mgcdistvec3lin3.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 "MgcDistVec3Lin3.h"

//----------------------------------------------------------------------------
MgcReal MgcSqrDistance (const MgcVector3& rkPoint, const MgcLine3& rkLine,
    MgcReal* pfParam)
{
    MgcVector3 kDiff = rkPoint - rkLine.Origin();
    MgcReal fSqrLen = rkLine.Direction().SquaredLength();
    MgcReal fT = kDiff.Dot(rkLine.Direction())/fSqrLen;
    kDiff -= fT*rkLine.Direction();

    if ( pfParam )
        *pfParam = fT;

    return kDiff.SquaredLength();
}
//----------------------------------------------------------------------------
MgcReal MgcSqrDistance (const MgcVector3& rkPoint, const MgcRay3& rkRay,
    MgcReal* pfParam)
{
    MgcVector3 kDiff = rkPoint - rkRay.Origin();
    MgcReal fT = kDiff.Dot(rkRay.Direction());

    if ( fT <= 0.0 )
    {
        fT = 0.0;
    }
    else
    {
        fT /= rkRay.Direction().SquaredLength();
        kDiff -= fT*rkRay.Direction();
    }

    if ( pfParam )
        *pfParam = fT;

    return kDiff.SquaredLength();
}
//----------------------------------------------------------------------------
MgcReal MgcSqrDistance (const MgcVector3& rkPoint,
    const MgcSegment3& rkSegment, MgcReal* pfParam)
{
    MgcVector3 kDiff = rkPoint - rkSegment.Origin();
    MgcReal fT = kDiff.Dot(rkSegment.Direction());

    if ( fT <= 0.0 )
    {
        fT = 0.0;
    }
    else
    {
        MgcReal fSqrLen= rkSegment.Direction().SquaredLength();
        if ( fT >= fSqrLen )
        {
            fT = 1.0;
            kDiff -= rkSegment.Direction();
        }
        else
        {
            fT /= fSqrLen;
            kDiff -= fT*rkSegment.Direction();
        }
    }

    if ( pfParam )
        *pfParam = fT;

    return kDiff.SquaredLength();
}
//----------------------------------------------------------------------------
MgcReal MgcDistance (const MgcVector3& rkPoint, const MgcLine3& rkLine,
    MgcReal* pfParam)
{
    return MgcMath::Sqrt(MgcSqrDistance(rkPoint,rkLine,pfParam));
}
//----------------------------------------------------------------------------
MgcReal MgcDistance (const MgcVector3& rkPoint, const MgcRay3& rkRay,
    MgcReal* pfParam)
{
    return MgcMath::Sqrt(MgcSqrDistance(rkPoint,rkRay,pfParam));
}
//----------------------------------------------------------------------------
MgcReal MgcDistance (const MgcVector3& rkPoint, const MgcSegment3& rkSegment,
    MgcReal* pfParam)
{
    return MgcMath::Sqrt(MgcSqrDistance(rkPoint,rkSegment,pfParam));
}
//----------------------------------------------------------------------------