assimp/code/Obj/ObjFileParser.cpp

/*
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Open Asset Import Library (assimp)
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Copyright (c) 2006-2020, 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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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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*/
#ifndef ASSIMP_BUILD_NO_OBJ_IMPORTER

#include "ObjFileParser.h"
#include "ObjFileMtlImporter.h"
#include "ObjTools.h"
#include "ObjFileData.h"
#include <assimp/ParsingUtils.h>
#include <assimp/BaseImporter.h>
#include <assimp/DefaultIOSystem.h>
#include <assimp/DefaultLogger.hpp>
#include <assimp/material.h>
#include <assimp/Importer.hpp>
#include <cstdlib>
#include <memory>
#include <utility>

namespace Assimp {

const std::string ObjFileParser::DEFAULT_MATERIAL = AI_DEFAULT_MATERIAL_NAME;

ObjFileParser::ObjFileParser()
: m_DataIt()
, m_DataItEnd()
, m_pModel( nullptr )
, m_uiLine( 0 )
, m_pIO( nullptr )
, m_progress( nullptr ) {
    // empty
}

ObjFileParser::ObjFileParser( IOStreamBuffer<char> &streamBuffer, const std::string &modelName,
                              IOSystem *io, ProgressHandler* progress,
                              std::string originalObjFileName) :
    m_DataIt(),
    m_DataItEnd(),
    m_pModel(nullptr),
    m_uiLine(0),
    m_pIO(io),
    m_progress(progress),
    m_originalObjFileName(std::move(originalObjFileName))
{
    std::fill_n(m_buffer, Buffersize,0);

    // Create the model instance to store all the data
    m_pModel.reset(new ObjFile::Model());
    m_pModel->m_ModelName = modelName;

    // create default material and store it
    m_pModel->m_pDefaultMaterial = new ObjFile::Material;
    m_pModel->m_pDefaultMaterial->MaterialName.Set( DEFAULT_MATERIAL );
    m_pModel->m_MaterialLib.push_back( DEFAULT_MATERIAL );
    m_pModel->m_MaterialMap[ DEFAULT_MATERIAL ] = m_pModel->m_pDefaultMaterial;

    // Start parsing the file
    parseFile( streamBuffer );
}

ObjFileParser::~ObjFileParser()
{
}

void ObjFileParser::setBuffer( std::vector<char> &buffer ) {
    m_DataIt = buffer.begin();
    m_DataItEnd = buffer.end();
}

ObjFile::Model *ObjFileParser::GetModel() const {
    return m_pModel.get();
}

void ObjFileParser::parseFile( IOStreamBuffer<char> &streamBuffer ) {
    // only update every 100KB or it'll be too slow
    //const unsigned int updateProgressEveryBytes = 100 * 1024;
    unsigned int progressCounter = 0;
    const unsigned int bytesToProcess = static_cast<unsigned int>(streamBuffer.size());
    const unsigned int progressTotal = bytesToProcess;
    unsigned int processed = 0;
    size_t lastFilePos( 0 );

    std::vector<char> buffer;
    while ( streamBuffer.getNextDataLine( buffer, '\\' ) ) {
        m_DataIt = buffer.begin();
        m_DataItEnd = buffer.end();

        // Handle progress reporting
        const size_t filePos( streamBuffer.getFilePos() );
        if ( lastFilePos < filePos ) {
            processed = static_cast<unsigned int>(filePos);
            lastFilePos = filePos;
            progressCounter++;
            m_progress->UpdateFileRead(processed, progressTotal);
        }

