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create/src/Mod/Mesh/App/WildMagic4/Wm4DistLine3Triangle3.cpp
2025-11-02 15:49:56 -06:00

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// SPDX-License-Identifier: LGPL-2.1-or-later
// Wild Magic Source Code
// David Eberly
// http://www.geometrictools.com
// Copyright (c) 1998-2007
//
// This library is free software; you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation; either version 2.1 of the License, or (at
// your option) any later version. The license is available for reading at
// either of the locations:
// http://www.gnu.org/copyleft/lgpl.html
// http://www.geometrictools.com/License/WildMagicLicense.pdf
// The license applies to versions 0 through 4 of Wild Magic.
//
// Version: 4.0.1 (2006/07/23)
#include "Wm4FoundationPCH.h"
#include "Wm4DistLine3Triangle3.h"
#include "Wm4DistLine3Segment3.h"
namespace Wm4
{
//----------------------------------------------------------------------------
template <class Real>
DistLine3Triangle3<Real>::DistLine3Triangle3 (const Line3<Real>& rkLine,
const Triangle3<Real>& rkTriangle)
:
m_rkLine(rkLine),
m_rkTriangle(rkTriangle)
{
}
//----------------------------------------------------------------------------
template <class Real>
const Line3<Real>& DistLine3Triangle3<Real>::GetLine () const
{
return m_rkLine;
}
//----------------------------------------------------------------------------
template <class Real>
const Triangle3<Real>& DistLine3Triangle3<Real>::GetTriangle () const
{
return m_rkTriangle;
}
//----------------------------------------------------------------------------
template <class Real>
Real DistLine3Triangle3<Real>::Get ()
{
Real fSqrDist = GetSquared();
return Math<Real>::Sqrt(fSqrDist);
}
//----------------------------------------------------------------------------
template <class Real>
Real DistLine3Triangle3<Real>::GetSquared ()
{
// Test if line intersects triangle. If so, the squared distance is zero.
Vector3<Real> kEdge0 = m_rkTriangle.V[1] - m_rkTriangle.V[0];
Vector3<Real> kEdge1 = m_rkTriangle.V[2] - m_rkTriangle.V[0];
Vector3<Real> kNormal = kEdge0.UnitCross(kEdge1);
Real fNdD = kNormal.Dot(m_rkLine.Direction);
if (Math<Real>::FAbs(fNdD) > Math<Real>::ZERO_TOLERANCE)
{
// The line and triangle are not parallel, so the line intersects
// the plane of the triangle.
Vector3<Real> kDiff = m_rkLine.Origin - m_rkTriangle.V[0];
Vector3<Real>& rkD = (Vector3<Real>&) m_rkLine.Direction;
Vector3<Real> kU, kV;
Vector3<Real>::GenerateComplementBasis(kU,kV,rkD);
Real fUdE0 = kU.Dot(kEdge0);
Real fUdE1 = kU.Dot(kEdge0);
Real fUdDiff = kU.Dot(kDiff);
Real fVdE0 = kV.Dot(kEdge0);
Real fVdE1 = kV.Dot(kEdge0);
Real fVdDiff = kV.Dot(kDiff);
Real fInvDet = ((Real)1.0)/(fUdE0*fVdE1 - fUdE1*fVdE0);
// Barycentric coordinates for the point of intersection.
Real fB1 = (fVdE1*fUdDiff - fUdE1*fVdDiff)*fInvDet;
Real fB2 = (fUdE0*fVdDiff - fVdE0*fUdDiff)*fInvDet;
Real fB0 = (Real)1.0 - fB1 - fB2;
if (fB0 >= (Real)0.0 && fB1 >= (Real)0.0 && fB2 >= (Real)0.0)
{
// Line parameter for the point of intersection.
