/*

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Open Asset Import Library (assimp)

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All rights reserved.

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/** @file  XFileImporter.cpp

 *  @brief Implementation of the XFile importer class

 */

#ifndef ASSIMP_BUILD_NO_X_IMPORTER

#include "XFileImporter.h"

#include "XFileParser.h"

#include "PostProcessing/ConvertToLHProcess.h"

#include <assimp/TinyFormatter.h>

#include <assimp/IOSystem.hpp>

#include <assimp/scene.h>

#include <assimp/DefaultLogger.hpp>

#include <assimp/importerdesc.h>

#include <cctype>

#include <memory>

namespace Assimp {

using namespace Assimp::Formatter;

static constexpr aiImporterDesc desc = {

    "Direct3D XFile Importer",

    "",

    "",

    "",

    aiImporterFlags_SupportTextFlavour | aiImporterFlags_SupportBinaryFlavour | aiImporterFlags_SupportCompressedFlavour,

    1,

    3,

    1,

    5,

    "x"

};

// ------------------------------------------------------------------------------------------------

// Returns whether the class can handle the format of the given file.

bool XFileImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {

    static constexpr uint32_t token[] = { AI_MAKE_MAGIC("xof ") };

    return CheckMagicToken(pIOHandler, pFile, token, AI_COUNT_OF(token));

}

// ------------------------------------------------------------------------------------------------

// Get file extension list

const aiImporterDesc *XFileImporter::GetInfo() const {

    return &desc;

}

// ------------------------------------------------------------------------------------------------

// Imports the given file into the given scene structure.

void XFileImporter::InternReadFile(const std::string &pFile, aiScene *pScene, IOSystem *pIOHandler) {

    // read file into memory

    std::unique_ptr<IOStream> file(pIOHandler->Open(pFile));

    if (file == nullptr) {

        throw DeadlyImportError("Failed to open file ", pFile, ".");

    }

    static const size_t MinSize = 16;

    size_t fileSize = file->FileSize();

    if (fileSize < MinSize) {

        throw DeadlyImportError("XFile is too small.");

    }

    // in the hope that binary files will never start with a BOM ...

    mBuffer.resize(fileSize + 1);

    file->Read(&mBuffer.front(), 1, fileSize);

    ConvertToUTF8(mBuffer);

    // parse the file into a temporary representation

    XFileParser parser(mBuffer);

    // and create the proper return structures out of it

    CreateDataRepresentationFromImport(pScene, parser.GetImportedData());

    // if nothing came from it, report it as error

    if (!pScene->mRootNode) {

        throw DeadlyImportError("XFile is ill-formatted - no content imported.");

    }

}

// ------------------------------------------------------------------------------------------------

// Constructs the return data structure out of the imported data.

void XFileImporter::CreateDataRepresentationFromImport(aiScene *pScene, XFile::Scene *pData) {

    // Read the global materials first so that meshes referring to them can find them later

    ConvertMaterials(pScene, pData->mGlobalMaterials);

    // copy nodes, extracting meshes and materials on the way

    pScene->mRootNode = CreateNodes(pScene, nullptr, pData->mRootNode);

    // extract animations

    CreateAnimations(pScene, pData);

    // read the global meshes that were stored outside of any node

    if (!pData->mGlobalMeshes.empty()) {

        // create a root node to hold them if there isn't any, yet

        if (pScene->mRootNode == nullptr) {

            pScene->mRootNode = new aiNode;

            pScene->mRootNode->mName.Set("$dummy_node");

        }

        // convert all global meshes and store them in the root node.

        // If there was one before, the global meshes now suddenly have its transformation matrix...

        // Don't know what to do there, I don't want to insert another node under the present root node

        // just to avoid this.