        // parse line
        switch (*m_DataIt) {
        case 'v': // Parse a vertex texture coordinate
            {
                ++m_DataIt;
                if (*m_DataIt == ' ' || *m_DataIt == '\t') {
                    size_t numComponents = getNumComponentsInDataDefinition();
                    if (numComponents == 3) {
                        // read in vertex definition
                        getVector3(m_pModel->m_Vertices);
                    } else if (numComponents == 4) {
                        // read in vertex definition (homogeneous coords)
                        getHomogeneousVector3(m_pModel->m_Vertices);
                    } else if (numComponents == 6) {
                        // read vertex and vertex-color
                        getTwoVectors3(m_pModel->m_Vertices, m_pModel->m_VertexColors);
                    }
                } else if (*m_DataIt == 't') {
                    // read in texture coordinate ( 2D or 3D )
                    ++m_DataIt;
                    size_t dim = getTexCoordVector(m_pModel->m_TextureCoord);
                    m_pModel->m_TextureCoordDim = std::max(m_pModel->m_TextureCoordDim, (unsigned int)dim);
                } else if (*m_DataIt == 'n') {
                    // Read in normal vector definition
                    ++m_DataIt;
                    getVector3( m_pModel->m_Normals );
                }
            }
            break;

        case 'p': // Parse a face, line or point statement
        case 'l':
        case 'f':
            {
                getFace(*m_DataIt == 'f' ? aiPrimitiveType_POLYGON : (*m_DataIt == 'l'
                    ? aiPrimitiveType_LINE : aiPrimitiveType_POINT));
            }
            break;

        case '#': // Parse a comment
            {
                getComment();
            }
            break;

        case 'u': // Parse a material desc. setter
            {
                std::string name;

                getNameNoSpace(m_DataIt, m_DataItEnd, name);

                size_t nextSpace = name.find(' ');
                if (nextSpace != std::string::npos)
                    name = name.substr(0, nextSpace);

                if(name == "usemtl")
                {
                    getMaterialDesc();
                }
            }
            break;

        case 'm': // Parse a material library or merging group ('mg')
            {
                std::string name;

                getNameNoSpace(m_DataIt, m_DataItEnd, name);

                size_t nextSpace = name.find(' ');
                if (nextSpace != std::string::npos)
                    name = name.substr(0, nextSpace);

                if (name == "mg")
                    getGroupNumberAndResolution();
                else if(name == "mtllib")
                    getMaterialLib();
				else
					goto pf_skip_line;
            }
            break;

        case 'g': // Parse group name
            {
                getGroupName();
            }
            break;

        case 's': // Parse group number
            {
                getGroupNumber();
            }
            break;

        case 'o': // Parse object name
            {
                getObjectName();
            }
            break;

        default:
            {
pf_skip_line:
                m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
            }
            break;
        }
    }
}

void ObjFileParser::copyNextWord(char *pBuffer, size_t length) {
    size_t index = 0;
    m_DataIt = getNextWord<DataArrayIt>(m_DataIt, m_DataItEnd);
    if ( *m_DataIt == '\\' ) {
        ++m_DataIt;
        ++m_DataIt;
        m_DataIt = getNextWord<DataArrayIt>( m_DataIt, m_DataItEnd );
    }
    while( m_DataIt != m_DataItEnd && !IsSpaceOrNewLine( *m_DataIt ) ) {
        pBuffer[index] = *m_DataIt;
        index++;
        if( index == length - 1 ) {
            break;
        }
        ++m_DataIt;
    }

    ai_assert(index < length);
    pBuffer[index] = '\0';
}

static bool isDataDefinitionEnd( const char *tmp ) {
    if ( *tmp == '\\' ) {
        tmp++;
        if ( IsLineEnd( *tmp ) ) {
            tmp++;
            return true;
        }
    }
    return false;
}

static bool isNanOrInf(const char * in) {
    // Look for "nan" or "inf", case insensitive
	return ((in[0] == 'N' || in[0] == 'n') && ASSIMP_strincmp(in, "nan", 3) == 0) ||
	       ((in[0] == 'I' || in[0] == 'i') && ASSIMP_strincmp(in, "inf", 3) == 0);
}

size_t ObjFileParser::getNumComponentsInDataDefinition() {
    size_t numComponents( 0 );
    const char* tmp( &m_DataIt[0] );
    bool end_of_definition = false;
    while ( !end_of_definition ) {
        if ( isDataDefinitionEnd( tmp ) ) {
            tmp += 2;
        } else if ( IsLineEnd( *tmp ) ) {
            end_of_definition = true;
        }
        if ( !SkipSpaces( &tmp ) ) {
            break;
        }
        const bool isNum( IsNumeric( *tmp ) || isNanOrInf(tmp));
        SkipToken( tmp );
        if ( isNum ) {
            ++numComponents;
        }
        if ( !SkipSpaces( &tmp ) ) {
            break;
        }
    }
    return numComponents;
}

