Method ComputeStructuredCoordinates

Common/DataModel/vtkRectilinearGrid.cxx:360–419

------------------------------------------------------------------------------ Convenience function computes the structured coordinates for a point x[3]. The cell is specified by the array ijk[3], and the parametric coordinates in the cell are specified with pcoords[3]. The function returns a 0 if the point x is outside of the grid, and a 1 if inside the grid.

// in the cell are specified with pcoords[3]. The function returns a 0 if the
// point x is outside of the grid, and a 1 if inside the grid.
int vtkRectilinearGrid::ComputeStructuredCoordinates(
  const double x[3], int ijk[3], double pcoords[3])
{
  int i, j;
  double xPrev, xNext, tmp;
  vtkDataArray* scalars[3];

  int dims[3];
  this->GetDimensions(dims);

  scalars[0] = this->XCoordinates;
  scalars[1] = this->YCoordinates;
  scalars[2] = this->ZCoordinates;
  //
  // Find locations in x-y-z direction
  //
  ijk[0] = ijk[1] = ijk[2] = 0;
  pcoords[0] = pcoords[1] = pcoords[2] = 0.0;

  for (j = 0; j < 3; j++)
  {
    xPrev = scalars[j]->GetComponent(0, 0);
    xNext = scalars[j]->GetComponent(scalars[j]->GetNumberOfTuples() - 1, 0);
    if (xNext < xPrev)
    {
      tmp = xNext;
      xNext = xPrev;
      xPrev = tmp;
    }
    if (x[j] < xPrev || x[j] > xNext)
    {
      return 0;
    }
    if (x[j] == xNext && dims[j] != 1)
    {
      return 0;
    }

    for (i = 1; i < scalars[j]->GetNumberOfTuples(); i++)
    {
      xNext = scalars[j]->GetComponent(i, 0);
      if (x[j] >= xPrev && x[j] < xNext)
      {
        ijk[j] = i - 1;
        pcoords[j] = (x[j] - xPrev) / (xNext - xPrev);
        break;
      }

      else if (x[j] == xNext)
      {
        ijk[j] = i - 1;
        pcoords[j] = 1.0;
        break;
      }
      xPrev = xNext;
    }
  }