assimp.assimp/code/MDL/MDLLoader.cpp

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/** @file MDLLoader.cpp
 *  @brief Implementation of the main parts of the MDL importer class
 *  *TODO* Cleanup and further testing of some parts necessary
 */

// internal headers

#ifndef ASSIMP_BUILD_NO_MDL_IMPORTER

#include "MDL/MDLLoader.h"
#include "MDL/MDLDefaultColorMap.h"
#include "MD2/MD2FileData.h"
#include "MDL/HalfLife/HL1MDLLoader.h"

#include <assimp/qnan.h>
#include <assimp/StringUtils.h>
#include <assimp/Importer.hpp>
#include <assimp/IOSystem.hpp>
#include <assimp/scene.h>
#include <assimp/DefaultLogger.hpp>
#include <assimp/importerdesc.h>

#include <memory>

using namespace Assimp;

static const aiImporterDesc desc = {
    "Quake Mesh / 3D GameStudio Mesh Importer",
    "",
    "",
    "",
    aiImporterFlags_SupportBinaryFlavour,
    0,
    0,
    7,
    0,
    "mdl"
};

// ------------------------------------------------------------------------------------------------
// Ugly stuff ... nevermind
#define _AI_MDL7_ACCESS(_data, _index, _limit, _type)               \
    (*((const _type*)(((const char*)_data) + _index * _limit)))

#define _AI_MDL7_ACCESS_PTR(_data, _index, _limit, _type)           \
    ((BE_NCONST _type*)(((const char*)_data) + _index * _limit))

#define _AI_MDL7_ACCESS_VERT(_data, _index, _limit)                 \
    _AI_MDL7_ACCESS(_data,_index,_limit,MDL::Vertex_MDL7)

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
MDLImporter::MDLImporter()
: configFrameID()
, mBuffer()
, iGSFileVersion()
, pIOHandler()
, pScene()
, iFileSize() {
    // empty
}

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

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

    // if check for extension is not enough, check for the magic tokens
    if (extension == "mdl"  || !extension.length() || checkSig) {
        uint32_t tokens[8];
        tokens[0] = AI_MDL_MAGIC_NUMBER_LE_HL2a;
        tokens[1] = AI_MDL_MAGIC_NUMBER_LE_HL2b;
        tokens[2] = AI_MDL_MAGIC_NUMBER_LE_GS7;
        tokens[3] = AI_MDL_MAGIC_NUMBER_LE_GS5b;
        tokens[4] = AI_MDL_MAGIC_NUMBER_LE_GS5a;
        tokens[5] = AI_MDL_MAGIC_NUMBER_LE_GS4;
        tokens[6] = AI_MDL_MAGIC_NUMBER_LE_GS3;
        tokens[7] = AI_MDL_MAGIC_NUMBER_LE;
        return CheckMagicToken(pIOHandler,pFile,tokens,8,0);
    }
    return false;
}

// ------------------------------------------------------------------------------------------------
// Setup configuration properties
void MDLImporter::SetupProperties(const Importer* pImp)
{
    configFrameID = pImp->GetPropertyInteger(AI_CONFIG_IMPORT_MDL_KEYFRAME,-1);

    // The
    // AI_CONFIG_IMPORT_MDL_KEYFRAME option overrides the
    // AI_CONFIG_IMPORT_GLOBAL_KEYFRAME option.
    if(static_cast<unsigned int>(-1) == configFrameID)  {
        configFrameID =  pImp->GetPropertyInteger(AI_CONFIG_IMPORT_GLOBAL_KEYFRAME,0);
    }

    // AI_CONFIG_IMPORT_MDL_COLORMAP - palette file
    configPalette =  pImp->GetPropertyString(AI_CONFIG_IMPORT_MDL_COLORMAP,"colormap.lmp");

    // Read configuration specific to MDL (Half-Life 1).
    mHL1ImportSettings.read_animations = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_ANIMATIONS, true);
    if (mHL1ImportSettings.read_animations) {
        mHL1ImportSettings.read_animation_events = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_ANIMATION_EVENTS, true);
        mHL1ImportSettings.read_blend_controllers = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_BLEND_CONTROLLERS, true);
        mHL1ImportSettings.read_sequence_transitions = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_SEQUENCE_TRANSITIONS, true);
    }
    mHL1ImportSettings.read_attachments = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_ATTACHMENTS, true);
    mHL1ImportSettings.read_bone_controllers = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_BONE_CONTROLLERS, true);
    mHL1ImportSettings.read_hitboxes = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_HITBOXES, true);
    mHL1ImportSettings.read_misc_global_info = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_MISC_GLOBAL_INFO, true);
}

// ------------------------------------------------------------------------------------------------
// Get a list of all supported extensions
const aiImporterDesc* MDLImporter::GetInfo () const
{
    return &desc;
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure.
void MDLImporter::InternReadFile( const std::string& pFile,
    aiScene* _pScene, IOSystem* _pIOHandler)
{
    pScene     = _pScene;
    pIOHandler = _pIOHandler;
    std::unique_ptr<IOStream> file( pIOHandler->Open( pFile));

    // Check whether we can read from the file
    if( file.get() == NULL) {
        throw DeadlyImportError( "Failed to open MDL file " + pFile + ".");
    }

    // This should work for all other types of MDL files, too ...
    // the quake header is one of the smallest, afaik
    iFileSize = (unsigned int)file->FileSize();
    if( iFileSize < sizeof(MDL::Header)) {
        throw DeadlyImportError( "MDL File is too small.");
    }

    // Allocate storage and copy the contents of the file to a memory buffer
    mBuffer =new unsigned char[iFileSize+1];
    file->Read( (void*)mBuffer, 1, iFileSize);

    // Append a binary zero to the end of the buffer.
    // this is just for safety that string parsing routines
    // find the end of the buffer ...
    mBuffer[iFileSize] = '\0';
    const uint32_t iMagicWord = *((uint32_t*)mBuffer);

    // Determine the file subtype and call the appropriate member function

    // Original Quake1 format
    if (AI_MDL_MAGIC_NUMBER_BE == iMagicWord || AI_MDL_MAGIC_NUMBER_LE == iMagicWord)   {
        ASSIMP_LOG_DEBUG("MDL subtype: Quake 1, magic word is IDPO");
        iGSFileVersion = 0;
        InternReadFile_Quake1();
    }
    // GameStudio A<old> MDL2 format - used by some test models that come with 3DGS
    else if (AI_MDL_MAGIC_NUMBER_BE_GS3 == iMagicWord || AI_MDL_MAGIC_NUMBER_LE_GS3 == iMagicWord)  {
        ASSIMP_LOG_DEBUG("MDL subtype: 3D GameStudio A2, magic word is MDL2");
        iGSFileVersion = 2;
        InternReadFile_Quake1();
    }
    // GameStudio A4 MDL3 format
    else if (AI_MDL_MAGIC_NUMBER_BE_GS4 == iMagicWord || AI_MDL_MAGIC_NUMBER_LE_GS4 == iMagicWord)  {
        ASSIMP_LOG_DEBUG("MDL subtype: 3D GameStudio A4, magic word is MDL3");
        iGSFileVersion = 3;
        InternReadFile_3DGS_MDL345();
    }
    // GameStudio A5+ MDL4 format
    else if (AI_MDL_MAGIC_NUMBER_BE_GS5a == iMagicWord || AI_MDL_MAGIC_NUMBER_LE_GS5a == iMagicWord)    {
        ASSIMP_LOG_DEBUG("MDL subtype: 3D GameStudio A4, magic word is MDL4");
        iGSFileVersion = 4;
        InternReadFile_3DGS_MDL345();
    }
    // GameStudio A5+ MDL5 format
    else if (AI_MDL_MAGIC_NUMBER_BE_GS5b == iMagicWord || AI_MDL_MAGIC_NUMBER_LE_GS5b == iMagicWord)    {
        ASSIMP_LOG_DEBUG("MDL subtype: 3D GameStudio A5, magic word is MDL5");
        iGSFileVersion = 5;
        InternReadFile_3DGS_MDL345();
    }
    // GameStudio A7 MDL7 format
    else if (AI_MDL_MAGIC_NUMBER_BE_GS7 == iMagicWord || AI_MDL_MAGIC_NUMBER_LE_GS7 == iMagicWord)  {
        ASSIMP_LOG_DEBUG("MDL subtype: 3D GameStudio A7, magic word is MDL7");
        iGSFileVersion = 7;
        InternReadFile_3DGS_MDL7();
    }
    // IDST/IDSQ Format (CS:S/HL^2, etc ...)
    else if (AI_MDL_MAGIC_NUMBER_BE_HL2a == iMagicWord || AI_MDL_MAGIC_NUMBER_LE_HL2a == iMagicWord ||
        AI_MDL_MAGIC_NUMBER_BE_HL2b == iMagicWord || AI_MDL_MAGIC_NUMBER_LE_HL2b == iMagicWord)
    {
        iGSFileVersion = 0;

        HalfLife::HalfLifeMDLBaseHeader *pHeader = (HalfLife::HalfLifeMDLBaseHeader *)mBuffer;
        if (pHeader->version == AI_MDL_HL1_VERSION)
        {
            ASSIMP_LOG_DEBUG("MDL subtype: Half-Life 1/Goldsrc Engine, magic word is IDST/IDSQ");
            InternReadFile_HL1(pFile, iMagicWord);
        }
        else
        {
            ASSIMP_LOG_DEBUG("MDL subtype: Source(tm) Engine, magic word is IDST/IDSQ");
            InternReadFile_HL2();
        }
    }
    else    {
        // print the magic word to the log file
        throw DeadlyImportError( "Unknown MDL subformat " + pFile +
            ". Magic word (" + std::string((char*)&iMagicWord,4) + ") is not known");
    }

    // Now rotate the whole scene 90 degrees around the x axis to convert to internal coordinate system
    pScene->mRootNode->mTransformation = aiMatrix4x4(1.f,0.f,0.f,0.f,
        0.f,0.f,1.f,0.f,0.f,-1.f,0.f,0.f,0.f,0.f,0.f,1.f);

    // delete the file buffer and cleanup
    delete [] mBuffer;
    mBuffer= nullptr;
    AI_DEBUG_INVALIDATE_PTR(pIOHandler);
    AI_DEBUG_INVALIDATE_PTR(pScene);
}

// ------------------------------------------------------------------------------------------------
// Check whether we're still inside the valid file range
void MDLImporter::SizeCheck(const void* szPos)
{
    if (!szPos || (const unsigned char*)szPos > this->mBuffer + this->iFileSize)
    {
        throw DeadlyImportError("Invalid MDL file. The file is too small "
            "or contains invalid data.");
    }
}

// ------------------------------------------------------------------------------------------------
// Just for debugging purposes
void MDLImporter::SizeCheck(const void* szPos, const char* szFile, unsigned int iLine)
{
    ai_assert(NULL != szFile);
    if (!szPos || (const unsigned char*)szPos > mBuffer + iFileSize)
    {
        // remove a directory if there is one
        const char* szFilePtr = ::strrchr(szFile,'\\');
        if (!szFilePtr) {
            if(!(szFilePtr = ::strrchr(szFile,'/')))
                szFilePtr = szFile;
        }
        if (szFilePtr)++szFilePtr;

        char szBuffer[1024];
        ::sprintf(szBuffer,"Invalid MDL file. The file is too small "
            "or contains invalid data (File: %s Line: %u)",szFilePtr,iLine);

        throw DeadlyImportError(szBuffer);
    }
}

// ------------------------------------------------------------------------------------------------
// Validate a quake file header
void MDLImporter::ValidateHeader_Quake1(const MDL::Header* pcHeader)
{
    // some values may not be NULL
    if (!pcHeader->num_frames)
        throw DeadlyImportError( "[Quake 1 MDL] There are no frames in the file");

    if (!pcHeader->num_verts)
        throw DeadlyImportError( "[Quake 1 MDL] There are no vertices in the file");

    if (!pcHeader->num_tris)
        throw DeadlyImportError( "[Quake 1 MDL] There are no triangles in the file");

