assimp/code/AssetLib/MDL/MDLMaterialLoader.cpp

/*
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Open Asset Import Library (assimp)
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  following disclaimer.

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*/

/** @file Implementation of the material part of the MDL importer class */

#ifndef ASSIMP_BUILD_NO_MDL_IMPORTER

#include "MDLDefaultColorMap.h"
#include "MDLLoader.h"

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

#include <memory>

using namespace Assimp;

static aiTexel *const bad_texel = reinterpret_cast<aiTexel *>(SIZE_MAX);

// ------------------------------------------------------------------------------------------------
// Find a suitable palette file or take the default one
void MDLImporter::SearchPalette(const unsigned char **pszColorMap) {
    // now try to find the color map in the current directory
    IOStream *pcStream = mIOHandler->Open(configPalette, "rb");

    const unsigned char *szColorMap = (const unsigned char *)::g_aclrDefaultColorMap;
    if (pcStream) {
        if (pcStream->FileSize() >= 768) {
            size_t len = 256 * 3;
            unsigned char *colorMap = new unsigned char[len];
            szColorMap = colorMap;
            pcStream->Read(colorMap, len, 1);
            ASSIMP_LOG_INFO("Found valid colormap.lmp in directory. "
                            "It will be used to decode embedded textures in palletized formats.");
        }
        delete pcStream;
        pcStream = nullptr;
    }
    *pszColorMap = szColorMap;
}

// ------------------------------------------------------------------------------------------------
// Free the palette again
void MDLImporter::FreePalette(const unsigned char *szColorMap) {
    if (szColorMap != (const unsigned char *)::g_aclrDefaultColorMap) {
        delete[] szColorMap;
    }
}

// ------------------------------------------------------------------------------------------------
// Check whether we can replace a texture with a single color
aiColor4D MDLImporter::ReplaceTextureWithColor(const aiTexture *pcTexture) {
    ai_assert(nullptr != pcTexture);

    aiColor4D clrOut;
    clrOut.r = get_qnan();
    if (!pcTexture->mHeight || !pcTexture->mWidth)
        return clrOut;

    const unsigned int iNumPixels = pcTexture->mHeight * pcTexture->mWidth;
    const aiTexel *pcTexel = pcTexture->pcData + 1;
    const aiTexel *const pcTexelEnd = &pcTexture->pcData[iNumPixels];

    while (pcTexel != pcTexelEnd) {
        if (*pcTexel != *(pcTexel - 1)) {
            pcTexel = nullptr;
            break;
        }
        ++pcTexel;
    }
    if (pcTexel) {
        clrOut.r = pcTexture->pcData->r / 255.0f;
        clrOut.g = pcTexture->pcData->g / 255.0f;
        clrOut.b = pcTexture->pcData->b / 255.0f;
        clrOut.a = pcTexture->pcData->a / 255.0f;
    }
    return clrOut;
}

// ------------------------------------------------------------------------------------------------
// Read a texture from a MDL3 file
void MDLImporter::CreateTextureARGB8_3DGS_MDL3(const unsigned char *szData) {
    const MDL::Header *pcHeader = (const MDL::Header *)mBuffer; //the endianness is already corrected in the InternReadFile_3DGS_MDL345 function

    VALIDATE_FILE_SIZE(szData + pcHeader->skinwidth *
                                        pcHeader->skinheight);

    // allocate a new texture object
    aiTexture *pcNew = new aiTexture();
    pcNew->mWidth = pcHeader->skinwidth;
    pcNew->mHeight = pcHeader->skinheight;

    if(pcNew->mWidth != 0 && pcNew->mHeight > UINT_MAX/pcNew->mWidth) {
        throw DeadlyImportError("Invalid MDL file. A texture is too big.");
    }
    pcNew->pcData = new aiTexel[pcNew->mWidth * pcNew->mHeight];

    const unsigned char *szColorMap;
    this->SearchPalette(&szColorMap);

    // copy texture data
    for (unsigned int i = 0; i < pcNew->mWidth * pcNew->mHeight; ++i) {
        const unsigned char val = szData[i];
        const unsigned char *sz = &szColorMap[val * 3];

        pcNew->pcData[i].a = 0xFF;
        pcNew->pcData[i].r = *sz++;
        pcNew->pcData[i].g = *sz++;
        pcNew->pcData[i].b = *sz;
    }

