Method GetCellNeighbors

Common/DataModel/vtkExplicitStructuredGrid.cxx:234–263

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//------------------------------------------------------------------------------
void vtkExplicitStructuredGrid::GetCellNeighbors(
  vtkIdType cellId, vtkIdType neighbors[6], int* wholeExtent)
{
  int ci, cj, ck;
  this->ComputeCellStructuredCoords(cellId, ci, cj, ck, true);
  int* extent = wholeExtent;
  if (!wholeExtent)
  {
    // If the whole extent have not been defined, use own extent
    extent = new int[6];
    this->GetExtent(extent);
  }
  int dims[3];
  vtkStructuredData::GetDimensionsFromExtent(extent, dims);
  dims[0]--;
  dims[1]--;
  dims[2]--;
  for (int faceId = 0; faceId < 6; faceId++)
  {
    int c[] = { ci - extent[0], cj - extent[2], ck - extent[4] };
    c[faceId / 2] += (faceId % 2) ? 1 : -1;
    bool invalidCellId =
      (c[0] < 0 || c[1] < 0 || c[2] < 0 || c[0] >= dims[0] || c[1] >= dims[1] || c[2] >= dims[2]);
    neighbors[faceId] = invalidCellId ? -1 : (c[0] + c[1] * dims[0] + c[2] * dims[0] * dims[1]);
  }
  if (!wholeExtent)
  {
    delete[] extent;
  }
}

namespace
{