mgcdisttri3tri3.cpp

3D Game Engine Design Source Code非常棒

// 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

#include "MgcDistLin3Tri3.h"
#include "MgcDistTri3Tri3.h"

//----------------------------------------------------------------------------
MgcReal MgcSqrDistance (const MgcTriangle3& rkTri0,
    const MgcTriangle3& rkTri1, MgcReal* pfTri0P0, MgcReal* pfTri0P1,
    MgcReal* pfTri1P0, MgcReal* pfTri1P1)
{
    MgcReal fS, fT, fU, fV, fS0, fT0, fU0, fV0, fSqrDist, fSqrDist0;
    MgcSegment3 kSeg;

    // compare edges of tri0 against all of tri1
    kSeg.Origin() = rkTri0.Origin();
    kSeg.Direction() = rkTri0.Edge0();
    fSqrDist = MgcSqrDistance(kSeg,rkTri1,&fS,&fU,&fV);
    fT = 0.0;

    kSeg.Direction() = rkTri0.Edge1();
    fSqrDist0 = MgcSqrDistance(kSeg,rkTri1,&fT0,&fU0,&fV0);
    fS0 = 0.0;
    if ( fSqrDist0 < fSqrDist )
    {
        fSqrDist = fSqrDist0;
        fS = fS0;
        fT = fT0;
        fU = fU0;
        fV = fV0;
    }

    kSeg.Origin() = kSeg.Origin() + rkTri0.Edge0();
    kSeg.Direction() = kSeg.Direction() - rkTri0.Edge0();
    fSqrDist0 = MgcSqrDistance(kSeg,rkTri1,&fT0,&fU0,&fV0);
    fS0 = 1.0-fT0;
    if ( fSqrDist0 < fSqrDist )
    {
        fSqrDist = fSqrDist0;
        fS = fS0;
        fT = fT0;
        fU = fU0;
        fV = fV0;
    }

    // compare edges of tri1 against all of tri0
    kSeg.Origin() = rkTri1.Origin();
    kSeg.Direction() = rkTri1.Edge0();
    fSqrDist0 = MgcSqrDistance(kSeg,rkTri0,&fU0,&fS0,&fT0);
    fV0 = 0.0;
    if ( fSqrDist0 < fSqrDist )
    {
        fSqrDist = fSqrDist0;
        fS = fS0;
        fT = fT0;
        fU = fU0;
        fV = fV0;
    }

    kSeg.Direction() = rkTri1.Edge1();
    fSqrDist0 = MgcSqrDistance(kSeg,rkTri0,&fV0,&fS0,&fT0);
    fU0 = 0.0;
    if ( fSqrDist0 < fSqrDist )
    {
        fSqrDist = fSqrDist0;
        fS = fS0;
        fT = fT0;
        fU = fU0;
        fV = fV0;
    }

    kSeg.Origin() = kSeg.Origin() + rkTri1.Edge0();
    kSeg.Direction() = kSeg.Direction() - rkTri1.Edge0();
    fSqrDist0 = MgcSqrDistance(kSeg,rkTri0,&fV0,&fS0,&fT0);
    fU0 = 1.0-fV0;
    if ( fSqrDist0 < fSqrDist )
    {
        fSqrDist = fSqrDist0;
        fS = fS0;
        fT = fT0;
        fU = fU0;
        fV = fV0;
    }

    if ( pfTri0P0 )
        *pfTri0P0 = fS;

    if ( pfTri0P1 )
        *pfTri0P1 = fT;

    if ( pfTri1P0 )
        *pfTri1P0 = fU;

    if ( pfTri1P1 )
        *pfTri1P1 = fV;

    return MgcMath::Abs(fSqrDist);
}
//----------------------------------------------------------------------------
MgcReal MgcDistance (const MgcTriangle3& rkTri0, const MgcTriangle3& rkTri1,
    MgcReal* pfTri0P0, MgcReal* pfTri0P1, MgcReal* pfTri1P0,
    MgcReal* pfTri1P1)
{
    return MgcMath::Sqrt(MgcSqrDistance(rkTri0,rkTri1,pfTri0P0,pfTri0P1,
        pfTri1P0,pfTri1P1));
}
//----------------------------------------------------------------------------