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/** @file Implementation of the LWO importer class for the older LWOB
    file formats, including materials */


#ifndef ASSIMP_BUILD_NO_LWO_IMPORTER

// Internal headers
#include "LWOLoader.h"
using namespace Assimp;

// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWOBFile() {
    LE_NCONST uint8_t* const end = mFileBuffer + fileSize;
    bool running = true;
    while (running) {
        if (mFileBuffer + sizeof(IFF::ChunkHeader) > end)
            break;
        const IFF::ChunkHeader head = IFF::LoadChunk(mFileBuffer);

        if (mFileBuffer + head.length > end) {
            throw DeadlyImportError("LWOB: Invalid chunk length");
        }
        uint8_t* const next = mFileBuffer+head.length;
        switch (head.type) {
            // vertex list
            case AI_LWO_PNTS: {
                if (!mCurLayer->mTempPoints.empty())
                    ASSIMP_LOG_WARN("LWO: PNTS chunk encountered twice");
                else
                    LoadLWOPoints(head.length);
                } break;
            case AI_LWO_POLS: {                 // face list
                    if (!mCurLayer->mFaces.empty())
                        ASSIMP_LOG_WARN("LWO: POLS chunk encountered twice");
                    else
                        LoadLWOBPolygons(head.length);
                } break;
                
            case AI_LWO_SRFS: // list of tags
                {
                    if (!mTags->empty())
                        ASSIMP_LOG_WARN("LWO: SRFS chunk encountered twice");
                    else
                        LoadLWOTags(head.length);
                } break;

            case AI_LWO_SURF: // surface chunk
                {
                    LoadLWOBSurface(head.length);
                } break;

            default:
                break;
        }
        mFileBuffer = next;
    }
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWOBPolygons(unsigned int length) {
    // first find out how many faces and vertices we'll finally need
    LE_NCONST uint16_t* const end   = (LE_NCONST uint16_t*)(mFileBuffer+length);
    LE_NCONST uint16_t* cursor      = (LE_NCONST uint16_t*)mFileBuffer;

    // perform endianness conversions
#ifndef AI_BUILD_BIG_ENDIAN
    while (cursor < end)ByteSwap::Swap2(cursor++);
    cursor = (LE_NCONST uint16_t*)mFileBuffer;
#endif

    unsigned int iNumFaces = 0,iNumVertices = 0;
    CountVertsAndFacesLWOB(iNumVertices,iNumFaces,cursor,end);

    // allocate the output array and copy face indices
    if (iNumFaces) {
        cursor = (LE_NCONST uint16_t*)mFileBuffer;

        mCurLayer->mFaces.resize(iNumFaces);
        FaceList::iterator it = mCurLayer->mFaces.begin();
        CopyFaceIndicesLWOB(it,cursor,end);
    }
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::CountVertsAndFacesLWOB(unsigned int& verts, unsigned int& faces,
    LE_NCONST uint16_t*& cursor, const uint16_t* const end, unsigned int max) {
    while (cursor < end && max--) {
        uint16_t numIndices;
        // must have 2 shorts left for numIndices and surface
        if (end - cursor < 2) {
            throw DeadlyImportError("LWOB: Unexpected end of file");
        }
        ::memcpy(&numIndices, cursor++, 2);
        // must have enough left for indices and surface
        if (end - cursor < (1 + numIndices)) {
            throw DeadlyImportError("LWOB: Unexpected end of file");
        }
        verts += numIndices;
        faces++;
        cursor += numIndices;
        int16_t surface;
        ::memcpy(&surface, cursor++, 2);
        if (surface < 0) {
            // there are detail polygons
            ::memcpy(&numIndices, cursor++, 2);
            CountVertsAndFacesLWOB(verts,faces,cursor,end,numIndices);
        }
    }
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::CopyFaceIndicesLWOB(FaceList::iterator &it,
    LE_NCONST uint16_t*& cursor,
    const uint16_t* const end,
    unsigned int max) {
    while (cursor < end && max--) {
        LWO::Face& face = *it;++it;
        uint16_t numIndices;
        ::memcpy(&numIndices, cursor++, 2);
        face.mNumIndices = numIndices;
        if(face.mNumIndices) {
            if (cursor + face.mNumIndices >= end) {
                break;
            }
            face.mIndices = new unsigned int[face.mNumIndices];
            for (unsigned int i = 0; i < face.mNumIndices;++i) {
                unsigned int & mi = face.mIndices[i];
                uint16_t index;
                ::memcpy(&index, cursor++, 2);
                mi = index;
                if (mi > mCurLayer->mTempPoints.size()) {
                    ASSIMP_LOG_WARN("LWOB: face index is out of range");
                    mi = (unsigned int)mCurLayer->mTempPoints.size()-1;
                }
            }
        } else {
            ASSIMP_LOG_WARN("LWOB: Face has 0 indices");
        }
        int16_t surface;
        ::memcpy(&surface, cursor++, 2);
        if (surface < 0) {
            surface = -surface;

