[vtkusers] How do I get triangles from the vtkPolyData that vtkDelaunay2D produces?

[Grant Edwards]

I've been Googling and wandering through the class references
most of the afternoon, but I can't figure out how to get the
triangles out of the vtkPolyData that vtkDelaunay2D produces?

I can get the vertex corredinates like this:

  delny = vtk.vtkDelaunay2D()
  delny.SetInput(profile)
  delny.SetTolerance(0.001)
  delny.Update()

  o = delny.GetOutput()

  vertexes = [o.GetPoint(i) for i in xrange(o.GetNumberOfPoints())]  

When I use vtkPolyDataWriter to write output to a file, I can
see that there are 84 triangles, and 'o' is a vtkPolyData
object that has 84 cells and 84 polygons, so they obviously
represent the triangles, but I can't figure out how to get
something useful out of the cells or polys.  What I'm
ultimately looking for is a list/array of 3-tuples containing
indexes into the vertex list obtained via the alls to GetPoint().
  
[I've probably stumbled past the answer multiple times but
didn't recognize because I don't really grok C++.]

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