Urho3D/Source/ThirdParty/Assimp/code/XGLLoader.cpp

/*
---------------------------------------------------------------------------
Open Asset Import Library (assimp)
---------------------------------------------------------------------------

Copyright (c) 2006-2017, assimp team


All rights reserved.

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* Redistributions of source code must retain the above
  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the
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  derived from this software without specific prior
  written permission of the assimp team.

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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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*/

/** @file Implementation of the XGL/ZGL importer class */


#ifndef ASSIMP_BUILD_NO_XGL_IMPORTER

#include "XGLLoader.h"
#include "ParsingUtils.h"
#include "fast_atof.h"

#include "StreamReader.h"
#include "MemoryIOWrapper.h"
#include <assimp/mesh.h>
#include <assimp/scene.h>
#include <assimp/importerdesc.h>
#include <cctype>
#include <memory>

using namespace Assimp;
using namespace irr;
using namespace irr::io;

// zlib is needed for compressed XGL files
#ifndef ASSIMP_BUILD_NO_COMPRESSED_XGL
#   ifdef ASSIMP_BUILD_NO_OWN_ZLIB
#       include <zlib.h>
#   else
#       include <contrib/zlib/zlib.h>
#   endif
#endif


// scopeguard for a malloc'ed buffer
struct free_it
{
    free_it(void* free) : free(free) {}
    ~free_it() {
        ::free(this->free);
    }

    void* free;
};

namespace Assimp { // this has to be in here because LogFunctions is in ::Assimp
    template<> const char* LogFunctions<XGLImporter>::Prefix()
    {
        static auto prefix = "XGL: ";
        return prefix;
    }
}

static const aiImporterDesc desc = {
    "XGL Importer",
    "",
    "",
    "",
    aiImporterFlags_SupportTextFlavour | aiImporterFlags_SupportCompressedFlavour,
    0,
    0,
    0,
    0,
    "xgl zgl"
};


// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
XGLImporter::XGLImporter()
: m_reader( nullptr )
, m_scene( nullptr ) {
    // empty
}

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

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file.
bool XGLImporter::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool checkSig) const
{
    /* NOTE: A simple check for the file extension is not enough
     * here. XGL and ZGL are ok, but xml is too generic
     * and might be collada as well. So open the file and
     * look for typical signal tokens.
     */
    const std::string extension = GetExtension(pFile);

    if (extension == "xgl" || extension == "zgl") {
        return true;
    }
    else if (extension == "xml" || checkSig) {
        ai_assert(pIOHandler != NULL);

        const char* tokens[] = {"<world>","<World>","<WORLD>"};
        return SearchFileHeaderForToken(pIOHandler,pFile,tokens,3);
    }
    return false;
}

// ------------------------------------------------------------------------------------------------
// Get a list of all file extensions which are handled by this class
const aiImporterDesc* XGLImporter::GetInfo () const
{
    return &desc;
}

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

    m_scene = pScene;
    std::shared_ptr<IOStream> stream( pIOHandler->Open( pFile, "rb"));

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

    // see if its compressed, if so uncompress it
    if (GetExtension(pFile) == "zgl") {
#ifdef ASSIMP_BUILD_NO_COMPRESSED_XGL
        ThrowException("Cannot read ZGL file since Assimp was built without compression support");
#else
        std::unique_ptr<StreamReaderLE> raw_reader(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;

        // raw decompression without a zlib or gzip header
        inflateInit2(&zstream, -MAX_WBITS);

        // skip two extra bytes, zgl files do carry a crc16 upfront (I think)
        raw_reader->IncPtr(2);

        zstream.next_in   = reinterpret_cast<Bytef*>( raw_reader->GetPtr() );
        zstream.avail_in  = raw_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 .XGL 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));
#endif
    }

    // construct the irrXML parser
    CIrrXML_IOStreamReader st(stream.get());
    m_reader.reset( createIrrXMLReader( ( IFileReadCallBack* ) &st ) );

    // parse the XML file
    TempScope scope;

    while (ReadElement())   {
        if (!ASSIMP_stricmp(m_reader->getNodeName(),"world")) {
            ReadWorld(scope);
        }
    }


    std::vector<aiMesh*>& meshes = scope.meshes_linear;
    std::vector<aiMaterial*>& materials = scope.materials_linear;
    if(!meshes.size() || !materials.size()) {
        ThrowException("failed to extract data from XGL file, no meshes loaded");
    }

