BlenderLoader.cpp

/*
Open Asset Import Library (assimp)
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/** @file  BlenderLoader.cpp
 *  @brief Implementation of the Blender3D importer class.
 */


//#define ASSIMP_BUILD_NO_COMPRESSED_BLEND
// Uncomment this to disable support for (gzip)compressed .BLEND files

#ifndef ASSIMP_BUILD_NO_BLEND_IMPORTER

#include "BlenderIntermediate.h"
#include "BlenderModifier.h"
#include "BlenderBMesh.h"
#include "StringUtils.h"
#include "../include/assimp/scene.h"
#include "StringComparison.h"

#include "StreamReader.h"
#include "MemoryIOWrapper.h"
#include <cctype>


// zlib is needed for compressed blend files
#ifndef ASSIMP_BUILD_NO_COMPRESSED_BLEND
#   ifdef ASSIMP_BUILD_NO_OWN_ZLIB
#       include <zlib.h>
#   else
#       include "../contrib/zlib/zlib.h"
#   endif
#endif

namespace Assimp {
    template<> const std::string LogFunctions<BlenderImporter>::log_prefix = "BLEND: ";
}

using namespace Assimp;
using namespace Assimp::Blender;
using namespace Assimp::Formatter;

static const aiImporterDesc blenderDesc = {
    "Blender 3D Importer \nhttp://www.blender3d.org",
    "",
    "",
    "No animation support yet",
    aiImporterFlags_SupportBinaryFlavour,
    0,
    0,
    2,
    50,
    "blend"
};


// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
BlenderImporter::BlenderImporter()
: modifier_cache(new BlenderModifierShowcase())
{}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well
BlenderImporter::~BlenderImporter()
{
    delete modifier_cache;
}

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

    else if ((!extension.length() || checkSig) && pIOHandler)   {
        // note: this won't catch compressed files
        const char* tokens[] = {"BLENDER"};
        return SearchFileHeaderForToken(pIOHandler,pFile,tokens,1);
    }
    return false;
}

// ------------------------------------------------------------------------------------------------
// List all extensions handled by this loader
void BlenderImporter::GetExtensionList(std::set<std::string>& app)
{
    app.insert("blend");
}

// ------------------------------------------------------------------------------------------------
// Loader registry entry
const aiImporterDesc* BlenderImporter::GetInfo () const
{
    return &blenderDesc;
}

// ------------------------------------------------------------------------------------------------
// Setup configuration properties for the loader
void BlenderImporter::SetupProperties(const Importer* /*pImp*/)
{
    // nothing to be done for the moment
}

struct free_it
{
    free_it(void* free) : free(free) {}
    ~free_it() {
        ::free(this->free);
    }

    void* free;
};

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure.
void BlenderImporter::InternReadFile( const std::string& pFile,
    aiScene* pScene, IOSystem* pIOHandler)
{
#ifndef ASSIMP_BUILD_NO_COMPRESSED_BLEND
    Bytef* dest = NULL;
    free_it free_it_really(dest);
#endif

    FileDatabase file;
    boost::shared_ptr<IOStream> stream(pIOHandler->Open(pFile,"rb"));
    if (!stream) {
        ThrowException("Could not open file for reading");
    }

    char magic[8] = {0};
    stream->Read(magic,7,1);
    if (strcmp(magic,"BLENDER")) {
        // Check for presence of the gzip header. If yes, assume it is a
        // compressed blend file and try uncompressing it, else fail. This is to
        // avoid uncompressing random files which our loader might end up with.
#ifdef ASSIMP_BUILD_NO_COMPRESSED_BLEND
        ThrowException("BLENDER magic bytes are missing, is this file compressed (Assimp was built without decompression support)?");
#else

        if (magic[0] != 0x1f || static_cast<uint8_t>(magic[1]) != 0x8b) {
            ThrowException("BLENDER magic bytes are missing, couldn't find GZIP header either");
        }

        LogDebug("Found no BLENDER magic word but a GZIP header, might be a compressed file");
        if (magic[2] != 8) {
            ThrowException("Unsupported GZIP compression method");
        }

        // http://www.gzip.org/zlib/rfc-gzip.html#header-trailer
        stream->Seek(0L,aiOrigin_SET);
        boost::shared_ptr<StreamReaderLE> reader = boost::shared_ptr<StreamReaderLE>(new StreamReaderLE(stream));

        // build a zlib stream
        z_stream zstream;
        zstream.opaque = Z_NULL;
        zstream.zalloc = Z_NULL;
        zstream.zfree  = Z_NULL;
        zstream.data_type = Z_BINARY;

        // http://hewgill.com/journal/entries/349-how-to-decompress-gzip-stream-with-zlib
        inflateInit2(&zstream, 16+MAX_WBITS);

        zstream.next_in   = reinterpret_cast<Bytef*>( reader->GetPtr() );
        zstream.avail_in  = reader->GetRemainingSize();

        size_t total = 0l;