    FreePalette(szColorMap);

    // store the texture
    aiTexture **pc = this->pScene->mTextures;
    this->pScene->mTextures = new aiTexture *[pScene->mNumTextures + 1];
    for (unsigned int i = 0; i < pScene->mNumTextures; ++i)
        pScene->mTextures[i] = pc[i];

    pScene->mTextures[this->pScene->mNumTextures] = pcNew;
    pScene->mNumTextures++;
    delete[] pc;
}

// ------------------------------------------------------------------------------------------------
// Read a texture from a MDL4 file
void MDLImporter::CreateTexture_3DGS_MDL4(const unsigned char *szData,
        unsigned int iType,
        unsigned int *piSkip) {
    ai_assert(nullptr != piSkip);

    const MDL::Header *pcHeader = (const MDL::Header *)mBuffer; //the endianness is already corrected in the InternReadFile_3DGS_MDL345 function

    if (iType == 1 || iType > 3) {
        ASSIMP_LOG_ERROR("Unsupported texture file format");
        return;
    }

    const bool bNoRead = *piSkip == UINT_MAX;

    // allocate a new texture object
    aiTexture *pcNew = new aiTexture();
    pcNew->mWidth = pcHeader->skinwidth;
    pcNew->mHeight = pcHeader->skinheight;

    if (bNoRead) pcNew->pcData = bad_texel;
    ParseTextureColorData(szData, iType, piSkip, pcNew);

    // store the texture
    if (!bNoRead) {
        if (!this->pScene->mNumTextures) {
            pScene->mNumTextures = 1;
            pScene->mTextures = new aiTexture *[1];
            pScene->mTextures[0] = pcNew;
        } else {
            aiTexture **pc = pScene->mTextures;
            pScene->mTextures = new aiTexture *[pScene->mNumTextures + 1];
            for (unsigned int i = 0; i < this->pScene->mNumTextures; ++i)
                pScene->mTextures[i] = pc[i];
            pScene->mTextures[pScene->mNumTextures] = pcNew;
            pScene->mNumTextures++;
            delete[] pc;
        }
    } else {
        pcNew->pcData = nullptr;
        delete pcNew;
    }
    return;
}

// ------------------------------------------------------------------------------------------------
// Load color data of a texture and convert it to our output format
void MDLImporter::ParseTextureColorData(const unsigned char *szData,
        unsigned int iType,
        unsigned int *piSkip,
        aiTexture *pcNew) {
    const bool do_read = bad_texel != pcNew->pcData;

    // allocate storage for the texture image
    if (do_read) {
        if(pcNew->mWidth != 0 && pcNew->mHeight > UINT_MAX/pcNew->mWidth) {
            throw DeadlyImportError("Invalid MDL file. A texture is too big.");
        }
        pcNew->pcData = new aiTexel[pcNew->mWidth * pcNew->mHeight];
    }

    // R5G6B5 format (with or without MIPs)
    // ****************************************************************
    if (2 == iType || 10 == iType) {
        VALIDATE_FILE_SIZE(szData + pcNew->mWidth * pcNew->mHeight * 2);

        // copy texture data
        unsigned int i;
        if (do_read) {
            for (i = 0; i < pcNew->mWidth * pcNew->mHeight; ++i) {
                MDL::RGB565 val = ((MDL::RGB565 *)szData)[i];
                AI_SWAP2(val);

                pcNew->pcData[i].a = 0xFF;
                pcNew->pcData[i].r = (unsigned char)val.b << 3;
                pcNew->pcData[i].g = (unsigned char)val.g << 2;
                pcNew->pcData[i].b = (unsigned char)val.r << 3;
            }
        } else {
            i = pcNew->mWidth * pcNew->mHeight;
        }
        *piSkip = i * 2;

        // apply MIP maps
        if (10 == iType) {
            *piSkip += ((i >> 2) + (i >> 4) + (i >> 6)) << 1;
            VALIDATE_FILE_SIZE(szData + *piSkip);
        }
    }
    // ARGB4 format (with or without MIPs)
    // ****************************************************************
    else if (3 == iType || 11 == iType) {
        VALIDATE_FILE_SIZE(szData + pcNew->mWidth * pcNew->mHeight * 4);