    // check whether the maxima are exceeded ...however, this applies for Quake 1 MDLs only
    if (!this->iGSFileVersion)
    {
        if (pcHeader->num_verts > AI_MDL_MAX_VERTS)
            ASSIMP_LOG_WARN("Quake 1 MDL model has more than AI_MDL_MAX_VERTS vertices");

        if (pcHeader->num_tris > AI_MDL_MAX_TRIANGLES)
            ASSIMP_LOG_WARN("Quake 1 MDL model has more than AI_MDL_MAX_TRIANGLES triangles");

        if (pcHeader->num_frames > AI_MDL_MAX_FRAMES)
            ASSIMP_LOG_WARN("Quake 1 MDL model has more than AI_MDL_MAX_FRAMES frames");

        // (this does not apply for 3DGS MDLs)
        if (!this->iGSFileVersion && pcHeader->version != AI_MDL_VERSION)
            ASSIMP_LOG_WARN("Quake 1 MDL model has an unknown version: AI_MDL_VERSION (=6) is "
                "the expected file format version");
        if(pcHeader->num_skins && (!pcHeader->skinwidth || !pcHeader->skinheight))
            ASSIMP_LOG_WARN("Skin width or height are 0");
    }
}

#ifdef AI_BUILD_BIG_ENDIAN
// ------------------------------------------------------------------------------------------------
void FlipQuakeHeader(BE_NCONST MDL::Header* pcHeader)
{
    AI_SWAP4( pcHeader->ident);
    AI_SWAP4( pcHeader->version);
    AI_SWAP4( pcHeader->boundingradius);
    AI_SWAP4( pcHeader->flags);
    AI_SWAP4( pcHeader->num_frames);
    AI_SWAP4( pcHeader->num_skins);
    AI_SWAP4( pcHeader->num_tris);
    AI_SWAP4( pcHeader->num_verts);
    for (unsigned int i = 0; i < 3;++i)
    {
        AI_SWAP4( pcHeader->scale[i]);
        AI_SWAP4( pcHeader->translate[i]);
    }
    AI_SWAP4( pcHeader->size);
    AI_SWAP4( pcHeader->skinheight);
    AI_SWAP4( pcHeader->skinwidth);
    AI_SWAP4( pcHeader->synctype);
}
#endif

// ------------------------------------------------------------------------------------------------
// Read a Quake 1 file
void MDLImporter::InternReadFile_Quake1() {
    ai_assert(NULL != pScene);

    BE_NCONST MDL::Header *pcHeader = (BE_NCONST MDL::Header*)this->mBuffer;

#ifdef AI_BUILD_BIG_ENDIAN
    FlipQuakeHeader(pcHeader);
#endif

    ValidateHeader_Quake1(pcHeader);

    // current cursor position in the file
    const unsigned char* szCurrent = (const unsigned char*)(pcHeader+1);

    // need to read all textures
    for ( unsigned int i = 0; i < (unsigned int)pcHeader->num_skins; ++i) {
        union {
            BE_NCONST MDL::Skin* pcSkin;
            BE_NCONST MDL::GroupSkin* pcGroupSkin;
        };
        if (szCurrent + sizeof(MDL::Skin) > this->mBuffer + this->iFileSize) {
            throw DeadlyImportError("[Quake 1 MDL] Unexpected EOF");
        }
        pcSkin = (BE_NCONST MDL::Skin*)szCurrent;

        AI_SWAP4( pcSkin->group );

        // Quake 1 group-skins
        if (1 == pcSkin->group) {
            AI_SWAP4( pcGroupSkin->nb );

            // need to skip multiple images
            const unsigned int iNumImages = (unsigned int)pcGroupSkin->nb;
            szCurrent += sizeof(uint32_t) * 2;

            if (0 != iNumImages) {
                if (!i) {
                    // however, create only one output image (the first)
                    this->CreateTextureARGB8_3DGS_MDL3(szCurrent + iNumImages * sizeof(float));
                }
                // go to the end of the skin section / the beginning of the next skin
                szCurrent += pcHeader->skinheight * pcHeader->skinwidth +
                    sizeof(float) * iNumImages;
            }
        } else {
            szCurrent += sizeof(uint32_t);
            unsigned int iSkip = i ? UINT_MAX : 0;
            CreateTexture_3DGS_MDL4(szCurrent,pcSkin->group,&iSkip);
            szCurrent += iSkip;
        }
    }
    // get a pointer to the texture coordinates
    BE_NCONST MDL::TexCoord* pcTexCoords = (BE_NCONST MDL::TexCoord*)szCurrent;
    szCurrent += sizeof(MDL::TexCoord) * pcHeader->num_verts;

    // get a pointer to the triangles
    BE_NCONST MDL::Triangle* pcTriangles = (BE_NCONST MDL::Triangle*)szCurrent;
    szCurrent += sizeof(MDL::Triangle) * pcHeader->num_tris;
    VALIDATE_FILE_SIZE(szCurrent);

    // now get a pointer to the first frame in the file
    BE_NCONST MDL::Frame* pcFrames = (BE_NCONST MDL::Frame*)szCurrent;
    MDL::SimpleFrame* pcFirstFrame;

    if (0 == pcFrames->type) {
        // get address of single frame
        pcFirstFrame =( MDL::SimpleFrame*) &pcFrames->frame;
    } else {
        // get the first frame in the group
        BE_NCONST MDL::GroupFrame* pcFrames2 = (BE_NCONST MDL::GroupFrame*) pcFrames;
        pcFirstFrame = &(pcFrames2->frames[0]);
    }
    BE_NCONST MDL::Vertex* pcVertices = (BE_NCONST MDL::Vertex*) ((pcFirstFrame->name) + sizeof(pcFirstFrame->name));
    VALIDATE_FILE_SIZE((const unsigned char*)(pcVertices + pcHeader->num_verts));

#ifdef AI_BUILD_BIG_ENDIAN
    for (int i = 0; i<pcHeader->num_verts;++i)
    {
        AI_SWAP4( pcTexCoords[i].onseam );
        AI_SWAP4( pcTexCoords[i].s );
        AI_SWAP4( pcTexCoords[i].t );
    }

    for (int i = 0; i<pcHeader->num_tris;++i)
    {
        AI_SWAP4( pcTriangles[i].facesfront);
        AI_SWAP4( pcTriangles[i].vertex[0]);
        AI_SWAP4( pcTriangles[i].vertex[1]);
        AI_SWAP4( pcTriangles[i].vertex[2]);
    }
#endif

    // setup materials
    SetupMaterialProperties_3DGS_MDL5_Quake1();

    // allocate enough storage to hold all vertices and triangles
    aiMesh* pcMesh = new aiMesh();

    pcMesh->mPrimitiveTypes = aiPrimitiveType_TRIANGLE;
    pcMesh->mNumVertices = pcHeader->num_tris * 3;
    pcMesh->mNumFaces = pcHeader->num_tris;
    pcMesh->mVertices = new aiVector3D[pcMesh->mNumVertices];
    pcMesh->mTextureCoords[0] = new aiVector3D[pcMesh->mNumVertices];
    pcMesh->mFaces = new aiFace[pcMesh->mNumFaces];
    pcMesh->mNormals = new aiVector3D[pcMesh->mNumVertices];
    pcMesh->mNumUVComponents[0] = 2;

    // there won't be more than one mesh inside the file
    pScene->mRootNode = new aiNode();
    pScene->mRootNode->mNumMeshes = 1;
    pScene->mRootNode->mMeshes = new unsigned int[1];
    pScene->mRootNode->mMeshes[0] = 0;
    pScene->mNumMeshes = 1;
    pScene->mMeshes = new aiMesh*[1];
    pScene->mMeshes[0] = pcMesh;

    // now iterate through all triangles
    unsigned int iCurrent = 0;
    for (unsigned int i = 0; i < (unsigned int) pcHeader->num_tris;++i)
    {
        pcMesh->mFaces[i].mIndices = new unsigned int[3];
        pcMesh->mFaces[i].mNumIndices = 3;

        unsigned int iTemp = iCurrent;
        for (unsigned int c = 0; c < 3;++c,++iCurrent)
        {
            pcMesh->mFaces[i].mIndices[c] = iCurrent;

            // read vertices
            unsigned int iIndex = pcTriangles->vertex[c];
            if (iIndex >= (unsigned int)pcHeader->num_verts)
            {
                iIndex = pcHeader->num_verts-1;
                ASSIMP_LOG_WARN("Index overflow in Q1-MDL vertex list.");
            }

            aiVector3D& vec = pcMesh->mVertices[iCurrent];
            vec.x = (float)pcVertices[iIndex].v[0] * pcHeader->scale[0];
            vec.x += pcHeader->translate[0];

            vec.y = (float)pcVertices[iIndex].v[1] * pcHeader->scale[1];
            vec.y += pcHeader->translate[1];
            //vec.y *= -1.0f;

            vec.z = (float)pcVertices[iIndex].v[2] * pcHeader->scale[2];
            vec.z += pcHeader->translate[2];

            // read the normal vector from the precalculated normal table
            MD2::LookupNormalIndex(pcVertices[iIndex].normalIndex,pcMesh->mNormals[iCurrent]);
            //pcMesh->mNormals[iCurrent].y *= -1.0f;

            // read texture coordinates
            float s = (float)pcTexCoords[iIndex].s;
            float t = (float)pcTexCoords[iIndex].t;

            // translate texture coordinates
            if (0 == pcTriangles->facesfront && 0 != pcTexCoords[iIndex].onseam)    {
                s += pcHeader->skinwidth * 0.5f;
            }

            // Scale s and t to range from 0.0 to 1.0
            pcMesh->mTextureCoords[0][iCurrent].x = (s + 0.5f) / pcHeader->skinwidth;
            pcMesh->mTextureCoords[0][iCurrent].y = 1.0f-(t + 0.5f) / pcHeader->skinheight;

        }
        pcMesh->mFaces[i].mIndices[0] = iTemp+2;
        pcMesh->mFaces[i].mIndices[1] = iTemp+1;
        pcMesh->mFaces[i].mIndices[2] = iTemp+0;
        pcTriangles++;
    }
    return;
}

// ------------------------------------------------------------------------------------------------
// Setup material properties for Quake and older GameStudio files
void MDLImporter::SetupMaterialProperties_3DGS_MDL5_Quake1( )
{
    const MDL::Header* const pcHeader = (const MDL::Header*)this->mBuffer;

    // allocate ONE material
    pScene->mMaterials    = new aiMaterial*[1];
    pScene->mMaterials[0] = new aiMaterial();
    pScene->mNumMaterials = 1;

