[vtkusers] material xml file structure for samplerUniform samplerCube type for GLSL shader

[charlie_zhang at moldflow.com]

I try to use SamplerCube type in my GLSL shader but couldn't find any
document or example to show me how to define a SamplerCube in material
definition XML file.  Has anyone come across this issue too?

Your help is very much appreciated.

Charlie