        CreateMeshes(pScene, pScene->mRootNode, pData->mGlobalMeshes);

    }

    if (!pScene->mRootNode) {

        throw DeadlyImportError("No root node");

    }

    // Convert everything to OpenGL space... it's the same operation as the conversion back, so we can reuse the step directly

    MakeLeftHandedProcess convertProcess;

    convertProcess.Execute(pScene);

    FlipWindingOrderProcess flipper;

    flipper.Execute(pScene);

    // finally: create a dummy material if not material was imported

    if (pScene->mNumMaterials == 0) {

        pScene->mNumMaterials = 1;

        // create the Material

        aiMaterial *mat = new aiMaterial;

        int shadeMode = (int)aiShadingMode_Gouraud;

        mat->AddProperty<int>(&shadeMode, 1, AI_MATKEY_SHADING_MODEL);

        // material colours

        int specExp = 1;

        aiColor3D clr = aiColor3D(0, 0, 0);

        mat->AddProperty(&clr, 1, AI_MATKEY_COLOR_EMISSIVE);

        mat->AddProperty(&clr, 1, AI_MATKEY_COLOR_SPECULAR);

        clr = aiColor3D(0.5f, 0.5f, 0.5f);

        mat->AddProperty(&clr, 1, AI_MATKEY_COLOR_DIFFUSE);

        mat->AddProperty(&specExp, 1, AI_MATKEY_SHININESS);

        pScene->mMaterials = new aiMaterial *[1];

        pScene->mMaterials[0] = mat;

    }

}

// ------------------------------------------------------------------------------------------------

// Recursively creates scene nodes from the imported hierarchy.

aiNode *XFileImporter::CreateNodes(aiScene *pScene, aiNode *pParent, const XFile::Node *pNode) {

    if (!pNode) {

        return nullptr;

    }

    // create node

    aiNode *node = new aiNode;

    node->mName.length = (ai_uint32)pNode->mName.length();

    node->mParent = pParent;

    memcpy(node->mName.data, pNode->mName.c_str(), pNode->mName.length());

    node->mName.data[node->mName.length] = 0;

    node->mTransformation = pNode->mTrafoMatrix;

    // convert meshes from the source node

    CreateMeshes(pScene, node, pNode->mMeshes);

    // handle children

    if (!pNode->mChildren.empty()) {

        node->mNumChildren = (unsigned int)pNode->mChildren.size();

        node->mChildren = new aiNode *[node->mNumChildren];

        for (unsigned int a = 0; a < pNode->mChildren.size(); ++a) {

            node->mChildren[a] = CreateNodes(pScene, node, pNode->mChildren[a]);

        }

    }

    return node;

}

// ------------------------------------------------------------------------------------------------

// Creates the meshes for the given node.

void XFileImporter::CreateMeshes(aiScene *pScene, aiNode *pNode, const std::vector<XFile::Mesh *> &pMeshes) {

    if (pMeshes.empty()) {

        return;

    }

    // create a mesh for each mesh-material combination in the source node

    std::vector<aiMesh *> meshes;

    for (unsigned int a = 0; a < pMeshes.size(); ++a) {

        XFile::Mesh *sourceMesh = pMeshes[a];

        if (nullptr == sourceMesh) {

            continue;

        }

        // first convert its materials so that we can find them with their index afterwards

        ConvertMaterials(pScene, sourceMesh->mMaterials);

        unsigned int numMaterials = std::max((unsigned int)sourceMesh->mMaterials.size(), 1u);

        for (unsigned int b = 0; b < numMaterials; ++b) {

            // collect the faces belonging to this material

            std::vector<unsigned int> faces;

            unsigned int numVertices = 0;

            if (!sourceMesh->mFaceMaterials.empty()) {

                // if there is a per-face material defined, select the faces with the corresponding material

                for (unsigned int c = 0; c < sourceMesh->mFaceMaterials.size(); ++c) {

                    if (sourceMesh->mFaceMaterials[c] == b) {

                        faces.push_back(c);

                        numVertices += (unsigned int)sourceMesh->mPosFaces[c].mIndices.size();

                    }

                }

            } else {

                // if there is no per-face material, place everything into one mesh

                for (unsigned int c = 0; c < sourceMesh->mPosFaces.size(); ++c) {

                    faces.push_back(c);

                    numVertices += (unsigned int)sourceMesh->mPosFaces[c].mIndices.size();

                }

            }

            // no faces/vertices using this material? strange...