size_t ObjFileParser::getTexCoordVector( std::vector<aiVector3D> &point3d_array ) {
    size_t numComponents = getNumComponentsInDataDefinition();
    ai_real x, y, z;
    if( 2 == numComponents ) {
        copyNextWord( m_buffer, Buffersize );
        x = ( ai_real ) fast_atof( m_buffer );

        copyNextWord( m_buffer, Buffersize );
        y = ( ai_real ) fast_atof( m_buffer );
        z = 0.0;
    } else if( 3 == numComponents ) {
        copyNextWord( m_buffer, Buffersize );
        x = ( ai_real ) fast_atof( m_buffer );

        copyNextWord( m_buffer, Buffersize );
        y = ( ai_real ) fast_atof( m_buffer );

        copyNextWord( m_buffer, Buffersize );
        z = ( ai_real ) fast_atof( m_buffer );
    } else {
        throw DeadlyImportError( "OBJ: Invalid number of components" );
    }

    // Coerce nan and inf to 0 as is the OBJ default value
    if (!std::isfinite(x))
        x = 0;

    if (!std::isfinite(y))
        y = 0;

    if (!std::isfinite(z))
        z = 0;

    point3d_array.emplace_back( x, y, z );
    m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
    return numComponents;
}

void ObjFileParser::getVector3( std::vector<aiVector3D> &point3d_array ) {
    ai_real x, y, z;
    copyNextWord(m_buffer, Buffersize);
    x = (ai_real) fast_atof(m_buffer);

    copyNextWord(m_buffer, Buffersize);
    y = (ai_real) fast_atof(m_buffer);

    copyNextWord( m_buffer, Buffersize );
    z = ( ai_real ) fast_atof( m_buffer );

    point3d_array.emplace_back( x, y, z );
    m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
}

void ObjFileParser::getHomogeneousVector3( std::vector<aiVector3D> &point3d_array ) {
    ai_real x, y, z, w;
    copyNextWord(m_buffer, Buffersize);
    x = (ai_real) fast_atof(m_buffer);

    copyNextWord(m_buffer, Buffersize);
    y = (ai_real) fast_atof(m_buffer);

    copyNextWord( m_buffer, Buffersize );
    z = ( ai_real ) fast_atof( m_buffer );

    copyNextWord( m_buffer, Buffersize );
    w = ( ai_real ) fast_atof( m_buffer );

    if (w == 0)
      throw DeadlyImportError("OBJ: Invalid component in homogeneous vector (Division by zero)");

    point3d_array.emplace_back( x/w, y/w, z/w );
    m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
}

void ObjFileParser::getTwoVectors3( std::vector<aiVector3D> &point3d_array_a, std::vector<aiVector3D> &point3d_array_b ) {
    ai_real x, y, z;
    copyNextWord(m_buffer, Buffersize);
    x = (ai_real) fast_atof(m_buffer);

    copyNextWord(m_buffer, Buffersize);
    y = (ai_real) fast_atof(m_buffer);

    copyNextWord( m_buffer, Buffersize );
    z = ( ai_real ) fast_atof( m_buffer );

    point3d_array_a.emplace_back( x, y, z );

    copyNextWord(m_buffer, Buffersize);
    x = (ai_real) fast_atof(m_buffer);

    copyNextWord(m_buffer, Buffersize);
    y = (ai_real) fast_atof(m_buffer);

    copyNextWord( m_buffer, Buffersize );
    z = ( ai_real ) fast_atof( m_buffer );

    point3d_array_b.emplace_back( x, y, z );

    m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
}

void ObjFileParser::getVector2( std::vector<aiVector2D> &point2d_array ) {
    ai_real x, y;
    copyNextWord(m_buffer, Buffersize);
    x = (ai_real) fast_atof(m_buffer);

    copyNextWord(m_buffer, Buffersize);
    y = (ai_real) fast_atof(m_buffer);

    point2d_array.emplace_back(x, y);

    m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
}

static const std::string DefaultObjName = "defaultobject";

void ObjFileParser::getFace( aiPrimitiveType type ) {
    m_DataIt = getNextToken<DataArrayIt>( m_DataIt, m_DataItEnd );
    if ( m_DataIt == m_DataItEnd || *m_DataIt == '\0' ) {
        return;
    }

