[vtkusers] Multitexturing in VTK?

[Peter Schmitt]

Is there any sort of multitexturing in VTK?  I am having a hard time
googling around for information, but maybe I'm searching for the wrong
keywords.

I would like to have a transparency map overlayed on a texture, such
that my object is colored/shaded only for darker regions on a
transparency map.

Another way to look at this:  Is there functionality to 
1. load colored texture into vtk
2. set the alpha-channel for the afforementioned colormap according to
a second texture

-- 
Pete