[vtkusers] Update vtkDelaunay2d object

[Jordi Gutiérrez Hermoso]

I have code like this in a class:

    //add the grid points to the polydata object
    vtkSmartPointer<vtkPolyData> polydata = vtkPolyData::New();
    polydata->SetPoints(points);
    polydata->GetPointData() -> SetScalars(scalars);

    //triangulate the grid points
    vtkSmartPointer<vtkDelaunay2D> delaunay = vtkDelaunay2D::New();
    delaunay->SetInput(polydata);
    delaunay->Update();

And later this goes through the pipeline until I generate a plot.

I want to plot a moving surface, so that the polydata object needs to
be updated but only the z-coordinates, so that the actual Delaunay
triangulation shouldn't have to be computed again.

How can I update the polydata object with new points and scalars
without recomputing a Delaunay triangulation?

Thanks,
- Jordi G. H.