        // and decompress the data .... do 1k chunks in the hope that we won't kill the stack
#define MYBLOCK 1024
        Bytef block[MYBLOCK];
        int ret;
        do {
            zstream.avail_out = MYBLOCK;
            zstream.next_out = block;
            ret = inflate(&zstream, Z_NO_FLUSH);

            if (ret != Z_STREAM_END && ret != Z_OK) {
                ThrowException("Failure decompressing this file using gzip, seemingly it is NOT a compressed .BLEND file");
            }
            const size_t have = MYBLOCK - zstream.avail_out;
            total += have;
            dest = reinterpret_cast<Bytef*>( realloc(dest,total) );
            memcpy(dest + total - have,block,have);
        }
        while (ret != Z_STREAM_END);

        // terminate zlib
        inflateEnd(&zstream);

        // replace the input stream with a memory stream
        stream.reset(new MemoryIOStream(reinterpret_cast<uint8_t*>(dest),total));

        // .. and retry
        stream->Read(magic,7,1);
        if (strcmp(magic,"BLENDER")) {
            ThrowException("Found no BLENDER magic word in decompressed GZIP file");
        }
#endif
    }

    file.i64bit = (stream->Read(magic,1,1),magic[0]=='-');
    file.little = (stream->Read(magic,1,1),magic[0]=='v');

    stream->Read(magic,3,1);
    magic[3] = '\0';

    LogInfo((format(),"Blender version is ",magic[0],".",magic+1,
        " (64bit: ",file.i64bit?"true":"false",
        ", little endian: ",file.little?"true":"false",")"
    ));

    ParseBlendFile(file,stream);

    Scene scene;
    ExtractScene(scene,file);

    ConvertBlendFile(pScene,scene,file);
}

// ------------------------------------------------------------------------------------------------
void BlenderImporter::ParseBlendFile(FileDatabase& out, boost::shared_ptr<IOStream> stream)
{
    out.reader = boost::shared_ptr<StreamReaderAny>(new StreamReaderAny(stream,out.little));

    DNAParser dna_reader(out);
    const DNA* dna = NULL;

    out.entries.reserve(128); { // even small BLEND files tend to consist of many file blocks
        SectionParser parser(*out.reader.get(),out.i64bit);

        // first parse the file in search for the DNA and insert all other sections into the database
        while ((parser.Next(),1)) {
            const FileBlockHead& head = parser.GetCurrent();

            if (head.id == "ENDB") {
                break; // only valid end of the file
            }
            else if (head.id == "DNA1") {
                dna_reader.Parse();
                dna = &dna_reader.GetDNA();
                continue;
            }

            out.entries.push_back(head);
        }
    }
    if (!dna) {
        ThrowException("SDNA not found");
    }

    std::sort(out.entries.begin(),out.entries.end());
}

// ------------------------------------------------------------------------------------------------
void BlenderImporter::ExtractScene(Scene& out, const FileDatabase& file)
{
    const FileBlockHead* block = NULL;
    std::map<std::string,size_t>::const_iterator it = file.dna.indices.find("Scene");
    if (it == file.dna.indices.end()) {
        ThrowException("There is no `Scene` structure record");
    }

    const Structure& ss = file.dna.structures[(*it).second];

    // we need a scene somewhere to start with.
    for_each(const FileBlockHead& bl,file.entries) {

        // Fix: using the DNA index is more reliable to locate scenes
        //if (bl.id == "SC") {

        if (bl.dna_index == (*it).second) {
            block = &bl;
            break;
        }
    }

    if (!block) {
        ThrowException("There is not a single `Scene` record to load");
    }

    file.reader->SetCurrentPos(block->start);
    ss.Convert(out,file);

#ifndef ASSIMP_BUILD_BLENDER_NO_STATS
    DefaultLogger::get()->info((format(),
        "(Stats) Fields read: " ,file.stats().fields_read,
        ", pointers resolved: " ,file.stats().pointers_resolved,
        ", cache hits: "        ,file.stats().cache_hits,
        ", cached objects: "    ,file.stats().cached_objects
    ));
#endif
}

// ------------------------------------------------------------------------------------------------
void BlenderImporter::ConvertBlendFile(aiScene* out, const Scene& in,const FileDatabase& file)
{
    ConversionData conv(file);

    // FIXME it must be possible to take the hierarchy directly from
    // the file. This is terrible. Here, we're first looking for
    // all objects which don't have parent objects at all -
    std::deque<const Object*> no_parents;
    for (boost::shared_ptr<Base> cur = boost::static_pointer_cast<Base> ( in.base.first ); cur; cur = cur->next) {
        if (cur->object) {
            if(!cur->object->parent) {
                no_parents.push_back(cur->object.get());
            }
            else conv.objects.insert(cur->object.get());
        }
    }
    for (boost::shared_ptr<Base> cur = in.basact; cur; cur = cur->next) {
        if (cur->object) {
            if(cur->object->parent) {
                conv.objects.insert(cur->object.get());
            }
        }
    }

    if (no_parents.empty()) {
        ThrowException("Expected at least one object with no parent");
    }

    aiNode* root = out->mRootNode = new aiNode("<BlenderRoot>");

    root->mNumChildren = static_cast<unsigned int>(no_parents.size());
    root->mChildren = new aiNode*[root->mNumChildren]();
    for (unsigned int i = 0; i < root->mNumChildren; ++i) {
        root->mChildren[i] = ConvertNode(in, no_parents[i], conv, aiMatrix4x4());
        root->mChildren[i]->mParent = root;
    }

