assimp/code/PlyLoader.cpp

/*
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*/

/** @file  PlyLoader.cpp
 *  @brief Implementation of the PLY importer class
 */

#ifndef ASSIMP_BUILD_NO_PLY_IMPORTER

// internal headers
#include "PlyLoader.h"
#include "Macros.h"
#include <memory>
#include <assimp/IOSystem.hpp>
#include <assimp/scene.h>


using namespace Assimp;

static const aiImporterDesc desc = {
    "Stanford Polygon Library (PLY) Importer",
    "",
    "",
    "",
    aiImporterFlags_SupportBinaryFlavour | aiImporterFlags_SupportTextFlavour,
    0,
    0,
    0,
    0,
    "ply"
};


// ------------------------------------------------------------------------------------------------
// Internal stuff
namespace
{
    // ------------------------------------------------------------------------------------------------
    // Checks that property index is within range
    template <class T>
    const T &GetProperty(const std::vector<T> &props, int idx)
    {
        if( static_cast< size_t >( idx ) >= props.size() ) {
            throw DeadlyImportError( "Invalid .ply file: Property index is out of range." );
        }

        return props[idx];
    }
}


// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
PLYImporter::PLYImporter()
    : mBuffer(),
    pcDOM()
{}

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

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

    if (extension == "ply")
        return true;
    else if (!extension.length() || checkSig)
    {
        if (!pIOHandler)return true;
        const char* tokens[] = {"ply"};
        return SearchFileHeaderForToken(pIOHandler,pFile,tokens,1);
    }
    return false;
}

// ------------------------------------------------------------------------------------------------
const aiImporterDesc* PLYImporter::GetInfo () const
{
    return &desc;
}

// ------------------------------------------------------------------------------------------------
static bool isBigEndian( const char* szMe ) {
    ai_assert( NULL != szMe );

    // binary_little_endian
    // binary_big_endian
    bool isBigEndian( false );
#if (defined AI_BUILD_BIG_ENDIAN)
    if ( 'l' == *szMe || 'L' == *szMe ) {
        isBigEndian = true;
}
#else
    if ( 'b' == *szMe || 'B' == *szMe ) {
        isBigEndian = true;
    }
#endif // ! AI_BUILD_BIG_ENDIAN

    return isBigEndian;
}

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

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

    // allocate storage and copy the contents of the file to a memory buffer
    std::vector<char> mBuffer2;
    TextFileToBuffer(file.get(),mBuffer2);
    mBuffer = (unsigned char*)&mBuffer2[0];

    // the beginning of the file must be PLY - magic, magic
    if ((mBuffer[0] != 'P' && mBuffer[0] != 'p') ||
        (mBuffer[1] != 'L' && mBuffer[1] != 'l') ||
        (mBuffer[2] != 'Y' && mBuffer[2] != 'y'))   {
        throw DeadlyImportError( "Invalid .ply file: Magic number \'ply\' is no there");
    }

    char* szMe = (char*)&this->mBuffer[3];
    SkipSpacesAndLineEnd(szMe,(const char**)&szMe);

    // determine the format of the file data
    PLY::DOM sPlyDom;
    if (TokenMatch(szMe,"format",6)) {
        if (TokenMatch(szMe,"ascii",5)) {
            SkipLine(szMe,(const char**)&szMe);
            if(!PLY::DOM::ParseInstance(szMe,&sPlyDom))
                throw DeadlyImportError( "Invalid .ply file: Unable to build DOM (#1)");
        } else if (!::strncmp(szMe,"binary_",7))
        {
            szMe += 7;
            const bool bIsBE( isBigEndian( szMe ) );

            // skip the line, parse the rest of the header and build the DOM
            SkipLine(szMe,(const char**)&szMe);
            if ( !PLY::DOM::ParseInstanceBinary( szMe, &sPlyDom, bIsBE ) ) {
                throw DeadlyImportError( "Invalid .ply file: Unable to build DOM (#2)" );
            }
        } else {
            throw DeadlyImportError( "Invalid .ply file: Unknown file format" );
        }
    }
    else
    {
        AI_DEBUG_INVALIDATE_PTR(this->mBuffer);
        throw DeadlyImportError( "Invalid .ply file: Missing format specification");
    }
    this->pcDOM = &sPlyDom;

    // now load a list of vertices. This must be successfully in order to procedure
    std::vector<aiVector3D> avPositions;
    this->LoadVertices(&avPositions,false);

    if ( avPositions.empty() ) {
        throw DeadlyImportError( "Invalid .ply file: No vertices found. "
            "Unable to parse the data format of the PLY file." );
    }

    // now load a list of normals.
    std::vector<aiVector3D> avNormals;
    LoadVertices(&avNormals,true);