            // there are detail polygons.
            uint16_t numPolygons;
            ::memcpy(&numPolygons, cursor++, 2);
            if (cursor < end) {
                CopyFaceIndicesLWOB(it,cursor,end,numPolygons);
            }
        }
        face.surfaceIndex = surface-1;
    }
}

// ------------------------------------------------------------------------------------------------
LWO::Texture* LWOImporter::SetupNewTextureLWOB(LWO::TextureList& list,unsigned int size) {
    list.emplace_back();
    LWO::Texture* tex = &list.back();

    std::string type;
    GetS0(type,size);
    const char* s = type.c_str();

    if(strstr(s, "Image Map")) {
        // Determine mapping type
        if(strstr(s, "Planar"))
            tex->mapMode = LWO::Texture::Planar;
        else if(strstr(s, "Cylindrical"))
            tex->mapMode = LWO::Texture::Cylindrical;
        else if(strstr(s, "Spherical"))
            tex->mapMode = LWO::Texture::Spherical;
        else if(strstr(s, "Cubic"))
            tex->mapMode = LWO::Texture::Cubic;
        else if(strstr(s, "Front"))
            tex->mapMode = LWO::Texture::FrontProjection;
    } else {
        // procedural or gradient, not supported
        ASSIMP_LOG_ERROR("LWOB: Unsupported legacy texture: ", type);
    }

    return tex;
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWOBSurface(unsigned int size) {
    LE_NCONST uint8_t* const end = mFileBuffer + size;

    mSurfaces->push_back( LWO::Surface () );
    LWO::Surface& surf = mSurfaces->back();
    LWO::Texture *pTex = nullptr;

    GetS0(surf.mName,size);
    bool running = true;
    while (running)    {
        if (mFileBuffer + 6 >= end)
            break;

        IFF::SubChunkHeader head = IFF::LoadSubChunk(mFileBuffer);

        /*  A single test file (sonycam.lwo) seems to have invalid surface chunks.
         *  I'm assuming it's the fault of a single, unknown exporter so there are
         *  probably THOUSANDS of them. Here's a dirty workaround:
         *
         *  We don't break if the chunk limit is exceeded. Instead, we're computing
         *  how much storage is actually left and work with this value from now on.
         */
        if (mFileBuffer + head.length > end) {
            ASSIMP_LOG_ERROR("LWOB: Invalid surface chunk length. Trying to continue.");
            head.length = (uint16_t) (end - mFileBuffer);
        }