    BuildMaterials(conv);

    if (conv.meshes->size()) {
        out->mMeshes = new aiMesh*[out->mNumMeshes = static_cast<unsigned int>( conv.meshes->size() )];
        std::copy(conv.meshes->begin(),conv.meshes->end(),out->mMeshes);
        conv.meshes.dismiss();
    }

    if (conv.lights->size()) {
        out->mLights = new aiLight*[out->mNumLights = static_cast<unsigned int>( conv.lights->size() )];
        std::copy(conv.lights->begin(),conv.lights->end(),out->mLights);
        conv.lights.dismiss();
    }

    if (conv.cameras->size()) {
        out->mCameras = new aiCamera*[out->mNumCameras = static_cast<unsigned int>( conv.cameras->size() )];
        std::copy(conv.cameras->begin(),conv.cameras->end(),out->mCameras);
        conv.cameras.dismiss();
    }

    if (conv.materials->size()) {
        out->mMaterials = new aiMaterial*[out->mNumMaterials = static_cast<unsigned int>( conv.materials->size() )];
        std::copy(conv.materials->begin(),conv.materials->end(),out->mMaterials);
        conv.materials.dismiss();
    }

    if (conv.textures->size()) {
        out->mTextures = new aiTexture*[out->mNumTextures = static_cast<unsigned int>( conv.textures->size() )];
        std::copy(conv.textures->begin(),conv.textures->end(),out->mTextures);
        conv.textures.dismiss();
    }

    // acknowledge that the scene might come out incomplete
    // by Assimps definition of `complete`: blender scenes
    // can consist of thousands of cameras or lights with
    // not a single mesh between them.
    if (!out->mNumMeshes) {
        out->mFlags |= AI_SCENE_FLAGS_INCOMPLETE;
    }
}

// ------------------------------------------------------------------------------------------------
void BlenderImporter::ResolveImage(aiMaterial* out, const Material* mat, const MTex* tex, const Image* img, ConversionData& conv_data)
{
    (void)mat; (void)tex; (void)conv_data;
    aiString name;

    // check if the file contents are bundled with the BLEND file
    if (img->packedfile) {
        name.data[0] = '*';
        name.length = 1+ ASSIMP_itoa10(name.data+1,MAXLEN-1,conv_data.textures->size());

        conv_data.textures->push_back(new aiTexture());
        aiTexture* tex = conv_data.textures->back();

        // usually 'img->name' will be the original file name of the embedded textures,
        // so we can extract the file extension from it.
        const size_t nlen = strlen( img->name );
        const char* s = img->name+nlen, *e = s;

        while (s >= img->name && *s != '.')--s;

        tex->achFormatHint[0] = s+1>e ? '\0' : ::tolower( s[1] );
        tex->achFormatHint[1] = s+2>e ? '\0' : ::tolower( s[2] );
        tex->achFormatHint[2] = s+3>e ? '\0' : ::tolower( s[3] );
        tex->achFormatHint[3] = '\0';

        // tex->mHeight = 0;
        tex->mWidth = img->packedfile->size;
        uint8_t* ch = new uint8_t[tex->mWidth];

        conv_data.db.reader->SetCurrentPos(static_cast<size_t>( img->packedfile->data->val));
        conv_data.db.reader->CopyAndAdvance(ch,tex->mWidth);

        tex->pcData = reinterpret_cast<aiTexel*>(ch);

        LogInfo("Reading embedded texture, original file was "+std::string(img->name));
    }
    else {
        name = aiString( img->name );
    }

    aiTextureType texture_type = aiTextureType_UNKNOWN;
    MTex::MapType map_type = tex->mapto;

    if (map_type & MTex::MapType_COL)
        texture_type = aiTextureType_DIFFUSE;
    else if (map_type & MTex::MapType_NORM) {
        if (tex->tex->imaflag & Tex::ImageFlags_NORMALMAP) {
            texture_type = aiTextureType_NORMALS;
        }
        else {
            texture_type = aiTextureType_HEIGHT;
        }
        out->AddProperty(&tex->norfac,1,AI_MATKEY_BUMPSCALING);
    }
    else if (map_type & MTex::MapType_COLSPEC)
        texture_type = aiTextureType_SPECULAR;
    else if (map_type & MTex::MapType_COLMIR)
        texture_type = aiTextureType_REFLECTION;
    //else if (map_type & MTex::MapType_REF)
    else if (map_type & MTex::MapType_SPEC)
        texture_type = aiTextureType_SHININESS;
    else if (map_type & MTex::MapType_EMIT)
        texture_type = aiTextureType_EMISSIVE;
    //else if (map_type & MTex::MapType_ALPHA)
    //else if (map_type & MTex::MapType_HAR)
    //else if (map_type & MTex::MapType_RAYMIRR)
    //else if (map_type & MTex::MapType_TRANSLU)
    else if (map_type & MTex::MapType_AMB)
        texture_type = aiTextureType_AMBIENT;
    else if (map_type & MTex::MapType_DISPLACE)
        texture_type = aiTextureType_DISPLACEMENT;
    //else if (map_type & MTex::MapType_WARP)

    out->AddProperty(&name,AI_MATKEY_TEXTURE(texture_type,
        conv_data.next_texture[texture_type]++));