    // setup the material's properties
    const int iMode = (int)aiShadingMode_Gouraud;
    aiMaterial* const pcHelper = (aiMaterial*)pScene->mMaterials[0];
    pcHelper->AddProperty<int>(&iMode, 1, AI_MATKEY_SHADING_MODEL);

    aiColor4D clr;
    if (0 != pcHeader->num_skins && pScene->mNumTextures)   {
        // can we replace the texture with a single color?
        clr = this->ReplaceTextureWithColor(pScene->mTextures[0]);
        if (is_not_qnan(clr.r)) {
            delete pScene->mTextures[0];
            delete[] pScene->mTextures;

            pScene->mTextures = NULL;
            pScene->mNumTextures = 0;
        }
        else    {
            clr.b = clr.a = clr.g = clr.r = 1.0f;
            aiString szString;
            ::memcpy(szString.data,AI_MAKE_EMBEDDED_TEXNAME(0),3);
            szString.length = 2;
            pcHelper->AddProperty(&szString,AI_MATKEY_TEXTURE_DIFFUSE(0));
        }
    }

    pcHelper->AddProperty<aiColor4D>(&clr, 1,AI_MATKEY_COLOR_DIFFUSE);
    pcHelper->AddProperty<aiColor4D>(&clr, 1,AI_MATKEY_COLOR_SPECULAR);

    clr.r *= 0.05f;clr.g *= 0.05f;
    clr.b *= 0.05f;clr.a  = 1.0f;
    pcHelper->AddProperty<aiColor4D>(&clr, 1,AI_MATKEY_COLOR_AMBIENT);
}

// ------------------------------------------------------------------------------------------------
// Read a MDL 3,4,5 file
void MDLImporter::InternReadFile_3DGS_MDL345( )
{
    ai_assert(NULL != pScene);

    // the header of MDL 3/4/5 is nearly identical to the original Quake1 header
    BE_NCONST MDL::Header *pcHeader = (BE_NCONST MDL::Header*)this->mBuffer;
#ifdef AI_BUILD_BIG_ENDIAN
    FlipQuakeHeader(pcHeader);
#endif
    ValidateHeader_Quake1(pcHeader);

    // current cursor position in the file
    const unsigned char* szCurrent = (const unsigned char*)(pcHeader+1);
    const unsigned char* szEnd = mBuffer + iFileSize;

    // need to read all textures
    for (unsigned int i = 0; i < (unsigned int)pcHeader->num_skins;++i) {
        if (szCurrent >= szEnd) {
            throw DeadlyImportError( "Texture data past end of file.");
        }
        BE_NCONST MDL::Skin* pcSkin;
        pcSkin = (BE_NCONST  MDL::Skin*)szCurrent;
        AI_SWAP4( pcSkin->group);
        // create one output image
        unsigned int iSkip = i ? UINT_MAX : 0;
        if (5 <= iGSFileVersion)
        {
            // MDL5 format could contain MIPmaps
            CreateTexture_3DGS_MDL5((unsigned char*)pcSkin + sizeof(uint32_t),
                pcSkin->group,&iSkip);
        }
        else    {
            CreateTexture_3DGS_MDL4((unsigned char*)pcSkin + sizeof(uint32_t),
                pcSkin->group,&iSkip);
        }
        // need to skip one image
        szCurrent += iSkip + sizeof(uint32_t);

    }
    // get a pointer to the texture coordinates
    BE_NCONST MDL::TexCoord_MDL3* pcTexCoords = (BE_NCONST MDL::TexCoord_MDL3*)szCurrent;
    szCurrent += sizeof(MDL::TexCoord_MDL3) * pcHeader->synctype;

    // NOTE: for MDLn formats "synctype" corresponds to the number of UV coords

    // get a pointer to the triangles
    BE_NCONST MDL::Triangle_MDL3* pcTriangles = (BE_NCONST MDL::Triangle_MDL3*)szCurrent;
    szCurrent += sizeof(MDL::Triangle_MDL3) * pcHeader->num_tris;

#ifdef AI_BUILD_BIG_ENDIAN

    for (int i = 0; i<pcHeader->synctype;++i)   {
        AI_SWAP2( pcTexCoords[i].u );
        AI_SWAP2( pcTexCoords[i].v );
    }

    for (int i = 0; i<pcHeader->num_tris;++i)   {
        AI_SWAP2( pcTriangles[i].index_xyz[0]);
        AI_SWAP2( pcTriangles[i].index_xyz[1]);
        AI_SWAP2( pcTriangles[i].index_xyz[2]);
        AI_SWAP2( pcTriangles[i].index_uv[0]);
        AI_SWAP2( pcTriangles[i].index_uv[1]);
        AI_SWAP2( pcTriangles[i].index_uv[2]);
    }

#endif

    VALIDATE_FILE_SIZE(szCurrent);

    // setup materials
    SetupMaterialProperties_3DGS_MDL5_Quake1();

    // allocate enough storage to hold all vertices and triangles
    aiMesh* pcMesh = new aiMesh();
    pcMesh->mPrimitiveTypes = aiPrimitiveType_TRIANGLE;

    pcMesh->mNumVertices = pcHeader->num_tris * 3;
    pcMesh->mNumFaces = pcHeader->num_tris;
    pcMesh->mFaces = new aiFace[pcMesh->mNumFaces];

    // there won't be more than one mesh inside the file
    pScene->mRootNode = new aiNode();
    pScene->mRootNode->mNumMeshes = 1;
    pScene->mRootNode->mMeshes = new unsigned int[1];
    pScene->mRootNode->mMeshes[0] = 0;
    pScene->mNumMeshes = 1;
    pScene->mMeshes = new aiMesh*[1];
    pScene->mMeshes[0] = pcMesh;

    // allocate output storage
    pcMesh->mNumVertices = (unsigned int)pcHeader->num_tris*3;
    pcMesh->mVertices    = new aiVector3D[pcMesh->mNumVertices];
    pcMesh->mNormals     = new aiVector3D[pcMesh->mNumVertices];

    if (pcHeader->synctype) {
        pcMesh->mTextureCoords[0] = new aiVector3D[pcMesh->mNumVertices];
        pcMesh->mNumUVComponents[0] = 2;
    }

    // now get a pointer to the first frame in the file
    BE_NCONST MDL::Frame* pcFrames = (BE_NCONST MDL::Frame*)szCurrent;
    AI_SWAP4(pcFrames->type);

    // byte packed vertices
    // FIXME: these two snippets below are almost identical ... join them?
    /////////////////////////////////////////////////////////////////////////////////////
    if (0 == pcFrames->type || 3 >= this->iGSFileVersion)   {

        const MDL::SimpleFrame* pcFirstFrame = (const MDL::SimpleFrame*)(szCurrent + sizeof(uint32_t));
        const MDL::Vertex* pcVertices = (const MDL::Vertex*) ((pcFirstFrame->name) + sizeof(pcFirstFrame->name));

        VALIDATE_FILE_SIZE(pcVertices + pcHeader->num_verts);

        // now iterate through all triangles
        unsigned int iCurrent = 0;
        for (unsigned int i = 0; i < (unsigned int) pcHeader->num_tris;++i) {
            pcMesh->mFaces[i].mIndices = new unsigned int[3];
            pcMesh->mFaces[i].mNumIndices = 3;

            unsigned int iTemp = iCurrent;
            for (unsigned int c = 0; c < 3;++c,++iCurrent)  {
                // read vertices
                unsigned int iIndex = pcTriangles->index_xyz[c];
                if (iIndex >= (unsigned int)pcHeader->num_verts)    {
                    iIndex = pcHeader->num_verts-1;
                    ASSIMP_LOG_WARN("Index overflow in MDLn vertex list");
                }

                aiVector3D& vec = pcMesh->mVertices[iCurrent];
                vec.x = (float)pcVertices[iIndex].v[0] * pcHeader->scale[0];
                vec.x += pcHeader->translate[0];

                vec.y = (float)pcVertices[iIndex].v[1] * pcHeader->scale[1];
                vec.y += pcHeader->translate[1];
                // vec.y *= -1.0f;

                vec.z = (float)pcVertices[iIndex].v[2] * pcHeader->scale[2];
                vec.z += pcHeader->translate[2];

                // read the normal vector from the precalculated normal table
                MD2::LookupNormalIndex(pcVertices[iIndex].normalIndex,pcMesh->mNormals[iCurrent]);
                // pcMesh->mNormals[iCurrent].y *= -1.0f;

                // read texture coordinates
                if (pcHeader->synctype) {
                    ImportUVCoordinate_3DGS_MDL345(pcMesh->mTextureCoords[0][iCurrent],
                        pcTexCoords,pcTriangles->index_uv[c]);
                }
            }
            pcMesh->mFaces[i].mIndices[0] = iTemp+2;
            pcMesh->mFaces[i].mIndices[1] = iTemp+1;
            pcMesh->mFaces[i].mIndices[2] = iTemp+0;
            pcTriangles++;
        }

    }
    // short packed vertices
    /////////////////////////////////////////////////////////////////////////////////////
    else    {
        // now get a pointer to the first frame in the file
        const MDL::SimpleFrame_MDLn_SP* pcFirstFrame = (const MDL::SimpleFrame_MDLn_SP*) (szCurrent + sizeof(uint32_t));

        // get a pointer to the vertices
        const MDL::Vertex_MDL4* pcVertices = (const MDL::Vertex_MDL4*) ((pcFirstFrame->name) +
            sizeof(pcFirstFrame->name));

        VALIDATE_FILE_SIZE(pcVertices + pcHeader->num_verts);

        // now iterate through all triangles
        unsigned int iCurrent = 0;
        for (unsigned int i = 0; i < (unsigned int) pcHeader->num_tris;++i) {
            pcMesh->mFaces[i].mIndices = new unsigned int[3];
            pcMesh->mFaces[i].mNumIndices = 3;

            unsigned int iTemp = iCurrent;
            for (unsigned int c = 0; c < 3;++c,++iCurrent)  {
                // read vertices
                unsigned int iIndex = pcTriangles->index_xyz[c];
                if (iIndex >= (unsigned int)pcHeader->num_verts)    {
                    iIndex = pcHeader->num_verts-1;
                    ASSIMP_LOG_WARN("Index overflow in MDLn vertex list");
                }

                aiVector3D& vec = pcMesh->mVertices[iCurrent];
                vec.x = (float)pcVertices[iIndex].v[0] * pcHeader->scale[0];
                vec.x += pcHeader->translate[0];

                vec.y = (float)pcVertices[iIndex].v[1] * pcHeader->scale[1];
                vec.y += pcHeader->translate[1];
                // vec.y *= -1.0f;

                vec.z = (float)pcVertices[iIndex].v[2] * pcHeader->scale[2];
                vec.z += pcHeader->translate[2];

                // read the normal vector from the precalculated normal table
                MD2::LookupNormalIndex(pcVertices[iIndex].normalIndex,pcMesh->mNormals[iCurrent]);
                // pcMesh->mNormals[iCurrent].y *= -1.0f;

                // read texture coordinates
                if (pcHeader->synctype) {
                    ImportUVCoordinate_3DGS_MDL345(pcMesh->mTextureCoords[0][iCurrent],
                        pcTexCoords,pcTriangles->index_uv[c]);
                }
            }
            pcMesh->mFaces[i].mIndices[0] = iTemp+2;
            pcMesh->mFaces[i].mIndices[1] = iTemp+1;
            pcMesh->mFaces[i].mIndices[2] = iTemp+0;
            pcTriangles++;
        }
    }

    // For MDL5 we will need to build valid texture coordinates
    // basing upon the file loaded (only support one file as skin)
    if (0x5 == iGSFileVersion)
        CalculateUVCoordinates_MDL5();
    return;
}

// ------------------------------------------------------------------------------------------------
// Get a single UV coordinate for Quake and older GameStudio files
void MDLImporter::ImportUVCoordinate_3DGS_MDL345(
    aiVector3D& vOut,
    const MDL::TexCoord_MDL3* pcSrc,
    unsigned int iIndex)
{
    ai_assert(NULL != pcSrc);
    const MDL::Header* const pcHeader = (const MDL::Header*)this->mBuffer;

