mgcboundingvolumetree.h

《3D游戏引擎设计》的源码

// Magic Software, Inc.
// http://www.magic-software.com
// Copyright (c) 2000, All Rights Reserved
//
// Source code from Magic Software is supplied under the terms of a license
// agreement and may not be copied or disclosed except in accordance with the
// terms of that agreement.  The various license agreements may be found at
// the Magic Software web site.  This file is subject to the license
//
// FREE SOURCE CODE
// http://www.magic-software.com/License/free.pdf

#ifndef MGCBOUNDINGVOLUMETREE_H
#define MGCBOUNDINGVOLUMETREE_H

#include "MgcVector3.h"


class MgcBoundingVolume
{
public:
    virtual ~MgcBoundingVolume () { /**/ }
};


class MgcBoundingVolumeTree
{
public:
    typedef void (*CreateBound)(unsigned short usVertexCount,
        const MgcVector3* akVertex, const unsigned short* ausConnect,
        unsigned short usI0, unsigned short usI1, unsigned short* ausISplit,
        MgcBoundingVolume*& rpkBound, MgcVector3& rkOrigin,
        MgcVector3& rkDirection);

    MgcBoundingVolumeTree (unsigned short usVertexCount,
        const MgcVector3* akVertex, unsigned short usTriangleCount,
        const unsigned short* ausConnect, unsigned short usMaxTrisPerLeaf,
        CreateBound oCreateBound);

    virtual ~MgcBoundingVolumeTree ();

    const MgcBoundingVolume* GetBound () const;
    unsigned short GetTriangleCount () const;
    unsigned short GetTriangle (unsigned short usI) const;
    const unsigned short* GetTriangles () const;
    const MgcBoundingVolumeTree* GetLChild () const;
    const MgcBoundingVolumeTree* GetRChild () const;

protected:
    MgcBoundingVolumeTree ();

    void CreateTree (unsigned short usVertexCount, const MgcVector3* akVertex,
        unsigned short usTriangleCount, const unsigned short* ausConnect,
        unsigned short usMaxTrisPerLeaf, CreateBound oCreateBound,
        const MgcVector3* akCentroid, unsigned short usI0,
        unsigned short usI1, unsigned short* ausISplit,
        unsigned short* ausOSplit);

    void SplitTriangles (const MgcVector3* akCentroid, unsigned short usI0,
        unsigned short usI1, unsigned short* ausISplit, unsigned short& usJ0,
        unsigned short& usJ1, unsigned short* ausOSplit,
        const MgcVector3& rkOrigin, const MgcVector3& rkDirection);


    // for quick-sort of centroid projections on axes
    class ProjectionInfo
    {
    public:
        unsigned short m_usTriangle;
        MgcReal m_fProjection;
    };

    static int Compare (const void* pvElement0, const void* pvElement1);


    // Interior nodes set count to zero, array to null.  Leaf nodes set count
    // to number of triangles at that node (1 if usMaxTrianglesPerLeaf was
    // set to 1) and allocate an array of triangle indices that are relative
    // to the input mesh of the top level constructor.
    unsigned short m_usTriangleCount;
    unsigned short* m_ausTriangle;

    MgcBoundingVolume* m_pkBound;
    MgcBoundingVolumeTree* m_pkLChild;
    MgcBoundingVolumeTree* m_pkRChild;
};

//----------------------------------------------------------------------------
inline const MgcBoundingVolume* MgcBoundingVolumeTree::GetBound () const
{
    return m_pkBound;
}
//----------------------------------------------------------------------------
inline unsigned short MgcBoundingVolumeTree::GetTriangleCount () const
{
    return m_usTriangleCount;
}
//----------------------------------------------------------------------------
inline unsigned short MgcBoundingVolumeTree::GetTriangle (
    unsigned short usI) const
{
    return m_ausTriangle[usI];
}
//----------------------------------------------------------------------------
inline const unsigned short* MgcBoundingVolumeTree::GetTriangles () const
{
    return m_ausTriangle;
}
//----------------------------------------------------------------------------
inline const MgcBoundingVolumeTree* MgcBoundingVolumeTree::GetLChild () const
{
    return m_pkLChild;
}
//----------------------------------------------------------------------------
inline const MgcBoundingVolumeTree* MgcBoundingVolumeTree::GetRChild () const
{
    return m_pkRChild;
}
//----------------------------------------------------------------------------

#endif