        // copy texture data
        unsigned int i;
        if (do_read) {
            for (i = 0; i < pcNew->mWidth * pcNew->mHeight; ++i) {
                MDL::ARGB4 val = ((MDL::ARGB4 *)szData)[i];
                AI_SWAP2(val);

                pcNew->pcData[i].a = (unsigned char)val.a << 4;
                pcNew->pcData[i].r = (unsigned char)val.r << 4;
                pcNew->pcData[i].g = (unsigned char)val.g << 4;
                pcNew->pcData[i].b = (unsigned char)val.b << 4;
            }
        } else
            i = pcNew->mWidth * pcNew->mHeight;
        *piSkip = i * 2;

        // apply MIP maps
        if (11 == iType) {
            *piSkip += ((i >> 2) + (i >> 4) + (i >> 6)) << 1;
            VALIDATE_FILE_SIZE(szData + *piSkip);
        }
    }
    // RGB8 format (with or without MIPs)
    // ****************************************************************
    else if (4 == iType || 12 == iType) {
        VALIDATE_FILE_SIZE(szData + pcNew->mWidth * pcNew->mHeight * 3);

        // copy texture data
        unsigned int i;
        if (do_read) {
            for (i = 0; i < pcNew->mWidth * pcNew->mHeight; ++i) {
                const unsigned char *_szData = &szData[i * 3];

                pcNew->pcData[i].a = 0xFF;
                pcNew->pcData[i].b = *_szData++;
                pcNew->pcData[i].g = *_szData++;
                pcNew->pcData[i].r = *_szData;
            }
        } else
            i = pcNew->mWidth * pcNew->mHeight;

        // apply MIP maps
        *piSkip = i * 3;
        if (12 == iType) {
            *piSkip += ((i >> 2) + (i >> 4) + (i >> 6)) * 3;
            VALIDATE_FILE_SIZE(szData + *piSkip);
        }
    }
    // ARGB8 format (with ir without MIPs)
    // ****************************************************************
    else if (5 == iType || 13 == iType) {
        VALIDATE_FILE_SIZE(szData + pcNew->mWidth * pcNew->mHeight * 4);

        // copy texture data
        unsigned int i;
        if (do_read) {
            for (i = 0; i < pcNew->mWidth * pcNew->mHeight; ++i) {
                const unsigned char *_szData = &szData[i * 4];

                pcNew->pcData[i].b = *_szData++;
                pcNew->pcData[i].g = *_szData++;
                pcNew->pcData[i].r = *_szData++;
                pcNew->pcData[i].a = *_szData;
            }
        } else {
            i = pcNew->mWidth * pcNew->mHeight;
        }

        // apply MIP maps
        *piSkip = i << 2;
        if (13 == iType) {
            *piSkip += ((i >> 2) + (i >> 4) + (i >> 6)) << 2;
        }
    }
    // palletized 8 bit texture. As for Quake 1
    // ****************************************************************
    else if (0 == iType) {
        VALIDATE_FILE_SIZE(szData + pcNew->mWidth * pcNew->mHeight);

        // copy texture data
        unsigned int i;
        if (do_read) {

            const unsigned char *szColorMap;
            SearchPalette(&szColorMap);

            for (i = 0; i < pcNew->mWidth * pcNew->mHeight; ++i) {
                const unsigned char val = szData[i];
                const unsigned char *sz = &szColorMap[val * 3];

                pcNew->pcData[i].a = 0xFF;
                pcNew->pcData[i].r = *sz++;
                pcNew->pcData[i].g = *sz++;
                pcNew->pcData[i].b = *sz;
            }
            this->FreePalette(szColorMap);

        } else
            i = pcNew->mWidth * pcNew->mHeight;
        *piSkip = i;

        // FIXME: Also support for MIP maps?
    }
}

// ------------------------------------------------------------------------------------------------
// Get a texture from a MDL5 file
void MDLImporter::CreateTexture_3DGS_MDL5(const unsigned char *szData,
        unsigned int iType,
        unsigned int *piSkip) {
    ai_assert(nullptr != piSkip);
    bool bNoRead = *piSkip == UINT_MAX;