    // validate UV indices
    if (iIndex >= (unsigned int) pcHeader->synctype)    {
        iIndex = pcHeader->synctype-1;
        ASSIMP_LOG_WARN("Index overflow in MDLn UV coord list");
    }

    float s = (float)pcSrc[iIndex].u;
    float t = (float)pcSrc[iIndex].v;

    // Scale s and t to range from 0.0 to 1.0
    if (0x5 != iGSFileVersion)  {
        s = (s + 0.5f)      / pcHeader->skinwidth;
        t = 1.0f-(t + 0.5f) / pcHeader->skinheight;
    }

    vOut.x = s;
    vOut.y = t;
    vOut.z = 0.0f;
}

// ------------------------------------------------------------------------------------------------
// Compute UV coordinates for a MDL5 file
void MDLImporter::CalculateUVCoordinates_MDL5()
{
    const MDL::Header* const pcHeader = (const MDL::Header*)this->mBuffer;
    if (pcHeader->num_skins && this->pScene->mNumTextures)  {
        const aiTexture* pcTex = this->pScene->mTextures[0];

        // if the file is loaded in DDS format: get the size of the
        // texture from the header of the DDS file
        // skip three DWORDs and read first height, then the width
        unsigned int iWidth, iHeight;
        if (!pcTex->mHeight)    {
            const uint32_t* piPtr = (uint32_t*)pcTex->pcData;

            piPtr += 3;
            iHeight = (unsigned int)*piPtr++;
            iWidth  = (unsigned int)*piPtr;
            if (!iHeight || !iWidth)
            {
                ASSIMP_LOG_WARN("Either the width or the height of the "
                    "embedded DDS texture is zero. Unable to compute final texture "
                    "coordinates. The texture coordinates remain in their original "
                    "0-x/0-y (x,y = texture size) range.");
                iWidth  = 1;
                iHeight = 1;
            }
        }
        else    {
            iWidth  = pcTex->mWidth;
            iHeight = pcTex->mHeight;
        }

        if (1 != iWidth || 1 != iHeight)    {
            const float fWidth = (float)iWidth;
            const float fHeight = (float)iHeight;
            aiMesh* pcMesh = this->pScene->mMeshes[0];
            for (unsigned int i = 0; i < pcMesh->mNumVertices;++i)
            {
                pcMesh->mTextureCoords[0][i].x /= fWidth;
                pcMesh->mTextureCoords[0][i].y /= fHeight;
                pcMesh->mTextureCoords[0][i].y = 1.0f - pcMesh->mTextureCoords[0][i].y; // DX to OGL
            }
        }
    }
}

// ------------------------------------------------------------------------------------------------
// Validate the header of a MDL7 file
void MDLImporter::ValidateHeader_3DGS_MDL7(const MDL::Header_MDL7* pcHeader)
{
    ai_assert(NULL != pcHeader);

    // There are some fixed sizes ...
    if (sizeof(MDL::ColorValue_MDL7) != pcHeader->colorvalue_stc_size)  {
        throw DeadlyImportError(
            "[3DGS MDL7] sizeof(MDL::ColorValue_MDL7) != pcHeader->colorvalue_stc_size");
    }
    if (sizeof(MDL::TexCoord_MDL7) != pcHeader->skinpoint_stc_size) {
        throw DeadlyImportError(
            "[3DGS MDL7] sizeof(MDL::TexCoord_MDL7) != pcHeader->skinpoint_stc_size");
    }
    if (sizeof(MDL::Skin_MDL7) != pcHeader->skin_stc_size)  {
        throw DeadlyImportError(
            "sizeof(MDL::Skin_MDL7) != pcHeader->skin_stc_size");
    }

    // if there are no groups ... how should we load such a file?
    if(!pcHeader->groups_num)   {
        throw DeadlyImportError( "[3DGS MDL7] No frames found");
    }
}

// ------------------------------------------------------------------------------------------------
// resolve bone animation matrices
void MDLImporter::CalcAbsBoneMatrices_3DGS_MDL7(MDL::IntBone_MDL7** apcOutBones)
{
    const MDL::Header_MDL7 *pcHeader = (const MDL::Header_MDL7*)this->mBuffer;
    const MDL::Bone_MDL7* pcBones = (const MDL::Bone_MDL7*)(pcHeader+1);
    ai_assert(NULL != apcOutBones);

    // first find the bone that has NO parent, calculate the
    // animation matrix for it, then go on and search for the next parent
    // index (0) and so on until we can't find a new node.
    uint16_t iParent = 0xffff;
    uint32_t iIterations = 0;
    while (iIterations++ < pcHeader->bones_num) {
        for (uint32_t iBone = 0; iBone < pcHeader->bones_num;++iBone)   {
            BE_NCONST MDL::Bone_MDL7* pcBone = _AI_MDL7_ACCESS_PTR(pcBones,iBone,
                pcHeader->bone_stc_size,MDL::Bone_MDL7);

            AI_SWAP2(pcBone->parent_index);
            AI_SWAP4(pcBone->x);
            AI_SWAP4(pcBone->y);
            AI_SWAP4(pcBone->z);

            if (iParent == pcBone->parent_index)    {
                // MDL7 readme
                ////////////////////////////////////////////////////////////////
                /*
                The animation matrix is then calculated the following way:

                vector3 bPos = <absolute bone position>
                matrix44 laM;   // local animation matrix
                sphrvector key_rotate = <bone rotation>

                matrix44 m1,m2;
                create_trans_matrix(m1, -bPos.x, -bPos.y, -bPos.z);
                create_trans_matrix(m2, -bPos.x, -bPos.y, -bPos.z);

                create_rotation_matrix(laM,key_rotate);

                laM = sm1 * laM;
                laM = laM * sm2;
                */
                /////////////////////////////////////////////////////////////////

                MDL::IntBone_MDL7* const pcOutBone = apcOutBones[iBone];

                // store the parent index of the bone
                pcOutBone->iParent = pcBone->parent_index;
                if (0xffff != iParent)  {
                    const MDL::IntBone_MDL7* pcParentBone = apcOutBones[iParent];
                    pcOutBone->mOffsetMatrix.a4 = -pcParentBone->vPosition.x;
                    pcOutBone->mOffsetMatrix.b4 = -pcParentBone->vPosition.y;
                    pcOutBone->mOffsetMatrix.c4 = -pcParentBone->vPosition.z;
                }
                pcOutBone->vPosition.x = pcBone->x;
                pcOutBone->vPosition.y = pcBone->y;
                pcOutBone->vPosition.z = pcBone->z;
                pcOutBone->mOffsetMatrix.a4 -= pcBone->x;
                pcOutBone->mOffsetMatrix.b4 -= pcBone->y;
                pcOutBone->mOffsetMatrix.c4 -= pcBone->z;

                if (AI_MDL7_BONE_STRUCT_SIZE__NAME_IS_NOT_THERE == pcHeader->bone_stc_size) {
                    // no real name for our poor bone is specified :-(
                    pcOutBone->mName.length = ai_snprintf(pcOutBone->mName.data, MAXLEN,
                        "UnnamedBone_%i",iBone);
                }
                else    {
                    // Make sure we won't run over the buffer's end if there is no
                    // terminal 0 character (however the documentation says there
                    // should be one)
                    uint32_t iMaxLen = pcHeader->bone_stc_size-16;
                    for (uint32_t qq = 0; qq < iMaxLen;++qq)    {
                        if (!pcBone->name[qq])  {
                            iMaxLen = qq;
                            break;
                        }
                    }

                    // store the name of the bone
                    pcOutBone->mName.length = (size_t)iMaxLen;
                    ::memcpy(pcOutBone->mName.data,pcBone->name,pcOutBone->mName.length);
                    pcOutBone->mName.data[pcOutBone->mName.length] = '\0';
                }
            }
        }
        ++iParent;
    }
}

// ------------------------------------------------------------------------------------------------
// read bones from a MDL7 file
MDL::IntBone_MDL7** MDLImporter::LoadBones_3DGS_MDL7()
{
  const MDL::Header_MDL7 *pcHeader = (const MDL::Header_MDL7*)this->mBuffer;
    if (pcHeader->bones_num)    {
        // validate the size of the bone data structure in the file
        if (AI_MDL7_BONE_STRUCT_SIZE__NAME_IS_20_CHARS  != pcHeader->bone_stc_size &&
            AI_MDL7_BONE_STRUCT_SIZE__NAME_IS_32_CHARS  != pcHeader->bone_stc_size &&
            AI_MDL7_BONE_STRUCT_SIZE__NAME_IS_NOT_THERE != pcHeader->bone_stc_size)
        {
            ASSIMP_LOG_WARN("Unknown size of bone data structure");
            return NULL;
        }

        MDL::IntBone_MDL7** apcBonesOut = new MDL::IntBone_MDL7*[pcHeader->bones_num];
        for (uint32_t crank = 0; crank < pcHeader->bones_num;++crank)
            apcBonesOut[crank] = new MDL::IntBone_MDL7();

        // and calculate absolute bone offset matrices ...
        CalcAbsBoneMatrices_3DGS_MDL7(apcBonesOut);
        return apcBonesOut;
    }
    return NULL;
}

// ------------------------------------------------------------------------------------------------
// read faces from a MDL7 file
void MDLImporter::ReadFaces_3DGS_MDL7(const MDL::IntGroupInfo_MDL7& groupInfo,
    MDL::IntGroupData_MDL7& groupData)
{
    const MDL::Header_MDL7 *pcHeader = (const MDL::Header_MDL7*)this->mBuffer;
    MDL::Triangle_MDL7* pcGroupTris = groupInfo.pcGroupTris;

    // iterate through all triangles and build valid display lists
    unsigned int iOutIndex = 0;
    for (unsigned int iTriangle = 0; iTriangle < (unsigned int)groupInfo.pcGroup->numtris; ++iTriangle) {
        AI_SWAP2(pcGroupTris->v_index[0]);
        AI_SWAP2(pcGroupTris->v_index[1]);
        AI_SWAP2(pcGroupTris->v_index[2]);

        // iterate through all indices of the current triangle
        for (unsigned int c = 0; c < 3;++c,++iOutIndex) {

            // validate the vertex index
            unsigned int iIndex = pcGroupTris->v_index[c];
            if(iIndex > (unsigned int)groupInfo.pcGroup->numverts)  {
                // (we might need to read this section a second time - to process frame vertices correctly)
                pcGroupTris->v_index[c] = iIndex = groupInfo.pcGroup->numverts-1;
                ASSIMP_LOG_WARN("Index overflow in MDL7 vertex list");
            }

            // write the output face index
            groupData.pcFaces[iTriangle].mIndices[2-c] = iOutIndex;

            aiVector3D& vPosition = groupData.vPositions[ iOutIndex ];
            vPosition.x = _AI_MDL7_ACCESS_VERT(groupInfo.pcGroupVerts,iIndex, pcHeader->mainvertex_stc_size) .x;
            vPosition.y = _AI_MDL7_ACCESS_VERT(groupInfo.pcGroupVerts,iIndex,pcHeader->mainvertex_stc_size) .y;
            vPosition.z = _AI_MDL7_ACCESS_VERT(groupInfo.pcGroupVerts,iIndex,pcHeader->mainvertex_stc_size) .z;

            // if we have bones, save the index
            if (!groupData.aiBones.empty()) {
                groupData.aiBones[iOutIndex] = _AI_MDL7_ACCESS_VERT(groupInfo.pcGroupVerts,
                    iIndex,pcHeader->mainvertex_stc_size).vertindex;
            }

