bone->mNumWeights];
            std::copy( dstBones[a].begin(), dstBones[a].end(), bone->mWeights);

            // apply bind shape matrix to offset matrix
            aiMatrix4x4 bindShapeMatrix;
            bindShapeMatrix.a1 = pSrcController->mBindShapeMatrix[0];
            bindShapeMatrix.a2 = pSrcController->mBindShapeMatrix[1];
            bindShapeMatrix.a3 = pSrcController->mBindShapeMatrix[2];
            bindShapeMatrix.a4 = pSrcController->mBindShapeMatrix[3];
            bindShapeMatrix.b1 = pSrcController->mBindShapeMatrix[4];
            bindShapeMatrix.b2 = pSrcController->mBindShapeMatrix[5];
            bindShapeMatrix.b3 = pSrcController->mBindShapeMatrix[6];
            bindShapeMatrix.b4 = pSrcController->mBindShapeMatrix[7];
            bindShapeMatrix.c1 = pSrcController->mBindShapeMatrix[8];
            bindShapeMatrix.c2 = pSrcController->mBindShapeMatrix[9];
            bindShapeMatrix.c3 = pSrcController->mBindShapeMatrix[10];
            bindShapeMatrix.c4 = pSrcController->mBindShapeMatrix[11];
            bindShapeMatrix.d1 = pSrcController->mBindShapeMatrix[12];
            bindShapeMatrix.d2 = pSrcController->mBindShapeMatrix[13];
            bindShapeMatrix.d3 = pSrcController->mBindShapeMatrix[14];
            bindShapeMatrix.d4 = pSrcController->mBindShapeMatrix[15];
            bone->mOffsetMatrix *= bindShapeMatrix;

            // HACK: (thom) Some exporters address the bone nodes by SID, others address them by ID or even name.
            // Therefore I added a little name replacement here: I search for the bone's node by either name, ID or SID,
            // and replace the bone's name by the node's name so that the user can use the standard
            // find-by-name method to associate nodes with bones.
            const Collada::Node* bnode = FindNode( pParser.mRootNode, bone->mName.data);
            if( !bnode)
                bnode = FindNodeBySID( pParser.mRootNode, bone->mName.data);

            // assign the name that we would have assigned for the source node
            if( bnode)
                bone->mName.Set( FindNameForNode( bnode));
            else
                DefaultLogger::get()->warn( format() << "ColladaLoader::CreateMesh(): could not find corresponding node for joint \"" << bone->mName.data << "\"." );

            // and insert bone
            dstMesh->mBones[boneCount++] = bone;
        }
    }

    return dstMesh;
}

// ------------------------------------------------------------------------------------------------
// Stores all meshes in the given scene
void ColladaLoader::StoreSceneMeshes( aiScene* pScene)
{
    pScene->mNumMeshes = static_cast<unsigned int>(mMeshes.size());
    if( mMeshes.size() > 0)
    {
        pScene->mMeshes = new aiMesh*[mMeshes.size()];
        std::copy( mMeshes.begin(), mMeshes.end(), pScene->mMeshes);
        mMeshes.clear();
    }
}

// ------------------------------------------------------------------------------------------------
// Stores all cameras in the given scene
void ColladaLoader::StoreSceneCameras( aiScene* pScene)
{
    pScene->mNumCameras = static_cast<unsigned int>(mCameras.size());
    if( mCameras.size() > 0)
    {
        pScene->mCameras = new aiCamera*[mCameras.size()];
        std::copy( mCameras.begin(), mCameras.end(), pScene->mCameras);
        mCameras.clear();
    }
}

// ------------------------------------------------------------------------------------------------
// Stores all lights in the given scene
void ColladaLoader::StoreSceneLights( aiScene* pScene)
{
    pScene->mNumLights = static_cast<unsigned int>(mLights.size());
    if( mLights.size() > 0)
    {
        pScene->mLights = new aiLight*[mLights.size()];
        std::copy( mLights.begin(), mLights.end(), pScene->mLights);
        mLights.clear();
    }
}

// ------------------------------------------------------------------------------------------------
// Stores all textures in the given scene
void ColladaLoader::StoreSceneTextures( aiScene* pScene)
{
    pScene->mNumTextures = static_cast<unsigned int>(mTextures.size());
    if( mTextures.size() > 0)
    {
        pScene->mTextures = new aiTexture*[mTextures.size()];
        std::copy( mTextures.begin(), mTextures.end(), pScene->mTextures);
        mTextures.clear();
    }
}

// ------------------------------------------------------------------------------------------------
// Stores all materials in the given scene
void ColladaLoader::StoreSceneMaterials( aiScene* pScene)
{
    pScene->mNumMaterials = static_cast<unsigned int>(newMats.size());

    if (newMats.size() > 0) {
        pScene->mMaterials = new aiMaterial*[newMats.size()];
        for (unsigned int i = 0; i < newMats.size();++i)
            pScene->mMaterials[i] = newMats[i].second;

        newMats.clear();
    }
}

// ------------------------------------------------------------------------------------------------
// Stores all animations
void ColladaLoader::StoreAnimations( aiScene* pScene, const ColladaParser& pParser)
{
    // recursivly collect all animations from the collada scene
    StoreAnimations( pScene, pParser, &pParser.mAnims, "");

