/*

Open Asset Import Library (assimp)

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  following disclaimer.

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*/

/** @file Defines a helper class to compute a vertex-triangle adjacency map */

#ifndef AI_VTADJACENCY_H_INC

#define AI_VTADJACENCY_H_INC

#include "BaseProcess.h"

#include <assimp/types.h>

#include <assimp/ai_assert.h>

struct aiMesh;

struct aiFace;

namespace Assimp {

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

/** @brief The VertexTriangleAdjacency class computes a vertex-triangle

 *  adjacency map from a given index buffer.

 *

 *  @note Although it is called #VertexTriangleAdjacency, the current version does also

 *    support arbitrary polygons. */

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

class ASSIMP_API VertexTriangleAdjacency {

public:

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

    /** @brief Construction from an existing index buffer

     *  @param pcFaces Index buffer

     *  @param iNumFaces Number of faces in the buffer

     *  @param iNumVertices Number of referenced vertices. This value

     *    is computed automatically if 0 is specified.

     *  @param bComputeNumTriangles If you want the class to compute

     *    a list containing the number of referenced triangles per vertex

     *    per vertex - pass true.  */

    VertexTriangleAdjacency(aiFace* pcFaces,unsigned int iNumFaces,

        unsigned int iNumVertices = 0,

        bool bComputeNumTriangles = true);

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

    /** @brief Destructor */

    ~VertexTriangleAdjacency();

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

    /** @brief Get all triangles adjacent to a vertex

     *  @param iVertIndex Index of the vertex

     *  @return A pointer to the adjacency list. */

    unsigned int* GetAdjacentTriangles(unsigned int iVertIndex) const {

        ai_assert(iVertIndex < mNumVertices);

        return &mAdjacencyTable[ mOffsetTable[iVertIndex]];

    }

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

    /** @brief Get the number of triangles that are referenced by

     *    a vertex. This function returns a reference that can be modified

     *  @param iVertIndex Index of the vertex

     *  @return Number of referenced triangles */

    unsigned int& GetNumTrianglesPtr(unsigned int iVertIndex) {

        ai_assert( iVertIndex < mNumVertices );

        ai_assert( nullptr != mLiveTriangles );

        return mLiveTriangles[iVertIndex];

    }

    //! Offset table

    unsigned int* mOffsetTable;

    //! Adjacency table

    unsigned int* mAdjacencyTable;

    //! Table containing the number of referenced triangles per vertex

    unsigned int* mLiveTriangles;

    //! Debug: Number of referenced vertices

    unsigned int mNumVertices;

};

} //! ns Assimp

#endif // !! AI_VTADJACENCY_H_INC