    // load the face list
    std::vector<PLY::Face> avFaces;
    LoadFaces(&avFaces);

    // if no face list is existing we assume that the vertex
    // list is containing a list of triangles
    if (avFaces.empty())
    {
        if (avPositions.size() < 3)
        {
            throw DeadlyImportError( "Invalid .ply file: Not enough "
                "vertices to build a proper face list. ");
        }

        const unsigned int iNum = (unsigned int)avPositions.size() / 3;
        for (unsigned int i = 0; i< iNum;++i)
        {
            PLY::Face sFace;
            sFace.mIndices.push_back((iNum*3));
            sFace.mIndices.push_back((iNum*3)+1);
            sFace.mIndices.push_back((iNum*3)+2);
            avFaces.push_back(sFace);
        }
    }

    // now load a list of all materials
    std::vector<aiMaterial*> avMaterials;
    LoadMaterial(&avMaterials);

    // now load a list of all vertex color channels
    std::vector<aiColor4D> avColors;
    avColors.reserve(avPositions.size());
    LoadVertexColor(&avColors);

    // now try to load texture coordinates
    std::vector<aiVector2D> avTexCoords;
    avTexCoords.reserve(avPositions.size());
    LoadTextureCoordinates(&avTexCoords);

    // now replace the default material in all faces and validate all material indices
    ReplaceDefaultMaterial(&avFaces,&avMaterials);

    // now convert this to a list of aiMesh instances
    std::vector<aiMesh*> avMeshes;
    avMeshes.reserve(avMaterials.size()+1);
    ConvertMeshes(&avFaces,&avPositions,&avNormals,
        &avColors,&avTexCoords,&avMaterials,&avMeshes);

    if ( avMeshes.empty() ) {
        throw DeadlyImportError( "Invalid .ply file: Unable to extract mesh data " );
    }

    // now generate the output scene object. Fill the material list
    pScene->mNumMaterials = (unsigned int)avMaterials.size();
    pScene->mMaterials = new aiMaterial*[pScene->mNumMaterials];
    for ( unsigned int i = 0; i < pScene->mNumMaterials; ++i ) {
        pScene->mMaterials[ i ] = avMaterials[ i ];
    }

    // fill the mesh list
    pScene->mNumMeshes = (unsigned int)avMeshes.size();
    pScene->mMeshes = new aiMesh*[pScene->mNumMeshes];
    for ( unsigned int i = 0; i < pScene->mNumMeshes; ++i ) {
        pScene->mMeshes[ i ] = avMeshes[ i ];
    }

    // generate a simple node structure
    pScene->mRootNode = new aiNode();
    pScene->mRootNode->mNumMeshes = pScene->mNumMeshes;
    pScene->mRootNode->mMeshes = new unsigned int[pScene->mNumMeshes];

    for ( unsigned int i = 0; i < pScene->mRootNode->mNumMeshes; ++i ) {
        pScene->mRootNode->mMeshes[ i ] = i;
    }
}

// ------------------------------------------------------------------------------------------------
// Split meshes by material IDs
void PLYImporter::ConvertMeshes(std::vector<PLY::Face>* avFaces,
    const std::vector<aiVector3D>*          avPositions,
    const std::vector<aiVector3D>*          avNormals,
    const std::vector<aiColor4D>*           avColors,
    const std::vector<aiVector2D>*          avTexCoords,
    const std::vector<aiMaterial*>*     avMaterials,
    std::vector<aiMesh*>* avOut)
{
    ai_assert(NULL != avFaces);
    ai_assert(NULL != avPositions);
    ai_assert(NULL != avMaterials);

    // split by materials
    std::vector<unsigned int>* aiSplit = new std::vector<unsigned int>[avMaterials->size()];

    unsigned int iNum = 0;
    for (std::vector<PLY::Face>::const_iterator i = avFaces->begin();i != avFaces->end();++i,++iNum)
        aiSplit[(*i).iMaterialIndex].push_back(iNum);

    // now generate sub-meshes
    for (unsigned int p = 0; p < avMaterials->size();++p)
    {
        if (aiSplit[p].size() != 0)
        {
            // allocate the mesh object
            aiMesh* p_pcOut = new aiMesh();
            p_pcOut->mMaterialIndex = p;

            p_pcOut->mNumFaces = (unsigned int)aiSplit[p].size();
            p_pcOut->mFaces = new aiFace[aiSplit[p].size()];

