assimp/code/BlenderTessellator.h

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

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  following disclaimer.

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*/

/** @file  BlenderTessellator.h
 *  @brief A simple tessellation wrapper
 */
#ifndef INCLUDED_AI_BLEND_TESSELLATOR_H
#define INCLUDED_AI_BLEND_TESSELLATOR_H

// Use these to toggle between GLU Tessellate or poly2tri
// Note (acg) keep GLU Tessellate disabled by default - if it is turned on,
// assimp needs to be linked against GLU, which is currently not yet
// made configurable in CMake and potentially not wanted by most users
// as it requires a Gl environment.
#ifndef ASSIMP_BLEND_WITH_GLU_TESSELLATE
#   define ASSIMP_BLEND_WITH_GLU_TESSELLATE 0
#endif

#ifndef ASSIMP_BLEND_WITH_POLY_2_TRI
#   define ASSIMP_BLEND_WITH_POLY_2_TRI 1
#endif

#include <assimp/LogAux.h>

#if ASSIMP_BLEND_WITH_GLU_TESSELLATE

#if defined( WIN32 ) || defined( _WIN32 ) || defined( _MSC_VER )
#include <windows.h>
#endif
#include <GL/glu.h>

namespace Assimp
{
    class BlenderBMeshConverter;

    // TinyFormatter.h
    namespace Formatter
    {
        template < typename T,typename TR, typename A > class basic_formatter;
        typedef class basic_formatter< char, std::char_traits< char >, std::allocator< char > > format;
    }

    // BlenderScene.h
    namespace Blender
    {
        struct MLoop;
        struct MVert;

        struct VertexGL
        {
            GLdouble X;
            GLdouble Y;
            GLdouble Z;
            int index;
            int magic;

            VertexGL( GLdouble X, GLdouble Y, GLdouble Z, int index, int magic ): X( X ), Y( Y ), Z( Z ), index( index ), magic( magic ) { }
        };

        struct DrawCallGL
        {
            GLenum drawMode;
            int baseVertex;
            int vertexCount;

            DrawCallGL( GLenum drawMode, int baseVertex ): drawMode( drawMode ), baseVertex( baseVertex ), vertexCount( 0 ) { }
        };

        struct TessDataGL
        {
            std::vector< DrawCallGL > drawCalls;
            std::vector< VertexGL > vertices;
        };
    }

    class BlenderTessellatorGL: public LogFunctions< BlenderTessellatorGL >
    {
    public:
        BlenderTessellatorGL( BlenderBMeshConverter& converter );
        ~BlenderTessellatorGL( );

        void Tessellate( const Blender::MLoop* polyLoop, int vertexCount, const std::vector< Blender::MVert >& vertices );

    private:
        void AssertVertexCount( int vertexCount );
        void GenerateLoopVerts( std::vector< Blender::VertexGL >& polyLoopGL, const Blender::MLoop* polyLoop, int vertexCount, const std::vector< Blender::MVert >& vertices );
        void Tesssellate( std::vector< Blender::VertexGL >& polyLoopGL, Blender::TessDataGL& tessData );
        void TriangulateDrawCalls( const Blender::TessDataGL& tessData );
        void MakeFacesFromTris( const Blender::VertexGL* vertices, int vertexCount );
        void MakeFacesFromTriStrip( const Blender::VertexGL* vertices, int vertexCount );
        void MakeFacesFromTriFan( const Blender::VertexGL* vertices, int vertexCount );

        static void TessellateBegin( GLenum drawModeGL, void* userData );
        static void TessellateEnd( void* userData );
        static void TessellateVertex( const void* vtxData, void* userData );
        static void TessellateCombine( const GLdouble intersection[ 3 ], const GLdouble* [ 4 ], const GLfloat [ 4 ], GLdouble** out, void* userData );
        static void TessellateEdgeFlag( GLboolean edgeFlag, void* userData );
        static void TessellateError( GLenum errorCode, void* userData );

        BlenderBMeshConverter* converter;
    };
} // end of namespace Assimp

#endif // ASSIMP_BLEND_WITH_GLU_TESSELLATE

#if ASSIMP_BLEND_WITH_POLY_2_TRI

#include "../contrib/poly2tri/poly2tri/poly2tri.h"

namespace Assimp
{
    class BlenderBMeshConverter;

    // TinyFormatter.h
    namespace Formatter
    {
        template < typename T,typename TR, typename A > class basic_formatter;
        typedef class basic_formatter< char, std::char_traits< char >, std::allocator< char > > format;
    }

    // BlenderScene.h
    namespace Blender
    {
        struct MLoop;
        struct MVert;

        struct PointP2T
        {
            aiVector3D point3D;
            p2t::Point point2D;
            int magic;
            int index;
        };

        struct PlaneP2T
        {
            aiVector3D centre;
            aiVector3D normal;
        };
    }

    class BlenderTessellatorP2T: public LogFunctions< BlenderTessellatorP2T >
    {
    public:
        BlenderTessellatorP2T( BlenderBMeshConverter& converter );
        ~BlenderTessellatorP2T( );

        void Tessellate( const Blender::MLoop* polyLoop, int vertexCount, const std::vector< Blender::MVert >& vertices );

    private:
        void AssertVertexCount( int vertexCount );
        void Copy3DVertices( const Blender::MLoop* polyLoop, int vertexCount, const std::vector< Blender::MVert >& vertices, std::vector< Blender::PointP2T >& targetVertices ) const;
        aiMatrix4x4 GeneratePointTransformMatrix( const Blender::PlaneP2T& plane ) const;
        void TransformAndFlattenVectices( const aiMatrix4x4& transform, std::vector< Blender::PointP2T >& vertices ) const;
        void ReferencePoints( std::vector< Blender::PointP2T >& points, std::vector< p2t::Point* >& pointRefs ) const;
        inline Blender::PointP2T& GetActualPointStructure( p2t::Point& point ) const;
        void MakeFacesFromTriangles( std::vector< p2t::Triangle* >& triangles ) const;

        // Adapted from: http://missingbytes.blogspot.co.uk/2012/06/fitting-plane-to-point-cloud.html
        float FindLargestMatrixElem( const aiMatrix3x3& mtx ) const;
        aiMatrix3x3 ScaleMatrix( const aiMatrix3x3& mtx, float scale ) const;
        aiVector3D GetEigenVectorFromLargestEigenValue( const aiMatrix3x3& mtx ) const;
        Blender::PlaneP2T FindLLSQPlane( const std::vector< Blender::PointP2T >& points ) const;

        BlenderBMeshConverter* converter;
    };
} // end of namespace Assimp

#endif // ASSIMP_BLEND_WITH_POLY_2_TRI

#endif // INCLUDED_AI_BLEND_TESSELLATOR_H