    // copy meshes
    m_scene->mNumMeshes = static_cast<unsigned int>(meshes.size());
    m_scene->mMeshes = new aiMesh*[m_scene->mNumMeshes]();
    std::copy(meshes.begin(),meshes.end(),m_scene->mMeshes);

    // copy materials
    m_scene->mNumMaterials = static_cast<unsigned int>(materials.size());
    m_scene->mMaterials = new aiMaterial*[m_scene->mNumMaterials]();
    std::copy(materials.begin(),materials.end(),m_scene->mMaterials);

    if (scope.light) {
        m_scene->mNumLights = 1;
        m_scene->mLights = new aiLight*[1];
        m_scene->mLights[0] = scope.light;

        scope.light->mName = m_scene->mRootNode->mName;
    }

    scope.dismiss();
}

// ------------------------------------------------------------------------------------------------
bool XGLImporter::ReadElement()
{
    while(m_reader->read()) {
        if (m_reader->getNodeType() == EXN_ELEMENT) {
            return true;
        }
    }
    return false;
}

// ------------------------------------------------------------------------------------------------
bool XGLImporter::ReadElementUpToClosing(const char* closetag)
{
    while(m_reader->read()) {
        if (m_reader->getNodeType() == EXN_ELEMENT) {
            return true;
        }
        else if (m_reader->getNodeType() == EXN_ELEMENT_END && !ASSIMP_stricmp(m_reader->getNodeName(),closetag)) {
            return false;
        }
    }
    LogError("unexpected EOF, expected closing <" + std::string(closetag) + "> tag");
    return false;
}

// ------------------------------------------------------------------------------------------------
bool XGLImporter::SkipToText()
{
    while(m_reader->read()) {
        if (m_reader->getNodeType() == EXN_TEXT) {
            return true;
        }
        else if (m_reader->getNodeType() == EXN_ELEMENT || m_reader->getNodeType() == EXN_ELEMENT_END) {
            ThrowException("expected text contents but found another element (or element end)");
        }
    }
    return false;
}

// ------------------------------------------------------------------------------------------------
std::string XGLImporter::GetElementName()
{
    const char* s  = m_reader->getNodeName();
    size_t len = strlen(s);

    std::string ret;
    ret.resize(len);

    std::transform(s,s+len,ret.begin(),::tolower);
    return ret;
}

// ------------------------------------------------------------------------------------------------
void XGLImporter::ReadWorld(TempScope& scope)
{
    while (ReadElementUpToClosing("world")) {
        const std::string& s = GetElementName();
        // XXX right now we'd skip <lighting> if it comes after
        // <object> or <mesh>
        if (s == "lighting") {
            ReadLighting(scope);
        }
        else if (s == "object" || s == "mesh" || s == "mat") {
            break;
        }
    }


    aiNode* const nd = ReadObject(scope,true,"world");
    if(!nd) {
        ThrowException("failure reading <world>");
    }
    if(!nd->mName.length) {
        nd->mName.Set("WORLD");
    }

    m_scene->mRootNode = nd;
}

// ------------------------------------------------------------------------------------------------
void XGLImporter::ReadLighting(TempScope& scope)
{
    while (ReadElementUpToClosing("lighting"))  {
        const std::string& s = GetElementName();
        if (s == "directionallight") {
            scope.light = ReadDirectionalLight();
        }
        else if (s == "ambient") {
            LogWarn("ignoring <ambient> tag");
        }
        else if (s == "spheremap") {
            LogWarn("ignoring <spheremap> tag");
        }
    }
}

// ------------------------------------------------------------------------------------------------
aiLight* XGLImporter::ReadDirectionalLight()
{
    std::unique_ptr<aiLight> l(new aiLight());
    l->mType = aiLightSource_DIRECTIONAL;

    while (ReadElementUpToClosing("directionallight"))  {
        const std::string& s = GetElementName();
        if (s == "direction") {
            l->mDirection = ReadVec3();
        }
        else if (s == "diffuse") {
            l->mColorDiffuse = ReadCol3();
        }
        else if (s == "specular") {
            l->mColorSpecular = ReadCol3();
        }
    }
    return l.release();
}