    // catch special case: many animations with the same length, each affecting only a single node.
    // we need to unite all those single-node-anims to a proper combined animation
    for( size_t a = 0; a < mAnims.size(); ++a)
    {
        aiAnimation* templateAnim = mAnims[a];
        if( templateAnim->mNumChannels == 1)
        {
            // search for other single-channel-anims with the same duration
            std::vector<size_t> collectedAnimIndices;
            for( size_t b = a+1; b < mAnims.size(); ++b)
            {
                aiAnimation* other = mAnims[b];
                if( other->mNumChannels == 1 && other->mDuration == templateAnim->mDuration && other->mTicksPerSecond == templateAnim->mTicksPerSecond )
                    collectedAnimIndices.push_back( b);
            }

            // if there are other animations which fit the template anim, combine all channels into a single anim
            if( !collectedAnimIndices.empty() )
            {
                aiAnimation* combinedAnim = new aiAnimation();
                combinedAnim->mName = aiString( std::string( "combinedAnim_") + char( '0' + a));
                combinedAnim->mDuration = templateAnim->mDuration;
                combinedAnim->mTicksPerSecond = templateAnim->mTicksPerSecond;
                combinedAnim->mNumChannels = static_cast<unsigned int>(collectedAnimIndices.size() + 1);
                combinedAnim->mChannels = new aiNodeAnim*[combinedAnim->mNumChannels];
                // add the template anim as first channel by moving its aiNodeAnim to the combined animation
                combinedAnim->mChannels[0] = templateAnim->mChannels[0];
                templateAnim->mChannels[0] = NULL;
                delete templateAnim;
                // combined animation replaces template animation in the anim array
                mAnims[a] = combinedAnim;

                // move the memory of all other anims to the combined anim and erase them from the source anims
                for( size_t b = 0; b < collectedAnimIndices.size(); ++b)
                {
                    aiAnimation* srcAnimation = mAnims[collectedAnimIndices[b]];
                    combinedAnim->mChannels[1 + b] = srcAnimation->mChannels[0];
                    srcAnimation->mChannels[0] = NULL;
                    delete srcAnimation;
                }

                // in a second go, delete all the single-channel-anims that we've stripped from their channels
                // back to front to preserve indices - you know, removing an element from a vector moves all elements behind the removed one
                while( !collectedAnimIndices.empty() )
                {
                    mAnims.erase( mAnims.begin() + collectedAnimIndices.back());
                    collectedAnimIndices.pop_back();
                }
            }
        }
    }

    // now store all anims in the scene
    if( !mAnims.empty())
    {
        pScene->mNumAnimations = static_cast<unsigned int>(mAnims.size());
        pScene->mAnimations = new aiAnimation*[mAnims.size()];
        std::copy( mAnims.begin(), mAnims.end(), pScene->mAnimations);
    }

    mAnims.clear();
}

// ------------------------------------------------------------------------------------------------
// Constructs the animations for the given source anim
void ColladaLoader::StoreAnimations( aiScene* pScene, const ColladaParser& pParser, const Collada::Animation* pSrcAnim, const std::string &pPrefix)
{
    std::string animName = pPrefix.empty() ? pSrcAnim->mName : pPrefix + "_" + pSrcAnim->mName;

    // create nested animations, if given
    for( std::vector<Collada::Animation*>::const_iterator it = pSrcAnim->mSubAnims.begin(); it != pSrcAnim->mSubAnims.end(); ++it)
        StoreAnimations( pScene, pParser, *it, animName);

    // create animation channels, if any
    if( !pSrcAnim->mChannels.empty())
        CreateAnimation( pScene, pParser, pSrcAnim, animName);
}

// ------------------------------------------------------------------------------------------------
// Constructs the animation for the given source anim
void ColladaLoader::CreateAnimation( aiScene* pScene, const ColladaParser& pParser, const Collada::Animation* pSrcAnim, const std::string& pName)
{
    // collect a list of animatable nodes
    std::vector<const aiNode*> nodes;
    CollectNodes( pScene->mRootNode, nodes);

    std::vector<aiNodeAnim*> anims;
    for( std::vector<const aiNode*>::const_iterator nit = nodes.begin(); nit != nodes.end(); ++nit)
    {
        // find all the collada anim channels which refer to the current node
        std::vector<Collada::ChannelEntry> entries;
        std::string nodeName = (*nit)->mName.data;

        // find the collada node corresponding to the aiNode
        const Collada::Node* srcNode = FindNode( pParser.mRootNode, nodeName);
//      ai_assert( srcNode != NULL);
        if( !srcNode)
            continue;

        // now check all channels if they affect the current node
        for( std::vector<Collada::AnimationChannel>::const_iterator cit = pSrcAnim->mChannels.begin();
            cit != pSrcAnim->mChannels.end(); ++cit)
        {
            const Collada::AnimationChannel& srcChannel = *cit;
            Collada::ChannelEntry entry;