            // at first we need to determine the size of the output vector array
            unsigned int iNum = 0;
            for (unsigned int i = 0; i < aiSplit[p].size();++i)
            {
                iNum += (unsigned int)(*avFaces)[aiSplit[p][i]].mIndices.size();
            }
            p_pcOut->mNumVertices = iNum;
            if( 0 == iNum ) {     // nothing to do
                delete[] aiSplit; // cleanup
                delete p_pcOut;
                return;
            }
            p_pcOut->mVertices = new aiVector3D[iNum];

            if (!avColors->empty())
                p_pcOut->mColors[0] = new aiColor4D[iNum];
            if (!avTexCoords->empty())
            {
                p_pcOut->mNumUVComponents[0] = 2;
                p_pcOut->mTextureCoords[0] = new aiVector3D[iNum];
            }
            if (!avNormals->empty())
                p_pcOut->mNormals = new aiVector3D[iNum];

            // add all faces
            iNum = 0;
            unsigned int iVertex = 0;
            for (std::vector<unsigned int>::const_iterator i =  aiSplit[p].begin();
                i != aiSplit[p].end();++i,++iNum)
            {
                p_pcOut->mFaces[iNum].mNumIndices = (unsigned int)(*avFaces)[*i].mIndices.size();
                p_pcOut->mFaces[iNum].mIndices = new unsigned int[p_pcOut->mFaces[iNum].mNumIndices];

                // build an unique set of vertices/colors for this face
                for (unsigned int q = 0; q <  p_pcOut->mFaces[iNum].mNumIndices;++q)
                {
                    p_pcOut->mFaces[iNum].mIndices[q] = iVertex;
                    const size_t idx = ( *avFaces )[ *i ].mIndices[ q ];
                    if( idx >= ( *avPositions ).size() ) {
                        // out of border
                        continue;
                    }
                    p_pcOut->mVertices[ iVertex ] = ( *avPositions )[ idx ];

                    if (!avColors->empty())
                        p_pcOut->mColors[ 0 ][ iVertex ] = ( *avColors )[ idx ];

                    if (!avTexCoords->empty())
                    {
                        const aiVector2D& vec = ( *avTexCoords )[ idx ];
                        p_pcOut->mTextureCoords[0][iVertex].x = vec.x;
                        p_pcOut->mTextureCoords[0][iVertex].y = vec.y;
                    }

                    if (!avNormals->empty())
                        p_pcOut->mNormals[ iVertex ] = ( *avNormals )[ idx ];
                    iVertex++;
                }

            }
            // add the mesh to the output list
            avOut->push_back(p_pcOut);
        }
    }
    delete[] aiSplit; // cleanup
}

// ------------------------------------------------------------------------------------------------
// Generate a default material if none was specified and apply it to all vanilla faces
void PLYImporter::ReplaceDefaultMaterial(std::vector<PLY::Face>* avFaces,
    std::vector<aiMaterial*>* avMaterials)
{
    bool bNeedDefaultMat = false;

    for (std::vector<PLY::Face>::iterator i =  avFaces->begin();i != avFaces->end();++i)    {
        if (0xFFFFFFFF == (*i).iMaterialIndex)  {
            bNeedDefaultMat = true;
            (*i).iMaterialIndex = (unsigned int)avMaterials->size();
        }
        else if ((*i).iMaterialIndex >= avMaterials->size() )   {
            // clamp the index
            (*i).iMaterialIndex = (unsigned int)avMaterials->size()-1;
        }
    }

    if (bNeedDefaultMat)    {
        // generate a default material
        aiMaterial* pcHelper = new aiMaterial();

        // fill in a default material
        int iMode = (int)aiShadingMode_Gouraud;
        pcHelper->AddProperty<int>(&iMode, 1, AI_MATKEY_SHADING_MODEL);

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

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

        // The face order is absolutely undefined for PLY, so we have to
        // use two-sided rendering to be sure it's ok.
        const int two_sided = 1;
        pcHelper->AddProperty(&two_sided,1,AI_MATKEY_TWOSIDED);

        avMaterials->push_back(pcHelper);
    }
}

// ------------------------------------------------------------------------------------------------
void PLYImporter::LoadTextureCoordinates(std::vector<aiVector2D>* pvOut)
{
    ai_assert(NULL != pvOut);

    unsigned int aiPositions[2] = {0xFFFFFFFF,0xFFFFFFFF};
    PLY::EDataType aiTypes[2] = {EDT_Char,EDT_Char};
    PLY::ElementInstanceList* pcList = NULL;
    unsigned int cnt = 0;

    // search in the DOM for a vertex entry
    unsigned int _i = 0;
    for (std::vector<PLY::Element>::const_iterator i = pcDOM->alElements.begin();
        i != pcDOM->alElements.end();++i,++_i)
    {
        if (PLY::EEST_Vertex == (*i).eSemantic)
        {
            pcList = &this->pcDOM->alElementData[_i];