// ------------------------------------------------------------------------------------------------
aiNode* XGLImporter::ReadObject(TempScope& scope, bool skipFirst, const char* closetag)
{
    std::unique_ptr<aiNode> nd(new aiNode());
    std::vector<aiNode*> children;
    std::vector<unsigned int> meshes;

    try {
        while (skipFirst || ReadElementUpToClosing(closetag))   {
            skipFirst = false;

            const std::string& s = GetElementName();
            if (s == "mesh") {
                const size_t prev = scope.meshes_linear.size();
                if(ReadMesh(scope)) {
                    const size_t newc = scope.meshes_linear.size();
                    for(size_t i = 0; i < newc-prev; ++i) {
                        meshes.push_back(static_cast<unsigned int>(i+prev));
                    }
                }
            }
            else if (s == "mat") {
                ReadMaterial(scope);
            }
            else if (s == "object") {
                children.push_back(ReadObject(scope));
            }
            else if (s == "objectref") {
                // XXX
            }
            else if (s == "meshref") {
                const unsigned int id = static_cast<unsigned int>( ReadIndexFromText() );

                std::multimap<unsigned int, aiMesh*>::iterator it = scope.meshes.find(id), end = scope.meshes.end();
                if (it == end) {
                    ThrowException("<meshref> index out of range");
                }

                for(; it != end && (*it).first == id; ++it) {
                    // ok, this is n^2 and should get optimized one day
                    aiMesh* const m = (*it).second;

                    unsigned int i = 0, mcount = static_cast<unsigned int>(scope.meshes_linear.size());
                    for(; i < mcount; ++i) {
                        if (scope.meshes_linear[i] == m) {
                            meshes.push_back(i);
                            break;
                        }
                    }

                    ai_assert(i < mcount);
                }
            }
            else if (s == "transform") {
                nd->mTransformation = ReadTrafo();
            }
        }

    } catch(...) {
        for(aiNode* ch : children) {
            delete ch;
        }
        throw;
    }

    // FIX: since we used std::multimap<> to keep meshes by id, mesh order now depends on the behaviour
    // of the multimap implementation with respect to the ordering of entries with same values.
    // C++11 gives the guarantee that it uses insertion order, before it is implementation-specific.
    // Sort by material id to always guarantee a deterministic result.
    std::sort(meshes.begin(), meshes.end(), SortMeshByMaterialId(scope));

    // link meshes to node
    nd->mNumMeshes = static_cast<unsigned int>(meshes.size());
    if (nd->mNumMeshes) {
        nd->mMeshes = new unsigned int[nd->mNumMeshes]();
        for(unsigned int i = 0; i < nd->mNumMeshes; ++i) {
            nd->mMeshes[i] = meshes[i];
        }
    }

    // link children to parent
    nd->mNumChildren = static_cast<unsigned int>(children.size());
    if (nd->mNumChildren) {
        nd->mChildren = new aiNode*[nd->mNumChildren]();
        for(unsigned int i = 0; i < nd->mNumChildren; ++i) {
            nd->mChildren[i] = children[i];
            children[i]->mParent = nd.get();
        }
    }

    return nd.release();
}

// ------------------------------------------------------------------------------------------------
aiMatrix4x4 XGLImporter::ReadTrafo()
{
    aiVector3D forward, up, right, position;
    float scale = 1.0f;

    while (ReadElementUpToClosing("transform")) {
        const std::string& s = GetElementName();
        if (s == "forward") {
            forward = ReadVec3();
        }
        else if (s == "up") {
            up = ReadVec3();
        }
        else if (s == "position") {
            position = ReadVec3();
        }
        if (s == "scale") {
            scale = ReadFloat();
            if(scale < 0.f) {
                // this is wrong, but we can leave the value and pass it to the caller
                LogError("found negative scaling in <transform>, ignoring");
            }
        }
    }

    aiMatrix4x4 m;
    if(forward.SquareLength() < 1e-4 || up.SquareLength() < 1e-4) {
        LogError("A direction vector in <transform> is zero, ignoring trafo");
        return m;
    }

    forward.Normalize();
    up.Normalize();

    right = forward ^ up;
    if (std::fabs(up * forward) > 1e-4) {
        // this is definitely wrong - a degenerate coordinate space ruins everything
        // so subtitute identity transform.
        LogError("<forward> and <up> vectors in <transform> are skewing, ignoring trafo");
        return m;
    }

    right *= scale;
    up *= scale;
    forward *= scale;

    m.a1 = right.x;
    m.b1 = right.y;
    m.c1 = right.z;

    m.a2 = up.x;
    m.b2 = up.y;
    m.c2 = up.z;

    m.a3 = forward.x;
    m.b3 = forward.y;
    m.c3 = forward.z;