            if (numVertices == 0) {

                continue;

            }

            // create a submesh using this material

            aiMesh *mesh = new aiMesh;

            meshes.push_back(mesh);

            // find the material in the scene's material list. Either own material

            // or referenced material, it should already have a valid index

            if (!sourceMesh->mFaceMaterials.empty()) {

                mesh->mMaterialIndex = static_cast<unsigned int>(sourceMesh->mMaterials[b].sceneIndex);

            } else {

                mesh->mMaterialIndex = 0;

            }

            // Create properly sized data arrays in the mesh. We store unique vertices per face,

            // as specified

            mesh->mNumVertices = numVertices;

            mesh->mVertices = new aiVector3D[numVertices];

            mesh->mNumFaces = (unsigned int)faces.size();

            mesh->mFaces = new aiFace[mesh->mNumFaces];

            // name

            mesh->mName.Set(sourceMesh->mName);

            // normals?

            if (sourceMesh->mNormals.size() > 0) {

                mesh->mNormals = new aiVector3D[numVertices];

            }

            // texture coords

            for (unsigned int c = 0; c < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++c) {

                if (!sourceMesh->mTexCoords[c].empty()) {

                    mesh->mTextureCoords[c] = new aiVector3D[numVertices];

                }

            }

            // vertex colors

            for (unsigned int c = 0; c < AI_MAX_NUMBER_OF_COLOR_SETS; ++c) {

                if (!sourceMesh->mColors[c].empty()) {

                    mesh->mColors[c] = new aiColor4D[numVertices];

                }

            }

            // now collect the vertex data of all data streams present in the imported mesh

            unsigned int newIndex(0);

            std::vector<unsigned int> orgPoints; // from which original point each new vertex stems

            orgPoints.resize(numVertices, 0);

            for (unsigned int c = 0; c < faces.size(); ++c) {

                unsigned int f = faces[c]; // index of the source face

                const XFile::Face &pf = sourceMesh->mPosFaces[f]; // position source face

                // create face. either triangle or triangle fan depending on the index count

                aiFace &df = mesh->mFaces[c]; // destination face

                df.mNumIndices = (unsigned int)pf.mIndices.size();

                df.mIndices = new unsigned int[df.mNumIndices];

                // collect vertex data for indices of this face

                for (unsigned int d = 0; d < df.mNumIndices; ++d) {

                    df.mIndices[d] = newIndex;

                    const unsigned int newIdx = pf.mIndices[d];

                    if (newIdx >= sourceMesh->mPositions.size()) {

                        continue;

                    }

                    orgPoints[newIndex] = pf.mIndices[d];

                    // Position

                    mesh->mVertices[newIndex] = sourceMesh->mPositions[pf.mIndices[d]];

                    // Normal, if present

                    if (mesh->HasNormals()) {

                        if (sourceMesh->mNormFaces[f].mIndices.size() > d) {

                            const size_t idx(sourceMesh->mNormFaces[f].mIndices[d]);

                            if (idx < sourceMesh->mNormals.size()) {

                                mesh->mNormals[newIndex] = sourceMesh->mNormals[idx];

                            }

                        }

                    }

                    // texture coord sets

                    for (unsigned int e = 0; e < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++e) {

                        if (mesh->HasTextureCoords(e)) {

                            aiVector2D tex = sourceMesh->mTexCoords[e][pf.mIndices[d]];

                            mesh->mTextureCoords[e][newIndex] = aiVector3D(tex.x, 1.0f - tex.y, 0.0f);

                        }

                    }

                    // vertex color sets

                    for (unsigned int e = 0; e < AI_MAX_NUMBER_OF_COLOR_SETS; ++e) {

                        if (mesh->HasVertexColors(e)) {

                            mesh->mColors[e][newIndex] = sourceMesh->mColors[e][pf.mIndices[d]];

                        }

                    }

                    newIndex++;

                }

            }

            // there should be as much new vertices as we calculated before

            ai_assert(newIndex == numVertices);

