This subdirectory contains materials that apply shaders from the 
'OrangeBook', "The OpenGL Shading Language" by Randi J. Rost.

Some materials shaders work fine, some don't. The main reason is
that VTK currently can only populate 4 vertex attributes and a
single 2D texture. Work is currently being done to overcome this
and allow VTK full access to set these values.
