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Common/vtkTriangle.h

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00001 /*=========================================================================
00002 
00003   Program:   Visualization Toolkit
00004   Module:    $RCSfile: vtkTriangle.h,v $
00005   Language:  C++
00006 
00007   Copyright (c) 1993-2002 Ken Martin, Will Schroeder, Bill Lorensen 
00008   All rights reserved.
00009   See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
00010 
00011      This software is distributed WITHOUT ANY WARRANTY; without even 
00012      the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
00013      PURPOSE.  See the above copyright notice for more information.
00014 
00015 =========================================================================*/
00032 #ifndef __vtkTriangle_h
00033 #define __vtkTriangle_h
00034 
00035 #include "vtkCell.h"
00036 
00037 #include "vtkMath.h" // Needed for inline methods
00038 
00039 class vtkLine;
00040 class vtkQuadric;
00041 
00042 class VTK_COMMON_EXPORT vtkTriangle : public vtkCell
00043 {
00044 public:
00045   static vtkTriangle *New();
00046   vtkTypeRevisionMacro(vtkTriangle,vtkCell);
00047 
00053   vtkCell *GetEdge(int edgeId);
00054 
00056 
00057   int GetCellType() {return VTK_TRIANGLE;};
00058   int GetCellDimension() {return 2;};
00059   int GetNumberOfEdges() {return 3;};
00060   int GetNumberOfFaces() {return 0;};
00061   vtkCell *GetFace(int) {return 0;};
00062   int CellBoundary(int subId, float pcoords[3], vtkIdList *pts);
00063   void Contour(float value, vtkDataArray *cellScalars, 
00064                vtkPointLocator *locator, vtkCellArray *verts,
00065                vtkCellArray *lines, vtkCellArray *polys, 
00066                vtkPointData *inPd, vtkPointData *outPd,
00067                vtkCellData *inCd, vtkIdType cellId, vtkCellData *outCd);
00068   int EvaluatePosition(float x[3], float* closestPoint,
00069                        int& subId, float pcoords[3],
00070                        float& dist2, float *weights);
00071   void EvaluateLocation(int& subId, float pcoords[3], float x[3],
00072                         float *weights);
00073   int Triangulate(int index, vtkIdList *ptIds, vtkPoints *pts);
00074   void Derivatives(int subId, float pcoords[3], float *values, 
00075                    int dim, float *derivs);
00077 
00079 
00081   void Clip(float value, vtkDataArray *cellScalars, 
00082             vtkPointLocator *locator, vtkCellArray *polys,
00083             vtkPointData *inPd, vtkPointData *outPd,
00084             vtkCellData *inCd, vtkIdType cellId, vtkCellData *outCd,
00085             int insideOut);
00087 
00089 
00091   int IntersectWithLine(float p1[3], float p2[3], float tol, float& t,
00092                         float x[3], float pcoords[3], int& subId);
00094 
00096   int GetParametricCenter(float pcoords[3]);
00097 
00099 
00100   static void TriangleCenter(float p1[3], float p2[3], float p3[3], 
00101                              float center[3]);
00103 
00105   static float TriangleArea(float p1[3], float p2[3], float p3[3]);
00106   
00108 
00112   static double Circumcircle(double  p1[2], double p2[2], double p3[2], 
00113                             double center[2]);
00115 
00117 
00128   static int BarycentricCoords(double x[2], double  x1[2], double x2[2], 
00129                                double x3[2], double bcoords[3]);
00131   
00132   
00134 
00137   static int ProjectTo2D(double x1[3], double x2[3], double x3[3],
00138                          double v1[2], double v2[2], double v3[2]);
00140 
00142 
00144   static void ComputeNormal(vtkPoints *p, int numPts, vtkIdType *pts,
00145                             float n[3]);
00147 
00149   static void ComputeNormal(float v1[3], float v2[3], float v3[3], float n[3]);
00150 
00152 
00154   static void ComputeNormalDirection(float v1[3], float v2[3], float v3[3],
00155                                      float n[3]);
00157   
00159 
00161   static void ComputeNormal(double v1[3], double v2[3], double v3[3], 
00162                             double n[3]);
00164   
00166 
00168   static void ComputeNormalDirection(double v1[3], double v2[3], double v3[3],
00169                                      double n[3]);
00171 
00173 
00178   static int PointInTriangle(float x[3], float x1[3], float x2[3], float x3[3], 
00179                              float tol2);
00181 
00183 
00186   static void ComputeQuadric(float x1[3], float x2[3], float x3[3],
00187                              float quadric[4][4]);
00188   static void ComputeQuadric(float x1[3], float x2[3], float x3[3],
00189                              vtkQuadric *quadric);
00191   
00192 
00193 protected:
00194   vtkTriangle();
00195   ~vtkTriangle();
00196 
00197   vtkLine *Line;
00198 
00199 private:
00200   vtkTriangle(const vtkTriangle&);  // Not implemented.