            // convert all bones of the source mesh which influence vertices in this newly created mesh

            const std::vector<XFile::Bone> &bones = sourceMesh->mBones;

            std::vector<aiBone *> newBones;

            for (unsigned int c = 0; c < bones.size(); ++c) {

                const XFile::Bone &obone = bones[c];

                // set up a vertex-linear array of the weights for quick searching if a bone influences a vertex

                std::vector<ai_real> oldWeights(sourceMesh->mPositions.size(), 0.0);

                for (unsigned int d = 0; d < obone.mWeights.size(); ++d) {

                    // TODO  The conditional against boneIdx which was added in commit f844c33

                    // TODO      (https://github.com/assimp/assimp/commit/f844c3397d7726477ab0fdca8efd3df56c18366b)

                    // TODO  causes massive breakage as detailed in:

                    // TODO      https://github.com/assimp/assimp/issues/5332

                    // TODO  In cases like this unit tests are less useful, since the model still has

                    // TODO  meshes, textures, animations etc. and asserts against these values may pass;

                    // TODO  when touching importer code, it is crucial that developers also run manual, visual

                    // TODO  checks to ensure there's no obvious breakage _before_ commiting to main branch

                    //const unsigned int boneIdx = obone.mWeights[d].mVertex;

                    //if (boneIdx < obone.mWeights.size()) {

                        oldWeights[obone.mWeights[d].mVertex] = obone.mWeights[d].mWeight;

                    //}

                }

                // collect all vertex weights that influence a vertex in the new mesh

                std::vector<aiVertexWeight> newWeights;

                newWeights.reserve(numVertices);

                for (unsigned int d = 0; d < orgPoints.size(); ++d) {

                    // does the new vertex stem from an old vertex which was influenced by this bone?

                    ai_real w = oldWeights[orgPoints[d]];

                    if (w > 0.0) {

                        newWeights.emplace_back(d, w);

                    }

                }

                // if the bone has no weights in the newly created mesh, ignore it

                if (newWeights.empty()) {

                    continue;

                }

                // create

                aiBone *nbone = new aiBone;

                newBones.push_back(nbone);

                // copy name and matrix

                nbone->mName.Set(obone.mName);

                nbone->mOffsetMatrix = obone.mOffsetMatrix;

                nbone->mNumWeights = (unsigned int)newWeights.size();

                nbone->mWeights = new aiVertexWeight[nbone->mNumWeights];

                for (unsigned int d = 0; d < newWeights.size(); ++d) {

                    nbone->mWeights[d] = newWeights[d];

                }

            }

            // store the bones in the mesh

            mesh->mNumBones = (unsigned int)newBones.size();

            if (!newBones.empty()) {

                mesh->mBones = new aiBone *[mesh->mNumBones];

                std::copy(newBones.begin(), newBones.end(), mesh->mBones);

            }

        }

    }

    // reallocate scene mesh array to be large enough

    aiMesh **prevArray = pScene->mMeshes;

    pScene->mMeshes = new aiMesh *[pScene->mNumMeshes + meshes.size()];

    if (prevArray) {

        memcpy(pScene->mMeshes, prevArray, pScene->mNumMeshes * sizeof(aiMesh *));

        delete[] prevArray;

    }

    // allocate mesh index array in the node

    pNode->mNumMeshes = (unsigned int)meshes.size();

    pNode->mMeshes = new unsigned int[pNode->mNumMeshes];

    // store all meshes in the mesh library of the scene and store their indices in the node

    for (unsigned int a = 0; a < meshes.size(); a++) {

        pScene->mMeshes[pScene->mNumMeshes] = meshes[a];

        pNode->mMeshes[a] = pScene->mNumMeshes;

        pScene->mNumMeshes++;

    }

}

// ------------------------------------------------------------------------------------------------

// Converts the animations from the given imported data and creates them in the scene.

void XFileImporter::CreateAnimations(aiScene *pScene, const XFile::Scene *pData) {

    std::vector<aiAnimation *> newAnims;

    for (unsigned int a = 0; a < pData->mAnims.size(); ++a) {

        const XFile::Animation *anim = pData->mAnims[a];

        // some exporters mock me with empty animation tags.

