Method BuildUseSets

Rendering/Volume/vtkUnstructuredGridVolumeZSweepMapper.cxx:2853–2927

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//------------------------------------------------------------------------------
void vtkUnstructuredGridVolumeZSweepMapper::BuildUseSets()
{
  int needsUpdate = 0;

  // If we have never created the list, we need updating
  if (this->UseSet == nullptr)
  {
    needsUpdate = 1;
  }

  // If the data has changed in some way then we need to update
  vtkUnstructuredGridBase* input = this->GetInput();
  if (input->GetMTime() > this->SavedTriangleListMTime.GetMTime())
  {
    needsUpdate = 1;
  }

  if (this->CellScalars && this->GetMTime() > this->SavedTriangleListMTime.GetMTime())
  {
    needsUpdate = 1;
  }

  // If we don't need updating, return
  if (!needsUpdate)
  {
    return;
  }

  vtkIdType numberOfPoints = input->GetNumberOfPoints();

  vtkIdList* cellNeighbors = vtkIdList::New();

  // init the use set of each vertex
  this->AllocateUseSet(numberOfPoints);

  this->UseSet->SetCellScalars(this->CellScalars);
  if (this->CellScalars)
  {
    this->UseSet->SetNumberOfComponents(this->Scalars->GetNumberOfComponents());
  }
  // for each cell
  vtkSmartPointer<vtkCellIterator> cellIter =
    vtkSmartPointer<vtkCellIterator>::Take(input->NewCellIterator());
  for (cellIter->InitTraversal(); !cellIter->IsDoneWithTraversal(); cellIter->GoToNextCell())
  {
    cellIter->GetCell(this->Cell);
    vtkIdType faces = this->Cell->GetNumberOfFaces();
    if (faces > 0)
    {
      vtkIdType faceidx = 0;
      vtkCell* face;
      vtkIdType faceIds[3];
      vtkIdType orderedFaceIds[3];
      // for each face
      while (faceidx < faces)
      {
        face = this->Cell->GetFace(faceidx);
        faceIds[0] = face->GetPointId(0);