mgcdistlin3pgm3.cpp

3D Game Engine Design Source Code非常棒

                    kSegPgm.Origin() = rkPgm.Origin()+rkPgm.Edge0();
                    kSegPgm.Direction() = rkPgm.Edge1();
                    fSqrDist = MgcSqrDistance(rkSeg,kSegPgm,&fR,&fT);
                    fS = 1.0;
                }
                else  // region 2
                {
                    // min on face s=1 or t=1
                    kSegPgm.Origin() = rkPgm.Origin()+rkPgm.Edge0();
                    kSegPgm.Direction() = rkPgm.Edge1();
                    fSqrDist = MgcSqrDistance(rkSeg,kSegPgm,&fR,&fT);
                    fS = 1.0;
                    kSegPgm.Origin() = rkPgm.Origin()+rkPgm.Edge1();
                    kSegPgm.Direction() = rkPgm.Edge0();
                    fSqrDist0 = MgcSqrDistance(rkSeg,kSegPgm,&fR0,&fS0);
                    fT0 = 1.0;
                    if ( fSqrDist0 < fSqrDist )
                    {
                        fSqrDist = fSqrDist0;
                        fR = fR0;
                        fS = fS0;
                        fT = fT0;
                    }
                }
            }
        }
        else
        {
            if ( fS < 0.0 )
            {
                if ( fT < 0.0 )  // region 6p
                {
                    // min on face s=0 or t=0 or r=1
                    kSegPgm.Origin() = rkPgm.Origin();
                    kSegPgm.Direction() = rkPgm.Edge1();
                    fSqrDist = MgcSqrDistance(rkSeg,kSegPgm,&fR,&fT);
                    fS = 0.0;
                    kSegPgm.Origin() = rkPgm.Origin();
                    kSegPgm.Direction() = rkPgm.Edge0();
                    fSqrDist0 = MgcSqrDistance(rkSeg,kSegPgm,&fR0,&fS0);
                    fT0 = 0.0;
                    if ( fSqrDist0 < fSqrDist )
                    {
                        fSqrDist = fSqrDist0;
                        fR = fR0;
                        fS = fS0;
                        fT = fT0;
                    }
                    kPt = rkSeg.Origin()+rkSeg.Direction();
                    fSqrDist0 = MgcSqrDistance(kPt,rkPgm,&fS0,&fT0);
                    fR0 = 1.0;
                    if ( fSqrDist0 < fSqrDist )
                    {
                        fSqrDist = fSqrDist0;
                        fR = fR0;
                        fS = fS0;
                        fT = fT0;
                    }
                }
                else if ( fT <= 1.0 )  // region 5p
                {
                    // min on face s=0 or r=1
                    kSegPgm.Origin() = rkPgm.Origin();
                    kSegPgm.Direction() = rkPgm.Edge1();
                    fSqrDist = MgcSqrDistance(rkSeg,kSegPgm,&fR,&fT);
                    fS = 0.0;
                    fSqrDist0 = MgcSqrDistance(rkSeg.Origin(),rkPgm,&fS0,
                        &fT0);
                    kPt = rkSeg.Origin()+rkSeg.Direction();
                    fSqrDist0 = MgcSqrDistance(kPt,rkPgm,&fS0,&fT0);
                    fR0 = 1.0;
                    if ( fSqrDist0 < fSqrDist )
                    {
                        fSqrDist = fSqrDist0;
                        fR = fR0;
                        fS = fS0;
                        fT = fT0;
                    }
                }
                else  // region 4p
                {
                    // min on face s=0 or t=1 or r=1
                    kSegPgm.Origin() = rkPgm.Origin();
                    kSegPgm.Direction() = rkPgm.Edge1();
                    fSqrDist = MgcSqrDistance(rkSeg,kSegPgm,&fR,&fT);
                    fS = 0.0;
                    kSegPgm.Origin() = rkPgm.Origin()+rkPgm.Edge1();
                    kSegPgm.Direction() = rkPgm.Edge0();
                    fSqrDist0 = MgcSqrDistance(rkSeg,kSegPgm,&fR0,&fS0);
                    fT0 = 1.0;
                    if ( fSqrDist0 < fSqrDist )
                    {
                        fSqrDist = fSqrDist0;
                        fR = fR0;
                        fS = fS0;
                        fT = fT0;
                    }
                    kPt = rkSeg.Origin()+rkSeg.Direction();
                    fSqrDist0 = MgcSqrDistance(kPt,rkPgm,&fS0,&fT0);
                    fR0 = 1.0;
                    if ( fSqrDist0 < fSqrDist )
                    {
                        fSqrDist = fSqrDist0;
                        fR = fR0;
                        fS = fS0;
                        fT = fT0;
                    }
                }
            }
            else if ( fS <= 1.0 )
            {
                if ( fT < 0.0 )  // region 7p
                {
                    // min on face t=0 or r=1
                    kSegPgm.Origin() = rkPgm.Origin();
                    kSegPgm.Direction() = rkPgm.Edge0();
                    fSqrDist = MgcSqrDistance(rkSeg,kSegPgm,&fR,&fS);
                    fT = 0.0;
                    kPt = rkSeg.Origin()+rkSeg.Direction();