    // allocate a new texture object
    aiTexture *pcNew = new aiTexture();

    VALIDATE_FILE_SIZE(szData + 8);

    // first read the size of the texture
    pcNew->mWidth = *((uint32_t *)szData);
    AI_SWAP4(pcNew->mWidth);
    szData += sizeof(uint32_t);

    pcNew->mHeight = *((uint32_t *)szData);
    AI_SWAP4(pcNew->mHeight);
    szData += sizeof(uint32_t);

    if (bNoRead) {
        pcNew->pcData = bad_texel;
    }

    // this should not occur - at least the docs say it shouldn't.
    // however, one can easily try out what MED does if you have
    // a model with a DDS texture and export it to MDL5 ...
    // yeah, it embeds the DDS file.
    if (6 == iType) {
        // this is a compressed texture in DDS format
        *piSkip = pcNew->mWidth;
        VALIDATE_FILE_SIZE(szData + *piSkip);

        if (!bNoRead) {
            // place a hint and let the application know that this is a DDS file
            pcNew->mHeight = 0;
            pcNew->achFormatHint[0] = 'd';
            pcNew->achFormatHint[1] = 'd';
            pcNew->achFormatHint[2] = 's';
            pcNew->achFormatHint[3] = '\0';

            pcNew->pcData = (aiTexel *)new unsigned char[pcNew->mWidth];
            ::memcpy(pcNew->pcData, szData, pcNew->mWidth);
        }
    } else {
        // parse the color data of the texture
        ParseTextureColorData(szData, iType, piSkip, pcNew);
    }
    *piSkip += sizeof(uint32_t) * 2;

    if (!bNoRead) {
        // store the texture
        if (!this->pScene->mNumTextures) {
            pScene->mNumTextures = 1;
            pScene->mTextures = new aiTexture *[1];
            pScene->mTextures[0] = pcNew;
        } else {
            aiTexture **pc = pScene->mTextures;
            pScene->mTextures = new aiTexture *[pScene->mNumTextures + 1];
            for (unsigned int i = 0; i < pScene->mNumTextures; ++i)
                this->pScene->mTextures[i] = pc[i];

            pScene->mTextures[pScene->mNumTextures] = pcNew;
            pScene->mNumTextures++;
            delete[] pc;
        }
    } else {
        pcNew->pcData = nullptr;
        delete pcNew;
    }
    return;
}

// ------------------------------------------------------------------------------------------------
// Get a skin from a MDL7 file - more complex than all other subformats
void MDLImporter::ParseSkinLump_3DGS_MDL7(
        const unsigned char *szCurrent,
        const unsigned char **szCurrentOut,
        aiMaterial *pcMatOut,
        unsigned int iType,
        unsigned int iWidth,
        unsigned int iHeight) {
    std::unique_ptr<aiTexture> pcNew;

    // get the type of the skin
    unsigned int iMasked = (unsigned int)(iType & 0xF);

    if (0x1 == iMasked) {
        // ***** REFERENCE TO ANOTHER SKIN INDEX *****
        int referrer = (int)iWidth;
        pcMatOut->AddProperty<int>(&referrer, 1, AI_MDL7_REFERRER_MATERIAL);
    } else if (0x6 == iMasked) {
        // ***** EMBEDDED DDS FILE *****
        if (1 != iHeight) {
            ASSIMP_LOG_WARN("Found a reference to an embedded DDS texture, "
                            "but texture height is not equal to 1, which is not supported by MED");
        }
        if (iWidth == 0) {
            ASSIMP_LOG_ERROR("Found a reference to an embedded DDS texture, but texture width is zero, aborting import.");
            return;
        }
        
        pcNew.reset(new aiTexture);
        pcNew->mHeight = 0;
        pcNew->mWidth = iWidth;