}

// ------------------------------------------------------------------------------------------------
void BlenderImporter::AddSentinelTexture(aiMaterial* out, const Material* mat, const MTex* tex, ConversionData& conv_data)
{
    (void)mat; (void)tex; (void)conv_data;

    aiString name;
    name.length = ai_snprintf(name.data, MAXLEN, "Procedural,num=%i,type=%s",conv_data.sentinel_cnt++,
        GetTextureTypeDisplayString(tex->tex->type)
    );
    out->AddProperty(&name,AI_MATKEY_TEXTURE_DIFFUSE(
        conv_data.next_texture[aiTextureType_DIFFUSE]++)
    );
}

// ------------------------------------------------------------------------------------------------
void BlenderImporter::ResolveTexture(aiMaterial* out, const Material* mat, const MTex* tex, ConversionData& conv_data)
{
    const Tex* rtex = tex->tex.get();
    if(!rtex || !rtex->type) {
        return;
    }

    // We can't support most of the texture types because they're mostly procedural.
    // These are substituted by a dummy texture.
    const char* dispnam = "";
    switch( rtex->type )
    {
            // these are listed in blender's UI
        case Tex::Type_CLOUDS       :
        case Tex::Type_WOOD         :
        case Tex::Type_MARBLE       :
        case Tex::Type_MAGIC        :
        case Tex::Type_BLEND        :
        case Tex::Type_STUCCI       :
        case Tex::Type_NOISE        :
        case Tex::Type_PLUGIN       :
        case Tex::Type_MUSGRAVE     :
        case Tex::Type_VORONOI      :
        case Tex::Type_DISTNOISE    :
        case Tex::Type_ENVMAP       :

            // these do no appear in the UI, why?
        case Tex::Type_POINTDENSITY :
        case Tex::Type_VOXELDATA    :

            LogWarn(std::string("Encountered a texture with an unsupported type: ")+dispnam);
            AddSentinelTexture(out, mat, tex, conv_data);
            break;

        case Tex::Type_IMAGE        :
            if (!rtex->ima) {
                LogError("A texture claims to be an Image, but no image reference is given");
                break;
            }
            ResolveImage(out, mat, tex, rtex->ima.get(),conv_data);
            break;

        default:
            ai_assert(false);
    };
}

// ------------------------------------------------------------------------------------------------
void BlenderImporter::BuildMaterials(ConversionData& conv_data)
{
    conv_data.materials->reserve(conv_data.materials_raw.size());

    // add a default material if necessary
    unsigned int index = static_cast<unsigned int>( -1 );
    for_each( aiMesh* mesh, conv_data.meshes.get() ) {
        if (mesh->mMaterialIndex == static_cast<unsigned int>( -1 )) {

            if (index == static_cast<unsigned int>( -1 )) {
                // Setup a default material.
                boost::shared_ptr<Material> p(new Material());
                ai_assert(::strlen(AI_DEFAULT_MATERIAL_NAME) < sizeof(p->id.name)-2);
                strcpy( p->id.name+2, AI_DEFAULT_MATERIAL_NAME );

                // Note: MSVC11 does not zero-initialize Material here, although it should.
                // Thus all relevant fields should be explicitly initialized. We cannot add
                // a default constructor to Material since the DNA codegen does not support
                // parsing it.
                p->r = p->g = p->b = 0.6f;
                p->specr = p->specg = p->specb = 0.6f;
                p->ambr = p->ambg = p->ambb = 0.0f;
                p->mirr = p->mirg = p->mirb = 0.0f;
                p->emit = 0.f;
                p->alpha = 0.f;
                p->har = 0;

                index = static_cast<unsigned int>( conv_data.materials_raw.size() );
                conv_data.materials_raw.push_back(p);
                LogInfo("Adding default material");
            }
            mesh->mMaterialIndex = index;
        }
    }

    for_each(boost::shared_ptr<Material> mat, conv_data.materials_raw) {

        // reset per material global counters
        for (size_t i = 0; i < sizeof(conv_data.next_texture)/sizeof(conv_data.next_texture[0]);++i) {
            conv_data.next_texture[i] = 0 ;
        }

        aiMaterial* mout = new aiMaterial();
        conv_data.materials->push_back(mout);
        // For any new material field handled here, the default material above must be updated with an appropriate default value.

