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/*=========================================================================
Program: Insight Segmentation & Registration Toolkit
Module: $RCSfile: itkSimplexMeshGeometry.cxx,v $
Language: C++
Date: $Date: 2005-01-14 05:17:43 $
Version: $Revision: 1.6 $
Copyright (c) Insight Software Consortium. All rights reserved.
See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notices for more information.
=========================================================================*/
#include "itkSimplexMeshGeometry.h"
#include "itkNumericTraits.h"
#include <vxl_version.h>
#if VXL_VERSION_DATE_FULL > 20040406
# include <vnl/vnl_cross.h>
# define cross_3d vnl_cross_3d
#endif
namespace itk
{
SimplexMeshGeometry
::SimplexMeshGeometry()
{
double c = 1.0/3.0;
PointType p;
p.Fill(0.0);
pos.Fill(0);
oldPos.Fill(0);
referenceMetrics.Fill(c);
eps.Fill(c);
normal.Fill(0);
externalForce.Fill(0);
internalForce.Fill(0);
circleRadius = 0;
circleCenter.Fill(0);
sphereRadius = 0;
distance = 0;
phi = 0;
neighborIndices.Fill((unsigned long) NumericTraits<unsigned long>::max());
neighbors.Fill(p);
meanCurvature = c;
}
SimplexMeshGeometry
::~SimplexMeshGeometry()
{
}
void
SimplexMeshGeometry
::ComputeGeometry()
{
VectorType b,c,cXb, tmp;
//compute the circum circle (center and radius)
b = this->neighbors[2] - this->neighbors[0];
c = this->neighbors[1] - this->neighbors[0];
cXb.SetVnlVector( cross_3d<double>(c.GetVnlVector(),b.GetVnlVector()) );
tmp.SetVnlVector( b.GetSquaredNorm() *
cross_3d<double>( cXb.GetVnlVector(), c.GetVnlVector() ) +
c.GetSquaredNorm() *
cross_3d<double>( b.GetVnlVector() , cXb.GetVnlVector() ) );
double cXbSquaredNorm = 2 * cXb.GetSquaredNorm();
circleRadius = tmp.GetNorm()/(cXbSquaredNorm);
tmp[0] /= (cXbSquaredNorm);
tmp[1] /= (cXbSquaredNorm);
tmp[2] /= (cXbSquaredNorm);
circleCenter = this->neighbors[0] + tmp;
// Compute the circum sphere (center and radius) of a point
VectorType d,dXc,bXd,sphereTmp, denom;
d = pos - this->neighbors[0];
dXc.SetVnlVector( cross_3d<double>(d.GetVnlVector(),c.GetVnlVector()) );
bXd.SetVnlVector( cross_3d<double>(b.GetVnlVector(),d.GetVnlVector()) );
sphereTmp.SetVnlVector( d.GetSquaredNorm()* cXb.GetVnlVector() +
b.GetSquaredNorm()* dXc.GetVnlVector() +
c.GetSquaredNorm()* bXd.GetVnlVector()
);
double val = 2 * (c[0]*(b[1]*d[2]-b[2]*d[1]) -
c[1]*( b[0]*d[2]-b[2]*d[0] ) +
c[2]*( b[0]*d[1]-b[1]*d[0] ));
// fix for points which lay on their neighbors plane
// necessary ??
if (val == 0)
{
val = 1; // assert (val != 0 );
}
sphereRadius = sphereTmp.GetNorm()/val;
if (sphereRadius < 0) {
sphereRadius = -1 * sphereRadius;
}
}
} // end namespace itk
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