            // now read the normal vector
            if (AI_MDL7_FRAMEVERTEX030305_STCSIZE <= pcHeader->mainvertex_stc_size) {
                // read the full normal vector
                aiVector3D& vNormal = groupData.vNormals[ iOutIndex ];
                vNormal.x = _AI_MDL7_ACCESS_VERT(groupInfo.pcGroupVerts,iIndex,pcHeader->mainvertex_stc_size) .norm[0];
                AI_SWAP4(vNormal.x);
                vNormal.y = _AI_MDL7_ACCESS_VERT(groupInfo.pcGroupVerts,iIndex,pcHeader->mainvertex_stc_size) .norm[1];
                AI_SWAP4(vNormal.y);
                vNormal.z = _AI_MDL7_ACCESS_VERT(groupInfo.pcGroupVerts,iIndex,pcHeader->mainvertex_stc_size) .norm[2];
                AI_SWAP4(vNormal.z);
            }
            else if (AI_MDL7_FRAMEVERTEX120503_STCSIZE <= pcHeader->mainvertex_stc_size)    {
                // read the normal vector from Quake2's smart table
                aiVector3D& vNormal = groupData.vNormals[ iOutIndex ];
                MD2::LookupNormalIndex(_AI_MDL7_ACCESS_VERT(groupInfo.pcGroupVerts,iIndex,
                    pcHeader->mainvertex_stc_size) .norm162index,vNormal);
            }
            // validate and process the first uv coordinate set
            if (pcHeader->triangle_stc_size >= AI_MDL7_TRIANGLE_STD_SIZE_ONE_UV)    {

                if (groupInfo.pcGroup->num_stpts)   {
                    AI_SWAP2(pcGroupTris->skinsets[0].st_index[0]);
                    AI_SWAP2(pcGroupTris->skinsets[0].st_index[1]);
                    AI_SWAP2(pcGroupTris->skinsets[0].st_index[2]);

                    iIndex = pcGroupTris->skinsets[0].st_index[c];
                    if(iIndex > (unsigned int)groupInfo.pcGroup->num_stpts) {
                        iIndex = groupInfo.pcGroup->num_stpts-1;
                        ASSIMP_LOG_WARN("Index overflow in MDL7 UV coordinate list (#1)");
                    }

                    float u = groupInfo.pcGroupUVs[iIndex].u;
                    float v = 1.0f-groupInfo.pcGroupUVs[iIndex].v; // DX to OGL

                    groupData.vTextureCoords1[iOutIndex].x = u;
                    groupData.vTextureCoords1[iOutIndex].y = v;
                }
                // assign the material index, but only if it is existing
                if (pcHeader->triangle_stc_size >= AI_MDL7_TRIANGLE_STD_SIZE_ONE_UV_WITH_MATINDEX){
                    AI_SWAP4(pcGroupTris->skinsets[0].material);
                    groupData.pcFaces[iTriangle].iMatIndex[0] = pcGroupTris->skinsets[0].material;
                }
            }
            // validate and process the second uv coordinate set
            if (pcHeader->triangle_stc_size >= AI_MDL7_TRIANGLE_STD_SIZE_TWO_UV)    {

                if (groupInfo.pcGroup->num_stpts)   {
                    AI_SWAP2(pcGroupTris->skinsets[1].st_index[0]);
                    AI_SWAP2(pcGroupTris->skinsets[1].st_index[1]);
                    AI_SWAP2(pcGroupTris->skinsets[1].st_index[2]);
                    AI_SWAP4(pcGroupTris->skinsets[1].material);

                    iIndex = pcGroupTris->skinsets[1].st_index[c];
                    if(iIndex > (unsigned int)groupInfo.pcGroup->num_stpts) {
                        iIndex = groupInfo.pcGroup->num_stpts-1;
                        ASSIMP_LOG_WARN("Index overflow in MDL7 UV coordinate list (#2)");
                    }

                    float u = groupInfo.pcGroupUVs[ iIndex ].u;
                    float v = 1.0f-groupInfo.pcGroupUVs[ iIndex ].v;

                    groupData.vTextureCoords2[ iOutIndex ].x = u;
                    groupData.vTextureCoords2[ iOutIndex ].y = v; // DX to OGL

                    // check whether we do really need the second texture
                    // coordinate set ... wastes memory and loading time
                    if (0 != iIndex && (u != groupData.vTextureCoords1[ iOutIndex ].x ||
                        v != groupData.vTextureCoords1[ iOutIndex ].y ) )
                        groupData.bNeed2UV = true;

                    // if the material differs, we need a second skin, too
                    if (pcGroupTris->skinsets[ 1 ].material != pcGroupTris->skinsets[ 0 ].material)
                        groupData.bNeed2UV = true;
                }
                // assign the material index
                groupData.pcFaces[ iTriangle ].iMatIndex[ 1 ] = pcGroupTris->skinsets[ 1 ].material;
            }
        }
        // get the next triangle in the list
        pcGroupTris = (MDL::Triangle_MDL7*)((const char*)pcGroupTris + pcHeader->triangle_stc_size);
    }
}

// ------------------------------------------------------------------------------------------------
// handle frames in a MDL7 file
bool MDLImporter::ProcessFrames_3DGS_MDL7(const MDL::IntGroupInfo_MDL7& groupInfo,
    MDL::IntGroupData_MDL7&  groupData,
    MDL::IntSharedData_MDL7& shared,
    const unsigned char*     szCurrent,
    const unsigned char**    szCurrentOut)
{
    ai_assert( nullptr != szCurrent );
    ai_assert( nullptr != szCurrentOut);

    const MDL::Header_MDL7 *pcHeader = (const MDL::Header_MDL7*)mBuffer;

    // if we have no bones we can simply skip all frames,
    // otherwise we'll need to process them.
    // FIX: If we need another frame than the first we must apply frame vertex replacements ...
    for(unsigned int iFrame = 0; iFrame < (unsigned int)groupInfo.pcGroup->numframes;++iFrame)  {
        MDL::IntFrameInfo_MDL7 frame ((BE_NCONST MDL::Frame_MDL7*)szCurrent,iFrame);

        AI_SWAP4(frame.pcFrame->vertices_count);
        AI_SWAP4(frame.pcFrame->transmatrix_count);

        const unsigned int iAdd = pcHeader->frame_stc_size +
            frame.pcFrame->vertices_count * pcHeader->framevertex_stc_size +
            frame.pcFrame->transmatrix_count * pcHeader->bonetrans_stc_size;

        if (((const char*)szCurrent - (const char*)pcHeader) + iAdd > (unsigned int)pcHeader->data_size)    {
            ASSIMP_LOG_WARN("Index overflow in frame area. "
                "Ignoring all frames and all further mesh groups, too.");

            // don't parse more groups if we can't even read one
            // FIXME: sometimes this seems to occur even for valid files ...
            *szCurrentOut = szCurrent;
            return false;
        }
        // our output frame?
        if (configFrameID == iFrame)    {
            BE_NCONST MDL::Vertex_MDL7* pcFrameVertices = (BE_NCONST MDL::Vertex_MDL7*)(szCurrent+pcHeader->frame_stc_size);

            for (unsigned int qq = 0; qq < frame.pcFrame->vertices_count;++qq)  {
                // I assume this are simple replacements for normal vertices, the bone index serving
                // as the index of the vertex to be replaced.
                uint16_t iIndex = _AI_MDL7_ACCESS(pcFrameVertices,qq,pcHeader->framevertex_stc_size,MDL::Vertex_MDL7).vertindex;
                AI_SWAP2(iIndex);
                if (iIndex >= groupInfo.pcGroup->numverts)  {
                    ASSIMP_LOG_WARN("Invalid vertex index in frame vertex section");
                    continue;
                }

                aiVector3D vPosition,vNormal;

                vPosition.x = _AI_MDL7_ACCESS_VERT(pcFrameVertices,qq,pcHeader->framevertex_stc_size) .x;
                AI_SWAP4(vPosition.x);
                vPosition.y = _AI_MDL7_ACCESS_VERT(pcFrameVertices,qq,pcHeader->framevertex_stc_size) .y;
                AI_SWAP4(vPosition.y);
                vPosition.z = _AI_MDL7_ACCESS_VERT(pcFrameVertices,qq,pcHeader->framevertex_stc_size) .z;
                AI_SWAP4(vPosition.z);

                // now read the normal vector
                if (AI_MDL7_FRAMEVERTEX030305_STCSIZE <= pcHeader->mainvertex_stc_size) {
                    // read the full normal vector
                    vNormal.x = _AI_MDL7_ACCESS_VERT(pcFrameVertices,qq,pcHeader->framevertex_stc_size) .norm[0];
                    AI_SWAP4(vNormal.x);
                    vNormal.y = _AI_MDL7_ACCESS_VERT(pcFrameVertices,qq,pcHeader->framevertex_stc_size) .norm[1];
                    AI_SWAP4(vNormal.y);
                    vNormal.z = _AI_MDL7_ACCESS_VERT(pcFrameVertices,qq,pcHeader->framevertex_stc_size) .norm[2];
                    AI_SWAP4(vNormal.z);
                }
                else if (AI_MDL7_FRAMEVERTEX120503_STCSIZE <= pcHeader->mainvertex_stc_size)    {
                    // read the normal vector from Quake2's smart table
                    MD2::LookupNormalIndex(_AI_MDL7_ACCESS_VERT(pcFrameVertices,qq,
                        pcHeader->framevertex_stc_size) .norm162index,vNormal);
                }

                // FIXME: O(n^2) at the moment ...
                BE_NCONST MDL::Triangle_MDL7* pcGroupTris = groupInfo.pcGroupTris;
                unsigned int iOutIndex = 0;
                for (unsigned int iTriangle = 0; iTriangle < (unsigned int)groupInfo.pcGroup->numtris; ++iTriangle) {
                    // iterate through all indices of the current triangle
                    for (unsigned int c = 0; c < 3;++c,++iOutIndex) {
                        // replace the vertex with the new data
                        const unsigned int iCurIndex = pcGroupTris->v_index[c];
                        if (iCurIndex == iIndex)    {
                            groupData.vPositions[iOutIndex] = vPosition;
                            groupData.vNormals[iOutIndex] = vNormal;
                        }
                    }
                    // get the next triangle in the list
                    pcGroupTris = (BE_NCONST MDL::Triangle_MDL7*)((const char*)
                        pcGroupTris + pcHeader->triangle_stc_size);
                }
            }
        }
        // parse bone trafo matrix keys (only if there are bones ...)
        if (shared.apcOutBones) {
            ParseBoneTrafoKeys_3DGS_MDL7(groupInfo,frame,shared);
        }
        szCurrent += iAdd;
    }
    *szCurrentOut = szCurrent;
    return true;
}

// ------------------------------------------------------------------------------------------------
// Sort faces by material, handle multiple UVs correctly
void MDLImporter::SortByMaterials_3DGS_MDL7(
    const MDL::IntGroupInfo_MDL7&   groupInfo,
    MDL::IntGroupData_MDL7&         groupData,
    MDL::IntSplitGroupData_MDL7& splitGroupData)
{
    const unsigned int iNumMaterials = (unsigned int)splitGroupData.shared.pcMats.size();
    if (!groupData.bNeed2UV)    {
        // if we don't need a second set of texture coordinates there is no reason to keep it in memory ...
        groupData.vTextureCoords2.clear();

        // allocate the array
        splitGroupData.aiSplit = new std::vector<unsigned int>*[iNumMaterials];

        for (unsigned int m = 0; m < iNumMaterials;++m)
            splitGroupData.aiSplit[m] = new std::vector<unsigned int>();

        // iterate through all faces and sort by material
        for (unsigned int iFace = 0; iFace < (unsigned int)groupInfo.pcGroup->numtris;++iFace)  {
            // check range
            if (groupData.pcFaces[iFace].iMatIndex[0] >= iNumMaterials) {
                // use the last material instead
                splitGroupData.aiSplit[iNumMaterials-1]->push_back(iFace);

