r_aclip   : clip routines for drawing Alias models directly to the screen.
r_alias   :
r_bsp     :
r_draw    :
r_edge    :
r_image   :
r_light   :
r_main    :
r_misc    :
r_model   : model loading and caching
r_part    :
r_poly    : routines primarily for drawing perspective correct translucent world
            polygons.  Texture date comes directly from textures rather than
            surface cache.
r_polyse  : routines for drawing sets of polygons sharing the same texture (used for Alias models)
r_rast    :
r_scan    : Portable C scan-level rasterization code, all pixel depths.
r_sprite  :
r_surf    : surface-related refresh code.