            // we expect the animation target to be of type "nodeName/transformID.subElement". Ignore all others
            // find the slash that separates the node name - there should be only one
            std::string::size_type slashPos = srcChannel.mTarget.find( '/');
            if( slashPos == std::string::npos)
                continue;
            if( srcChannel.mTarget.find( '/', slashPos+1) != std::string::npos)
                continue;
            std::string targetID = srcChannel.mTarget.substr( 0, slashPos);
            if( targetID != srcNode->mID)
                continue;

            // find the dot that separates the transformID - there should be only one or zero
            std::string::size_type dotPos = srcChannel.mTarget.find( '.');
            if( dotPos != std::string::npos)
            {
                if( srcChannel.mTarget.find( '.', dotPos+1) != std::string::npos)
                    continue;

                entry.mTransformId = srcChannel.mTarget.substr( slashPos+1, dotPos - slashPos - 1);

                std::string subElement = srcChannel.mTarget.substr( dotPos+1);
                if( subElement == "ANGLE")
                    entry.mSubElement = 3; // last number in an Axis-Angle-Transform is the angle
                else if( subElement == "X")
                    entry.mSubElement = 0;
                else if( subElement == "Y")
                    entry.mSubElement = 1;
                else if( subElement == "Z")
                    entry.mSubElement = 2;
                else
                    DefaultLogger::get()->warn( format() << "Unknown anim subelement <" << subElement << ">. Ignoring" );
            } else
            {
                // no subelement following, transformId is remaining string
                entry.mTransformId = srcChannel.mTarget.substr( slashPos+1);
            }

            std::string::size_type bracketPos = srcChannel.mTarget.find('(');
            if (bracketPos != std::string::npos)
            {
                entry.mTransformId = srcChannel.mTarget.substr(slashPos + 1, bracketPos - slashPos - 1);
                std::string subElement = srcChannel.mTarget.substr(bracketPos);

                if (subElement == "(0)(0)")
                    entry.mSubElement = 0;
                else if (subElement == "(1)(0)")
                    entry.mSubElement = 1;
                else if (subElement == "(2)(0)")
                    entry.mSubElement = 2;
                else if (subElement == "(3)(0)")
                    entry.mSubElement = 3;
                else if (subElement == "(0)(1)")
                    entry.mSubElement = 4;
                else if (subElement == "(1)(1)")
                    entry.mSubElement = 5;
                else if (subElement == "(2)(1)")
                    entry.mSubElement = 6;
                else if (subElement == "(3)(1)")
                    entry.mSubElement = 7;
                else if (subElement == "(0)(2)")
                    entry.mSubElement = 8;
                else if (subElement == "(1)(2)")
                    entry.mSubElement = 9;
                else if (subElement == "(2)(2)")
                    entry.mSubElement = 10;
                else if (subElement == "(3)(2)")
                    entry.mSubElement = 11;
                else if (subElement == "(0)(3)")
                    entry.mSubElement = 12;
                else if (subElement == "(1)(3)")
                    entry.mSubElement = 13;
                else if (subElement == "(2)(3)")
                    entry.mSubElement = 14;
                else if (subElement == "(3)(3)")
                    entry.mSubElement = 15;

            }

            // determine which transform step is affected by this channel
            entry.mTransformIndex = SIZE_MAX;
            for( size_t a = 0; a < srcNode->mTransforms.size(); ++a)
                if( srcNode->mTransforms[a].mID == entry.mTransformId)
                    entry.mTransformIndex = a;

            if( entry.mTransformIndex == SIZE_MAX) {
                continue;
            }

            entry.mChannel = &(*cit);
            entries.push_back( entry);
        }

        // if there's no channel affecting the current node, we skip it
        if( entries.empty())
            continue;

        // resolve the data pointers for all anim channels. Find the minimum time while we're at it
        ai_real startTime = ai_real( 1e20 ), endTime = ai_real( -1e20 );
        for( std::vector<Collada::ChannelEntry>::iterator it = entries.begin(); it != entries.end(); ++it)
        {
            Collada::ChannelEntry& e = *it;
            e.mTimeAccessor = &pParser.ResolveLibraryReference( pParser.mAccessorLibrary, e.mChannel->mSourceTimes);
            e.mTimeData = &pParser.ResolveLibraryReference( pParser.mDataLibrary, e.mTimeAccessor->mSource);
            e.mValueAccessor = &pParser.ResolveLibraryReference( pParser.mAccessorLibrary, e.mChannel->mSourceValues);
            e.mValueData = &pParser.ResolveLibraryReference( pParser.mDataLibrary, e.mValueAccessor->mSource);