                // sometimes MED writes -1, but normally only if there is only
                // one skin assigned. No warning in this case
                if(0xFFFFFFFF != groupData.pcFaces[iFace].iMatIndex[0])
                    ASSIMP_LOG_WARN("Index overflow in MDL7 material list [#0]");
            }
            else splitGroupData.aiSplit[groupData.pcFaces[iFace].
                iMatIndex[0]]->push_back(iFace);
        }
    }
    else
    {
        // we need to build combined materials for each combination of
        std::vector<MDL::IntMaterial_MDL7> avMats;
        avMats.reserve(iNumMaterials*2);

        // fixme: why on the heap?
        std::vector<std::vector<unsigned int>* > aiTempSplit(iNumMaterials*2);
        for (unsigned int m = 0; m < iNumMaterials;++m)
            aiTempSplit[m] = new std::vector<unsigned int>();

        // iterate through all faces and sort by material
        for (unsigned int iFace = 0; iFace < (unsigned int)groupInfo.pcGroup->numtris;++iFace)  {
            // check range
            unsigned int iMatIndex = groupData.pcFaces[iFace].iMatIndex[0];
            if (iMatIndex >= iNumMaterials) {
                // sometimes MED writes -1, but normally only if there is only
                // one skin assigned. No warning in this case
                if(UINT_MAX != iMatIndex)
                    ASSIMP_LOG_WARN("Index overflow in MDL7 material list [#1]");
                iMatIndex = iNumMaterials-1;
            }
            unsigned int iMatIndex2 = groupData.pcFaces[iFace].iMatIndex[1];

            unsigned int iNum = iMatIndex;
            if (UINT_MAX != iMatIndex2 && iMatIndex != iMatIndex2)  {
                if (iMatIndex2 >= iNumMaterials)    {
                    // sometimes MED writes -1, but normally only if there is only
                    // one skin assigned. No warning in this case
                    ASSIMP_LOG_WARN("Index overflow in MDL7 material list [#2]");
                    iMatIndex2 = iNumMaterials-1;
                }

                // do a slow search in the list ...
                iNum = 0;
                bool bFound = false;
                for (std::vector<MDL::IntMaterial_MDL7>::iterator i =  avMats.begin();i != avMats.end();++i,++iNum){
                    if ((*i).iOldMatIndices[0] == iMatIndex && (*i).iOldMatIndices[1] == iMatIndex2)    {
                        // reuse this material
                        bFound = true;
                        break;
                    }
                }
                if (!bFound)    {
                    //  build a new material ...
                    MDL::IntMaterial_MDL7 sHelper;
                    sHelper.pcMat = new aiMaterial();
                    sHelper.iOldMatIndices[0] = iMatIndex;
                    sHelper.iOldMatIndices[1] = iMatIndex2;
                    JoinSkins_3DGS_MDL7(splitGroupData.shared.pcMats[iMatIndex],
                        splitGroupData.shared.pcMats[iMatIndex2],sHelper.pcMat);

                    // and add it to the list
                    avMats.push_back(sHelper);
                    iNum = (unsigned int)avMats.size()-1;
                }
                // adjust the size of the file array
                if (iNum == aiTempSplit.size()) {
                    aiTempSplit.push_back(new std::vector<unsigned int>());
                }
            }
            aiTempSplit[iNum]->push_back(iFace);
        }

        // now add the newly created materials to the old list
        if (0 == groupInfo.iIndex)  {
            splitGroupData.shared.pcMats.resize(avMats.size());
            for (unsigned int o = 0; o < avMats.size();++o)
                splitGroupData.shared.pcMats[o] = avMats[o].pcMat;
        }
        else    {
            // This might result in redundant materials ...
            splitGroupData.shared.pcMats.resize(iNumMaterials + avMats.size());
            for (unsigned int o = iNumMaterials; o < avMats.size();++o)
                splitGroupData.shared.pcMats[o] = avMats[o].pcMat;
        }

        // and build the final face-to-material array
        splitGroupData.aiSplit = new std::vector<unsigned int>*[aiTempSplit.size()];
        for (unsigned int m = 0; m < iNumMaterials;++m)
            splitGroupData.aiSplit[m] = aiTempSplit[m];
    }
}

// ------------------------------------------------------------------------------------------------
// Read a MDL7 file
void MDLImporter::InternReadFile_3DGS_MDL7( )
{
    ai_assert(NULL != pScene);

    MDL::IntSharedData_MDL7 sharedData;

    // current cursor position in the file
    BE_NCONST MDL::Header_MDL7 *pcHeader = (BE_NCONST MDL::Header_MDL7*)this->mBuffer;
    const unsigned char* szCurrent = (const unsigned char*)(pcHeader+1);

    AI_SWAP4(pcHeader->version);
    AI_SWAP4(pcHeader->bones_num);
    AI_SWAP4(pcHeader->groups_num);
    AI_SWAP4(pcHeader->data_size);
    AI_SWAP4(pcHeader->entlump_size);
    AI_SWAP4(pcHeader->medlump_size);
    AI_SWAP2(pcHeader->bone_stc_size);
    AI_SWAP2(pcHeader->skin_stc_size);
    AI_SWAP2(pcHeader->colorvalue_stc_size);
    AI_SWAP2(pcHeader->material_stc_size);
    AI_SWAP2(pcHeader->skinpoint_stc_size);
    AI_SWAP2(pcHeader->triangle_stc_size);
    AI_SWAP2(pcHeader->mainvertex_stc_size);
    AI_SWAP2(pcHeader->framevertex_stc_size);
    AI_SWAP2(pcHeader->bonetrans_stc_size);
    AI_SWAP2(pcHeader->frame_stc_size);

    // validate the header of the file. There are some structure
    // sizes that are expected by the loader to be constant
    this->ValidateHeader_3DGS_MDL7(pcHeader);

    // load all bones (they are shared by all groups, so
    // we'll need to add them to all groups/meshes later)
    // apcBonesOut is a list of all bones or NULL if they could not been loaded
    szCurrent += pcHeader->bones_num * pcHeader->bone_stc_size;
    sharedData.apcOutBones = this->LoadBones_3DGS_MDL7();

    // vector to held all created meshes
    std::vector<aiMesh*>* avOutList;

    // 3 meshes per group - that should be OK for most models
    avOutList = new std::vector<aiMesh*>[pcHeader->groups_num];
    for (uint32_t i = 0; i < pcHeader->groups_num;++i)
        avOutList[i].reserve(3);

    // buffer to held the names of all groups in the file
	const size_t buffersize( AI_MDL7_MAX_GROUPNAMESIZE*pcHeader->groups_num );
	char* aszGroupNameBuffer = new char[ buffersize ];

    // read all groups
    for (unsigned int iGroup = 0; iGroup < (unsigned int)pcHeader->groups_num;++iGroup) {
        MDL::IntGroupInfo_MDL7 groupInfo((BE_NCONST MDL::Group_MDL7*)szCurrent,iGroup);
        szCurrent = (const unsigned char*)(groupInfo.pcGroup+1);

        VALIDATE_FILE_SIZE(szCurrent);

        AI_SWAP4(groupInfo.pcGroup->groupdata_size);
        AI_SWAP4(groupInfo.pcGroup->numskins);
        AI_SWAP4(groupInfo.pcGroup->num_stpts);
        AI_SWAP4(groupInfo.pcGroup->numtris);
        AI_SWAP4(groupInfo.pcGroup->numverts);
        AI_SWAP4(groupInfo.pcGroup->numframes);

        if (1 != groupInfo.pcGroup->typ)    {
            // Not a triangle-based mesh
            ASSIMP_LOG_WARN("[3DGS MDL7] Not a triangle mesh group. Continuing happily");
        }

        // store the name of the group
        const unsigned int ofs = iGroup*AI_MDL7_MAX_GROUPNAMESIZE;
        ::memcpy(&aszGroupNameBuffer[ofs],
            groupInfo.pcGroup->name,AI_MDL7_MAX_GROUPNAMESIZE);

        // make sure '\0' is at the end
        aszGroupNameBuffer[ofs+AI_MDL7_MAX_GROUPNAMESIZE-1] = '\0';

        // read all skins
        sharedData.pcMats.reserve(sharedData.pcMats.size() + groupInfo.pcGroup->numskins);
        sharedData.abNeedMaterials.resize(sharedData.abNeedMaterials.size() +
            groupInfo.pcGroup->numskins,false);

        for (unsigned int iSkin = 0; iSkin < (unsigned int)groupInfo.pcGroup->numskins;++iSkin) {
            ParseSkinLump_3DGS_MDL7(szCurrent,&szCurrent,sharedData.pcMats);
        }
        // if we have absolutely no skin loaded we need to generate a default material
        if (sharedData.pcMats.empty())  {
            const int iMode = (int)aiShadingMode_Gouraud;
            sharedData.pcMats.push_back(new aiMaterial());
            aiMaterial* pcHelper = (aiMaterial*)sharedData.pcMats[0];
            pcHelper->AddProperty<int>(&iMode, 1, AI_MATKEY_SHADING_MODEL);

            aiColor3D clr;
            clr.b = clr.g = clr.r = 0.6f;
            pcHelper->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_DIFFUSE);
            pcHelper->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_SPECULAR);

            clr.b = clr.g = clr.r = 0.05f;
            pcHelper->AddProperty<aiColor3D>(&clr, 1,AI_MATKEY_COLOR_AMBIENT);

            aiString szName;
            szName.Set(AI_DEFAULT_MATERIAL_NAME);
            pcHelper->AddProperty(&szName,AI_MATKEY_NAME);

            sharedData.abNeedMaterials.resize(1,false);
        }

        // now get a pointer to all texture coords in the group
        groupInfo.pcGroupUVs = (BE_NCONST MDL::TexCoord_MDL7*)szCurrent;
        for(int i = 0; i < groupInfo.pcGroup->num_stpts; ++i){
            AI_SWAP4(groupInfo.pcGroupUVs[i].u);
            AI_SWAP4(groupInfo.pcGroupUVs[i].v);
        }
        szCurrent += pcHeader->skinpoint_stc_size * groupInfo.pcGroup->num_stpts;

        // now get a pointer to all triangle in the group
        groupInfo.pcGroupTris = (Triangle_MDL7*)szCurrent;
        szCurrent += pcHeader->triangle_stc_size * groupInfo.pcGroup->numtris;

        // now get a pointer to all vertices in the group
        groupInfo.pcGroupVerts = (BE_NCONST MDL::Vertex_MDL7*)szCurrent;
        for(int i = 0; i < groupInfo.pcGroup->numverts; ++i){
            AI_SWAP4(groupInfo.pcGroupVerts[i].x);
            AI_SWAP4(groupInfo.pcGroupVerts[i].y);
            AI_SWAP4(groupInfo.pcGroupVerts[i].z);

            AI_SWAP2(groupInfo.pcGroupVerts[i].vertindex);
            //We can not swap the normal information now as we don't know which of the two kinds it is
        }
        szCurrent += pcHeader->mainvertex_stc_size * groupInfo.pcGroup->numverts;
        VALIDATE_FILE_SIZE(szCurrent);

        MDL::IntSplitGroupData_MDL7 splitGroupData(sharedData,avOutList[iGroup]);
        MDL::IntGroupData_MDL7 groupData;
        if (groupInfo.pcGroup->numtris && groupInfo.pcGroup->numverts)
        {
            // build output vectors
            const unsigned int iNumVertices = groupInfo.pcGroup->numtris*3;
            groupData.vPositions.resize(iNumVertices);
            groupData.vNormals.resize(iNumVertices);

            if (sharedData.apcOutBones)groupData.aiBones.resize(iNumVertices,UINT_MAX);

