VTK
dox/Filtering/vtkTriangle.h
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00001 /*=========================================================================
00002 
00003   Program:   Visualization Toolkit
00004   Module:    vtkTriangle.h
00005 
00006   Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
00007   All rights reserved.
00008   See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
00009 
00010      This software is distributed WITHOUT ANY WARRANTY; without even
00011      the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
00012      PURPOSE.  See the above copyright notice for more information.
00013 
00014 =========================================================================*/
00028 #ifndef __vtkTriangle_h
00029 #define __vtkTriangle_h
00030 
00031 #include "vtkCell.h"
00032 
00033 #include "vtkMath.h" // Needed for inline methods
00034 
00035 class vtkLine;
00036 class vtkQuadric;
00037 class vtkIncrementalPointLocator;
00038 
00039 class VTK_FILTERING_EXPORT vtkTriangle : public vtkCell
00040 {
00041 public:
00042   static vtkTriangle *New();
00043   vtkTypeMacro(vtkTriangle,vtkCell);
00044   void PrintSelf(ostream& os, vtkIndent indent);
00045 
00048   vtkCell *GetEdge(int edgeId);
00049 
00051 
00052   int GetCellType() {return VTK_TRIANGLE;};
00053   int GetCellDimension() {return 2;};
00054   int GetNumberOfEdges() {return 3;};
00055   int GetNumberOfFaces() {return 0;};
00056   vtkCell *GetFace(int) {return 0;};
00057   int CellBoundary(int subId, double pcoords[3], vtkIdList *pts);
00058   void Contour(double value, vtkDataArray *cellScalars,
00059                vtkIncrementalPointLocator *locator, vtkCellArray *verts,
00060                vtkCellArray *lines, vtkCellArray *polys,
00061                vtkPointData *inPd, vtkPointData *outPd,
00062                vtkCellData *inCd, vtkIdType cellId, vtkCellData *outCd);
00063   int EvaluatePosition(double x[3], double* closestPoint,
00064                        int& subId, double pcoords[3],
00065                        double& dist2, double *weights);
00066   void EvaluateLocation(int& subId, double pcoords[3], double x[3],
00067                         double *weights);
00068   int Triangulate(int index, vtkIdList *ptIds, vtkPoints *pts);
00069   void Derivatives(int subId, double pcoords[3], double *values,
00070                    int dim, double *derivs);
00071   virtual double *GetParametricCoords();
00073 
00075   double ComputeArea();
00076 
00078 
00080   void Clip(double value, vtkDataArray *cellScalars,
00081             vtkIncrementalPointLocator *locator, vtkCellArray *polys,
00082             vtkPointData *inPd, vtkPointData *outPd,
00083             vtkCellData *inCd, vtkIdType cellId, vtkCellData *outCd,
00084             int insideOut);
00086 
00088 
00090   static void InterpolationFunctions(double pcoords[3], double sf[3]);
00091   // Description:
00092   // @deprecated Replaced by vtkTriangle::InterpolateDerivs as of VTK 5.2
00093   static void InterpolationDerivs(double pcoords[3], double derivs[6]);
00094   // Description:
00095   // Compute the interpolation functions/derivatives
00096   // (aka shape functions/derivatives)
00097   virtual void InterpolateFunctions(double pcoords[3], double sf[3])
00098     {
00099     vtkTriangle::InterpolationFunctions(pcoords,sf);
00100     }
00101   virtual void InterpolateDerivs(double pcoords[3], double derivs[6])
00102     {
00103     vtkTriangle::InterpolationDerivs(pcoords,derivs);
00104     }
00105   // Description:
00106   // Return the ids of the vertices defining edge (`edgeId`).
00107   // Ids are related to the cell, not to the dataset.