    ObjFile::Face *face = new ObjFile::Face( type );
    bool hasNormal = false;

    const int vSize = static_cast<unsigned int>(m_pModel->m_Vertices.size());
    const int vtSize = static_cast<unsigned int>(m_pModel->m_TextureCoord.size());
    const int vnSize = static_cast<unsigned int>(m_pModel->m_Normals.size());

    const bool vt = (!m_pModel->m_TextureCoord.empty());
    const bool vn = (!m_pModel->m_Normals.empty());
    int iPos = 0;
    while ( m_DataIt != m_DataItEnd ) {
        int iStep = 1;

        if ( IsLineEnd( *m_DataIt ) ) {
            break;
        }

        if ( *m_DataIt =='/' ) {
            if (type == aiPrimitiveType_POINT) {
                ASSIMP_LOG_ERROR("Obj: Separator unexpected in point statement");
            }
            iPos++;
        } else if( IsSpaceOrNewLine( *m_DataIt ) ) {
            iPos = 0;
        } else {
            //OBJ USES 1 Base ARRAYS!!!!
            const int iVal( ::atoi( & ( *m_DataIt ) ) );

            // increment iStep position based off of the sign and # of digits
            int tmp = iVal;
            if ( iVal < 0 ) {
                ++iStep;
            }
            while ( ( tmp = tmp / 10 ) != 0 ) {
                ++iStep;
            }

            if (iPos == 1 && !vt && vn)
                iPos = 2; // skip texture coords for normals if there are no tex coords

            if ( iVal > 0 ) {
                // Store parsed index
                if ( 0 == iPos ) {
                    face->m_vertices.push_back( iVal - 1 );
                } else if ( 1 == iPos ) {
                    face->m_texturCoords.push_back( iVal - 1 );
                } else if ( 2 == iPos ) {
                    face->m_normals.push_back( iVal - 1 );
                    hasNormal = true;
                } else {
                    reportErrorTokenInFace();
                }
            } else if ( iVal < 0 ) {
                // Store relatively index
                if ( 0 == iPos ) {
                    face->m_vertices.push_back( vSize + iVal );
                } else if ( 1 == iPos ) {
                    face->m_texturCoords.push_back( vtSize + iVal );
                } else if ( 2 == iPos ) {
                    face->m_normals.push_back( vnSize + iVal );
                    hasNormal = true;
                } else {
                    reportErrorTokenInFace();
                }
            } else {
                //On error, std::atoi will return 0 which is not a valid value
                delete face;
                throw DeadlyImportError("OBJ: Invalid face indice");
            }

        }
        m_DataIt += iStep;
    }

    if ( face->m_vertices.empty() ) {
        ASSIMP_LOG_ERROR("Obj: Ignoring empty face");
        // skip line and clean up
        m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
        delete face;
        return;
    }

    // Set active material, if one set
    if( NULL != m_pModel->m_pCurrentMaterial ) {
        face->m_pMaterial = m_pModel->m_pCurrentMaterial;
    } else {
        face->m_pMaterial = m_pModel->m_pDefaultMaterial;
    }

    // Create a default object, if nothing is there
    if( NULL == m_pModel->m_pCurrent ) {
        createObject( DefaultObjName );
    }

    // Assign face to mesh
    if ( NULL == m_pModel->m_pCurrentMesh ) {
        createMesh( DefaultObjName );
    }

