Method Triangulate

Common/DataModel/vtkSimpleCellTessellator.cxx:2371–2468

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void vtkSimpleCellTessellator::Triangulate(vtkGenericAdaptorCell* cell,
  vtkGenericAttributeCollection* att, vtkDoubleArray* points, vtkCellArray* cellArray,
  vtkPointData* internalPd)
{
  assert("pre: cell_exists" && cell != nullptr);
  assert("pre: valid_dimension" && cell->GetDimension() == 2);
  assert("pre: att_exists" && att != nullptr);
  assert("pre: points_exists" && points != nullptr);
  assert("pre: cellArray_exists" && cellArray != nullptr);
  assert("pre: internalPd_exists" && internalPd != nullptr);

  int j;

  if (cell->GetType() != VTK_HIGHER_ORDER_TRIANGLE)
  {
    // build a linear polygon, call tessellate() on it and iterate over each triangle
    // by sending it to the tessellator

    //    int *faceVerts=cell->GetFaceArray(index); // implicit
    //    int numVerts=cell->GetNumberOfVerticesOnFace(index);
    int numVerts = cell->GetNumberOfBoundaries(0);

    this->Polygon->PointIds->SetNumberOfIds(numVerts);
    this->Polygon->Points->SetNumberOfPoints(numVerts);

    this->AllocatePointIds(cell->GetNumberOfBoundaries(0));
    cell->GetPointIds(this->PointIds);
    double* pcoords = cell->GetParametricCoords();

    int i = 0;
    while (i < numVerts)
    {
      this->Polygon->PointIds->SetId(i, i);                // this->PointIds[i]
      this->Polygon->Points->SetPoint(i, pcoords + 3 * i); // should be global?
      ++i;
    }

    this->Polygon->TriangulateLocalIds(0, this->TriangleIds);

    // now iterate over any sub-triangle and call triangulateface on it
    vtkIdType pts[3];
    vtkIdType ids[3];
    int c = this->TriangleIds->GetNumberOfIds();
    i = 0;
    while (i < c)
    {
      // Build the next sub-triangle
      j = 0;
      while (j < 3)
      {
        pts[j] = this->TriangleIds->GetId(i);
        // Get the point Ids (global)
        ids[j] = this->PointIds[pts[j]];
        ++j;
        ++i;
      }

      //