                    fSqrDist0 = MgcSqrDistance(kPt,rkPgm,&fS0,&fT0);
                    fR0 = 1.0;
                    if ( fSqrDist0 < fSqrDist )
                    {
                        fSqrDist = fSqrDist0;
                        fR = fR0;
                        fS = fS0;
                        fT = fT0;
                    }
                }
                else if ( fT <= 1.0 )  // region 0p
                {
                    // min on face r=1
                    kPt = rkSeg.Origin()+rkSeg.Direction();
                    fSqrDist = MgcSqrDistance(kPt,rkPgm,&fS,&fT);
                    fR = 1.0;
                }
                else  // region 3p
                {
                    // min on face t=1 or r=1
                    kSegPgm.Origin() = rkPgm.Origin()+rkPgm.Edge1();
                    kSegPgm.Direction() = rkPgm.Edge0();
                    fSqrDist = MgcSqrDistance(rkSeg,kSegPgm,&fR,&fS);
                    fT = 1.0;
                    kPt = rkSeg.Origin()+rkSeg.Direction();
                    fSqrDist0 = MgcSqrDistance(kPt,rkPgm,&fS0,&fT0);
                    fR0 = 1.0;
                    if ( fSqrDist0 < fSqrDist )
                    {
                        fSqrDist = fSqrDist0;
                        fR = fR0;
                        fS = fS0;
                        fT = fT0;
                    }
                }
            }
            else
            {
                if ( fT < 0.0 )  // region 8p
                {
                    // min on face s=1 or t=0 or r=1
                    kSegPgm.Origin() = rkPgm.Origin()+rkPgm.Edge0();
                    kSegPgm.Direction() = rkPgm.Edge1();
                    fSqrDist = MgcSqrDistance(rkSeg,kSegPgm,&fR,&fT);
                    fS = 1.0;
                    kSegPgm.Origin() = rkPgm.Origin();
                    kSegPgm.Direction() = rkPgm.Edge0();
                    fSqrDist0 = MgcSqrDistance(rkSeg,kSegPgm,&fR0,&fS0);
                    fT0 = 0.0;
                    if ( fSqrDist0 < fSqrDist )
                    {
                        fSqrDist = fSqrDist0;
                        fR = fR0;
                        fS = fS0;
                        fT = fT0;
                    }
                    kPt = rkSeg.Origin()+rkSeg.Direction();
                    fSqrDist0 = MgcSqrDistance(kPt,rkPgm,&fS0,&fT0);
                    fR0 = 1.0;
                    if ( fSqrDist0 < fSqrDist )
                    {
                        fSqrDist = fSqrDist0;
                        fR = fR0;
                        fS = fS0;
                        fT = fT0;
                    }
                }
                else if ( fT <= 1.0 )  // region 1p
                {
                    // min on face s=1 or r=1
                    kSegPgm.Origin() = rkPgm.Origin()+rkPgm.Edge0();
                    kSegPgm.Direction() = rkPgm.Edge1();
                    fSqrDist = MgcSqrDistance(rkSeg,kSegPgm,&fR,&fT);
                    fS = 1.0;
                    kPt = rkSeg.Origin()+rkSeg.Direction();
                    fSqrDist0 = MgcSqrDistance(kPt,rkPgm,&fS0,&fT0);
                    fR0 = 1.0;
                    if ( fSqrDist0 < fSqrDist )
                    {
                        fSqrDist = fSqrDist0;
                        fR = fR0;
                        fS = fS0;
                        fT = fT0;
                    }
                }
                else  // region 2p
                {
                    // min on face s=1 or t=1 or r=1
                    kSegPgm.Origin() = rkPgm.Origin()+rkPgm.Edge0();
                    kSegPgm.Direction() = rkPgm.Edge1();
                    fSqrDist = MgcSqrDistance(rkSeg,kSegPgm,&fR,&fT);
                    fS = 1.0;
                    kSegPgm.Origin() = rkPgm.Origin()+rkPgm.Edge1();
                    kSegPgm.Direction() = rkPgm.Edge0();
                    fSqrDist0 = MgcSqrDistance(rkSeg,kSegPgm,&fR0,&fS0);
                    fT0 = 1.0;
                    if ( fSqrDist0 < fSqrDist )
                    {
                        fSqrDist = fSqrDist0;
                        fR = fR0;
                        fS = fS0;
                        fT = fT0;
                    }
                    kPt = rkSeg.Origin()+rkSeg.Direction();
                    fSqrDist0 = MgcSqrDistance(kPt,rkPgm,&fS0,&fT0);
                    fR0 = 1.0;
                    if ( fSqrDist0 < fSqrDist )
                    {
                        fSqrDist = fSqrDist0;
                        fR = fR0;
                        fS = fS0;
                        fT = fT0;
                    }
                }
            }
        }
    }
    else
    {
        // segment and parallelogram are parallel
        kSegPgm.Origin() = rkPgm.Origin();
        kSegPgm.Direction() = rkPgm.Edge0();
        fSqrDist = MgcSqrDistance(rkSeg,kSegPgm,&fR,&fS);
        fT = 0.0;