    // Store the face
    m_pModel->m_pCurrentMesh->m_Faces.push_back( face );
    m_pModel->m_pCurrentMesh->m_uiNumIndices += (unsigned int) face->m_vertices.size();
    m_pModel->m_pCurrentMesh->m_uiUVCoordinates[ 0 ] += (unsigned int) face->m_texturCoords.size();
    if( !m_pModel->m_pCurrentMesh->m_hasNormals && hasNormal ) {
        m_pModel->m_pCurrentMesh->m_hasNormals = true;
    }
    // Skip the rest of the line
    m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
}

void ObjFileParser::getMaterialDesc() {
    // Get next data for material data
    m_DataIt = getNextToken<DataArrayIt>(m_DataIt, m_DataItEnd);
    if (m_DataIt == m_DataItEnd) {
        return;
    }

    char *pStart = &(*m_DataIt);
    while( m_DataIt != m_DataItEnd && !IsLineEnd( *m_DataIt ) ) {
        ++m_DataIt;
    }

    // In some cases we should ignore this 'usemtl' command, this variable helps us to do so
    bool skip = false;

    // Get name
    std::string strName(pStart, &(*m_DataIt));
    strName = trim_whitespaces(strName);
    if (strName.empty())
        skip = true;

    // If the current mesh has the same material, we simply ignore that 'usemtl' command
    // There is no need to create another object or even mesh here
    if ( m_pModel->m_pCurrentMaterial && m_pModel->m_pCurrentMaterial->MaterialName == aiString( strName ) ) {
        skip = true;
    }

    if (!skip) {
        // Search for material
        auto it = m_pModel->m_MaterialMap.find(strName);
        if (it == m_pModel->m_MaterialMap.end()) {
			// Not found, so we don't know anything about the material except for its name.
			// This may be the case if the material library is missing. We don't want to lose all
			// materials if that happens, so create a new named material instead of discarding it
			// completely.
            ASSIMP_LOG_ERROR("OBJ: failed to locate material " + strName + ", creating new material");
			m_pModel->m_pCurrentMaterial = new ObjFile::Material();
			m_pModel->m_pCurrentMaterial->MaterialName.Set(strName);
			m_pModel->m_MaterialLib.push_back(strName);
			m_pModel->m_MaterialMap[strName] = m_pModel->m_pCurrentMaterial;
        } else {
            // Found, using detected material
            m_pModel->m_pCurrentMaterial = (*it).second;
        }

        if ( needsNewMesh( strName ) ) {
            createMesh( strName );
        }

        m_pModel->m_pCurrentMesh->m_uiMaterialIndex = getMaterialIndex(strName);
    }

    // Skip rest of line
    m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
}

// -------------------------------------------------------------------
//  Get a comment, values will be skipped
void ObjFileParser::getComment() {
    m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
}

// -------------------------------------------------------------------
//  Get material library from file.
void ObjFileParser::getMaterialLib() {
    // Translate tuple
    m_DataIt = getNextToken<DataArrayIt>(m_DataIt, m_DataItEnd);
    if( m_DataIt == m_DataItEnd ) {
        return;
    }

    char *pStart = &(*m_DataIt);
    while( m_DataIt != m_DataItEnd && !IsLineEnd( *m_DataIt ) ) {
        ++m_DataIt;
    }

    // Check for existence
    const std::string strMatName(pStart, &(*m_DataIt));
    std::string absName;

	// Check if directive is valid.
    if ( 0 == strMatName.length() ) {
        ASSIMP_LOG_WARN( "OBJ: no name for material library specified." );
        return;
    }

    if ( m_pIO->StackSize() > 0 ) {
        std::string path = m_pIO->CurrentDirectory();
        if ( '/' != *path.rbegin() ) {
          path += '/';
        }
        absName += path;
        absName += strMatName;
    } else {
        absName = strMatName;
    }

