Method FillMarksInRegion

Filters/Modeling/vtkSelectPolyData.cxx:525–602

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//------------------------------------------------------------------------------
void vtkSelectPolyData::FillMarksInRegion(vtkPolyData* mesh, vtkIdList* edgePointIds,
  vtkIntArray* pointMarks, vtkIntArray* cellMarks, vtkIdType cellIdInSelectedRegion)
{
  // We do the fill as a moving front. This is an alternative to recursion. The
  // fill negates one region of the mesh on one side of the loop.
  // In contrast to ComputeTopologicalDistance, current and next front
  // in this method contain cell IDs.
  vtkSmartPointer<vtkIdList> currentFront = vtkSmartPointer<vtkIdList>::New();
  vtkSmartPointer<vtkIdList> nextFront = vtkSmartPointer<vtkIdList>::New();
  currentFront->InsertNextId(cellIdInSelectedRegion);

  // Initialize the front with the received cell ID
  constexpr int fillValue = -1;
  constexpr int boundaryValue = 0;
  cellMarks->SetValue(cellIdInSelectedRegion, fillValue);

  vtkNew<vtkIdList> neighbors;
  neighbors->Allocate(10000);
  vtkIdType numCellsInFront;
  while ((numCellsInFront = currentFront->GetNumberOfIds()) > 0)
  {
    // Iterate through all the triangles and visit all the neighbor triangles
    for (vtkIdType i = 0; i < numCellsInFront; i++)
    {
      vtkIdType id = currentFront->GetId(i);

      const vtkIdType* pts;
      vtkIdType npts;
      mesh->GetCellPoints(id, npts, pts);
      for (vtkIdType j = 0; j < 3; j++)
      {
        vtkIdType cellPointId1 = pts[j];
        vtkIdType cellPointId2 = pts[(j + 1) % 3];
        int cellPointValue1 = pointMarks->GetValue(cellPointId1);
        int cellPointValue2 = pointMarks->GetValue(cellPointId2);

        if (cellPointValue1 != boundaryValue)
        {
          pointMarks->SetValue(cellPointId1, fillValue);
        }

        if (cellPointValue1 == boundaryValue && cellPointValue2 == boundaryValue)
        {
          // This may be a boundary edge or just an edge that connects two boundary points.
          // Do a full search in the boundary edge list to find out.
          if (vtkSelectPolyData::IsBoundaryEdge(cellPointId1, cellPointId2, edgePointIds))
          {
            // cannot cross boundary
            continue;
          }
        }

        // add neighbors of this edge to the advancing front
        mesh->GetCellEdgeNeighbors(id, cellPointId1, cellPointId2, neighbors);
        vtkIdType numNei = neighbors->GetNumberOfIds();
        for (vtkIdType k = 0; k < numNei; k++)
        {
          vtkIdType neiId = neighbors->GetId(k);