text: /*
  Open Asset Import Library (assimp)
  ----------------------------------------------------------------------
  
  Copyright (c) 2006-2020, assimp team
  All rights reserved.
  
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  with or without modification, are permitted provided that the
  following conditions are met:
  
  * 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
    following disclaimer in the documentation and/or other
    materials provided with the distribution.
  
  * Neither the name of the assimp team, nor the names of its
    contributors may be used to endorse or promote products
    derived from this software without specific prior
    written permission of the assimp team.
  
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  ----------------------------------------------------------------------
  */
  
  /** @file  BlenderBMesh.cpp
   *  @brief Conversion of Blender's new BMesh stuff
   */
  
  #ifndef ASSIMP_BUILD_NO_BLEND_IMPORTER
  
  #include "BlenderDNA.h"
  #include "BlenderScene.h"
  #include "BlenderBMesh.h"
  #include "BlenderTessellator.h"
  
  namespace Assimp
  {
      template< > const char* LogFunctions< BlenderBMeshConverter >::Prefix()
      {
          static auto prefix = "BLEND_BMESH: ";
          return prefix;
      }
  }
  
  using namespace Assimp;
  using namespace Assimp::Blender;
  using namespace Assimp::Formatter;
  
  // ------------------------------------------------------------------------------------------------
  BlenderBMeshConverter::BlenderBMeshConverter( const Mesh* mesh ):
      BMesh( mesh ),
      triMesh( NULL )
  {
  }
  
  // ------------------------------------------------------------------------------------------------
  BlenderBMeshConverter::~BlenderBMeshConverter( )
  {
      DestroyTriMesh( );
  }
  
  // ------------------------------------------------------------------------------------------------
  bool BlenderBMeshConverter::ContainsBMesh( ) const
  {
      // TODO - Should probably do some additional verification here
      return BMesh->totpoly && BMesh->totloop && BMesh->totvert;
  }
  
  // ------------------------------------------------------------------------------------------------
  const Mesh* BlenderBMeshConverter::TriangulateBMesh( )
  {
      AssertValidMesh( );
      AssertValidSizes( );
      PrepareTriMesh( );
  
      for ( int i = 0; i < BMesh->totpoly; ++i )
      {
          const MPoly& poly = BMesh->mpoly[ i ];
          ConvertPolyToFaces( poly );
      }
  
      return triMesh;
  }
  
  // ------------------------------------------------------------------------------------------------
  void BlenderBMeshConverter::AssertValidMesh( )
  {
      if ( !ContainsBMesh( ) )
      {
          ThrowException( "BlenderBMeshConverter requires a BMesh with \"polygons\" - please call BlenderBMeshConverter::ContainsBMesh to check this first" );
      }
  }
  
  // ------------------------------------------------------------------------------------------------
  void BlenderBMeshConverter::AssertValidSizes( )
  {
      if ( BMesh->totpoly != static_cast<int>( BMesh->mpoly.size( ) ) )
      {
          ThrowException( "BMesh poly array has incorrect size" );
      }
      if ( BMesh->totloop != static_cast<int>( BMesh->mloop.size( ) ) )
      {
          ThrowException( "BMesh loop array has incorrect size" );
      }
  }
  
  // ------------------------------------------------------------------------------------------------
  void BlenderBMeshConverter::PrepareTriMesh( )
  {
      if ( triMesh )
      {
          DestroyTriMesh( );
      }
  
      triMesh = new Mesh( *BMesh );
      triMesh->totface = 0;
      triMesh->mface.clear( );
  }
  
  // ------------------------------------------------------------------------------------------------
  void BlenderBMeshConverter::DestroyTriMesh( )
  {
      delete triMesh;
      triMesh = NULL;
  }
  
  // ------------------------------------------------------------------------------------------------
  void BlenderBMeshConverter::ConvertPolyToFaces( const MPoly& poly )
  {
      const MLoop* polyLoop = &BMesh->mloop[ poly.loopstart ];
  
      if ( poly.totloop == 3 || poly.totloop == 4 )
      {
          AddFace( polyLoop[ 0 ].v, polyLoop[ 1 ].v, polyLoop[ 2 ].v, poly.totloop == 4 ? polyLoop[ 3 ].v : 0 );
  
          // UVs are optional, so only convert when present.
          if ( BMesh->mloopuv.size() )
          {
              if ( (poly.loopstart + poly.totloop ) > static_cast<int>( BMesh->mloopuv.size() ) )
              {
                  ThrowException( "BMesh uv loop array has incorrect size" );
              }
              const MLoopUV* loopUV = &BMesh->mloopuv[ poly.loopstart ];
              AddTFace( loopUV[ 0 ].uv, loopUV[ 1 ].uv, loopUV[ 2 ].uv, poly.totloop == 4 ? loopUV[ 3 ].uv : 0 );
          }
      }
      else if ( poly.totloop > 4 )
      {
  #if ASSIMP_BLEND_WITH_GLU_TESSELLATE
          BlenderTessellatorGL tessGL( *this );
          tessGL.Tessellate( polyLoop, poly.totloop, triMesh->mvert );
  #elif ASSIMP_BLEND_WITH_POLY_2_TRI
          BlenderTessellatorP2T tessP2T( *this );
          tessP2T.Tessellate( polyLoop, poly.totloop, triMesh->mvert );
  #endif
      }
  }
  
  // ------------------------------------------------------------------------------------------------
  void BlenderBMeshConverter::AddFace( int v1, int v2, int v3, int v4 )
  {
      MFace face;
      face.v1 = v1;
      face.v2 = v2;
      face.v3 = v3;
      face.v4 = v4;
      face.flag = 0;
      // TODO - Work out how materials work
      face.mat_nr = 0;
      triMesh->mface.push_back( face );
      triMesh->totface = static_cast<int>(triMesh->mface.size( ));
  }
  
  // ------------------------------------------------------------------------------------------------
  void BlenderBMeshConverter::AddTFace( const float* uv1, const float *uv2, const float *uv3, const float* uv4 )
  {
      MTFace mtface;
      memcpy( &mtface.uv[ 0 ], uv1, sizeof(float) * 2 );
      memcpy( &mtface.uv[ 1 ], uv2, sizeof(float) * 2 );
      memcpy( &mtface.uv[ 2 ], uv3, sizeof(float) * 2 );
  
      if ( uv4 )
      {
          memcpy( &mtface.uv[ 3 ], uv4, sizeof(float) * 2 );
      }
  
      triMesh->mtface.push_back( mtface );
  }
  
  #endif // ASSIMP_BUILD_NO_BLEND_IMPORTER
  