            // it is also possible that there are 0 UV coordinate sets
            if (groupInfo.pcGroup->num_stpts){
                groupData.vTextureCoords1.resize(iNumVertices,aiVector3D());

                // check whether the triangle data structure is large enough
                // to contain a second UV coordinate set
                if (pcHeader->triangle_stc_size >= AI_MDL7_TRIANGLE_STD_SIZE_TWO_UV)    {
                    groupData.vTextureCoords2.resize(iNumVertices,aiVector3D());
                    groupData.bNeed2UV = true;
                }
            }
            groupData.pcFaces.resize(groupInfo.pcGroup->numtris);

            // read all faces into the preallocated arrays
            ReadFaces_3DGS_MDL7(groupInfo, groupData);

            // sort by materials
            SortByMaterials_3DGS_MDL7(groupInfo, groupData,
                splitGroupData);

            for (unsigned int qq = 0; qq < sharedData.pcMats.size();++qq)   {
                if (!splitGroupData.aiSplit[qq]->empty())
                    sharedData.abNeedMaterials[qq] = true;
            }
        }
        else ASSIMP_LOG_WARN("[3DGS MDL7] Mesh group consists of 0 "
            "vertices or faces. It will be skipped.");

        // process all frames and generate output meshes
        ProcessFrames_3DGS_MDL7(groupInfo,groupData, sharedData,szCurrent,&szCurrent);
        GenerateOutputMeshes_3DGS_MDL7(groupData,splitGroupData);
    }

    // generate a nodegraph and subnodes for each group
    pScene->mRootNode = new aiNode();

    // now we need to build a final mesh list
    for (uint32_t i = 0; i < pcHeader->groups_num;++i)
        pScene->mNumMeshes += (unsigned int)avOutList[i].size();

    pScene->mMeshes = new aiMesh*[pScene->mNumMeshes];  {
        unsigned int p = 0,q = 0;
        for (uint32_t i = 0; i < pcHeader->groups_num;++i)  {
            for (unsigned int a = 0; a < avOutList[i].size();++a)   {
                pScene->mMeshes[p++] = avOutList[i][a];
            }
            if (!avOutList[i].empty())++pScene->mRootNode->mNumChildren;
        }
        // we will later need an extra node to serve as parent for all bones
        if (sharedData.apcOutBones)++pScene->mRootNode->mNumChildren;
        this->pScene->mRootNode->mChildren = new aiNode*[pScene->mRootNode->mNumChildren];
        p = 0;
        for (uint32_t i = 0; i < pcHeader->groups_num;++i)  {
            if (avOutList[i].empty())continue;

            aiNode* const pcNode = pScene->mRootNode->mChildren[p] = new aiNode();
            pcNode->mNumMeshes = (unsigned int)avOutList[i].size();
            pcNode->mMeshes = new unsigned int[pcNode->mNumMeshes];
            pcNode->mParent = this->pScene->mRootNode;
            for (unsigned int a = 0; a < pcNode->mNumMeshes;++a)
                pcNode->mMeshes[a] = q + a;
            q += (unsigned int)avOutList[i].size();

            // setup the name of the node
            char* const szBuffer = &aszGroupNameBuffer[i*AI_MDL7_MAX_GROUPNAMESIZE];
			if ('\0' == *szBuffer) {
				const size_t maxSize(buffersize - (i*AI_MDL7_MAX_GROUPNAMESIZE));
				pcNode->mName.length = ai_snprintf(szBuffer, maxSize, "Group_%u", p);
			} else {
				pcNode->mName.length = ::strlen(szBuffer);
			}
            ::strncpy(pcNode->mName.data,szBuffer,MAXLEN-1);
            ++p;
        }
    }

    // if there is only one root node with a single child we can optimize it a bit ...
    if (1 == pScene->mRootNode->mNumChildren && !sharedData.apcOutBones)    {
        aiNode* pcOldRoot = this->pScene->mRootNode;
        pScene->mRootNode = pcOldRoot->mChildren[0];
        pcOldRoot->mChildren[0] = NULL;
        delete pcOldRoot;
        pScene->mRootNode->mParent = NULL;
    }
    else pScene->mRootNode->mName.Set("<mesh_root>");

    delete[] avOutList;
    delete[] aszGroupNameBuffer;
    AI_DEBUG_INVALIDATE_PTR(avOutList);
    AI_DEBUG_INVALIDATE_PTR(aszGroupNameBuffer);

    // build a final material list.
    CopyMaterials_3DGS_MDL7(sharedData);
    HandleMaterialReferences_3DGS_MDL7();

    // generate output bone animations and add all bones to the scenegraph
    if (sharedData.apcOutBones) {
        // this step adds empty dummy bones to the nodegraph
        // insert another dummy node to avoid name conflicts
        aiNode* const pc = pScene->mRootNode->mChildren[pScene->mRootNode->mNumChildren-1] = new aiNode();

        pc->mName.Set("<skeleton_root>");

        // add bones to the nodegraph
        AddBonesToNodeGraph_3DGS_MDL7((const Assimp::MDL::IntBone_MDL7 **)
            sharedData.apcOutBones,pc,0xffff);

        // this steps build a valid output animation
        BuildOutputAnims_3DGS_MDL7((const Assimp::MDL::IntBone_MDL7 **)
            sharedData.apcOutBones);
    }
}

// ------------------------------------------------------------------------------------------------
// Copy materials
void MDLImporter::CopyMaterials_3DGS_MDL7(MDL::IntSharedData_MDL7 &shared)
{
    pScene->mNumMaterials = (unsigned int)shared.pcMats.size();
    pScene->mMaterials = new aiMaterial*[pScene->mNumMaterials];
    for (unsigned int i = 0; i < pScene->mNumMaterials;++i)
        pScene->mMaterials[i] = shared.pcMats[i];
}


// ------------------------------------------------------------------------------------------------
// Process material references
void MDLImporter::HandleMaterialReferences_3DGS_MDL7()
{
    // search for referrer materials
    for (unsigned int i = 0; i < pScene->mNumMaterials;++i) {
        int iIndex = 0;
        if (AI_SUCCESS == aiGetMaterialInteger(pScene->mMaterials[i],AI_MDL7_REFERRER_MATERIAL, &iIndex) )  {
            for (unsigned int a = 0; a < pScene->mNumMeshes;++a)    {
                aiMesh* const pcMesh = pScene->mMeshes[a];
                if (i == pcMesh->mMaterialIndex) {
                    pcMesh->mMaterialIndex = iIndex;
                }
            }
            // collapse the rest of the array
            delete pScene->mMaterials[i];
            for (unsigned int pp = i; pp < pScene->mNumMaterials-1;++pp)    {

                pScene->mMaterials[pp] = pScene->mMaterials[pp+1];
                for (unsigned int a = 0; a < pScene->mNumMeshes;++a)    {
                    aiMesh* const pcMesh = pScene->mMeshes[a];
                    if (pcMesh->mMaterialIndex > i)--pcMesh->mMaterialIndex;
                }
            }
            --pScene->mNumMaterials;
        }
    }
}

// ------------------------------------------------------------------------------------------------
// Read bone transformation keys
void MDLImporter::ParseBoneTrafoKeys_3DGS_MDL7(
    const MDL::IntGroupInfo_MDL7& groupInfo,
    IntFrameInfo_MDL7&            frame,
    MDL::IntSharedData_MDL7&      shared)
{
    const MDL::Header_MDL7* const pcHeader = (const MDL::Header_MDL7*)this->mBuffer;

    // only the first group contains bone animation keys
    if (frame.pcFrame->transmatrix_count)   {
        if (!groupInfo.iIndex)  {
            // skip all frames vertices. We can't support them
            const MDL::BoneTransform_MDL7* pcBoneTransforms = (const MDL::BoneTransform_MDL7*)
                (((const char*)frame.pcFrame) + pcHeader->frame_stc_size +
                frame.pcFrame->vertices_count * pcHeader->framevertex_stc_size);

            // read all transformation matrices
            for (unsigned int iTrafo = 0; iTrafo < frame.pcFrame->transmatrix_count;++iTrafo)   {
                if(pcBoneTransforms->bone_index >= pcHeader->bones_num) {
                    ASSIMP_LOG_WARN("Index overflow in frame area. "
                        "Unable to parse this bone transformation");
                }
                else    {
                    AddAnimationBoneTrafoKey_3DGS_MDL7(frame.iIndex,
                        pcBoneTransforms,shared.apcOutBones);
                }
                pcBoneTransforms = (const MDL::BoneTransform_MDL7*)(
                    (const char*)pcBoneTransforms + pcHeader->bonetrans_stc_size);
            }
        }
        else    {
            ASSIMP_LOG_WARN("Ignoring animation keyframes in groups != 0");
        }
    }
}

// ------------------------------------------------------------------------------------------------
// Attach bones to the output nodegraph
void MDLImporter::AddBonesToNodeGraph_3DGS_MDL7(const MDL::IntBone_MDL7** apcBones,
    aiNode* pcParent,uint16_t iParentIndex)
{
    ai_assert(NULL != apcBones && NULL != pcParent);

    // get a pointer to the header ...
    const MDL::Header_MDL7* const pcHeader = (const MDL::Header_MDL7*)this->mBuffer;

    const MDL::IntBone_MDL7** apcBones2 = apcBones;
    for (uint32_t i = 0; i <  pcHeader->bones_num;++i)  {

        const MDL::IntBone_MDL7* const pcBone = *apcBones2++;
        if (pcBone->iParent == iParentIndex) {
            ++pcParent->mNumChildren;
        }
    }
    pcParent->mChildren = new aiNode*[pcParent->mNumChildren];
    unsigned int qq = 0;
    for (uint32_t i = 0; i <  pcHeader->bones_num;++i)  {

        const MDL::IntBone_MDL7* const pcBone = *apcBones++;
        if (pcBone->iParent != iParentIndex)continue;

        aiNode* pcNode = pcParent->mChildren[qq++] = new aiNode();
        pcNode->mName = aiString( pcBone->mName );

        AddBonesToNodeGraph_3DGS_MDL7(apcBones,pcNode,(uint16_t)i);
    }
}

// ------------------------------------------------------------------------------------------------
// Build output animations
void MDLImporter::BuildOutputAnims_3DGS_MDL7(
    const MDL::IntBone_MDL7** apcBonesOut)
{
    ai_assert(NULL != apcBonesOut);
    const MDL::Header_MDL7* const pcHeader = (const MDL::Header_MDL7*)mBuffer;

    // one animation ...
    aiAnimation* pcAnim = new aiAnimation();
    for (uint32_t i = 0; i < pcHeader->bones_num;++i)   {
        if (!apcBonesOut[i]->pkeyPositions.empty()) {

            // get the last frame ... (needn't be equal to pcHeader->frames_num)
            for (size_t qq = 0; qq < apcBonesOut[i]->pkeyPositions.size();++qq) {
                pcAnim->mDuration = std::max(pcAnim->mDuration, (double)
                    apcBonesOut[i]->pkeyPositions[qq].mTime);
            }
            ++pcAnim->mNumChannels;
        }
    }
    if (pcAnim->mDuration)  {
        pcAnim->mChannels = new aiNodeAnim*[pcAnim->mNumChannels];

        unsigned int iCnt = 0;
        for (uint32_t i = 0; i < pcHeader->bones_num;++i)   {
            if (!apcBonesOut[i]->pkeyPositions.empty()) {
                const MDL::IntBone_MDL7* const intBone = apcBonesOut[i];

                aiNodeAnim* const pcNodeAnim = pcAnim->mChannels[iCnt++] = new aiNodeAnim();
                pcNodeAnim->mNodeName = aiString( intBone->mName );

