[vtkusers] render rgba volume

[Martin Dulovits]

I have a volume in rgba png files and would like to render them without 
any further processing.
I got the advice to use IndependentComponentsOff() and the 
vtkFixedPointVolumeRayCastMapper, but I could not get it to work.
In older forum posts its claimed not to be possible in vtk 4, but I 
think it is possible with vtk 5.8 which I am using. So my questions are:
Does anybody have a working example of rgba volume rendering ?
Is it possible in vtk 5.8 ?
Does it need special opengl features or should it work anywhere ?
Is it possible for 16bit images ?
Is it possible for floating point images ?

best martin