[vtk-developers] Bug in vtkMapper

[Prabhu Ramachandran]

Hi,

I found a bug in vtkMapper.cxx.  I have a test case and fix that I will 
check in but I thought I'd mention the bug here and get consent before I 
check in.

The vtkMapper::MapScalars(double alpha) sets the lookup table's Alpha 
ivar to alpha and does not reset the lookup table's Alpha back to what 
it originally was.  This is a bug and manifests itself nicely when you 
have a translucent actor along with an ImagePlaneWidget say and they 
share a LUT.  The IPW will incorrectly and mysteriously acquire the 
alpha of the actor because of this.

The bug is also present in vtkMapper::MapScalarsToTexture which I will 
also fix.

Please let me know if this is not a bug and I'm missing something.  If 
no one objects I'll check in a test case for this and a fix as well. 
Thanks.

cheers,
prabhu