        // set material name
        aiString name = aiString(mat->id.name+2); // skip over the name prefix 'MA'
        mout->AddProperty(&name,AI_MATKEY_NAME);


        // basic material colors
        aiColor3D col(mat->r,mat->g,mat->b);
        if (mat->r || mat->g || mat->b ) {

            // Usually, zero diffuse color means no diffuse color at all in the equation.
            // So we omit this member to express this intent.
            mout->AddProperty(&col,1,AI_MATKEY_COLOR_DIFFUSE);

            if (mat->emit) {
                aiColor3D emit_col(mat->emit * mat->r, mat->emit * mat->g, mat->emit * mat->b) ;
                mout->AddProperty(&emit_col, 1, AI_MATKEY_COLOR_EMISSIVE) ;
            }
        }

        col = aiColor3D(mat->specr,mat->specg,mat->specb);
        mout->AddProperty(&col,1,AI_MATKEY_COLOR_SPECULAR);

        // is hardness/shininess set?
        if( mat->har ) {
            const float har = mat->har;
            mout->AddProperty(&har,1,AI_MATKEY_SHININESS);
        }

        col = aiColor3D(mat->ambr,mat->ambg,mat->ambb);
        mout->AddProperty(&col,1,AI_MATKEY_COLOR_AMBIENT);

        col = aiColor3D(mat->mirr,mat->mirg,mat->mirb);
        mout->AddProperty(&col,1,AI_MATKEY_COLOR_REFLECTIVE);

        for(size_t i = 0; i < sizeof(mat->mtex) / sizeof(mat->mtex[0]); ++i) {
            if (!mat->mtex[i]) {
                continue;
            }

            ResolveTexture(mout,mat.get(),mat->mtex[i].get(),conv_data);
        }
    }
}

// ------------------------------------------------------------------------------------------------
void BlenderImporter::CheckActualType(const ElemBase* dt, const char* check)
{
    ai_assert(dt);
    if (strcmp(dt->dna_type,check)) {
        ThrowException((format(),
            "Expected object at ",std::hex,dt," to be of type `",check,
            "`, but it claims to be a `",dt->dna_type,"`instead"
        ));
    }
}

// ------------------------------------------------------------------------------------------------
void BlenderImporter::NotSupportedObjectType(const Object* obj, const char* type)
{
    LogWarn((format(), "Object `",obj->id.name,"` - type is unsupported: `",type, "`, skipping" ));
}

// ------------------------------------------------------------------------------------------------
void BlenderImporter::ConvertMesh(const Scene& /*in*/, const Object* /*obj*/, const Mesh* mesh,
    ConversionData& conv_data, TempArray<std::vector,aiMesh>&  temp
    )
{
    // TODO: Resolve various problems with BMesh triangluation before re-enabling.
    //       See issues #400, #373, #318  #315 and #132.
#if defined(TODO_FIX_BMESH_CONVERSION)
    BlenderBMeshConverter BMeshConverter( mesh );
    if ( BMeshConverter.ContainsBMesh( ) )
    {
        mesh = BMeshConverter.TriangulateBMesh( );
    }
#endif

    typedef std::pair<const int,size_t> MyPair;
    if ((!mesh->totface && !mesh->totloop) || !mesh->totvert) {
        return;
    }

    // some sanity checks
    if (static_cast<size_t> ( mesh->totface ) > mesh->mface.size() ){
        ThrowException("Number of faces is larger than the corresponding array");
    }

    if (static_cast<size_t> ( mesh->totvert ) > mesh->mvert.size()) {
        ThrowException("Number of vertices is larger than the corresponding array");
    }

    if (static_cast<size_t> ( mesh->totloop ) > mesh->mloop.size()) {
        ThrowException("Number of vertices is larger than the corresponding array");
    }

    // collect per-submesh numbers
    std::map<int,size_t> per_mat;
    std::map<int,size_t> per_mat_verts;
    for (int i = 0; i < mesh->totface; ++i) {

        const MFace& mf = mesh->mface[i];
        per_mat[ mf.mat_nr ]++;
        per_mat_verts[ mf.mat_nr ] += mf.v4?4:3;
    }

    for (int i = 0; i < mesh->totpoly; ++i) {
        const MPoly& mp = mesh->mpoly[i];
        per_mat[ mp.mat_nr ]++;
        per_mat_verts[ mp.mat_nr ] += mp.totloop;
    }

    // ... and allocate the corresponding meshes
    const size_t old = temp->size();
    temp->reserve(temp->size() + per_mat.size());

    std::map<size_t,size_t> mat_num_to_mesh_idx;
    for_each(MyPair& it, per_mat) {

        mat_num_to_mesh_idx[it.first] = temp->size();
        temp->push_back(new aiMesh());

        aiMesh* out = temp->back();
        out->mVertices = new aiVector3D[per_mat_verts[it.first]];
        out->mNormals  = new aiVector3D[per_mat_verts[it.first]];

        //out->mNumFaces = 0
        //out->mNumVertices = 0
        out->mFaces = new aiFace[it.second]();

        // all submeshes created from this mesh are named equally. this allows
        // curious users to recover the original adjacency.
        out->mName = aiString(mesh->id.name+2);
            // skip over the name prefix 'ME'