00108   int *GetEdgeArray(int edgeId);
00110 
00112 
00114   int IntersectWithLine(double p1[3], double p2[3], double tol, double& t,
00115                         double x[3], double pcoords[3], int& subId);
00117 
00119   int GetParametricCenter(double pcoords[3]);
00120 
00123   double GetParametricDistance(double pcoords[3]);
00124 
00126 
00127   static void TriangleCenter(double p1[3], double p2[3], double p3[3],
00128                              double center[3]);
00130 
00133   static double TriangleArea(double p1[3], double p2[3], double p3[3]);
00134 
00136 
00140   static double Circumcircle(double  p1[2], double p2[2], double p3[2],
00141                             double center[2]);
00143 
00145 
00156   static int BarycentricCoords(double x[2], double  x1[2], double x2[2],
00157                                double x3[2], double bcoords[3]);
00159 
00160 
00162 
00165   static int ProjectTo2D(double x1[3], double x2[3], double x3[3],
00166                          double v1[2], double v2[2], double v3[2]);
00168 
00170 
00172   static void ComputeNormal(vtkPoints *p, int numPts, vtkIdType *pts,
00173                             double n[3]);
00175 
00177   static void ComputeNormal(double v1[3], double v2[3], double v3[3], double n[3]);
00178 
00180 
00182   static void ComputeNormalDirection(double v1[3], double v2[3], double v3[3],
00183                                      double n[3]);
00185 
00187 
00192   static int PointInTriangle(double x[3], double x1[3],
00193                              double x2[3], double x3[3],
00194                              double tol2);
00196 
00198 
00201   static void ComputeQuadric(double x1[3], double x2[3], double x3[3],
00202                              double quadric[4][4]);
00203   static void ComputeQuadric(double x1[3], double x2[3], double x3[3],
00204                              vtkQuadric *quadric);
00206 
00207 
00208 protected:
00209   vtkTriangle();
00210   ~vtkTriangle();
00211 
00212   vtkLine *Line;
00213 
00214 private:
00215   vtkTriangle(const vtkTriangle&);  // Not implemented.
00216   void operator=(const vtkTriangle&);  // Not implemented.
00217 };
00218 
00219 //----------------------------------------------------------------------------
00220 inline int vtkTriangle::GetParametricCenter(double pcoords[3])
00221 {
00222   pcoords[0] = pcoords[1] = 1./3; pcoords[2] = 0.0;
00223   return 0;
00224 }
00225 
00226 //----------------------------------------------------------------------------
00227 inline void vtkTriangle::ComputeNormalDirection(double v1[3], double v2[3],
00228                                        double v3[3], double n[3])
00229 {
00230   double ax, ay, az, bx, by, bz;
00231 
00232   // order is important!!! maintain consistency with triangle vertex order
00233   ax = v3[0] - v2[0]; ay = v3[1] - v2[1]; az = v3[2] - v2[2];
00234   bx = v1[0] - v2[0]; by = v1[1] - v2[1]; bz = v1[2] - v2[2];
00235 
00236   n[0] = (ay * bz - az * by);
00237   n[1] = (az * bx - ax * bz);
00238   n[2] = (ax * by - ay * bx);
00239 }
00240 
00241 //----------------------------------------------------------------------------
00242 inline void vtkTriangle::ComputeNormal(double v1[3], double v2[3],
00243                                        double v3[3], double n[3])
00244 {
00245   double length;
00246 
00247   vtkTriangle::ComputeNormalDirection(v1, v2, v3, n);
00248 
00249   if ( (length = sqrt((n[0]*n[0] + n[1]*n[1] + n[2]*n[2]))) != 0.0 )
00250     {
00251     n[0] /= length;
00252     n[1] /= length;
00253     n[2] /= length;
00254     }
00255 }
00256 
00257 //----------------------------------------------------------------------------
00258 inline void vtkTriangle::TriangleCenter(double p1[3], double p2[3],
00259                                         double p3[3], double center[3])
00260 {
00261   center[0] = (p1[0]+p2[0]+p3[0]) / 3.0;
00262   center[1] = (p1[1]+p2[1]+p3[1]) / 3.0;
00263   center[2] = (p1[2]+p2[2]+p3[2]) / 3.0;
00264 }
00265 
00266 //----------------------------------------------------------------------------
00267 inline double vtkTriangle::TriangleArea(double p1[3], double p2[3], double p3[3])
00268 {
00269   double a,b,c;
00270   a = vtkMath::Distance2BetweenPoints(p1,p2);
00271   b = vtkMath::Distance2BetweenPoints(p2,p3);
00272   c = vtkMath::Distance2BetweenPoints(p3,p1);
00273   return (0.25* sqrt(fabs(4.0*a*c - (a-b+c)*(a-b+c))));
00274 }
00275 
00276 #endif
00277 
00278