    m.a4 = position.x;
    m.b4 = position.y;
    m.c4 = position.z;

    return m;
}

// ------------------------------------------------------------------------------------------------
aiMesh* XGLImporter::ToOutputMesh(const TempMaterialMesh& m)
{
    std::unique_ptr<aiMesh> mesh(new aiMesh());

    mesh->mNumVertices = static_cast<unsigned int>(m.positions.size());
    mesh->mVertices = new aiVector3D[mesh->mNumVertices];
    std::copy(m.positions.begin(),m.positions.end(),mesh->mVertices);

    if(m.normals.size()) {
        mesh->mNormals = new aiVector3D[mesh->mNumVertices];
        std::copy(m.normals.begin(),m.normals.end(),mesh->mNormals);
    }

    if(m.uvs.size()) {
        mesh->mNumUVComponents[0] = 2;
        mesh->mTextureCoords[0] = new aiVector3D[mesh->mNumVertices];

        for(unsigned int i = 0; i < mesh->mNumVertices; ++i) {
            mesh->mTextureCoords[0][i] = aiVector3D(m.uvs[i].x,m.uvs[i].y,0.f);
        }
    }

    mesh->mNumFaces =  static_cast<unsigned int>(m.vcounts.size());
    mesh->mFaces = new aiFace[m.vcounts.size()];

    unsigned int idx = 0;
    for(unsigned int i = 0; i < mesh->mNumFaces; ++i) {
        aiFace& f = mesh->mFaces[i];
        f.mNumIndices = m.vcounts[i];
        f.mIndices = new unsigned int[f.mNumIndices];
        for(unsigned int c = 0; c < f.mNumIndices; ++c) {
            f.mIndices[c] = idx++;
        }
    }

    ai_assert(idx == mesh->mNumVertices);

    mesh->mPrimitiveTypes = m.pflags;
    mesh->mMaterialIndex = m.matid;
    return mesh.release();
}

// ------------------------------------------------------------------------------------------------
bool XGLImporter::ReadMesh(TempScope& scope)
{
    TempMesh t;

    std::map<unsigned int, TempMaterialMesh> bymat;
    const unsigned int mesh_id = ReadIDAttr();

    while (ReadElementUpToClosing("mesh"))  {
        const std::string& s = GetElementName();

        if (s == "mat") {
            ReadMaterial(scope);
        }
        else if (s == "p") {
            if (!m_reader->getAttributeValue("ID")) {
                LogWarn("no ID attribute on <p>, ignoring");
            }
            else {
                int id = m_reader->getAttributeValueAsInt("ID");
                t.points[id] = ReadVec3();
            }
        }
        else if (s == "n") {
            if (!m_reader->getAttributeValue("ID")) {
                LogWarn("no ID attribute on <n>, ignoring");
            }
            else {
                int id = m_reader->getAttributeValueAsInt("ID");
                t.normals[id] = ReadVec3();
            }
        }
        else if (s == "tc") {
            if (!m_reader->getAttributeValue("ID")) {
                LogWarn("no ID attribute on <tc>, ignoring");
            }
            else {
                int id = m_reader->getAttributeValueAsInt("ID");
                t.uvs[id] = ReadVec2();
            }
        }
        else if (s == "f" || s == "l" || s == "p") {
            const unsigned int vcount = s == "f" ? 3 : (s == "l" ? 2 : 1);

            unsigned int mid = ~0u;
            TempFace tf[3];
            bool has[3] = {0};

            while (ReadElementUpToClosing(s.c_str()))   {
                const std::string& s = GetElementName();
                if (s == "fv1" || s == "lv1" || s == "pv1") {
                    ReadFaceVertex(t,tf[0]);
                    has[0] = true;
                }
                else if (s == "fv2" || s == "lv2") {
                    ReadFaceVertex(t,tf[1]);
                    has[1] = true;
                }
                else if (s == "fv3") {
                    ReadFaceVertex(t,tf[2]);
                    has[2] = true;
                }
                else if (s == "mat") {
                    if (mid != ~0u) {
                        LogWarn("only one material tag allowed per <f>");
                    }
                    mid = ResolveMaterialRef(scope);
                }
                else if (s == "matref") {
                    if (mid != ~0u) {
                        LogWarn("only one material tag allowed per <f>");
                    }
                    mid = ResolveMaterialRef(scope);
                }
            }

            if (mid == ~0u) {
                ThrowException("missing material index");
            }

            bool nor = false;
            bool uv = false;
            for(unsigned int i = 0; i < vcount; ++i) {
                if (!has[i]) {
                    ThrowException("missing face vertex data");
                }

                nor = nor || tf[i].has_normal;
                uv = uv || tf[i].has_uv;
            }

            if (mid >= (1<<30)) {
                LogWarn("material indices exhausted, this may cause errors in the output");
            }
            unsigned int meshId = mid | ((nor?1:0)<<31) | ((uv?1:0)<<30);