        // resolve the material reference and add this material to the set of
        // output materials. The (temporary) material index is the index
        // of the material entry within the list of resolved materials.
        if (mesh->mat) {

            if (static_cast<size_t> ( it.first ) >= mesh->mat.size() ) {
                ThrowException("Material index is out of range");
            }

            boost::shared_ptr<Material> mat = mesh->mat[it.first];
            const std::deque< boost::shared_ptr<Material> >::iterator has = std::find(
                    conv_data.materials_raw.begin(),
                    conv_data.materials_raw.end(),mat
            );

            if (has != conv_data.materials_raw.end()) {
                out->mMaterialIndex = static_cast<unsigned int>( std::distance(conv_data.materials_raw.begin(),has));
            }
            else {
                out->mMaterialIndex = static_cast<unsigned int>( conv_data.materials_raw.size() );
                conv_data.materials_raw.push_back(mat);
            }
        }
        else out->mMaterialIndex = static_cast<unsigned int>( -1 );
    }

    for (int i = 0; i < mesh->totface; ++i) {

        const MFace& mf = mesh->mface[i];

        aiMesh* const out = temp[ mat_num_to_mesh_idx[ mf.mat_nr ] ];
        aiFace& f = out->mFaces[out->mNumFaces++];

        f.mIndices = new unsigned int[ f.mNumIndices = mf.v4?4:3 ];
        aiVector3D* vo = out->mVertices + out->mNumVertices;
        aiVector3D* vn = out->mNormals + out->mNumVertices;

        // XXX we can't fold this easily, because we are restricted
        // to the member names from the BLEND file (v1,v2,v3,v4)
        // which are assigned by the genblenddna.py script and
        // cannot be changed without breaking the entire
        // import process.

        if (mf.v1 >= mesh->totvert) {
            ThrowException("Vertex index v1 out of range");
        }
        const MVert* v = &mesh->mvert[mf.v1];
        vo->x = v->co[0];
        vo->y = v->co[1];
        vo->z = v->co[2];
        vn->x = v->no[0];
        vn->y = v->no[1];
        vn->z = v->no[2];
        f.mIndices[0] = out->mNumVertices++;
        ++vo;
        ++vn;

        //  if (f.mNumIndices >= 2) {
        if (mf.v2 >= mesh->totvert) {
            ThrowException("Vertex index v2 out of range");
        }
        v = &mesh->mvert[mf.v2];
        vo->x = v->co[0];
        vo->y = v->co[1];
        vo->z = v->co[2];
        vn->x = v->no[0];
        vn->y = v->no[1];
        vn->z = v->no[2];
        f.mIndices[1] = out->mNumVertices++;
        ++vo;
        ++vn;

        if (mf.v3 >= mesh->totvert) {
            ThrowException("Vertex index v3 out of range");
        }
        //  if (f.mNumIndices >= 3) {
        v = &mesh->mvert[mf.v3];
        vo->x = v->co[0];
        vo->y = v->co[1];
        vo->z = v->co[2];
        vn->x = v->no[0];
        vn->y = v->no[1];
        vn->z = v->no[2];
        f.mIndices[2] = out->mNumVertices++;
        ++vo;
        ++vn;

        if (mf.v4 >= mesh->totvert) {
            ThrowException("Vertex index v4 out of range");
        }
        //  if (f.mNumIndices >= 4) {
        if (mf.v4) {
            v = &mesh->mvert[mf.v4];
            vo->x = v->co[0];
            vo->y = v->co[1];
            vo->z = v->co[2];
            vn->x = v->no[0];
            vn->y = v->no[1];
            vn->z = v->no[2];
            f.mIndices[3] = out->mNumVertices++;
            ++vo;
            ++vn;

            out->mPrimitiveTypes |= aiPrimitiveType_POLYGON;
        }
        else out->mPrimitiveTypes |= aiPrimitiveType_TRIANGLE;

        //  }
        //  }
        //  }
    }

    for (int i = 0; i < mesh->totpoly; ++i) {

        const MPoly& mf = mesh->mpoly[i];

        aiMesh* const out = temp[ mat_num_to_mesh_idx[ mf.mat_nr ] ];
        aiFace& f = out->mFaces[out->mNumFaces++];

        f.mIndices = new unsigned int[ f.mNumIndices = mf.totloop ];
        aiVector3D* vo = out->mVertices + out->mNumVertices;
        aiVector3D* vn = out->mNormals + out->mNumVertices;

        // XXX we can't fold this easily, because we are restricted
        // to the member names from the BLEND file (v1,v2,v3,v4)
        // which are assigned by the genblenddna.py script and
        // cannot be changed without breaking the entire
        // import process.
        for (int j = 0;j < mf.totloop; ++j)
        {
            const MLoop& loop = mesh->mloop[mf.loopstart + j];

            if (loop.v >= mesh->totvert) {
                ThrowException("Vertex index out of range");
            }

            const MVert& v = mesh->mvert[loop.v];

            vo->x = v.co[0];
            vo->y = v.co[1];
            vo->z = v.co[2];
            vn->x = v.no[0];
            vn->y = v.no[1];
            vn->z = v.no[2];
            f.mIndices[j] = out->mNumVertices++;

            ++vo;
            ++vn;

        }
        if (mf.totloop == 3)
        {
            out->mPrimitiveTypes |= aiPrimitiveType_TRIANGLE;
        }
        else
        {
            out->mPrimitiveTypes |= aiPrimitiveType_POLYGON;
        }
    }

    // collect texture coordinates, they're stored in a separate per-face buffer
    if (mesh->mtface || mesh->mloopuv) {
        if (mesh->totface > static_cast<int> ( mesh->mtface.size())) {
            ThrowException("Number of UV faces is larger than the corresponding UV face array (#1)");
        }
        for (std::vector<aiMesh*>::iterator it = temp->begin()+old; it != temp->end(); ++it) {
            ai_assert((*it)->mNumVertices && (*it)->mNumFaces);