            // now check whether which normal components are available
            unsigned int _a = 0;
            for (std::vector<PLY::Property>::const_iterator a =  (*i).alProperties.begin();
                a != (*i).alProperties.end();++a,++_a)
            {
                if ((*a).bIsList)continue;
                if (PLY::EST_UTextureCoord == (*a).Semantic)
                {
                    cnt++;
                    aiPositions[0] = _a;
                    aiTypes[0] = (*a).eType;
                }
                else if (PLY::EST_VTextureCoord == (*a).Semantic)
                {
                    cnt++;
                    aiPositions[1] = _a;
                    aiTypes[1] = (*a).eType;
                }
            }
        }
    }
    // check whether we have a valid source for the texture coordinates data
    if (NULL != pcList && 0 != cnt)
    {
        pvOut->reserve(pcList->alInstances.size());
        for (std::vector<ElementInstance>::const_iterator i = pcList->alInstances.begin();
            i != pcList->alInstances.end();++i)
        {
            // convert the vertices to sp floats
            aiVector2D vOut;

            if (0xFFFFFFFF != aiPositions[0])
            {
                vOut.x = PLY::PropertyInstance::ConvertTo<ai_real>(
                    GetProperty((*i).alProperties, aiPositions[0]).avList.front(),aiTypes[0]);
            }

            if (0xFFFFFFFF != aiPositions[1])
            {
                vOut.y = PLY::PropertyInstance::ConvertTo<ai_real>(
                    GetProperty((*i).alProperties, aiPositions[1]).avList.front(),aiTypes[1]);
            }
            // and add them to our nice list
            pvOut->push_back(vOut);
        }
    }
}

// ------------------------------------------------------------------------------------------------
// Try to extract vertices from the PLY DOM
void PLYImporter::LoadVertices(std::vector<aiVector3D>* pvOut, bool p_bNormals)
{
    ai_assert(NULL != pvOut);

    ai_uint aiPositions[3] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF};
    PLY::EDataType aiTypes[3] = {EDT_Char,EDT_Char,EDT_Char};
    PLY::ElementInstanceList* pcList = NULL;
    unsigned int cnt = 0;

    // search in the DOM for a vertex entry
    unsigned int _i = 0;
    for (std::vector<PLY::Element>::const_iterator i =  pcDOM->alElements.begin();
        i != pcDOM->alElements.end();++i,++_i)
    {
        if (PLY::EEST_Vertex == (*i).eSemantic)
        {
            pcList = &pcDOM->alElementData[_i];

            // load normal vectors?
            if (p_bNormals)
            {
                // now check whether which normal components are available
                unsigned int _a = 0;
                for (std::vector<PLY::Property>::const_iterator a = (*i).alProperties.begin();
                    a != (*i).alProperties.end();++a,++_a)
                {
                    if ((*a).bIsList)continue;
                    if (PLY::EST_XNormal == (*a).Semantic)
                    {
                        cnt++;
                        aiPositions[0] = _a;
                        aiTypes[0] = (*a).eType;
                    }
                    else if (PLY::EST_YNormal == (*a).Semantic)
                    {
                        cnt++;
                        aiPositions[1] = _a;
                        aiTypes[1] = (*a).eType;
                    }
                    else if (PLY::EST_ZNormal == (*a).Semantic)
                    {
                        cnt++;
                        aiPositions[2] = _a;
                        aiTypes[2] = (*a).eType;
                    }
                }
            }
            // load vertex coordinates
            else
            {
                // now check whether which coordinate sets are available
                unsigned int _a = 0;
                for (std::vector<PLY::Property>::const_iterator a = (*i).alProperties.begin();
                    a != (*i).alProperties.end();++a,++_a)
                {
                    if ((*a).bIsList)continue;
                    if (PLY::EST_XCoord == (*a).Semantic)
                    {
                        cnt++;
                        aiPositions[0] = _a;
                        aiTypes[0] = (*a).eType;
                    }
                    else if (PLY::EST_YCoord == (*a).Semantic)
                    {
                        cnt++;
                        aiPositions[1] = _a;
                        aiTypes[1] = (*a).eType;
                    }
                    else if (PLY::EST_ZCoord == (*a).Semantic)
                    {
                        cnt++;
                        aiPositions[2] = _a;
                        aiTypes[2] = (*a).eType;
                    }
                    if (3 == cnt)break;
                }
            }
            break;
        }
    }
    // check whether we have a valid source for the vertex data
    if (NULL != pcList && 0 != cnt)
    {
        pvOut->reserve(pcList->alInstances.size());
        for (std::vector<ElementInstance>::const_iterator
            i =  pcList->alInstances.begin();
            i != pcList->alInstances.end();++i)
        {
            // convert the vertices to sp floats
            aiVector3D vOut;

            if (0xFFFFFFFF != aiPositions[0])
            {
                vOut.x = PLY::PropertyInstance::ConvertTo<ai_real>(
                    GetProperty((*i).alProperties, aiPositions[0]).avList.front(),aiTypes[0]);
            }

            if (0xFFFFFFFF != aiPositions[1])
            {
                vOut.y = PLY::PropertyInstance::ConvertTo<ai_real>(
                    GetProperty((*i).alProperties, aiPositions[1]).avList.front(),aiTypes[1]);
            }

            if (0xFFFFFFFF != aiPositions[2])
            {
                vOut.z = PLY::PropertyInstance::ConvertTo<ai_real>(
                    GetProperty((*i).alProperties, aiPositions[2]).avList.front(),aiTypes[2]);
            }

