[vtkusers] vtkPointPicker peter_piper

[Erik Sobel]

Does anyone know how to convert a display point (x,y) to a world point?

I've tried...
	ren1  SetDisplayPoint $x $y 0
	ren1 DisplayToWorld
	set wp [ren1 GetWorldPoint]
This sort of worked until I moved the camera then the values were screwy.

I've tried
	vtkPointPicker pp
	pp Pick $x $y 0 ren1
(hmmm, ok now how do I get the world coords out of this confounded object ????)

What's the difference between a vtkPointPicker and a vtkWorldPointPicker? 
vtkNitPicker? vtkNosePicker?

vtkPointPicker peter_piper
proc  Pick_Pickled_Peppers {} {
	if  { [ peter_piper Pick $x $y 0 renP ] == $PECK } {
		return $NUM_PICKLED_PEPPERS
	}
}

-Erik