[vtkusers] Render/mapping progress

[Patrick D. Emond]

Hello all,

I was looking into how to add observers to a mapper's progress and from 
what I can tell the only mapper class that invokes progress events is 
vtkFixedPointVolumeRayCastMapper through a macro in 
vtkFixedPointVolumeRayCastHelper.h called 
VTKKWRCHelper_IncrementAndLoopEnd()

I was wondering if anyone out there knows why there are no progress 
events invoked in any other mappers.  My first thought was to go ahead 
and try to figure out how to implement them, but before I go to the 
trouble I wanted to know if there is a good reason why this has never 
been done.

Cheers,
Patrick