            // and add them to our nice list
            pvOut->push_back(vOut);
        }
    }
}

// ------------------------------------------------------------------------------------------------
// Convert a color component to [0...1]
ai_real PLYImporter::NormalizeColorValue (PLY::PropertyInstance::ValueUnion val,
    PLY::EDataType eType)
{
    switch (eType)
    {
    case EDT_Float:
        return val.fFloat;
    case EDT_Double:
        return (ai_real)val.fDouble;

    case EDT_UChar:
        return (ai_real)val.iUInt / (ai_real)0xFF;
    case EDT_Char:
        return (ai_real)(val.iInt+(0xFF/2)) / (ai_real)0xFF;
    case EDT_UShort:
        return (ai_real)val.iUInt / (ai_real)0xFFFF;
    case EDT_Short:
        return (ai_real)(val.iInt+(0xFFFF/2)) / (ai_real)0xFFFF;
    case EDT_UInt:
        return (ai_real)val.iUInt / (ai_real)0xFFFF;
    case EDT_Int:
        return ((ai_real)val.iInt / (ai_real)0xFF) + 0.5f;
    default: ;
    };
    return 0.0f;
}

// ------------------------------------------------------------------------------------------------
// Try to extract proper vertex colors from the PLY DOM
void PLYImporter::LoadVertexColor(std::vector<aiColor4D>* pvOut)
{
    ai_assert(NULL != pvOut);

    unsigned int aiPositions[4] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF};
    PLY::EDataType aiTypes[4] = {EDT_Char, EDT_Char, EDT_Char, EDT_Char}; // silencing gcc
    unsigned int cnt = 0;
    PLY::ElementInstanceList* pcList = NULL;

    // search in the DOM for a vertex entry
    unsigned int _i = 0;
    for (std::vector<PLY::Element>::const_iterator i = pcDOM->alElements.begin();
        i != pcDOM->alElements.end();++i,++_i)
    {
        if (PLY::EEST_Vertex == (*i).eSemantic)
        {
            pcList = &this->pcDOM->alElementData[_i];

            // now check whether which coordinate sets are available
            unsigned int _a = 0;
            for (std::vector<PLY::Property>::const_iterator
                a =  (*i).alProperties.begin();
                a != (*i).alProperties.end();++a,++_a)
            {
                if ((*a).bIsList)continue;
                if (PLY::EST_Red == (*a).Semantic)
                {
                    cnt++;
                    aiPositions[0] = _a;
                    aiTypes[0] = (*a).eType;
                }
                else if (PLY::EST_Green == (*a).Semantic)
                {
                    cnt++;
                    aiPositions[1] = _a;
                    aiTypes[1] = (*a).eType;
                }
                else if (PLY::EST_Blue == (*a).Semantic)
                {
                    cnt++;
                    aiPositions[2] = _a;
                    aiTypes[2] = (*a).eType;
                }
                else if (PLY::EST_Alpha == (*a).Semantic)
                {
                    cnt++;
                    aiPositions[3] = _a;
                    aiTypes[3] = (*a).eType;
                }
                if (4 == cnt)break;
            }
            break;
        }
    }
    // check whether we have a valid source for the vertex data
    if (NULL != pcList && 0 != cnt)
    {
        pvOut->reserve(pcList->alInstances.size());
        for (std::vector<ElementInstance>::const_iterator i = pcList->alInstances.begin();
            i != pcList->alInstances.end();++i)
        {
            // convert the vertices to sp floats
            aiColor4D vOut;

            if (0xFFFFFFFF != aiPositions[0])
            {
                vOut.r = NormalizeColorValue(GetProperty((*i).alProperties,
                    aiPositions[0]).avList.front(),aiTypes[0]);
            }

            if (0xFFFFFFFF != aiPositions[1])
            {
                vOut.g = NormalizeColorValue(GetProperty((*i).alProperties,
                    aiPositions[1]).avList.front(),aiTypes[1]);
            }

            if (0xFFFFFFFF != aiPositions[2])
            {
                vOut.b = NormalizeColorValue(GetProperty((*i).alProperties,
                    aiPositions[2]).avList.front(),aiTypes[2]);
            }