            (*it)->mTextureCoords[0] = new aiVector3D[(*it)->mNumVertices];
            (*it)->mNumFaces = (*it)->mNumVertices = 0;
        }

        for (int i = 0; i < mesh->totface; ++i) {
            const MTFace* v = &mesh->mtface[i];

            aiMesh* const out = temp[ mat_num_to_mesh_idx[ mesh->mface[i].mat_nr ] ];
            const aiFace& f = out->mFaces[out->mNumFaces++];

            aiVector3D* vo = &out->mTextureCoords[0][out->mNumVertices];
            for (unsigned int i = 0; i < f.mNumIndices; ++i,++vo,++out->mNumVertices) {
                vo->x = v->uv[i][0];
                vo->y = v->uv[i][1];
            }
        }

        for (int i = 0; i < mesh->totpoly; ++i) {
            const MPoly& v = mesh->mpoly[i];
            aiMesh* const out = temp[ mat_num_to_mesh_idx[ v.mat_nr ] ];
            const aiFace& f = out->mFaces[out->mNumFaces++];

            aiVector3D* vo = &out->mTextureCoords[0][out->mNumVertices];
            for (unsigned int j = 0; j < f.mNumIndices; ++j,++vo,++out->mNumVertices) {
                const MLoopUV& uv = mesh->mloopuv[v.loopstart + j];
                vo->x = uv.uv[0];
                vo->y = uv.uv[1];
            }

        }
    }

    // collect texture coordinates, old-style (marked as deprecated in current blender sources)
    if (mesh->tface) {
        if (mesh->totface > static_cast<int> ( mesh->tface.size())) {
            ThrowException("Number of faces is larger than the corresponding UV face array (#2)");
        }
        for (std::vector<aiMesh*>::iterator it = temp->begin()+old; it != temp->end(); ++it) {
            ai_assert((*it)->mNumVertices && (*it)->mNumFaces);

            (*it)->mTextureCoords[0] = new aiVector3D[(*it)->mNumVertices];
            (*it)->mNumFaces = (*it)->mNumVertices = 0;
        }

        for (int i = 0; i < mesh->totface; ++i) {
            const TFace* v = &mesh->tface[i];

            aiMesh* const out = temp[ mat_num_to_mesh_idx[ mesh->mface[i].mat_nr ] ];
            const aiFace& f = out->mFaces[out->mNumFaces++];

            aiVector3D* vo = &out->mTextureCoords[0][out->mNumVertices];
            for (unsigned int i = 0; i < f.mNumIndices; ++i,++vo,++out->mNumVertices) {
                vo->x = v->uv[i][0];
                vo->y = v->uv[i][1];
            }
        }
    }

    // collect vertex colors, stored separately as well
    if (mesh->mcol || mesh->mloopcol) {
        if (mesh->totface > static_cast<int> ( (mesh->mcol.size()/4)) ) {
            ThrowException("Number of faces is larger than the corresponding color face array");
        }
        for (std::vector<aiMesh*>::iterator it = temp->begin()+old; it != temp->end(); ++it) {
            ai_assert((*it)->mNumVertices && (*it)->mNumFaces);

            (*it)->mColors[0] = new aiColor4D[(*it)->mNumVertices];
            (*it)->mNumFaces = (*it)->mNumVertices = 0;
        }

        for (int i = 0; i < mesh->totface; ++i) {

            aiMesh* const out = temp[ mat_num_to_mesh_idx[ mesh->mface[i].mat_nr ] ];
            const aiFace& f = out->mFaces[out->mNumFaces++];

            aiColor4D* vo = &out->mColors[0][out->mNumVertices];
            for (unsigned int n = 0; n < f.mNumIndices; ++n, ++vo,++out->mNumVertices) {
                const MCol* col = &mesh->mcol[(i<<2)+n];

                vo->r = col->r;
                vo->g = col->g;
                vo->b = col->b;
                vo->a = col->a;
            }
            for (unsigned int n = f.mNumIndices; n < 4; ++n);
        }

        for (int i = 0; i < mesh->totpoly; ++i) {
            const MPoly& v = mesh->mpoly[i];
            aiMesh* const out = temp[ mat_num_to_mesh_idx[ v.mat_nr ] ];
            const aiFace& f = out->mFaces[out->mNumFaces++];

            aiColor4D* vo = &out->mColors[0][out->mNumVertices];
            for (unsigned int j = 0; j < f.mNumIndices; ++j,++vo,++out->mNumVertices) {
                const MLoopCol& col = mesh->mloopcol[v.loopstart + j];
                vo->r = col.r;
                vo->g = col.g;
                vo->b = col.b;
                vo->a = col.a;
            }