            // time count and value count must match
            if( e.mTimeAccessor->mCount != e.mValueAccessor->mCount)
                throw DeadlyImportError( format() << "Time count / value count mismatch in animation channel \"" << e.mChannel->mTarget << "\"." );

      if( e.mTimeAccessor->mCount > 0 )
      {
              // find bounding times
              startTime = std::min( startTime, ReadFloat( *e.mTimeAccessor, *e.mTimeData, 0, 0));
            endTime = std::max( endTime, ReadFloat( *e.mTimeAccessor, *e.mTimeData, e.mTimeAccessor->mCount-1, 0));
      }
        }

    std::vector<aiMatrix4x4> resultTrafos;
    if( !entries.empty() && entries.front().mTimeAccessor->mCount > 0 )
    {
          // create a local transformation chain of the node's transforms
          std::vector<Collada::Transform> transforms = srcNode->mTransforms;

          // now for every unique point in time, find or interpolate the key values for that time
          // and apply them to the transform chain. Then the node's present transformation can be calculated.
          ai_real time = startTime;
          while( 1)
          {
              for( std::vector<Collada::ChannelEntry>::iterator it = entries.begin(); it != entries.end(); ++it)
              {
                  Collada::ChannelEntry& e = *it;

                  // find the keyframe behind the current point in time
                  size_t pos = 0;
                  ai_real postTime = 0.0;
                  while( 1)
                  {
                      if( pos >= e.mTimeAccessor->mCount)
                          break;
                      postTime = ReadFloat( *e.mTimeAccessor, *e.mTimeData, pos, 0);
                      if( postTime >= time)
                          break;
                      ++pos;
                  }

                  pos = std::min( pos, e.mTimeAccessor->mCount-1);

                  // read values from there
                  ai_real temp[16];
                  for( size_t c = 0; c < e.mValueAccessor->mSize; ++c)
                      temp[c] = ReadFloat( *e.mValueAccessor, *e.mValueData, pos, c);

                  // if not exactly at the key time, interpolate with previous value set
                  if( postTime > time && pos > 0)
                  {
                      ai_real preTime = ReadFloat( *e.mTimeAccessor, *e.mTimeData, pos-1, 0);
                      ai_real factor = (time - postTime) / (preTime - postTime);

                      for( size_t c = 0; c < e.mValueAccessor->mSize; ++c)
                      {
                          ai_real v = ReadFloat( *e.mValueAccessor, *e.mValueData, pos-1, c);
                          temp[c] += (v - temp[c]) * factor;
                      }
                  }

                  // Apply values to current transformation
                  std::copy( temp, temp + e.mValueAccessor->mSize, transforms[e.mTransformIndex].f + e.mSubElement);
              }

              // Calculate resulting transformation
              aiMatrix4x4 mat = pParser.CalculateResultTransform( transforms);

              // out of laziness: we store the time in matrix.d4
              mat.d4 = time;
              resultTrafos.push_back( mat);

              // find next point in time to evaluate. That's the closest frame larger than the current in any channel
              ai_real nextTime = ai_real( 1e20 );
              for( std::vector<Collada::ChannelEntry>::iterator it = entries.begin(); it != entries.end(); ++it)
              {
                  Collada::ChannelEntry& channelElement = *it;

                  // find the next time value larger than the current
                  size_t pos = 0;
                  while( pos < channelElement.mTimeAccessor->mCount)
                  {
                      const ai_real t = ReadFloat( *channelElement.mTimeAccessor, *channelElement.mTimeData, pos, 0);
                      if( t > time)
                      {
                          nextTime = std::min( nextTime, t);
                          break;
                      }
                      ++pos;
                  }

				  // https://github.com/assimp/assimp/issues/458
			  	  // Sub-sample axis-angle channels if the delta between two consecutive
                  // key-frame angles is >= 180 degrees.
				  if (transforms[channelElement.mTransformIndex].mType == Collada::TF_ROTATE && channelElement.mSubElement == 3 && pos > 0 && pos < channelElement.mTimeAccessor->mCount) {
					  const ai_real cur_key_angle = ReadFloat(*channelElement.mValueAccessor, *channelElement.mValueData, pos, 0);
                      const ai_real last_key_angle = ReadFloat(*channelElement.mValueAccessor, *channelElement.mValueData, pos - 1, 0);
                      const ai_real cur_key_time = ReadFloat(*channelElement.mTimeAccessor, *channelElement.mTimeData, pos, 0);
                      const ai_real last_key_time = ReadFloat(*channelElement.mTimeAccessor, *channelElement.mTimeData, pos - 1, 0);
                      const ai_real last_eval_angle = last_key_angle + (cur_key_angle - last_key_angle) * (time - last_key_time) / (cur_key_time - last_key_time);
                      const ai_real delta = std::abs(cur_key_angle - last_eval_angle);
				      if (delta >= 180.0) {
						const int subSampleCount = static_cast<int>(std::floor(delta / 90.0));
						if (cur_key_time != time) {
							const ai_real nextSampleTime = time + (cur_key_time - time) / subSampleCount;
							nextTime = std::min(nextTime, nextSampleTime);
						  }
					  }
				  }
              }

              // no more keys on any channel after the current time -> we're done
              if( nextTime > 1e19)
                  break;

              // else construct next keyframe at this following time point
              time = nextTime;
          }
    }

