Method FindCell

Common/DataModel/vtkClosestPointStrategy.cxx:200–273

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//------------------------------------------------------------------------------
vtkIdType vtkClosestPointStrategy::FindCell(double x[3], vtkCell* cell, vtkGenericCell* gencell,
  vtkIdType cellId, double tol2, int& subId, double pcoords[3], double* weights)
{
  // Check to see if the point is within the bounds of the data.  This is not
  // a strict check, but it is fast.
  const double* bounds = this->Bounds;
  const double tol = std::sqrt(tol2);
  if ((x[0] < bounds[0] - tol) || (x[0] > bounds[1] + tol) || (x[1] < bounds[2] - tol) ||
    (x[1] > bounds[3] + tol) || (x[2] < bounds[4] - tol) || (x[2] > bounds[5] + tol))
  {
    return -1;
  }

  // reset the visited cells
  for (vtkIdType i = 0, max = this->VisitedCellIds->GetNumberOfIds(); i < max; ++i)
  {
    this->VisitedCells[this->VisitedCellIds->GetId(i)] = false;
  }
  this->VisitedCellIds->Reset();

  // If we are given a starting cell, try that.
  vtkIdType foundCell;
  if (cell && (cellId >= 0))
  {
    foundCell = FindCellWalk(this, this->PointSet, x, cell, gencell, cellId, tol2, subId, pcoords,
      weights, this->VisitedCells, this->VisitedCellIds, this->PointIds, this->Neighbors);
    if (foundCell >= 0)
    {
      return foundCell;
    }
  }

  // The starting cell didn't work, find the point closest to the coordinates
  // given and search the attached cells.
  vtkIdType ptId = this->PointLocator->FindClosestPoint(x);
  if (ptId < 0)
  {
    return -1;
  }
  this->PointSet->GetPointCells(ptId, this->CellIds);
  foundCell = FindCellWalk(this, this->PointSet, x, gencell, this->CellIds, tol2, subId, pcoords,
    weights, this->VisitedCells, this->VisitedCellIds, this->PointIds, this->Neighbors);
  if (foundCell >= 0)
  {
    return foundCell;
  }

  // It is possible that the topology is not fully connected as points may be
  // coincident.  Handle this by looking at every point within the tolerance
  // and consider all cells connected.  It has been suggested that we should
  // really do this coincident point check at every point as we walk through
  // neighbors, which would happen in FindCellWalk.  If that were ever
  // implemented, this step might become unnecessary.
  double ptCoord[3];
  this->PointSet->GetPoint(ptId, ptCoord);
  this->PointLocator->FindPointsWithinRadius(tol, ptCoord, this->NearPointIds);
  this->NearPointIds->DeleteId(ptId); // Already searched this one.
  for (vtkIdType i = 0, numPts = this->NearPointIds->GetNumberOfIds(); i < numPts; i++)