        }

    }

    return;
}

// ------------------------------------------------------------------------------------------------
aiCamera* BlenderImporter::ConvertCamera(const Scene& /*in*/, const Object* obj, const Camera* cam, ConversionData& /*conv_data*/)
{
    ScopeGuard<aiCamera> out(new aiCamera());
    out->mName = obj->id.name+2;
    out->mPosition = aiVector3D(0.f, 0.f, 0.f);
    out->mUp = aiVector3D(0.f, 1.f, 0.f);
    out->mLookAt = aiVector3D(0.f, 0.f, -1.f);
    if (cam->sensor_x && cam->lens) {
        out->mHorizontalFOV = atan2(cam->sensor_x,  2.f * cam->lens);
    }
    out->mClipPlaneNear = cam->clipsta;
    out->mClipPlaneFar = cam->clipend;

    return out.dismiss();
}

// ------------------------------------------------------------------------------------------------
aiLight* BlenderImporter::ConvertLight(const Scene& /*in*/, const Object* obj, const Lamp* lamp, ConversionData& /*conv_data*/)
{
    ScopeGuard<aiLight> out(new aiLight());
    out->mName = obj->id.name+2;

    switch (lamp->type)
    {
        case Lamp::Type_Local:
            out->mType = aiLightSource_POINT;
            break;
        case Lamp::Type_Sun:
            out->mType = aiLightSource_DIRECTIONAL;

            // blender orients directional lights as facing toward -z
            out->mDirection = aiVector3D(0.f, 0.f, -1.f);
            break;
        default:
            break;
    }

    out->mColorAmbient = aiColor3D(lamp->r, lamp->g, lamp->b) * lamp->energy;
    out->mColorSpecular = aiColor3D(lamp->r, lamp->g, lamp->b) * lamp->energy;
    out->mColorDiffuse = aiColor3D(lamp->r, lamp->g, lamp->b) * lamp->energy;
    return out.dismiss();
}

// ------------------------------------------------------------------------------------------------
aiNode* BlenderImporter::ConvertNode(const Scene& in, const Object* obj, ConversionData& conv_data, const aiMatrix4x4& parentTransform)
{
    std::deque<const Object*> children;
    for(ObjectSet::iterator it = conv_data.objects.begin(); it != conv_data.objects.end() ;) {
        const Object* object = *it;
        if (object->parent == obj) {
            children.push_back(object);

            conv_data.objects.erase(it++);
            continue;
        }
        ++it;
    }

    ScopeGuard<aiNode> node(new aiNode(obj->id.name+2)); // skip over the name prefix 'OB'
    if (obj->data) {
        switch (obj->type)
        {
        case Object :: Type_EMPTY:
            break; // do nothing


            // supported object types
        case Object :: Type_MESH: {
            const size_t old = conv_data.meshes->size();

            CheckActualType(obj->data.get(),"Mesh");
            ConvertMesh(in,obj,static_cast<const Mesh*>(obj->data.get()),conv_data,conv_data.meshes);

            if (conv_data.meshes->size() > old) {
                node->mMeshes = new unsigned int[node->mNumMeshes = static_cast<unsigned int>(conv_data.meshes->size()-old)];
                for (unsigned int i = 0; i < node->mNumMeshes; ++i) {
                    node->mMeshes[i] = i + old;
                }
            }}
            break;
        case Object :: Type_LAMP: {
            CheckActualType(obj->data.get(),"Lamp");
            aiLight* mesh = ConvertLight(in,obj,static_cast<const Lamp*>(
                obj->data.get()),conv_data);

            if (mesh) {
                conv_data.lights->push_back(mesh);
            }}
            break;
        case Object :: Type_CAMERA: {
            CheckActualType(obj->data.get(),"Camera");
            aiCamera* mesh = ConvertCamera(in,obj,static_cast<const Camera*>(
                obj->data.get()),conv_data);

            if (mesh) {
                conv_data.cameras->push_back(mesh);
            }}
            break;


            // unsupported object types / log, but do not break
        case Object :: Type_CURVE:
            NotSupportedObjectType(obj,"Curve");
            break;
        case Object :: Type_SURF:
            NotSupportedObjectType(obj,"Surface");
            break;
        case Object :: Type_FONT:
            NotSupportedObjectType(obj,"Font");
            break;
        case Object :: Type_MBALL:
            NotSupportedObjectType(obj,"MetaBall");
            break;
        case Object :: Type_WAVE:
            NotSupportedObjectType(obj,"Wave");
            break;
        case Object :: Type_LATTICE:
            NotSupportedObjectType(obj,"Lattice");
            break;

            // invalid or unknown type
        default:
            break;
        }
    }

    for(unsigned int x = 0; x < 4; ++x) {
        for(unsigned int y = 0; y < 4; ++y) {
            node->mTransformation[y][x] = obj->obmat[x][y];
        }
    }

    aiMatrix4x4 m = parentTransform;
    m = m.Inverse();

    node->mTransformation = m*node->mTransformation;

    if (children.size()) {
        node->mNumChildren = static_cast<unsigned int>(children.size());
        aiNode** nd = node->mChildren = new aiNode*[node->mNumChildren]();
        for_each (const Object* nobj,children) {
            *nd = ConvertNode(in,nobj,conv_data,node->mTransformation * parentTransform);
            (*nd++)->mParent = node;
        }
    }

    // apply modifiers
    modifier_cache->ApplyModifiers(*node,conv_data,in,*obj);

    return node.dismiss();
}


#endif