    IOStream *pFile = m_pIO->Open( absName );
    if ( nullptr == pFile ) {
        ASSIMP_LOG_ERROR("OBJ: Unable to locate material file " + strMatName);
        std::string strMatFallbackName = m_originalObjFileName.substr(0, m_originalObjFileName.length() - 3) + "mtl";
        ASSIMP_LOG_INFO("OBJ: Opening fallback material file " + strMatFallbackName);
        pFile = m_pIO->Open(strMatFallbackName);
        if (!pFile) {
            ASSIMP_LOG_ERROR("OBJ: Unable to locate fallback material file " + strMatFallbackName);
            m_DataIt = skipLine<DataArrayIt>(m_DataIt, m_DataItEnd, m_uiLine);
            return;
        }
    }

    // Import material library data from file.
    // Some exporters (e.g. Silo) will happily write out empty
    // material files if the model doesn't use any materials, so we
    // allow that.
    std::vector<char> buffer;
    BaseImporter::TextFileToBuffer( pFile, buffer, BaseImporter::ALLOW_EMPTY );
    m_pIO->Close( pFile );

    // Importing the material library
    ObjFileMtlImporter mtlImporter( buffer, strMatName, m_pModel.get() );
}

// -------------------------------------------------------------------
//  Set a new material definition as the current material.
void ObjFileParser::getNewMaterial() {
    m_DataIt = getNextToken<DataArrayIt>(m_DataIt, m_DataItEnd);
    m_DataIt = getNextWord<DataArrayIt>(m_DataIt, m_DataItEnd);
    if( m_DataIt == m_DataItEnd ) {
        return;
    }

    char *pStart = &(*m_DataIt);
    std::string strMat( pStart, *m_DataIt );
    while( m_DataIt != m_DataItEnd && IsSpaceOrNewLine( *m_DataIt ) ) {
        ++m_DataIt;
    }
    auto it = m_pModel->m_MaterialMap.find( strMat );
    if ( it == m_pModel->m_MaterialMap.end() ) {
        // Show a warning, if material was not found
        ASSIMP_LOG_WARN("OBJ: Unsupported material requested: " + strMat);
        m_pModel->m_pCurrentMaterial = m_pModel->m_pDefaultMaterial;
    } else {
        // Set new material
        if ( needsNewMesh( strMat ) ) {
            createMesh( strMat );
        }
        m_pModel->m_pCurrentMesh->m_uiMaterialIndex = getMaterialIndex( strMat );
    }

    m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
}

// -------------------------------------------------------------------
int ObjFileParser::getMaterialIndex( const std::string &strMaterialName )
{
    int mat_index = -1;
    if( strMaterialName.empty() ) {
        return mat_index;
    }
    for (size_t index = 0; index < m_pModel->m_MaterialLib.size(); ++index)
    {
        if ( strMaterialName == m_pModel->m_MaterialLib[ index ])
        {
            mat_index = (int)index;
            break;
        }
    }
    return mat_index;
}

// -------------------------------------------------------------------
//  Getter for a group name.
void ObjFileParser::getGroupName() {
    std::string groupName;

    // here we skip 'g ' from line
    m_DataIt = getNextToken<DataArrayIt>(m_DataIt, m_DataItEnd);
    m_DataIt = getName<DataArrayIt>(m_DataIt, m_DataItEnd, groupName);
    if( isEndOfBuffer( m_DataIt, m_DataItEnd ) ) {
        return;
    }

    // Change active group, if necessary
    if ( m_pModel->m_strActiveGroup != groupName ) {
        // Search for already existing entry
        ObjFile::Model::ConstGroupMapIt it = m_pModel->m_Groups.find(groupName);

        // We are mapping groups into the object structure
        createObject( groupName );

        // New group name, creating a new entry
        if (it == m_pModel->m_Groups.end())
        {
            std::vector<unsigned int> *pFaceIDArray = new std::vector<unsigned int>;
            m_pModel->m_Groups[ groupName ] = pFaceIDArray;
            m_pModel->m_pGroupFaceIDs = (pFaceIDArray);
        }
        else
        {
            m_pModel->m_pGroupFaceIDs = (*it).second;
        }
        m_pModel->m_strActiveGroup = groupName;
    }
    m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
}