        // there should be some keyframes, but we aren't that fixated on valid input data
//      ai_assert( resultTrafos.size() > 0);

        // build an animation channel for the given node out of these trafo keys
    if( !resultTrafos.empty() )
    {
          aiNodeAnim* dstAnim = new aiNodeAnim;
          dstAnim->mNodeName = nodeName;
          dstAnim->mNumPositionKeys = static_cast<unsigned int>(resultTrafos.size());
          dstAnim->mNumRotationKeys= static_cast<unsigned int>(resultTrafos.size());
          dstAnim->mNumScalingKeys = static_cast<unsigned int>(resultTrafos.size());
          dstAnim->mPositionKeys = new aiVectorKey[resultTrafos.size()];
          dstAnim->mRotationKeys = new aiQuatKey[resultTrafos.size()];
          dstAnim->mScalingKeys = new aiVectorKey[resultTrafos.size()];

          for( size_t a = 0; a < resultTrafos.size(); ++a)
          {
              aiMatrix4x4 mat = resultTrafos[a];
              double time = double( mat.d4); // remember? time is stored in mat.d4
        mat.d4 = 1.0f;

              dstAnim->mPositionKeys[a].mTime = time;
              dstAnim->mRotationKeys[a].mTime = time;
              dstAnim->mScalingKeys[a].mTime = time;
              mat.Decompose( dstAnim->mScalingKeys[a].mValue, dstAnim->mRotationKeys[a].mValue, dstAnim->mPositionKeys[a].mValue);
          }

          anims.push_back( dstAnim);
    } else
    {
      DefaultLogger::get()->warn( "Collada loader: found empty animation channel, ignored. Please check your exporter.");
    }
    }

    if( !anims.empty())
    {
        aiAnimation* anim = new aiAnimation;
        anim->mName.Set( pName);
        anim->mNumChannels = static_cast<unsigned int>(anims.size());
        anim->mChannels = new aiNodeAnim*[anims.size()];
        std::copy( anims.begin(), anims.end(), anim->mChannels);
        anim->mDuration = 0.0f;
        for( size_t a = 0; a < anims.size(); ++a)
        {
            anim->mDuration = std::max( anim->mDuration, anims[a]->mPositionKeys[anims[a]->mNumPositionKeys-1].mTime);
            anim->mDuration = std::max( anim->mDuration, anims[a]->mRotationKeys[anims[a]->mNumRotationKeys-1].mTime);
            anim->mDuration = std::max( anim->mDuration, anims[a]->mScalingKeys[anims[a]->mNumScalingKeys-1].mTime);
        }
        anim->mTicksPerSecond = 1;
        mAnims.push_back( anim);
    }
}

// ------------------------------------------------------------------------------------------------
// Add a texture to a material structure
void ColladaLoader::AddTexture ( aiMaterial& mat, const ColladaParser& pParser,
    const Collada::Effect& effect,
    const Collada::Sampler& sampler,
    aiTextureType type, unsigned int idx)
{
    // first of all, basic file name
    const aiString name = FindFilenameForEffectTexture( pParser, effect, sampler.mName );
    mat.AddProperty( &name, _AI_MATKEY_TEXTURE_BASE, type, idx );

    // mapping mode
    int map = aiTextureMapMode_Clamp;
    if (sampler.mWrapU)
        map = aiTextureMapMode_Wrap;
    if (sampler.mWrapU && sampler.mMirrorU)
        map = aiTextureMapMode_Mirror;

    mat.AddProperty( &map, 1, _AI_MATKEY_MAPPINGMODE_U_BASE, type, idx);

    map = aiTextureMapMode_Clamp;
    if (sampler.mWrapV)
        map = aiTextureMapMode_Wrap;
    if (sampler.mWrapV && sampler.mMirrorV)
        map = aiTextureMapMode_Mirror;

    mat.AddProperty( &map, 1, _AI_MATKEY_MAPPINGMODE_V_BASE, type, idx);

    // UV transformation
    mat.AddProperty(&sampler.mTransform, 1,
        _AI_MATKEY_UVTRANSFORM_BASE, type, idx);

    // Blend mode
    mat.AddProperty((int*)&sampler.mOp , 1,
        _AI_MATKEY_TEXBLEND_BASE, type, idx);

    // Blend factor
    mat.AddProperty((ai_real*)&sampler.mWeighting , 1,
        _AI_MATKEY_TEXBLEND_BASE, type, idx);

    // UV source index ... if we didn't resolve the mapping, it is actually just
    // a guess but it works in most cases. We search for the frst occurrence of a
    // number in the channel name. We assume it is the zero-based index into the
    // UV channel array of all corresponding meshes. It could also be one-based
    // for some exporters, but we won't care of it unless someone complains about.
    if (sampler.mUVId != UINT_MAX)
        map = sampler.mUVId;
    else {
        map = -1;
        for (std::string::const_iterator it = sampler.mUVChannel.begin();it != sampler.mUVChannel.end(); ++it){
            if (IsNumeric(*it)) {
                map = strtoul10(&(*it));
                break;
            }
        }
        if (-1 == map) {
            DefaultLogger::get()->warn("Collada: unable to determine UV channel for texture");
            map = 0;
        }
    }
    mat.AddProperty(&map,1,_AI_MATKEY_UVWSRC_BASE,type,idx);
}

