>>47 http://en.wikipedia.org/wiki/Glide_API Glide is based on the basic geometry and "world view" of OpenGL. OpenGL is a large graphics library with 336 calls[citation needed] in the API, many of which are of limited use. Glide was an effort to select primarily features that were useful for real-time rendering of 3D games.
i.e. it's a stripped down GL.