// -------------------------------------------------------------------
//  Not supported
void ObjFileParser::getGroupNumber()
{
    // Not used

    m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
}

// -------------------------------------------------------------------
//  Not supported
void ObjFileParser::getGroupNumberAndResolution()
{
    // Not used

    m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
}

// -------------------------------------------------------------------
//  Stores values for a new object instance, name will be used to
//  identify it.
void ObjFileParser::getObjectName()
{
    m_DataIt = getNextToken<DataArrayIt>(m_DataIt, m_DataItEnd);
    if( m_DataIt == m_DataItEnd ) {
        return;
    }
    char *pStart = &(*m_DataIt);
    while( m_DataIt != m_DataItEnd && !IsSpaceOrNewLine( *m_DataIt ) ) {
        ++m_DataIt;
    }

    std::string strObjectName(pStart, &(*m_DataIt));
    if (!strObjectName.empty())
    {
        // Reset current object
        m_pModel->m_pCurrent = NULL;

        // Search for actual object
        for (std::vector<ObjFile::Object*>::const_iterator it = m_pModel->m_Objects.begin();
            it != m_pModel->m_Objects.end();
            ++it)
        {
            if ((*it)->m_strObjName == strObjectName)
            {
                m_pModel->m_pCurrent = *it;
                break;
            }
        }

        // Allocate a new object, if current one was not found before
        if( NULL == m_pModel->m_pCurrent ) {
            createObject( strObjectName );
        }
    }
    m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
}
// -------------------------------------------------------------------
//  Creates a new object instance
void ObjFileParser::createObject(const std::string &objName)
{
    ai_assert( NULL != m_pModel );

    m_pModel->m_pCurrent = new ObjFile::Object;
    m_pModel->m_pCurrent->m_strObjName = objName;
    m_pModel->m_Objects.push_back( m_pModel->m_pCurrent );

    createMesh( objName  );

    if( m_pModel->m_pCurrentMaterial )
    {
        m_pModel->m_pCurrentMesh->m_uiMaterialIndex =
            getMaterialIndex( m_pModel->m_pCurrentMaterial->MaterialName.data );
        m_pModel->m_pCurrentMesh->m_pMaterial = m_pModel->m_pCurrentMaterial;
    }
}
// -------------------------------------------------------------------
//  Creates a new mesh
void ObjFileParser::createMesh( const std::string &meshName )
{
    ai_assert( NULL != m_pModel );
    m_pModel->m_pCurrentMesh = new ObjFile::Mesh( meshName );
    m_pModel->m_Meshes.push_back( m_pModel->m_pCurrentMesh );
    unsigned int meshId = static_cast<unsigned int>(m_pModel->m_Meshes.size()-1);
    if ( NULL != m_pModel->m_pCurrent )
    {
        m_pModel->m_pCurrent->m_Meshes.push_back( meshId );
    }
    else
    {
        ASSIMP_LOG_ERROR("OBJ: No object detected to attach a new mesh instance.");
    }
}

// -------------------------------------------------------------------
//  Returns true, if a new mesh must be created.
bool ObjFileParser::needsNewMesh( const std::string &materialName )
{
    // If no mesh data yet
    if (m_pModel->m_pCurrentMesh == nullptr)
    {
        return true;
    }
    bool newMat = false;
    int matIdx = getMaterialIndex( materialName );
    int curMatIdx = m_pModel->m_pCurrentMesh->m_uiMaterialIndex;
    if ( curMatIdx != int(ObjFile::Mesh::NoMaterial)
        && curMatIdx != matIdx
        // no need create a new mesh if no faces in current
        // lets say 'usemtl' goes straight after 'g'
        && !m_pModel->m_pCurrentMesh->m_Faces.empty() )
    {
        // New material -> only one material per mesh, so we need to create a new
        // material
        newMat = true;
    }
    return newMat;
}

// -------------------------------------------------------------------
//  Shows an error in parsing process.
void ObjFileParser::reportErrorTokenInFace()
{
    m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
    ASSIMP_LOG_ERROR("OBJ: Not supported token in face description detected");
}

// -------------------------------------------------------------------

}   // Namespace Assimp

#endif // !! ASSIMP_BUILD_NO_OBJ_IMPORTER