// ------------------------------------------------------------------------------------------------
// Fills materials from the collada material definitions
void ColladaLoader::FillMaterials( const ColladaParser& pParser, aiScene* /*pScene*/)
{
    for (auto &elem : newMats)
    {
        aiMaterial&  mat = (aiMaterial&)*elem.second;
        Collada::Effect& effect = *elem.first;

        // resolve shading mode
        int shadeMode;
        if (effect.mFaceted) /* fixme */
            shadeMode = aiShadingMode_Flat;
        else {
            switch( effect.mShadeType)
            {
            case Collada::Shade_Constant:
                shadeMode = aiShadingMode_NoShading;
                break;
            case Collada::Shade_Lambert:
                shadeMode = aiShadingMode_Gouraud;
                break;
            case Collada::Shade_Blinn:
                shadeMode = aiShadingMode_Blinn;
                break;
            case Collada::Shade_Phong:
                shadeMode = aiShadingMode_Phong;
                break;

            default:
                DefaultLogger::get()->warn("Collada: Unrecognized shading mode, using gouraud shading");
                shadeMode = aiShadingMode_Gouraud;
                break;
            }
        }
        mat.AddProperty<int>( &shadeMode, 1, AI_MATKEY_SHADING_MODEL);

        // double-sided?
        shadeMode = effect.mDoubleSided;
        mat.AddProperty<int>( &shadeMode, 1, AI_MATKEY_TWOSIDED);

        // wireframe?
        shadeMode = effect.mWireframe;
        mat.AddProperty<int>( &shadeMode, 1, AI_MATKEY_ENABLE_WIREFRAME);

        // add material colors
        mat.AddProperty( &effect.mAmbient, 1,AI_MATKEY_COLOR_AMBIENT);
        mat.AddProperty( &effect.mDiffuse, 1, AI_MATKEY_COLOR_DIFFUSE);
        mat.AddProperty( &effect.mSpecular, 1,AI_MATKEY_COLOR_SPECULAR);
        mat.AddProperty( &effect.mEmissive, 1,  AI_MATKEY_COLOR_EMISSIVE);
        mat.AddProperty( &effect.mReflective, 1, AI_MATKEY_COLOR_REFLECTIVE);

        // scalar properties
        mat.AddProperty( &effect.mShininess, 1, AI_MATKEY_SHININESS);
        mat.AddProperty( &effect.mReflectivity, 1, AI_MATKEY_REFLECTIVITY);
        mat.AddProperty( &effect.mRefractIndex, 1, AI_MATKEY_REFRACTI);

        // transparency, a very hard one. seemingly not all files are following the
        // specification here (1.0 transparency => completly opaque)...
        // therefore, we let the opportunity for the user to manually invert
        // the transparency if necessary and we add preliminary support for RGB_ZERO mode
        if(effect.mTransparency >= 0.f && effect.mTransparency <= 1.f) {
            // handle RGB transparency completely, cf Collada specs 1.5.0 pages 249 and 304
            if(effect.mRGBTransparency) {
				// use luminance as defined by ISO/CIE color standards (see ITU-R Recommendation BT.709-4)
                effect.mTransparency *= (
                    0.212671f * effect.mTransparent.r +
                    0.715160f * effect.mTransparent.g +
                    0.072169f * effect.mTransparent.b
                );

                effect.mTransparent.a = 1.f;

                mat.AddProperty( &effect.mTransparent, 1, AI_MATKEY_COLOR_TRANSPARENT );
            } else {
                effect.mTransparency *=  effect.mTransparent.a;
            }

            if(effect.mInvertTransparency) {
                effect.mTransparency = 1.f - effect.mTransparency;
            }

            // Is the material finally transparent ?
            if (effect.mHasTransparency || effect.mTransparency < 1.f) {
                mat.AddProperty( &effect.mTransparency, 1, AI_MATKEY_OPACITY );
            }
        }

        // add textures, if given
        if( !effect.mTexAmbient.mName.empty())
             /* It is merely a lightmap */
            AddTexture( mat, pParser, effect, effect.mTexAmbient, aiTextureType_LIGHTMAP);

        if( !effect.mTexEmissive.mName.empty())
            AddTexture( mat, pParser, effect, effect.mTexEmissive, aiTextureType_EMISSIVE);

        if( !effect.mTexSpecular.mName.empty())
            AddTexture( mat, pParser, effect, effect.mTexSpecular, aiTextureType_SPECULAR);

        if( !effect.mTexDiffuse.mName.empty())
            AddTexture( mat, pParser, effect, effect.mTexDiffuse, aiTextureType_DIFFUSE);

        if( !effect.mTexBump.mName.empty())
            AddTexture( mat, pParser, effect, effect.mTexBump, aiTextureType_NORMALS);

        if( !effect.mTexTransparent.mName.empty())
            AddTexture( mat, pParser, effect, effect.mTexTransparent, aiTextureType_OPACITY);

        if( !effect.mTexReflective.mName.empty())
            AddTexture( mat, pParser, effect, effect.mTexReflective, aiTextureType_REFLECTION);
    }
}

