Function BuildTopologyBufferToSend

Parallel/DIY/vtkDIYGhostUtilities.cxx:2765–2879

 */
template <class PointSetT>
void BuildTopologyBufferToSend(vtkIdList* seedPointIds,
  typename ::DataSetTypeToBlockTypeConverter<PointSetT>::BlockType ::InformationType& info,
  typename ::DataSetTypeToBlockTypeConverter<PointSetT>::BlockType ::BlockStructureType&
    blockStructure,
  int outputGhostLevels)
{
  vtkIdType maxPointId = 0;

  PointSetT* input = info.Input;

  std::set<vtkIdType> pointIdsToSend;
  std::set<vtkIdType> cellIdsToSend;
  vtkNew<vtkIdList> ids;

  for (vtkIdType pointId = 0; pointId < seedPointIds->GetNumberOfIds(); ++pointId)
  {
    pointIdsToSend.insert(seedPointIds->GetId(pointId));
  }

  std::set<vtkIdType> cellIdsToSendAtLastLevel;
  std::set<vtkIdType> pointIdsToSendAtLastLevel;

  pointIdsToSendAtLastLevel.insert(pointIdsToSend.cbegin(), pointIdsToSend.cend());

  vtkUnsignedCharArray* ghostCellArray = input->GetCellGhostArray();

  // At each level, we look at the last chunk of point its that we added (starting with
  // seed points that are on the interface between us and the neighboring block).
  for (int ghostLevel = 0; ghostLevel < outputGhostLevels; ++ghostLevel)
  {
    std::set<vtkIdType> cellIdsToSendAtThisLevel;
    std::set<vtkIdType> pointIdsToSendAtThisLevel;

    // For each point in this chunk of points, we look at every cells that use this point.
    // If the found cell has already been added as a cell to send, we skip. If not, we add it as a
    // cell to send.
    for (const vtkIdType& pointId : pointIdsToSendAtLastLevel)
    {
      input->GetPointCells(pointId, ids);
      for (vtkIdType id = 0; id < ids->GetNumberOfIds(); ++id)
      {
        vtkIdType cellIdToSend = ids->GetId(id);
        if ((!ghostCellArray ||
              !(ghostCellArray->GetValue(cellIdToSend) &
                ::GHOST_CELL_TO_PEEL_IN_UNSTRUCTURED_DATA)) &&
          !cellIdsToSend.count(cellIdToSend))
        {
          cellIdsToSendAtThisLevel.insert(cellIdToSend);
          cellIdsToSend.insert(cellIdToSend);

          ::UpdateCellBufferSize<PointSetT>(cellIdToSend, info, blockStructure);
        }
      }
    }

    // For each cells that we want to send at this level, we look at all points composing them, and
    // we add any point that has never been processed in the previous scope into the new chunk of
    // points.