            // assume 1.0 for the alpha channel ifit is not set
            if (0xFFFFFFFF == aiPositions[3])vOut.a = 1.0;
            else
            {
                vOut.a = NormalizeColorValue(GetProperty((*i).alProperties,
                    aiPositions[3]).avList.front(),aiTypes[3]);
            }

            // and add them to our nice list
            pvOut->push_back(vOut);
        }
    }
}

// ------------------------------------------------------------------------------------------------
// Try to extract proper faces from the PLY DOM
void PLYImporter::LoadFaces(std::vector<PLY::Face>* pvOut)
{
    ai_assert(NULL != pvOut);

    PLY::ElementInstanceList* pcList = NULL;
    bool bOne = false;

    // index of the vertex index list
    unsigned int iProperty = 0xFFFFFFFF;
    PLY::EDataType eType = EDT_Char;
    bool bIsTriStrip = false;

    // index of the material index property
    unsigned int iMaterialIndex = 0xFFFFFFFF;
    PLY::EDataType eType2 = EDT_Char;

    // search in the DOM for a face entry
    unsigned int _i = 0;
    for (std::vector<PLY::Element>::const_iterator i =  pcDOM->alElements.begin();
        i != pcDOM->alElements.end();++i,++_i)
    {
        // face = unique number of vertex indices
        if (PLY::EEST_Face == (*i).eSemantic)
        {
            pcList = &pcDOM->alElementData[_i];
            unsigned int _a = 0;
            for (std::vector<PLY::Property>::const_iterator a =  (*i).alProperties.begin();
                a != (*i).alProperties.end();++a,++_a)
            {
                if (PLY::EST_VertexIndex == (*a).Semantic)
                {
                    // must be a dynamic list!
                    if (!(*a).bIsList)continue;
                    iProperty   = _a;
                    bOne        = true;
                    eType       = (*a).eType;
                }
                else if (PLY::EST_MaterialIndex == (*a).Semantic)
                {
                    if ((*a).bIsList)continue;
                    iMaterialIndex  = _a;
                    bOne            = true;
                    eType2      = (*a).eType;
                }
            }
            break;
        }
        // triangle strip
        // TODO: triangle strip and material index support???
        else if (PLY::EEST_TriStrip == (*i).eSemantic)
        {
            // find a list property in this ...
            pcList = &this->pcDOM->alElementData[_i];
            unsigned int _a = 0;
            for (std::vector<PLY::Property>::const_iterator a =  (*i).alProperties.begin();
                a != (*i).alProperties.end();++a,++_a)
            {
                // must be a dynamic list!
                if (!(*a).bIsList)continue;
                iProperty   = _a;
                bOne        = true;
                bIsTriStrip = true;
                eType       = (*a).eType;
                break;
            }
            break;
        }
    }
    // check whether we have at least one per-face information set
    if (pcList && bOne)
    {
        if (!bIsTriStrip)
        {
            pvOut->reserve(pcList->alInstances.size());
            for (std::vector<ElementInstance>::const_iterator i =  pcList->alInstances.begin();
                i != pcList->alInstances.end();++i)
            {
                PLY::Face sFace;

                // parse the list of vertex indices
                if (0xFFFFFFFF != iProperty)
                {
                    const unsigned int iNum = (unsigned int)GetProperty((*i).alProperties, iProperty).avList.size();
                    sFace.mIndices.resize(iNum);

                    std::vector<PLY::PropertyInstance::ValueUnion>::const_iterator p =
                        GetProperty((*i).alProperties, iProperty).avList.begin();

                    for (unsigned int a = 0; a < iNum;++a,++p)
                    {
                        sFace.mIndices[a] = PLY::PropertyInstance::ConvertTo<unsigned int>(*p,eType);
                    }
                }

                // parse the material index
                if (0xFFFFFFFF != iMaterialIndex)
                {
                    sFace.iMaterialIndex = PLY::PropertyInstance::ConvertTo<unsigned int>(
                        GetProperty((*i).alProperties, iMaterialIndex).avList.front(),eType2);
                }
                pvOut->push_back(sFace);
            }
        }
        else // triangle strips
        {
            // normally we have only one triangle strip instance where
            // a value of -1 indicates a restart of the strip
            bool flip = false;
            for (std::vector<ElementInstance>::const_iterator i = pcList->alInstances.begin();i != pcList->alInstances.end();++i) {
                const std::vector<PLY::PropertyInstance::ValueUnion>& quak = GetProperty((*i).alProperties, iProperty).avList;
                pvOut->reserve(pvOut->size() + quak.size() + (quak.size()>>2u));

                int aiTable[2] = {-1,-1};
                for (std::vector<PLY::PropertyInstance::ValueUnion>::const_iterator a =  quak.begin();a != quak.end();++a)  {
                    const int p = PLY::PropertyInstance::ConvertTo<int>(*a,eType);