// ------------------------------------------------------------------------------------------------
// Constructs materials from the collada material definitions
void ColladaLoader::BuildMaterials( ColladaParser& pParser, aiScene* /*pScene*/)
{
    newMats.reserve(pParser.mMaterialLibrary.size());

    for( ColladaParser::MaterialLibrary::const_iterator matIt = pParser.mMaterialLibrary.begin(); matIt != pParser.mMaterialLibrary.end(); ++matIt)
    {
        const Collada::Material& material = matIt->second;
        // a material is only a reference to an effect
        ColladaParser::EffectLibrary::iterator effIt = pParser.mEffectLibrary.find( material.mEffect);
        if( effIt == pParser.mEffectLibrary.end())
            continue;
        Collada::Effect& effect = effIt->second;

        // create material
        aiMaterial* mat = new aiMaterial;
        aiString name( material.mName.empty() ? matIt->first : material.mName );
        mat->AddProperty(&name,AI_MATKEY_NAME);

        // store the material
        mMaterialIndexByName[matIt->first] = newMats.size();
        newMats.push_back( std::pair<Collada::Effect*, aiMaterial*>( &effect,mat) );
    }
    // ScenePreprocessor generates a default material automatically if none is there.
    // All further code here in this loader works well without a valid material so
    // we can safely let it to ScenePreprocessor.
#if 0
    if( newMats.size() == 0)
    {
        aiMaterial* mat = new aiMaterial;
        aiString name( AI_DEFAULT_MATERIAL_NAME );
        mat->AddProperty( &name, AI_MATKEY_NAME);

        const int shadeMode = aiShadingMode_Phong;
        mat->AddProperty<int>( &shadeMode, 1, AI_MATKEY_SHADING_MODEL);
        aiColor4D colAmbient( 0.2, 0.2, 0.2, 1.0), colDiffuse( 0.8, 0.8, 0.8, 1.0), colSpecular( 0.5, 0.5, 0.5, 0.5);
        mat->AddProperty( &colAmbient, 1, AI_MATKEY_COLOR_AMBIENT);
        mat->AddProperty( &colDiffuse, 1, AI_MATKEY_COLOR_DIFFUSE);
        mat->AddProperty( &colSpecular, 1, AI_MATKEY_COLOR_SPECULAR);
        const ai_real specExp = 5.0;
        mat->AddProperty( &specExp, 1, AI_MATKEY_SHININESS);
    }
#endif
}

// ------------------------------------------------------------------------------------------------
// Resolves the texture name for the given effect texture entry
aiString ColladaLoader::FindFilenameForEffectTexture( const ColladaParser& pParser,
    const Collada::Effect& pEffect, const std::string& pName)
{
    // recurse through the param references until we end up at an image
    std::string name = pName;
    while( 1)
    {
        // the given string is a param entry. Find it
        Collada::Effect::ParamLibrary::const_iterator it = pEffect.mParams.find( name);
        // if not found, we're at the end of the recursion. The resulting string should be the image ID
        if( it == pEffect.mParams.end())
            break;

        // else recurse on
        name = it->second.mReference;
    }

    // find the image referred by this name in the image library of the scene
    ColladaParser::ImageLibrary::const_iterator imIt = pParser.mImageLibrary.find( name);
    if( imIt == pParser.mImageLibrary.end())
    {
        throw DeadlyImportError( format() <<
            "Collada: Unable to resolve effect texture entry \"" << pName << "\", ended up at ID \"" << name << "\"." );
    }

    aiString result;

    // if this is an embedded texture image setup an aiTexture for it
    if (imIt->second.mFileName.empty())
    {
        if (imIt->second.mImageData.empty())  {
            throw DeadlyImportError("Collada: Invalid texture, no data or file reference given");
        }

        aiTexture* tex = new aiTexture();

        // setup format hint
        if (imIt->second.mEmbeddedFormat.length() > 3) {
            DefaultLogger::get()->warn("Collada: texture format hint is too long, truncating to 3 characters");
        }
        strncpy(tex->achFormatHint,imIt->second.mEmbeddedFormat.c_str(),3);

        // and copy texture data
        tex->mHeight = 0;
        tex->mWidth = static_cast<unsigned int>(imIt->second.mImageData.size());
        tex->pcData = (aiTexel*)new char[tex->mWidth];
        memcpy(tex->pcData,&imIt->second.mImageData[0],tex->mWidth);

        // setup texture reference string
        result.data[0] = '*';
        result.length = 1 + ASSIMP_itoa10(result.data+1,static_cast<unsigned int>(MAXLEN-1),static_cast<int32_t>(mTextures.size()));

