SGL: Simple (Small) Graphics Library

Mostly things from Graphics Gems I needed for the photorealistic 
renderer. The polygon scan convertor was optimized for flat
rendering (with or without Z buffer).

The point is that I often need to render a small number of polygons 
into a memory buffer. Software rendering into the buffer directly 
gives me more freedom to do what I want (I can for instance render
pointers into the "frame" buffer" without any conversions) and
avoids the overhead of copying the frame buffer from graphics hardware,
which is on most systems a very expensive operation.

Philippe Bekaert - June, 20, 1997.