        if (anim->mAnims.empty()) {

            continue;

        }

        // create a new animation to hold the data

        aiAnimation *nanim = new aiAnimation;

        newAnims.push_back(nanim);

        nanim->mName.Set(anim->mName);

        // duration will be determined by the maximum length

        nanim->mDuration = 0;

        nanim->mTicksPerSecond = pData->mAnimTicksPerSecond;

        nanim->mNumChannels = (unsigned int)anim->mAnims.size();

        nanim->mChannels = new aiNodeAnim *[nanim->mNumChannels];

        for (unsigned int b = 0; b < anim->mAnims.size(); ++b) {

            const XFile::AnimBone *bone = anim->mAnims[b];

            aiNodeAnim *nbone = new aiNodeAnim;

            nbone->mNodeName.Set(bone->mBoneName);

            nanim->mChannels[b] = nbone;

            // key-frames are given as combined transformation matrix keys

            if (!bone->mTrafoKeys.empty()) {

                nbone->mNumPositionKeys = (unsigned int)bone->mTrafoKeys.size();

                nbone->mPositionKeys = new aiVectorKey[nbone->mNumPositionKeys];

                nbone->mNumRotationKeys = (unsigned int)bone->mTrafoKeys.size();

                nbone->mRotationKeys = new aiQuatKey[nbone->mNumRotationKeys];

                nbone->mNumScalingKeys = (unsigned int)bone->mTrafoKeys.size();

                nbone->mScalingKeys = new aiVectorKey[nbone->mNumScalingKeys];

                for (unsigned int c = 0; c < bone->mTrafoKeys.size(); ++c) {

                    // deconstruct each matrix into separate position, rotation and scaling

                    double time = bone->mTrafoKeys[c].mTime;

                    aiMatrix4x4 trafo = bone->mTrafoKeys[c].mMatrix;

                    // extract position

                    aiVector3D pos(trafo.a4, trafo.b4, trafo.c4);

                    nbone->mPositionKeys[c].mTime = time;

                    nbone->mPositionKeys[c].mValue = pos;

                    // extract scaling

                    aiVector3D scale;

                    scale.x = aiVector3D(trafo.a1, trafo.b1, trafo.c1).Length();

                    scale.y = aiVector3D(trafo.a2, trafo.b2, trafo.c2).Length();

                    scale.z = aiVector3D(trafo.a3, trafo.b3, trafo.c3).Length();

                    nbone->mScalingKeys[c].mTime = time;

                    nbone->mScalingKeys[c].mValue = scale;

                    // reconstruct rotation matrix without scaling

                    aiMatrix3x3 rotmat(

                            trafo.a1 / scale.x, trafo.a2 / scale.y, trafo.a3 / scale.z,

                            trafo.b1 / scale.x, trafo.b2 / scale.y, trafo.b3 / scale.z,

                            trafo.c1 / scale.x, trafo.c2 / scale.y, trafo.c3 / scale.z);

                    // and convert it into a quaternion

                    nbone->mRotationKeys[c].mTime = time;

                    nbone->mRotationKeys[c].mValue = aiQuaternion(rotmat);

                }

                // longest lasting key sequence determines duration

                nanim->mDuration = std::max(nanim->mDuration, bone->mTrafoKeys.back().mTime);

            } else {

                // separate key sequences for position, rotation, scaling

                nbone->mNumPositionKeys = (unsigned int)bone->mPosKeys.size();

                if (nbone->mNumPositionKeys != 0) {

                    nbone->mPositionKeys = new aiVectorKey[nbone->mNumPositionKeys];

                    for (unsigned int c = 0; c < nbone->mNumPositionKeys; ++c) {

                        aiVector3D pos = bone->mPosKeys[c].mValue;

                        nbone->mPositionKeys[c].mTime = bone->mPosKeys[c].mTime;

                        nbone->mPositionKeys[c].mValue = pos;