        kSegPgm.Direction() = rkPgm.Edge1();
        fSqrDist0 = MgcSqrDistance(rkSeg,kSegPgm,&fR0,&fT0);
        fS0 = 0.0;
        if ( fSqrDist0 < fSqrDist )
        {
            fSqrDist = fSqrDist0;
            fR = fR0;
            fS = fS0;
            fT = fT0;
        }

        kSegPgm.Origin() = rkPgm.Origin()+rkPgm.Edge1();
        kSegPgm.Direction() = rkPgm.Edge0();
        fSqrDist0 = MgcSqrDistance(rkSeg,kSegPgm,&fR0,&fS0);
        fT0 = 1.0;
        if ( fSqrDist0 < fSqrDist )
        {
            fSqrDist = fSqrDist0;
            fR = fR0;
            fS = fS0;
            fT = fT0;
        }

        kSegPgm.Origin() = rkPgm.Origin()+rkPgm.Edge0();
        kSegPgm.Direction() = rkPgm.Edge1();
        fSqrDist0 = MgcSqrDistance(rkSeg,kSegPgm,&fR0,&fT0);
        fS0 = 1.0;
        if ( fSqrDist0 < fSqrDist )
        {
            fSqrDist = fSqrDist0;
            fR = fR0;
            fS = fS0;
            fT = fT0;
        }

        fSqrDist0 = MgcSqrDistance(rkSeg.Origin(),rkPgm,&fS0,&fT0);
        fR0 = 0.0;
        if ( fSqrDist0 < fSqrDist )
        {
            fSqrDist = fSqrDist0;
            fR = fR0;
            fS = fS0;
            fT = fT0;
        }

        kPt = rkSeg.Origin()+rkSeg.Direction();
        fSqrDist0 = MgcSqrDistance(kPt,rkPgm,&fS0,&fT0);
        fR0 = 1.0;
        if ( fSqrDist0 < fSqrDist )
        {
            fSqrDist = fSqrDist0;
            fR = fR0;
            fS = fS0;
            fT = fT0;
        }
    }

    if ( pfSegP )
        *pfSegP = fR;

    if ( pfPgmP0 )
        *pfPgmP0 = fS;

    if ( pfPgmP1 )
        *pfPgmP1 = fT;

    return MgcMath::Abs(fSqrDist);
}
//----------------------------------------------------------------------------
MgcReal MgcDistance (const MgcLine3& rkLine, const MgcParallelogram3& rkPgm,
    MgcReal* pfLinP, MgcReal* pfPgmP0, MgcReal* pfPgmP1)
{
    return MgcMath::Sqrt(MgcSqrDistance(rkLine,rkPgm,pfLinP,pfPgmP0,
        pfPgmP1));
}
//----------------------------------------------------------------------------
MgcReal MgcDistance (const MgcRay3& rkRay, const MgcParallelogram3& rkPgm,
    MgcReal* pfRayP, MgcReal* pfPgmP0, MgcReal* pfPgmP1)
{
    return MgcMath::Sqrt(MgcSqrDistance(rkRay,rkPgm,pfRayP,pfPgmP0,
        pfPgmP1));
}
//----------------------------------------------------------------------------
MgcReal MgcDistance (const MgcSegment3& rkSeg,
    const MgcParallelogram3& rkPgm, MgcReal* pfSegP, MgcReal* pfPgmP0,
    MgcReal* pfPgmP1)
{
    return MgcMath::Sqrt(MgcSqrDistance(rkSeg,rkPgm,pfSegP,pfPgmP0,
        pfPgmP1));
}
//----------------------------------------------------------------------------