OpenGLContext.shadow

Stencil-buffer-based shadowing implementation

From an article by Eric Lengyel in Gamasutra: http://www.gamasutra.com/features/20021011/lengyel_01.htm and the related paper: http://developer.nvidia.com/docs/IO/2585/ATT/RobustShadowVolumes.pdf

Python implementation by Mike Fletcher. Note that this is not a direct translation of the original approach.

Also note that, although I'm trying to follow the examples, most of the actual code in the article just wouldn't fly in Python, so I tend to use a lot of Numeric Python functions instead.

Usage: OpenGLContext.shadow.shadowcontext.ShadowContext is a mix-in class for Contexts which provides the necessary features for rendering shadows.

Notes: Only IndexedFaceSet nodes may cast shadows in the current implementation.

Single-face edges are not supported, and will cause artifacts.

There will be problems trying to render degenerate faces.