                    if (-1 == p)    {
                        // restart the strip ...
                        aiTable[0] = aiTable[1] = -1;
                        flip = false;
                        continue;
                    }
                    if (-1 == aiTable[0]) {
                        aiTable[0] = p;
                        continue;
                    }
                    if (-1 == aiTable[1]) {
                        aiTable[1] = p;
                        continue;
                    }

                    pvOut->push_back(PLY::Face());
                    PLY::Face& sFace = pvOut->back();
                    sFace.mIndices[0] = aiTable[0];
                    sFace.mIndices[1] = aiTable[1];
                    sFace.mIndices[2] = p;
                    if ((flip = !flip)) {
                        std::swap(sFace.mIndices[0],sFace.mIndices[1]);
                    }

                    aiTable[0] = aiTable[1];
                    aiTable[1] = p;
                }
            }
        }
    }
}

// ------------------------------------------------------------------------------------------------
// Get a RGBA color in [0...1] range
void PLYImporter::GetMaterialColor(const std::vector<PLY::PropertyInstance>& avList,
    unsigned int aiPositions[4],
    PLY::EDataType aiTypes[4],
     aiColor4D* clrOut)
{
    ai_assert(NULL != clrOut);

    if (0xFFFFFFFF == aiPositions[0])clrOut->r = 0.0f;
    else
    {
        clrOut->r = NormalizeColorValue(GetProperty(avList,
            aiPositions[0]).avList.front(),aiTypes[0]);
    }

    if (0xFFFFFFFF == aiPositions[1])clrOut->g = 0.0f;
    else
    {
        clrOut->g = NormalizeColorValue(GetProperty(avList,
            aiPositions[1]).avList.front(),aiTypes[1]);
    }

    if (0xFFFFFFFF == aiPositions[2])clrOut->b = 0.0f;
    else
    {
        clrOut->b = NormalizeColorValue(GetProperty(avList,
            aiPositions[2]).avList.front(),aiTypes[2]);
    }

    // assume 1.0 for the alpha channel ifit is not set
    if (0xFFFFFFFF == aiPositions[3])clrOut->a = 1.0f;
    else
    {
        clrOut->a = NormalizeColorValue(GetProperty(avList,
            aiPositions[3]).avList.front(),aiTypes[3]);
    }
}

// ------------------------------------------------------------------------------------------------
// Extract a material from the PLY DOM
void PLYImporter::LoadMaterial(std::vector<aiMaterial*>* pvOut)
{
    ai_assert(NULL != pvOut);

    // diffuse[4], specular[4], ambient[4]
    // rgba order
    unsigned int aaiPositions[3][4] = {

        {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
        {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
        {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
    };

    PLY::EDataType aaiTypes[3][4] = {
        {EDT_Char,EDT_Char,EDT_Char,EDT_Char},
        {EDT_Char,EDT_Char,EDT_Char,EDT_Char},
        {EDT_Char,EDT_Char,EDT_Char,EDT_Char}
    };
    PLY::ElementInstanceList* pcList = NULL;

    unsigned int iPhong = 0xFFFFFFFF;
    PLY::EDataType ePhong = EDT_Char;

    unsigned int iOpacity = 0xFFFFFFFF;
    PLY::EDataType eOpacity = EDT_Char;

    // search in the DOM for a vertex entry
    unsigned int _i = 0;
    for (std::vector<PLY::Element>::const_iterator i =  this->pcDOM->alElements.begin();
        i != this->pcDOM->alElements.end();++i,++_i)
    {
        if (PLY::EEST_Material == (*i).eSemantic)
        {
            pcList = &this->pcDOM->alElementData[_i];

            // now check whether which coordinate sets are available
            unsigned int _a = 0;
            for (std::vector<PLY::Property>::const_iterator
                a =  (*i).alProperties.begin();
                a != (*i).alProperties.end();++a,++_a)
            {
                if ((*a).bIsList)continue;

                // pohng specularity      -----------------------------------
                if (PLY::EST_PhongPower == (*a).Semantic)
                {
                    iPhong      = _a;
                    ePhong      = (*a).eType;
                }

                // general opacity        -----------------------------------
                if (PLY::EST_Opacity == (*a).Semantic)
                {
                    iOpacity        = _a;
                    eOpacity        = (*a).eType;
                }