                    }

                }

                // rotation

                nbone->mNumRotationKeys = (unsigned int)bone->mRotKeys.size();

                if (nbone->mNumRotationKeys != 0) {

                    nbone->mRotationKeys = new aiQuatKey[nbone->mNumRotationKeys];

                    for (unsigned int c = 0; c < nbone->mNumRotationKeys; ++c) {

                        aiMatrix3x3 rotmat = bone->mRotKeys[c].mValue.GetMatrix();

                        nbone->mRotationKeys[c].mTime = bone->mRotKeys[c].mTime;

                        nbone->mRotationKeys[c].mValue = aiQuaternion(rotmat);

                        nbone->mRotationKeys[c].mValue.w *= -1.0f; // needs quat inversion

                    }

                }

                // scaling

                nbone->mNumScalingKeys = (unsigned int)bone->mScaleKeys.size();

                if (nbone->mNumScalingKeys != 0) {

                    nbone->mScalingKeys = new aiVectorKey[nbone->mNumScalingKeys];

                    for (unsigned int c = 0; c < nbone->mNumScalingKeys; c++)

                        nbone->mScalingKeys[c] = bone->mScaleKeys[c];

                }

                // longest lasting key sequence determines duration

                if (bone->mPosKeys.size() > 0)

                    nanim->mDuration = std::max(nanim->mDuration, bone->mPosKeys.back().mTime);

                if (bone->mRotKeys.size() > 0)

                    nanim->mDuration = std::max(nanim->mDuration, bone->mRotKeys.back().mTime);

                if (bone->mScaleKeys.size() > 0)

                    nanim->mDuration = std::max(nanim->mDuration, bone->mScaleKeys.back().mTime);

            }

        }

    }

    // store all converted animations in the scene

    if (newAnims.size() > 0) {

        pScene->mNumAnimations = (unsigned int)newAnims.size();

        pScene->mAnimations = new aiAnimation *[pScene->mNumAnimations];

        for (unsigned int a = 0; a < newAnims.size(); a++)

            pScene->mAnimations[a] = newAnims[a];

    }

}

// ------------------------------------------------------------------------------------------------

// Converts all materials in the given array and stores them in the scene's material list.

void XFileImporter::ConvertMaterials(aiScene *pScene, std::vector<XFile::Material> &pMaterials) {

    // count the non-referrer materials in the array

    unsigned int numNewMaterials(0);

    for (unsigned int a = 0; a < pMaterials.size(); ++a) {

        if (!pMaterials[a].mIsReference) {

            ++numNewMaterials;

        }

    }

    // resize the scene's material list to offer enough space for the new materials

    if (numNewMaterials > 0) {

        aiMaterial **prevMats = pScene->mMaterials;

        pScene->mMaterials = new aiMaterial *[pScene->mNumMaterials + numNewMaterials];

        if (nullptr != prevMats) {

            ::memcpy(pScene->mMaterials, prevMats, pScene->mNumMaterials * sizeof(aiMaterial *));

            delete[] prevMats;

        }

    }

    // convert all the materials given in the array

    for (unsigned int a = 0; a < pMaterials.size(); ++a) {

        XFile::Material &oldMat = pMaterials[a];

        if (oldMat.mIsReference) {

            // find the material it refers to by name, and store its index

            for (size_t b = 0; b < pScene->mNumMaterials; ++b) {

                aiString name;

                pScene->mMaterials[b]->Get(AI_MATKEY_NAME, name);

                if (strcmp(name.C_Str(), oldMat.mName.data()) == 0) {

                    oldMat.sceneIndex = b;

                    break;

                }

            }

            if (oldMat.sceneIndex == SIZE_MAX) {

                ASSIMP_LOG_WARN("Could not resolve global material reference \"", oldMat.mName, "\"");

                oldMat.sceneIndex = 0;

            }

            continue;

        }

        aiMaterial *mat = new aiMaterial;

        aiString name;

        name.Set(oldMat.mName);

        mat->AddProperty(&name, AI_MATKEY_NAME);

        // Shading model: hard-coded to PHONG, there is no such information in an XFile

        // FIX (aramis): If the specular exponent is 0, use gouraud shading. This is a bugfix

        // for some models in the SDK (e.g. good old tiny.x)

        int shadeMode = (int)oldMat.mSpecularExponent == 0.0f ? aiShadingMode_Gouraud : aiShadingMode_Phong;

        mat->AddProperty<int>(&shadeMode, 1, AI_MATKEY_SHADING_MODEL);

        // material colours

        // Unclear: there's no ambient colour, but emissive. What to put for ambient?