            TempMaterialMesh& mesh = bymat[meshId];
            mesh.matid = mid;

            for(unsigned int i = 0; i < vcount; ++i) {
                mesh.positions.push_back(tf[i].pos);
                if(nor) {
                    mesh.normals.push_back(tf[i].normal);
                }
                if(uv) {
                    mesh.uvs.push_back(tf[i].uv);
                }

                mesh.pflags |= 1 << (vcount-1);
            }

            mesh.vcounts.push_back(vcount);
        }
    }

    // finally extract output meshes and add them to the scope
    typedef std::pair<unsigned int, TempMaterialMesh> pairt;
    for(const pairt& p : bymat) {
        aiMesh* const m  = ToOutputMesh(p.second);
        scope.meshes_linear.push_back(m);

        // if this is a definition, keep it on the stack
        if(mesh_id != ~0u) {
            scope.meshes.insert(std::pair<unsigned int, aiMesh*>(mesh_id,m));
        }
    }

    // no id == not a reference, insert this mesh right *here*
    return mesh_id == ~0u;
}

// ----------------------------------------------------------------------------------------------
unsigned int XGLImporter::ResolveMaterialRef(TempScope& scope)
{
    const std::string& s = GetElementName();
    if (s == "mat") {
        ReadMaterial(scope);
        return static_cast<unsigned int>(scope.materials_linear.size()-1);
    }

    const int id = ReadIndexFromText();

    std::map<unsigned int, aiMaterial*>::iterator it = scope.materials.find(id), end = scope.materials.end();
    if (it == end) {
        ThrowException("<matref> index out of range");
    }

    // ok, this is n^2 and should get optimized one day
    aiMaterial* const m = (*it).second;

    unsigned int i = 0, mcount = static_cast<unsigned int>(scope.materials_linear.size());
    for(; i < mcount; ++i) {
        if (scope.materials_linear[i] == m) {
            return i;
        }
    }

    ai_assert(false);
    return 0;
}

// ------------------------------------------------------------------------------------------------
void XGLImporter::ReadMaterial(TempScope& scope)
{
    const unsigned int mat_id = ReadIDAttr();

    std::unique_ptr<aiMaterial> mat(new aiMaterial());
    while (ReadElementUpToClosing("mat"))  {
        const std::string& s = GetElementName();
        if (s == "amb") {
            const aiColor3D c = ReadCol3();
            mat->AddProperty(&c,1,AI_MATKEY_COLOR_AMBIENT);
        }
        else if (s == "diff") {
            const aiColor3D c = ReadCol3();
            mat->AddProperty(&c,1,AI_MATKEY_COLOR_DIFFUSE);
        }
        else if (s == "spec") {
            const aiColor3D c = ReadCol3();
            mat->AddProperty(&c,1,AI_MATKEY_COLOR_SPECULAR);
        }
        else if (s == "emiss") {
            const aiColor3D c = ReadCol3();
            mat->AddProperty(&c,1,AI_MATKEY_COLOR_EMISSIVE);
        }
        else if (s == "alpha") {
            const float f = ReadFloat();
            mat->AddProperty(&f,1,AI_MATKEY_OPACITY);
        }
        else if (s == "shine") {
            const float f = ReadFloat();
            mat->AddProperty(&f,1,AI_MATKEY_SHININESS);
        }
    }

    scope.materials[mat_id] = mat.get();
    scope.materials_linear.push_back(mat.release());
}