                // diffuse color channels -----------------------------------
                if (PLY::EST_DiffuseRed == (*a).Semantic)
                {
                    aaiPositions[0][0]  = _a;
                    aaiTypes[0][0]      = (*a).eType;
                }
                else if (PLY::EST_DiffuseGreen == (*a).Semantic)
                {
                    aaiPositions[0][1]  = _a;
                    aaiTypes[0][1]      = (*a).eType;
                }
                else if (PLY::EST_DiffuseBlue == (*a).Semantic)
                {
                    aaiPositions[0][2]  = _a;
                    aaiTypes[0][2]      = (*a).eType;
                }
                else if (PLY::EST_DiffuseAlpha == (*a).Semantic)
                {
                    aaiPositions[0][3]  = _a;
                    aaiTypes[0][3]      = (*a).eType;
                }
                // specular color channels -----------------------------------
                else if (PLY::EST_SpecularRed == (*a).Semantic)
                {
                    aaiPositions[1][0]  = _a;
                    aaiTypes[1][0]      = (*a).eType;
                }
                else if (PLY::EST_SpecularGreen == (*a).Semantic)
                {
                    aaiPositions[1][1]  = _a;
                    aaiTypes[1][1]      = (*a).eType;
                }
                else if (PLY::EST_SpecularBlue == (*a).Semantic)
                {
                    aaiPositions[1][2]  = _a;
                    aaiTypes[1][2]      = (*a).eType;
                }
                else if (PLY::EST_SpecularAlpha == (*a).Semantic)
                {
                    aaiPositions[1][3]  = _a;
                    aaiTypes[1][3]      = (*a).eType;
                }
                // ambient color channels -----------------------------------
                else if (PLY::EST_AmbientRed == (*a).Semantic)
                {
                    aaiPositions[2][0]  = _a;
                    aaiTypes[2][0]      = (*a).eType;
                }
                else if (PLY::EST_AmbientGreen == (*a).Semantic)
                {
                    aaiPositions[2][1]  = _a;
                    aaiTypes[2][1]      = (*a).eType;
                }
                else if (PLY::EST_AmbientBlue == (*a).Semantic)
                {
                    aaiPositions[2][2]  = _a;
                    aaiTypes[2][2]      = (*a).eType;
                }
                else if (PLY::EST_AmbientAlpha == (*a).Semantic)
                {
                    aaiPositions[2][3]  = _a;
                    aaiTypes[2][3]      = (*a).eType;
                }
            }
            break;
        }
    }
    // check whether we have a valid source for the material data
    if (NULL != pcList) {
        for (std::vector<ElementInstance>::const_iterator i =  pcList->alInstances.begin();i != pcList->alInstances.end();++i)  {
            aiColor4D clrOut;
            aiMaterial* pcHelper = new aiMaterial();

            // build the diffuse material color
            GetMaterialColor((*i).alProperties,aaiPositions[0],aaiTypes[0],&clrOut);
            pcHelper->AddProperty<aiColor4D>(&clrOut,1,AI_MATKEY_COLOR_DIFFUSE);

            // build the specular material color
            GetMaterialColor((*i).alProperties,aaiPositions[1],aaiTypes[1],&clrOut);
            pcHelper->AddProperty<aiColor4D>(&clrOut,1,AI_MATKEY_COLOR_SPECULAR);

            // build the ambient material color
            GetMaterialColor((*i).alProperties,aaiPositions[2],aaiTypes[2],&clrOut);
            pcHelper->AddProperty<aiColor4D>(&clrOut,1,AI_MATKEY_COLOR_AMBIENT);

            // handle phong power and shading mode
            int iMode = (int)aiShadingMode_Gouraud;
            if (0xFFFFFFFF != iPhong)   {
                ai_real fSpec = PLY::PropertyInstance::ConvertTo<ai_real>(GetProperty((*i).alProperties, iPhong).avList.front(),ePhong);

                // if shininess is 0 (and the pow() calculation would therefore always
                // become 1, not depending on the angle), use gouraud lighting
                if (fSpec)  {
                    // scale this with 15 ... hopefully this is correct
                    fSpec *= 15;
                    pcHelper->AddProperty<ai_real>(&fSpec, 1, AI_MATKEY_SHININESS);

                    iMode = (int)aiShadingMode_Phong;
                }
            }
            pcHelper->AddProperty<int>(&iMode, 1, AI_MATKEY_SHADING_MODEL);

            // handle opacity
            if (0xFFFFFFFF != iOpacity) {
                ai_real fOpacity = PLY::PropertyInstance::ConvertTo<ai_real>(GetProperty((*i).alProperties, iPhong).avList.front(),eOpacity);
                pcHelper->AddProperty<ai_real>(&fOpacity, 1, AI_MATKEY_OPACITY);
            }

            // The face order is absolutely undefined for PLY, so we have to
            // use two-sided rendering to be sure it's ok.
            const int two_sided = 1;
            pcHelper->AddProperty(&two_sided,1,AI_MATKEY_TWOSIDED);

            // add the newly created material instance to the list
            pvOut->push_back(pcHelper);
        }
    }
}

#endif // !! ASSIMP_BUILD_NO_PLY_IMPORTER