        // Probably nothing at all, let the user select a suitable default.

        mat->AddProperty(&oldMat.mEmissive, 1, AI_MATKEY_COLOR_EMISSIVE);

        mat->AddProperty(&oldMat.mDiffuse, 1, AI_MATKEY_COLOR_DIFFUSE);

        mat->AddProperty(&oldMat.mSpecular, 1, AI_MATKEY_COLOR_SPECULAR);

        mat->AddProperty(&oldMat.mSpecularExponent, 1, AI_MATKEY_SHININESS);

        // texture, if there is one

        if (1 == oldMat.mTextures.size()) {

            const XFile::TexEntry &otex = oldMat.mTextures.back();

            if (otex.mName.length()) {

                // if there is only one texture assume it contains the diffuse color

                aiString tex(otex.mName);

                if (otex.mIsNormalMap) {

                    mat->AddProperty(&tex, AI_MATKEY_TEXTURE_NORMALS(0));

                } else {

                    mat->AddProperty(&tex, AI_MATKEY_TEXTURE_DIFFUSE(0));

                }

            }

        } else {

            // Otherwise ... try to search for typical strings in the

            // texture's file name like 'bump' or 'diffuse'

            unsigned int iHM = 0, iNM = 0, iDM = 0, iSM = 0, iAM = 0, iEM = 0;

            for (unsigned int b = 0; b < oldMat.mTextures.size(); ++b) {

                const XFile::TexEntry &otex = oldMat.mTextures[b];

                std::string sz = otex.mName;

                if (!sz.length()) {

                    continue;

                }

                // find the file name

                std::string::size_type s = sz.find_last_of("\\/");

                if (std::string::npos == s) {

                    s = 0;

                }

                // cut off the file extension

                std::string::size_type sExt = sz.find_last_of('.');

                if (std::string::npos != sExt) {

                    sz[sExt] = '\0';

                }

                // convert to lower case for easier comparison

                for (unsigned int c = 0; c < sz.length(); ++c) {

                    sz[c] = (char)tolower((unsigned char)sz[c]);

                }

                // Place texture filename property under the corresponding name

                aiString tex(oldMat.mTextures[b].mName);

                // bump map

                if (std::string::npos != sz.find("bump", s) || std::string::npos != sz.find("height", s)) {

                    mat->AddProperty(&tex, AI_MATKEY_TEXTURE_HEIGHT(iHM++));

                } else if (otex.mIsNormalMap || std::string::npos != sz.find("normal", s) || std::string::npos != sz.find("nm", s)) {

                    mat->AddProperty(&tex, AI_MATKEY_TEXTURE_NORMALS(iNM++));

                } else if (std::string::npos != sz.find("spec", s) || std::string::npos != sz.find("glanz", s)) {

                    mat->AddProperty(&tex, AI_MATKEY_TEXTURE_SPECULAR(iSM++));

                } else if (std::string::npos != sz.find("ambi", s) || std::string::npos != sz.find("env", s)) {

                    mat->AddProperty(&tex, AI_MATKEY_TEXTURE_AMBIENT(iAM++));

                } else if (std::string::npos != sz.find("emissive", s) || std::string::npos != sz.find("self", s)) {

                    mat->AddProperty(&tex, AI_MATKEY_TEXTURE_EMISSIVE(iEM++));

                } else {

                    // Assume it is a diffuse texture

                    mat->AddProperty(&tex, AI_MATKEY_TEXTURE_DIFFUSE(iDM++));

                }

            }

        }

        pScene->mMaterials[pScene->mNumMaterials] = mat;

        oldMat.sceneIndex = pScene->mNumMaterials;

        pScene->mNumMaterials++;

    }

}

} // namespace Assimp

#endif // !! ASSIMP_BUILD_NO_X_IMPORTER