        // place a proper format hint
        pcNew->achFormatHint[0] = 'd';
        pcNew->achFormatHint[1] = 'd';
        pcNew->achFormatHint[2] = 's';
        pcNew->achFormatHint[3] = '\0';

        pcNew->pcData = (aiTexel *)new unsigned char[pcNew->mWidth];
        memcpy(pcNew->pcData, szCurrent, pcNew->mWidth);
        szCurrent += iWidth;
    } else if (0x7 == iMasked) {
        // ***** REFERENCE TO EXTERNAL FILE *****
        if (1 != iHeight) {
            ASSIMP_LOG_WARN("Found a reference to an external texture, "
                            "but texture height is not equal to 1, which is not supported by MED");
        }

        aiString szFile;
        const size_t iLen = strlen((const char *)szCurrent);
        size_t iLen2 = iLen + 1;
        iLen2 = iLen2 > MAXLEN ? MAXLEN : iLen2;
        memcpy(szFile.data, (const char *)szCurrent, iLen2);
        szFile.length = static_cast<ai_uint32>(iLen2);

        szCurrent += iLen2;

        // place this as diffuse texture
        pcMatOut->AddProperty(&szFile, AI_MATKEY_TEXTURE_DIFFUSE(0));
    } else if (iMasked || !iType || (iType && iWidth && iHeight)) {
        pcNew.reset(new aiTexture());
        if (!iHeight || !iWidth) {
            ASSIMP_LOG_WARN("Found embedded texture, but its width "
                            "an height are both 0. Is this a joke?");

            // generate an empty chess pattern
            pcNew->mWidth = pcNew->mHeight = 8;
            pcNew->pcData = new aiTexel[64];
            for (unsigned int x = 0; x < 8; ++x) {
                for (unsigned int y = 0; y < 8; ++y) {
                    const bool bSet = ((0 == x % 2 && 0 != y % 2) ||
                                       (0 != x % 2 && 0 == y % 2));

                    aiTexel *pc = &pcNew->pcData[y * 8 + x];
                    pc->r = pc->b = pc->g = (bSet ? 0xFF : 0);
                    pc->a = 0xFF;
                }
            }
        } else {
            // it is a standard color texture. Fill in width and height
            // and call the same function we used for loading MDL5 files

            pcNew->mWidth = iWidth;
            pcNew->mHeight = iHeight;

            unsigned int iSkip = 0;
            ParseTextureColorData(szCurrent, iMasked, &iSkip, pcNew.get());

            // skip length of texture data
            szCurrent += iSkip;
        }
    }

    // sometimes there are MDL7 files which have a monochrome
    // texture instead of material colors ... possible they have
    // been converted to MDL7 from other formats, such as MDL5
    aiColor4D clrTexture;
    if (pcNew)
        clrTexture = ReplaceTextureWithColor(pcNew.get());
    else
        clrTexture.r = get_qnan();

    // check whether a material definition is contained in the skin
    if (iType & AI_MDL7_SKINTYPE_MATERIAL) {
        BE_NCONST MDL::Material_MDL7 *pcMatIn = (BE_NCONST MDL::Material_MDL7 *)szCurrent;
        szCurrent = (unsigned char *)(pcMatIn + 1);
        VALIDATE_FILE_SIZE(szCurrent);

        aiColor3D clrTemp;

#define COLOR_MULTIPLY_RGB()         \
    if (is_not_qnan(clrTexture.r)) { \
        clrTemp.r *= clrTexture.r;   \
        clrTemp.g *= clrTexture.g;   \
        clrTemp.b *= clrTexture.b;   \
    }

        // read diffuse color
        clrTemp.r = pcMatIn->Diffuse.r;
        AI_SWAP4(clrTemp.r);
        clrTemp.g = pcMatIn->Diffuse.g;
        AI_SWAP4(clrTemp.g);
        clrTemp.b = pcMatIn->Diffuse.b;
        AI_SWAP4(clrTemp.b);
        COLOR_MULTIPLY_RGB();
        pcMatOut->AddProperty<aiColor3D>(&clrTemp, 1, AI_MATKEY_COLOR_DIFFUSE);

        // read specular color
        clrTemp.r = pcMatIn->Specular.r;
        AI_SWAP4(clrTemp.r);
        clrTemp.g = pcMatIn->Specular.g;
        AI_SWAP4(clrTemp.g);
        clrTemp.b = pcMatIn->Specular.b;
        AI_SWAP4(clrTemp.b);
        COLOR_MULTIPLY_RGB();
        pcMatOut->AddProperty<aiColor3D>(&clrTemp, 1, AI_MATKEY_COLOR_SPECULAR);

