assimp/code/BlenderBMesh.cpp

/*
Open Asset Import Library (assimp)
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*/

/** @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 std::string LogFunctions< BlenderBMeshConverter >::log_prefix = "BLEND_BMESH: ";
}

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;
	// TODO - Work out how materials work
	face.mat_nr = 0;
	triMesh->mface.push_back( face );
	triMesh->totface = 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