Function FindCellWalk

Common/DataModel/vtkClosestPointStrategy.cxx:132–175

------------------------------------------------------------------------------ Used internally by FindCell to walk through neighbors from a starting cell. The arguments are the same as those for FindCell. In addition, visitedCells keeps a list of cells already traversed. If we run into such already visited, the walk terminates since we assume we already walked from that cell and found nothing.

// internally.  They are passed in so that they do not have to be continuously
// reallocated.
vtkIdType FindCellWalk(vtkClosestPointStrategy* self, vtkPointSet* ps, double x[3], vtkCell* cell,
  vtkGenericCell* gencell, vtkIdType cellId, double tol2, int& subId, double pcoords[3],
  double* weights, std::vector<unsigned char>& visitedCells, vtkIdList* visitedCellIds,
  vtkIdList* ptIds, vtkIdList* neighbors)
{
  constexpr int VTK_MAX_WALK = 12;
  double closestPoint[3];
  double dist2;
  for (int walk = 0; walk < VTK_MAX_WALK; walk++)
  {
    // Check to see if we already visited this cell.
    if (visitedCells[cellId])
    {
      break;
    }
    visitedCells[cellId] = true;
    visitedCellIds->InsertNextId(cellId);

    // Get information for the cell.
    cell = self->SelectCell(ps, cellId, cell, gencell);

    // Check to see if the current, cached cell contains the point.
    if ((cell->EvaluatePosition(x, closestPoint, subId, pcoords, dist2, weights) == 1) &&
      (dist2 <= tol2))
    {
      return cellId;
    }

    // This is not the right cell.  Find the next one.
    cell->CellBoundary(subId, pcoords, ptIds);
    ps->GetCellNeighbors(cellId, ptIds, neighbors);
    // If there is no next one, exit.
    if (neighbors->GetNumberOfIds() < 1)
    {
      break;
    }
    // Set the next cell as the current one and iterate.
    cellId = neighbors->GetId(0);
    cell = nullptr;
  }

  // Could not find a cell.
  return -1;
}

//------------------------------------------------------------------------------
vtkIdType FindCellWalk(vtkClosestPointStrategy* self, vtkPointSet* ps, double x[3],