Real fDdE0 = rkD.Dot(kEdge0);
Real fDdE1 = rkD.Dot(kEdge1);
Real fDdDiff = m_rkLine.Direction.Dot(kDiff);
m_fLineParameter = fB1*fDdE0 + fB2*fDdE1 - fDdDiff;
// Barycentric coordinates for the point of intersection.
m_afTriangleBary[0] = fB0;
m_afTriangleBary[1] = fB1;
m_afTriangleBary[2] = fB2;
// The intersection point is inside or on the triangle.
m_kClosestPoint0 = m_rkLine.Origin +
m_fLineParameter*m_rkLine.Direction;
m_kClosestPoint1 = m_rkTriangle.V[0] + fB1*kEdge0 + fB2*kEdge1;
return (Real)0.0;
}
}
// Either (1) the line is not parallel to the triangle and the point of
// intersection of the line and the plane of the triangle is outside the
// triangle or (2) the line and triangle are parallel. Regardless, the
// closest point on the triangle is on an edge of the triangle. Compare
// the line to all three edges of the triangle.
Real fSqrDist = Math<Real>::MAX_REAL;
for (int i0 = 2, i1 = 0; i1 < 3; i0 = i1++)
{
Segment3<Real> kSeg;
kSeg.Origin = ((Real)0.5)*(m_rkTriangle.V[i0] + m_rkTriangle.V[i1]);
kSeg.Direction = m_rkTriangle.V[i1] - m_rkTriangle.V[i0];
kSeg.Extent = ((Real)0.5)*kSeg.Direction.Normalize();
DistLine3Segment3<Real> kLSDist(m_rkLine,kSeg);
Real fSqrDistTmp = kLSDist.GetSquared();
if (fSqrDistTmp < fSqrDist)
{
m_kClosestPoint0 = kLSDist.GetClosestPoint0();
m_kClosestPoint1 = kLSDist.GetClosestPoint1();
fSqrDist = fSqrDistTmp;
m_fLineParameter = kLSDist.GetLineParameter();
Real fRatio = kLSDist.GetSegmentParameter()/kSeg.Extent;
m_afTriangleBary[i0] = ((Real)0.5)*((Real)1.0 - fRatio);
m_afTriangleBary[i1] = (Real)1.0 - m_afTriangleBary[i0];
m_afTriangleBary[3-i0-i1] = (Real)0.0;
}
}
return fSqrDist;
}
//----------------------------------------------------------------------------
template <class Real>
Real DistLine3Triangle3<Real>::Get (Real fT, const Vector3<Real>& rkVelocity0,
const Vector3<Real>& rkVelocity1)
{
Vector3<Real> kMOrigin = m_rkLine.Origin + fT*rkVelocity0;
Vector3<Real> kMV0 = m_rkTriangle.V[0] + fT*rkVelocity1;
Vector3<Real> kMV1 = m_rkTriangle.V[1] + fT*rkVelocity1;
Vector3<Real> kMV2 = m_rkTriangle.V[2] + fT*rkVelocity1;
Line3<Real> kMLine(kMOrigin,m_rkLine.Direction);
Triangle3<Real> kMTriangle(kMV0,kMV1,kMV2);
return DistLine3Triangle3<Real>(kMLine,kMTriangle).Get();
}
//----------------------------------------------------------------------------
template <class Real>
Real DistLine3Triangle3<Real>::GetSquared (Real fT,
const Vector3<Real>& rkVelocity0, const Vector3<Real>& rkVelocity1)
{
Vector3<Real> kMOrigin = m_rkLine.Origin + fT*rkVelocity0;
Vector3<Real> kMV0 = m_rkTriangle.V[0] + fT*rkVelocity1;
Vector3<Real> kMV1 = m_rkTriangle.V[1] + fT*rkVelocity1;
Vector3<Real> kMV2 = m_rkTriangle.V[2] + fT*rkVelocity1;
Line3<Real> kMLine(kMOrigin,m_rkLine.Direction);
Triangle3<Real> kMTriangle(kMV0,kMV1,kMV2);
return DistLine3Triangle3<Real>(kMLine,kMTriangle).GetSquared();
}
//----------------------------------------------------------------------------
template <class Real>
Real DistLine3Triangle3<Real>::GetLineParameter () const
{
return m_fLineParameter;
}
//----------------------------------------------------------------------------
template <class Real>
Real DistLine3Triangle3<Real>::GetTriangleBary (int i) const
{
assert(0 <= i && i < 3);
return m_afTriangleBary[i];
}
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------
// explicit instantiation
//----------------------------------------------------------------------------
template WM4_FOUNDATION_ITEM
class DistLine3Triangle3<float>;
template WM4_FOUNDATION_ITEM
class DistLine3Triangle3<double>;
//----------------------------------------------------------------------------
}