00201   void operator=(const vtkTriangle&);  // Not implemented.
00202 };
00203 
00204 inline int vtkTriangle::GetParametricCenter(float pcoords[3])
00205 {
00206   pcoords[0] = pcoords[1] = 0.333f; pcoords[2] = 0.0;
00207   return 0;
00208 }
00209 
00210 inline void vtkTriangle::ComputeNormalDirection(float v1[3], float v2[3], 
00211                                        float v3[3], float n[3])
00212 {
00213   float ax, ay, az, bx, by, bz;
00214 
00215   // order is important!!! maintain consistency with triangle vertex order 
00216   ax = v3[0] - v2[0]; ay = v3[1] - v2[1]; az = v3[2] - v2[2];
00217   bx = v1[0] - v2[0]; by = v1[1] - v2[1]; bz = v1[2] - v2[2];
00218 
00219   n[0] = (ay * bz - az * by);
00220   n[1] = (az * bx - ax * bz);
00221   n[2] = (ax * by - ay * bx);
00222 }
00223 
00224 inline void vtkTriangle::ComputeNormal(float v1[3], float v2[3], 
00225                                        float v3[3], float n[3])
00226 {
00227   float length;
00228   
00229   vtkTriangle::ComputeNormalDirection(v1, v2, v3, n);
00230   
00231   if ( (length = static_cast<float>(sqrt((n[0]*n[0] + n[1]*n[1] + n[2]*n[2])))) != 0.0 )
00232     {
00233     n[0] /= length;
00234     n[1] /= length;
00235     n[2] /= length;
00236     }
00237 }
00238 
00239 inline void vtkTriangle::ComputeNormalDirection(double v1[3], double v2[3], 
00240                                        double v3[3], double n[3])
00241 {
00242   double ax, ay, az, bx, by, bz;
00243 
00244   // order is important!!! maintain consistency with triangle vertex order 
00245   ax = v3[0] - v2[0]; ay = v3[1] - v2[1]; az = v3[2] - v2[2];
00246   bx = v1[0] - v2[0]; by = v1[1] - v2[1]; bz = v1[2] - v2[2];
00247 
00248   n[0] = (ay * bz - az * by);
00249   n[1] = (az * bx - ax * bz);
00250   n[2] = (ax * by - ay * bx);
00251 }
00252 
00253 inline void vtkTriangle::ComputeNormal(double v1[3], double v2[3], 
00254                                        double v3[3], double n[3])
00255 {
00256   double length;
00257 
00258   vtkTriangle::ComputeNormalDirection(v1, v2, v3, n);
00259 
00260   if ( (length = sqrt((n[0]*n[0] + n[1]*n[1] + n[2]*n[2]))) != 0.0 )
00261     {
00262     n[0] /= length;
00263     n[1] /= length;
00264     n[2] /= length;
00265     }
00266 }
00267 
00268 inline void vtkTriangle::TriangleCenter(float p1[3], float p2[3], float p3[3],
00269                                        float center[3])
00270 {
00271   center[0] = (p1[0]+p2[0]+p3[0]) / 3.0f;
00272   center[1] = (p1[1]+p2[1]+p3[1]) / 3.0f;
00273   center[2] = (p1[2]+p2[2]+p3[2]) / 3.0f;
00274 }
00275 
00276 inline float vtkTriangle::TriangleArea(float p1[3], float p2[3], float p3[3])
00277 {
00278   float a,b,c;
00279   a = vtkMath::Distance2BetweenPoints(p1,p2);
00280   b = vtkMath::Distance2BetweenPoints(p2,p3);
00281   c = vtkMath::Distance2BetweenPoints(p3,p1);
00282   return static_cast<float>(0.25* sqrt(fabs((double)4.0*a*c - (a-b+c)*(a-b+c))));
00283 } 
00284 
00285 #endif
00286 
00287