// ----------------------------------------------------------------------------------------------
void XGLImporter::ReadFaceVertex(const TempMesh& t, TempFace& out)
{
    const std::string& end = GetElementName();

    bool havep = false;
    while (ReadElementUpToClosing(end.c_str()))  {
        const std::string& s = GetElementName();
        if (s == "pref") {
            const unsigned int id = ReadIndexFromText();
            std::map<unsigned int, aiVector3D>::const_iterator it = t.points.find(id);
            if (it == t.points.end()) {
                ThrowException("point index out of range");
            }

            out.pos = (*it).second;
            havep = true;
        }
        else if (s == "nref") {
            const unsigned int id = ReadIndexFromText();
            std::map<unsigned int, aiVector3D>::const_iterator it = t.normals.find(id);
            if (it == t.normals.end()) {
                ThrowException("normal index out of range");
            }

            out.normal = (*it).second;
            out.has_normal = true;
        }
        else if (s == "tcref") {
            const unsigned int id = ReadIndexFromText();
            std::map<unsigned int, aiVector2D>::const_iterator it = t.uvs.find(id);
            if (it == t.uvs.end()) {
                ThrowException("uv index out of range");
            }

            out.uv = (*it).second;
            out.has_uv = true;
        }
        else if (s == "p") {
            out.pos = ReadVec3();
        }
        else if (s == "n") {
            out.normal = ReadVec3();
        }
        else if (s == "tc") {
            out.uv = ReadVec2();
        }
    }

    if (!havep) {
        ThrowException("missing <pref> in <fvN> element");
    }
}

// ------------------------------------------------------------------------------------------------
unsigned int XGLImporter::ReadIDAttr()
{
    for(int i = 0, e = m_reader->getAttributeCount(); i < e; ++i) {

        if(!ASSIMP_stricmp(m_reader->getAttributeName(i),"id")) {
            return m_reader->getAttributeValueAsInt(i);
        }
    }
    return ~0u;
}

// ------------------------------------------------------------------------------------------------
float XGLImporter::ReadFloat()
{
    if(!SkipToText()) {
        LogError("unexpected EOF reading float element contents");
        return 0.f;
    }
    const char* s = m_reader->getNodeData(), *se;

    if(!SkipSpaces(&s)) {
        LogError("unexpected EOL, failed to parse float");
        return 0.f;
    }

    float t;
    se = fast_atoreal_move(s,t);

    if (se == s) {
        LogError("failed to read float text");
        return 0.f;
    }

    return t;
}

// ------------------------------------------------------------------------------------------------
unsigned int XGLImporter::ReadIndexFromText()
{
    if(!SkipToText()) {
        LogError("unexpected EOF reading index element contents");
        return ~0u;
    }
    const char* s = m_reader->getNodeData(), *se;
    if(!SkipSpaces(&s)) {
        LogError("unexpected EOL, failed to parse index element");
        return ~0u;
    }

    const unsigned int t = strtoul10(s,&se);

    if (se == s) {
        LogError("failed to read index");
        return ~0u;
    }

    return t;
}

// ------------------------------------------------------------------------------------------------
aiVector2D XGLImporter::ReadVec2()
{
    aiVector2D vec;

    if(!SkipToText()) {
        LogError("unexpected EOF reading vec2 contents");
        return vec;
    }
    const char* s = m_reader->getNodeData();

    for(int i = 0; i < 2; ++i) {
        if(!SkipSpaces(&s)) {
            LogError("unexpected EOL, failed to parse vec2");
            return vec;
        }
        vec[i] = fast_atof(&s);

        SkipSpaces(&s);
        if (i != 1 && *s != ',') {
            LogError("expected comma, failed to parse vec2");
            return vec;
        }
        ++s;
    }

    return vec;
}

// ------------------------------------------------------------------------------------------------
aiVector3D XGLImporter::ReadVec3()
{
    aiVector3D vec;

    if(!SkipToText()) {
        LogError("unexpected EOF reading vec3 contents");
        return vec;
    }
    const char* s = m_reader->getNodeData();

    for(int i = 0; i < 3; ++i) {
        if(!SkipSpaces(&s)) {
            LogError("unexpected EOL, failed to parse vec3");
            return vec;
        }
        vec[i] = fast_atof(&s);

        SkipSpaces(&s);
        if (i != 2 && *s != ',') {
            LogError("expected comma, failed to parse vec3");
            return vec;
        }
        ++s;
    }

    return vec;
}

// ------------------------------------------------------------------------------------------------
aiColor3D XGLImporter::ReadCol3()
{
    const aiVector3D& v = ReadVec3();
    if (v.x < 0.f || v.x > 1.0f || v.y < 0.f || v.y > 1.0f || v.z < 0.f || v.z > 1.0f) {
        LogWarn("color values out of range, ignoring");
    }
    return aiColor3D(v.x,v.y,v.z);
}

#endif