        uint8_t* const next = mFileBuffer+head.length;
        switch (head.type) {
            // diffuse color
            case AI_LWO_COLR:
                {
                    AI_LWO_VALIDATE_CHUNK_LENGTH(head.length,COLR,3);
                    surf.mColor.r = GetU1() / 255.0f;
                    surf.mColor.g = GetU1() / 255.0f;
                    surf.mColor.b = GetU1() / 255.0f;
                    break;
                }
            // diffuse strength ...
            case AI_LWO_DIFF:
                {
                    AI_LWO_VALIDATE_CHUNK_LENGTH(head.length,DIFF,2);
                    surf.mDiffuseValue = GetU2() / 255.0f;
                    break;
                }
            // specular strength ...
            case AI_LWO_SPEC:
                {
                    AI_LWO_VALIDATE_CHUNK_LENGTH(head.length,SPEC,2);
                    surf.mSpecularValue = GetU2() / 255.0f;
                    break;
                }
            // luminosity ...
            case AI_LWO_LUMI:
                {
                    AI_LWO_VALIDATE_CHUNK_LENGTH(head.length,LUMI,2);
                    surf.mLuminosity = GetU2() / 255.0f;
                    break;
                }
            // transparency
            case AI_LWO_TRAN:
                {
                    AI_LWO_VALIDATE_CHUNK_LENGTH(head.length,TRAN,2);
                    surf.mTransparency = GetU2() / 255.0f;
                    break;
                }
            // surface flags
            case AI_LWO_FLAG:
                {
                    AI_LWO_VALIDATE_CHUNK_LENGTH(head.length,FLAG,2);
                    uint16_t flag = GetU2();
                    if (flag & 0x4 )   surf.mMaximumSmoothAngle = 1.56207f;
                    if (flag & 0x8 )   surf.mColorHighlights = 1.f;
                    if (flag & 0x100)  surf.bDoubleSided = true;
                    break;
                }
            // maximum smoothing angle
            case AI_LWO_SMAN:
                {
                    AI_LWO_VALIDATE_CHUNK_LENGTH(head.length,SMAN,4);
                    surf.mMaximumSmoothAngle = std::fabs( GetF4() );
                    break;
                }
            // glossiness
            case AI_LWO_GLOS:
                {
                    AI_LWO_VALIDATE_CHUNK_LENGTH(head.length,GLOS,2);
                    surf.mGlossiness = (float)GetU2();
                    break;
                }
            // color texture
            case AI_LWO_CTEX:
                {
                    pTex = SetupNewTextureLWOB(surf.mColorTextures,
                        head.length);
                    break;
                }
            // diffuse texture
            case AI_LWO_DTEX:
                {
                    pTex = SetupNewTextureLWOB(surf.mDiffuseTextures,
                        head.length);
                    break;
                }
            // specular texture
            case AI_LWO_STEX:
                {
                    pTex = SetupNewTextureLWOB(surf.mSpecularTextures,
                        head.length);
                    break;
                }
            // bump texture
            case AI_LWO_BTEX:
                {
                    pTex = SetupNewTextureLWOB(surf.mBumpTextures,
                        head.length);
                    break;
                }
            // transparency texture
            case AI_LWO_TTEX:
                {
                    pTex = SetupNewTextureLWOB(surf.mOpacityTextures,
                        head.length);
                    break;
                }
            // texture path
            case AI_LWO_TIMG:
                {
                    if (pTex)   {
                        GetS0(pTex->mFileName,head.length);
                    } else {
                        ASSIMP_LOG_WARN("LWOB: Unexpected TIMG chunk");
                    }
                    break;
                }
            // texture strength
            case AI_LWO_TVAL:
                {
                    AI_LWO_VALIDATE_CHUNK_LENGTH(head.length,TVAL,1);
                    if (pTex)   {
                        pTex->mStrength = (float)GetU1()/ 255.f;
                    } else {
                        ASSIMP_LOG_ERROR("LWOB: Unexpected TVAL chunk");
                    }
                    break;
                }
            // texture flags
            case AI_LWO_TFLG:
                {
                    AI_LWO_VALIDATE_CHUNK_LENGTH(head.length,TFLG,2);

                    if (nullptr != pTex) {
                        const uint16_t s = GetU2();
                        if (s & 1)
                            pTex->majorAxis = LWO::Texture::AXIS_X;
                        else if (s & 2)
                            pTex->majorAxis = LWO::Texture::AXIS_Y;
                        else if (s & 4)
                            pTex->majorAxis = LWO::Texture::AXIS_Z;

                        if (s & 16) {
                            ASSIMP_LOG_WARN("LWOB: Ignoring \'negate\' flag on texture");
                        }
                    }
                    else {
                        ASSIMP_LOG_WARN("LWOB: Unexpected TFLG chunk");
                    }
                    break;
                }
        }
        mFileBuffer = next;
    }
}

#endif // !! ASSIMP_BUILD_NO_LWO_IMPORTER