        // read ambient color
        clrTemp.r = pcMatIn->Ambient.r;
        AI_SWAP4(clrTemp.r);
        clrTemp.g = pcMatIn->Ambient.g;
        AI_SWAP4(clrTemp.g);
        clrTemp.b = pcMatIn->Ambient.b;
        AI_SWAP4(clrTemp.b);
        COLOR_MULTIPLY_RGB();
        pcMatOut->AddProperty<aiColor3D>(&clrTemp, 1, AI_MATKEY_COLOR_AMBIENT);

        // read emissive color
        clrTemp.r = pcMatIn->Emissive.r;
        AI_SWAP4(clrTemp.r);
        clrTemp.g = pcMatIn->Emissive.g;
        AI_SWAP4(clrTemp.g);
        clrTemp.b = pcMatIn->Emissive.b;
        AI_SWAP4(clrTemp.b);
        pcMatOut->AddProperty<aiColor3D>(&clrTemp, 1, AI_MATKEY_COLOR_EMISSIVE);

#undef COLOR_MULITPLY_RGB

        // FIX: Take the opacity from the ambient color.
        // The doc say something else, but it is fact that MED exports the
        // opacity like this .... oh well.
        clrTemp.r = pcMatIn->Ambient.a;
        AI_SWAP4(clrTemp.r);
        if (is_not_qnan(clrTexture.r)) {
            clrTemp.r *= clrTexture.a;
        }
        pcMatOut->AddProperty<ai_real>(&clrTemp.r, 1, AI_MATKEY_OPACITY);

        // read phong power
        int iShadingMode = (int)aiShadingMode_Gouraud;
        AI_SWAP4(pcMatIn->Power);
        if (0.0f != pcMatIn->Power) {
            iShadingMode = (int)aiShadingMode_Phong;
            // pcMatIn is packed, we can't form pointers to its members
            float power = pcMatIn->Power;
            pcMatOut->AddProperty<float>(&power, 1, AI_MATKEY_SHININESS);
        }
        pcMatOut->AddProperty<int>(&iShadingMode, 1, AI_MATKEY_SHADING_MODEL);
    } else if (is_not_qnan(clrTexture.r)) {
        pcMatOut->AddProperty<aiColor4D>(&clrTexture, 1, AI_MATKEY_COLOR_DIFFUSE);
        pcMatOut->AddProperty<aiColor4D>(&clrTexture, 1, AI_MATKEY_COLOR_SPECULAR);
    }
    // if the texture could be replaced by a single material color
    // we don't need the texture anymore
    if (is_not_qnan(clrTexture.r)) {
        pcNew.reset();
    }

    // If an ASCII effect description (HLSL?) is contained in the file,
    // we can simply ignore it ...
    if (iType & AI_MDL7_SKINTYPE_MATERIAL_ASCDEF) {
        VALIDATE_FILE_SIZE(szCurrent);
        int32_t iMe = *((int32_t *)szCurrent);
        AI_SWAP4(iMe);
        szCurrent += sizeof(char) * iMe + sizeof(int32_t);
        VALIDATE_FILE_SIZE(szCurrent);
    }

    // If an embedded texture has been loaded setup the corresponding
    // data structures in the aiScene instance
    if (pcNew && pScene->mNumTextures <= 999) {
        // place this as diffuse texture
        char current[5];
        ai_snprintf(current, 5, "*%i", this->pScene->mNumTextures);

        aiString szFile;
        const size_t iLen = strlen((const char *)current);
        ::memcpy(szFile.data, (const char *)current, iLen + 1);
        szFile.length = (ai_uint32)iLen;

        pcMatOut->AddProperty(&szFile, AI_MATKEY_TEXTURE_DIFFUSE(0));