                // allocate enough storage for all keys
                pcNodeAnim->mNumPositionKeys = (unsigned int)intBone->pkeyPositions.size();
                pcNodeAnim->mNumScalingKeys  = (unsigned int)intBone->pkeyPositions.size();
                pcNodeAnim->mNumRotationKeys = (unsigned int)intBone->pkeyPositions.size();

                pcNodeAnim->mPositionKeys = new aiVectorKey[pcNodeAnim->mNumPositionKeys];
                pcNodeAnim->mScalingKeys  = new aiVectorKey[pcNodeAnim->mNumPositionKeys];
                pcNodeAnim->mRotationKeys = new aiQuatKey[pcNodeAnim->mNumPositionKeys];

                // copy all keys
                for (unsigned int qq = 0; qq < pcNodeAnim->mNumPositionKeys;++qq)   {
                    pcNodeAnim->mPositionKeys[qq] = intBone->pkeyPositions[qq];
                    pcNodeAnim->mScalingKeys[qq] = intBone->pkeyScalings[qq];
                    pcNodeAnim->mRotationKeys[qq] = intBone->pkeyRotations[qq];
                }
            }
        }

        // store the output animation
        pScene->mNumAnimations = 1;
        pScene->mAnimations = new aiAnimation*[1];
        pScene->mAnimations[0] = pcAnim;
    }
    else delete pcAnim;
}

// ------------------------------------------------------------------------------------------------
void MDLImporter::AddAnimationBoneTrafoKey_3DGS_MDL7(unsigned int iTrafo,
    const MDL::BoneTransform_MDL7* pcBoneTransforms,
    MDL::IntBone_MDL7** apcBonesOut)
{
    ai_assert(NULL != pcBoneTransforms);
    ai_assert(NULL != apcBonesOut);

    // first .. get the transformation matrix
    aiMatrix4x4 mTransform;
    mTransform.a1 = pcBoneTransforms->m[0];
    mTransform.b1 = pcBoneTransforms->m[1];
    mTransform.c1 = pcBoneTransforms->m[2];
    mTransform.d1 = pcBoneTransforms->m[3];

    mTransform.a2 = pcBoneTransforms->m[4];
    mTransform.b2 = pcBoneTransforms->m[5];
    mTransform.c2 = pcBoneTransforms->m[6];
    mTransform.d2 = pcBoneTransforms->m[7];

    mTransform.a3 = pcBoneTransforms->m[8];
    mTransform.b3 = pcBoneTransforms->m[9];
    mTransform.c3 = pcBoneTransforms->m[10];
    mTransform.d3 = pcBoneTransforms->m[11];

    // now decompose the transformation matrix into separate
    // scaling, rotation and translation
    aiVectorKey vScaling,vPosition;
    aiQuatKey qRotation;

    // FIXME: Decompose will assert in debug builds if the matrix is invalid ...
    mTransform.Decompose(vScaling.mValue,qRotation.mValue,vPosition.mValue);

    // now generate keys
    vScaling.mTime = qRotation.mTime = vPosition.mTime = (double)iTrafo;

    // add the keys to the bone
    MDL::IntBone_MDL7* const pcBoneOut = apcBonesOut[pcBoneTransforms->bone_index];
    pcBoneOut->pkeyPositions.push_back  ( vPosition );
    pcBoneOut->pkeyScalings.push_back   ( vScaling  );
    pcBoneOut->pkeyRotations.push_back  ( qRotation );
}

// ------------------------------------------------------------------------------------------------
// Construct output meshes
void MDLImporter::GenerateOutputMeshes_3DGS_MDL7(
    MDL::IntGroupData_MDL7& groupData,
    MDL::IntSplitGroupData_MDL7& splitGroupData)
{
    const MDL::IntSharedData_MDL7& shared = splitGroupData.shared;

    // get a pointer to the header ...
    const MDL::Header_MDL7* const pcHeader = (const MDL::Header_MDL7*)this->mBuffer;
    const unsigned int iNumOutBones = pcHeader->bones_num;

    for (std::vector<aiMaterial*>::size_type i = 0; i < shared.pcMats.size();++i)   {
        if (!splitGroupData.aiSplit[i]->empty())    {

            // allocate the output mesh
            aiMesh* pcMesh = new aiMesh();

            pcMesh->mPrimitiveTypes = aiPrimitiveType_TRIANGLE;
            pcMesh->mMaterialIndex = (unsigned int)i;

            // allocate output storage
            pcMesh->mNumFaces = (unsigned int)splitGroupData.aiSplit[i]->size();
            pcMesh->mFaces = new aiFace[pcMesh->mNumFaces];

            pcMesh->mNumVertices = pcMesh->mNumFaces*3;
            pcMesh->mVertices = new aiVector3D[pcMesh->mNumVertices];
            pcMesh->mNormals = new aiVector3D[pcMesh->mNumVertices];

            if (!groupData.vTextureCoords1.empty()) {
                pcMesh->mNumUVComponents[0] = 2;
                pcMesh->mTextureCoords[0] = new aiVector3D[pcMesh->mNumVertices];
                if (!groupData.vTextureCoords2.empty()) {
                    pcMesh->mNumUVComponents[1] = 2;
                    pcMesh->mTextureCoords[1] = new aiVector3D[pcMesh->mNumVertices];
                }
            }

            // iterate through all faces and build an unique set of vertices
            unsigned int iCurrent = 0;
            for (unsigned int iFace = 0; iFace < pcMesh->mNumFaces;++iFace) {
                pcMesh->mFaces[iFace].mNumIndices = 3;
                pcMesh->mFaces[iFace].mIndices = new unsigned int[3];

                unsigned int iSrcFace = splitGroupData.aiSplit[i]->operator[](iFace);
                const MDL::IntFace_MDL7& oldFace = groupData.pcFaces[iSrcFace];

                // iterate through all face indices
                for (unsigned int c = 0; c < 3;++c) {
                    const uint32_t iIndex = oldFace.mIndices[c];
                    pcMesh->mVertices[iCurrent] = groupData.vPositions[iIndex];
                    pcMesh->mNormals[iCurrent] = groupData.vNormals[iIndex];

                    if (!groupData.vTextureCoords1.empty()) {

                        pcMesh->mTextureCoords[0][iCurrent] = groupData.vTextureCoords1[iIndex];
                        if (!groupData.vTextureCoords2.empty()) {
                            pcMesh->mTextureCoords[1][iCurrent] = groupData.vTextureCoords2[iIndex];
                        }
                    }
                    pcMesh->mFaces[iFace].mIndices[c] = iCurrent++;
                }
            }

            // if we have bones in the mesh we'll need to generate
            // proper vertex weights for them
            if (!groupData.aiBones.empty()) {
                std::vector<std::vector<unsigned int> > aaiVWeightList;
                aaiVWeightList.resize(iNumOutBones);

                int iCurrent = 0;
                for (unsigned int iFace = 0; iFace < pcMesh->mNumFaces;++iFace) {
                    unsigned int iSrcFace = splitGroupData.aiSplit[i]->operator[](iFace);
                    const MDL::IntFace_MDL7& oldFace = groupData.pcFaces[iSrcFace];

                    // iterate through all face indices
                    for (unsigned int c = 0; c < 3;++c) {
                        unsigned int iBone = groupData.aiBones[ oldFace.mIndices[c] ];
                        if (UINT_MAX != iBone)  {
                            if (iBone >= iNumOutBones)  {
                                ASSIMP_LOG_ERROR("Bone index overflow. "
                                    "The bone index of a vertex exceeds the allowed range. ");
                                iBone = iNumOutBones-1;
                            }
                            aaiVWeightList[ iBone ].push_back ( iCurrent );
                        }
                        ++iCurrent;
                    }
                }
                // now check which bones are required ...
                for (std::vector<std::vector<unsigned int> >::const_iterator k =  aaiVWeightList.begin();k != aaiVWeightList.end();++k) {
                    if (!(*k).empty()) {
                        ++pcMesh->mNumBones;
                    }
                }
                pcMesh->mBones = new aiBone*[pcMesh->mNumBones];
                iCurrent = 0;
                for (std::vector<std::vector<unsigned int> >::const_iterator k = aaiVWeightList.begin();k!= aaiVWeightList.end();++k,++iCurrent)
                {
                    if ((*k).empty())
                        continue;

                    // seems we'll need this node
                    aiBone* pcBone = pcMesh->mBones[ iCurrent ] = new aiBone();
                    pcBone->mName = aiString(shared.apcOutBones[ iCurrent ]->mName);
                    pcBone->mOffsetMatrix = shared.apcOutBones[ iCurrent ]->mOffsetMatrix;

                    // setup vertex weights
                    pcBone->mNumWeights = (unsigned int)(*k).size();
                    pcBone->mWeights = new aiVertexWeight[pcBone->mNumWeights];

                    for (unsigned int weight = 0; weight < pcBone->mNumWeights;++weight)    {
                        pcBone->mWeights[weight].mVertexId = (*k)[weight];
                        pcBone->mWeights[weight].mWeight = 1.0f;
                    }
                }
            }
            // add the mesh to the list of output meshes
            splitGroupData.avOutList.push_back(pcMesh);
        }
    }
}

// ------------------------------------------------------------------------------------------------
// Join to materials
void MDLImporter::JoinSkins_3DGS_MDL7(
    aiMaterial* pcMat1,
    aiMaterial* pcMat2,
    aiMaterial* pcMatOut)
{
    ai_assert(NULL != pcMat1 && NULL != pcMat2 && NULL != pcMatOut);

    // first create a full copy of the first skin property set
    // and assign it to the output material
    aiMaterial::CopyPropertyList(pcMatOut,pcMat1);

    int iVal = 0;
    pcMatOut->AddProperty<int>(&iVal,1,AI_MATKEY_UVWSRC_DIFFUSE(0));

    // then extract the diffuse texture from the second skin,
    // setup 1 as UV source and we have it
    aiString sString;
    if(AI_SUCCESS == aiGetMaterialString ( pcMat2, AI_MATKEY_TEXTURE_DIFFUSE(0),&sString )) {
        iVal = 1;
        pcMatOut->AddProperty<int>(&iVal,1,AI_MATKEY_UVWSRC_DIFFUSE(1));
        pcMatOut->AddProperty(&sString,AI_MATKEY_TEXTURE_DIFFUSE(1));
    }
}

// ------------------------------------------------------------------------------------------------
// Read a Half-life 1 MDL
void MDLImporter::InternReadFile_HL1(const std::string& pFile, const uint32_t iMagicWord)
{
    // We can't correctly load an MDL from a MDL "sequence" file.
    if (iMagicWord == AI_MDL_MAGIC_NUMBER_BE_HL2b || iMagicWord == AI_MDL_MAGIC_NUMBER_LE_HL2b)
        throw DeadlyImportError("Impossible to properly load a model from an MDL sequence file.");

    // Read the MDL file.
    HalfLife::HL1MDLLoader loader(
        pScene,
        pIOHandler,
        mBuffer,
        pFile,
        mHL1ImportSettings);
}

// ------------------------------------------------------------------------------------------------
// Read a half-life 2 MDL
void MDLImporter::InternReadFile_HL2( )
{
    //const MDL::Header_HL2* pcHeader = (const MDL::Header_HL2*)this->mBuffer;
    throw DeadlyImportError("HL2 MDLs are not implemented");
}

#endif // !! ASSIMP_BUILD_NO_MDL_IMPORTER