        // and add this texture to the list
        mTextures.push_back(tex);
    }
    else
    {
        result.Set( imIt->second.mFileName );
        ConvertPath(result);
    }
    return result;
}

// ------------------------------------------------------------------------------------------------
// Convert a path read from a collada file to the usual representation
void ColladaLoader::ConvertPath (aiString& ss)
{
    // TODO: collada spec, p 22. Handle URI correctly.
    // For the moment we're just stripping the file:// away to make it work.
    // Windoes doesn't seem to be able to find stuff like
    // 'file://..\LWO\LWO2\MappingModes\earthSpherical.jpg'
    if (0 == strncmp(ss.data,"file://",7))
    {
        ss.length -= 7;
        memmove(ss.data,ss.data+7,ss.length);
        ss.data[ss.length] = '\0';
    }

  // Maxon Cinema Collada Export writes "file:///C:\andsoon" with three slashes...
  // I need to filter it without destroying linux paths starting with "/somewhere"
  if( ss.data[0] == '/' && isalpha( ss.data[1]) && ss.data[2] == ':' )
  {
    ss.length--;
    memmove( ss.data, ss.data+1, ss.length);
    ss.data[ss.length] = 0;
  }

  // find and convert all %xy special chars
  char* out = ss.data;
  for( const char* it = ss.data; it != ss.data + ss.length; /**/ )
  {
    if( *it == '%' && (it + 3) < ss.data + ss.length )
    {
      // separate the number to avoid dragging in chars from behind into the parsing
      char mychar[3] = { it[1], it[2], 0 };
      size_t nbr = strtoul16( mychar);
      it += 3;
      *out++ = (char)(nbr & 0xFF);
    } else
    {
      *out++ = *it++;
    }
  }

  // adjust length and terminator of the shortened string
  *out = 0;
  ss.length = (ptrdiff_t) (out - ss.data);
}

// ------------------------------------------------------------------------------------------------
// Reads a float value from an accessor and its data array.
ai_real ColladaLoader::ReadFloat( const Collada::Accessor& pAccessor, const Collada::Data& pData, size_t pIndex, size_t pOffset) const
{
    // FIXME: (thom) Test for data type here in every access? For the moment, I leave this to the caller
    size_t pos = pAccessor.mStride * pIndex + pAccessor.mOffset + pOffset;
    ai_assert( pos < pData.mValues.size());
    return pData.mValues[pos];
}

// ------------------------------------------------------------------------------------------------
// Reads a string value from an accessor and its data array.
const std::string& ColladaLoader::ReadString( const Collada::Accessor& pAccessor, const Collada::Data& pData, size_t pIndex) const
{
    size_t pos = pAccessor.mStride * pIndex + pAccessor.mOffset;
    ai_assert( pos < pData.mStrings.size());
    return pData.mStrings[pos];
}

// ------------------------------------------------------------------------------------------------
// Collects all nodes into the given array
void ColladaLoader::CollectNodes( const aiNode* pNode, std::vector<const aiNode*>& poNodes) const
{
    poNodes.push_back( pNode);

    for( size_t a = 0; a < pNode->mNumChildren; ++a)
        CollectNodes( pNode->mChildren[a], poNodes);
}

// ------------------------------------------------------------------------------------------------
// Finds a node in the collada scene by the given name
const Collada::Node* ColladaLoader::FindNode( const Collada::Node* pNode, const std::string& pName) const
{
    if( pNode->mName == pName || pNode->mID == pName)
        return pNode;

    for( size_t a = 0; a < pNode->mChildren.size(); ++a)
    {
        const Collada::Node* node = FindNode( pNode->mChildren[a], pName);
        if( node)
            return node;
    }

    return NULL;
}

// ------------------------------------------------------------------------------------------------
// Finds a node in the collada scene by the given SID
const Collada::Node* ColladaLoader::FindNodeBySID( const Collada::Node* pNode, const std::string& pSID) const
{
  if( pNode->mSID == pSID)
    return pNode;

  for( size_t a = 0; a < pNode->mChildren.size(); ++a)
  {
    const Collada::Node* node = FindNodeBySID( pNode->mChildren[a], pSID);
    if( node)
      return node;
  }

  return NULL;
}

// ------------------------------------------------------------------------------------------------
// Finds a proper name for a node derived from the collada-node's properties
std::string ColladaLoader::FindNameForNode( const Collada::Node* pNode)
{
    // now setup the name of the node. We take the name if not empty, otherwise the collada ID
    // FIX: Workaround for XSI calling the instanced visual scene 'untitled' by default.
    if (!pNode->mName.empty() && pNode->mName != "untitled")
        return pNode->mName;
    else if (!pNode->mID.empty())
        return pNode->mID;
    else if (!pNode->mSID.empty())
    return pNode->mSID;
  else
    {
        // No need to worry. Unnamed nodes are no problem at all, except
        // if cameras or lights need to be assigned to them.
    return format() << "$ColladaAutoName$_" << mNodeNameCounter++;
    }
}

#endif // !! ASSIMP_BUILD_NO_DAE_IMPORTER