        // store the texture
        if (!pScene->mNumTextures) {
            pScene->mNumTextures = 1;
            pScene->mTextures = new aiTexture *[1];
            pScene->mTextures[0] = pcNew.release();
        } else {
            aiTexture **pc = pScene->mTextures;
            pScene->mTextures = new aiTexture *[pScene->mNumTextures + 1];
            for (unsigned int i = 0; i < pScene->mNumTextures; ++i) {
                pScene->mTextures[i] = pc[i];
            }

            pScene->mTextures[pScene->mNumTextures] = pcNew.release();
            pScene->mNumTextures++;
            delete[] pc;
        }
    }
    VALIDATE_FILE_SIZE(szCurrent);
    *szCurrentOut = szCurrent;
}

// ------------------------------------------------------------------------------------------------
// Skip a skin lump
void MDLImporter::SkipSkinLump_3DGS_MDL7(
        const unsigned char *szCurrent,
        const unsigned char **szCurrentOut,
        unsigned int iType,
        unsigned int iWidth,
        unsigned int iHeight) {
    // get the type of the skin
    const unsigned int iMasked = (unsigned int)(iType & 0xF);

    if (0x6 == iMasked) {
        szCurrent += iWidth;
    }
    if (0x7 == iMasked) {
        const size_t iLen = std::strlen((const char *)szCurrent);
        szCurrent += iLen + 1;
    } else if (iMasked || !iType) {
        if (iMasked || !iType || (iType && iWidth && iHeight)) {
            // ParseTextureColorData(..., aiTexture::pcData == bad_texel) will simply
            // return the size of the color data in bytes in iSkip
            unsigned int iSkip = 0;

            aiTexture tex;
            tex.pcData = bad_texel;
            tex.mHeight = iHeight;
            tex.mWidth = iWidth;
            ParseTextureColorData(szCurrent, iMasked, &iSkip, &tex);

            // FIX: Important, otherwise the destructor will crash
            tex.pcData = nullptr;

            // skip length of texture data
            szCurrent += iSkip;
        }
    }

    // check whether a material definition is contained in the skin
    if (iType & AI_MDL7_SKINTYPE_MATERIAL) {
        BE_NCONST MDL::Material_MDL7 *pcMatIn = (BE_NCONST MDL::Material_MDL7 *)szCurrent;
        szCurrent = (unsigned char *)(pcMatIn + 1);
    }

    // if an ASCII effect description (HLSL?) is contained in the file,
    // we can simply ignore it ...
    if (iType & AI_MDL7_SKINTYPE_MATERIAL_ASCDEF) {
        int32_t iMe = *((int32_t *)szCurrent);
        AI_SWAP4(iMe);
        szCurrent += sizeof(char) * iMe + sizeof(int32_t);
    }
    *szCurrentOut = szCurrent;
}

// ------------------------------------------------------------------------------------------------
void MDLImporter::ParseSkinLump_3DGS_MDL7(
        const unsigned char *szCurrent,
        const unsigned char **szCurrentOut,
        std::vector<aiMaterial *> &pcMats) {
    ai_assert(nullptr != szCurrent);
    ai_assert(nullptr != szCurrentOut);

    *szCurrentOut = szCurrent;
    BE_NCONST MDL::Skin_MDL7 *pcSkin = (BE_NCONST MDL::Skin_MDL7 *)szCurrent;
    AI_SWAP4(pcSkin->width);
    AI_SWAP4(pcSkin->height);
    szCurrent += 12;

    // allocate an output material
    aiMaterial *pcMatOut = new aiMaterial();
    pcMats.push_back(pcMatOut);

    // skip length of file name
    szCurrent += AI_MDL7_MAX_TEXNAMESIZE;

    ParseSkinLump_3DGS_MDL7(szCurrent, szCurrentOut, pcMatOut,
            pcSkin->typ, pcSkin->width, pcSkin->height);

    // place the name of the skin in the material
    if (pcSkin->texture_name[0]) {
        // the 0 termination could be there or not - we can't know
        aiString szFile;
        ::memcpy(szFile.data, pcSkin->texture_name, sizeof(pcSkin->texture_name));
        szFile.data[sizeof(pcSkin->texture_name)] = '\0';
        szFile.length = (ai_uint32)::strlen(szFile.data);

        pcMatOut->AddProperty(&szFile, AI_MATKEY_NAME);
    }
}

#endif // !! ASSIMP_BUILD_NO_MDL_IMPORTER