[Quake-devel] FSAA on the cheap?

[Jeff E. <je...@us...>]

Aside from accumulation buffer (t-buffer) and similar tricks,
OpenGL provides for polygon antialiasing by selecting the
following bits of state:
     // enable polygon antialiasing
     glBlendFunc( GL_SRC_ALPHA_SATURATE, GL_ONE );
     glEnable( GL_BLEND );
     glEnable( GL_POLYGON_SMOOTH );
and additionally rendering all polys in depth-sorted order.

It's my understanding that Quake uses a BSP tree with additional visibility
information to cull portions of the tree.  One property of a BSP tree
is that you can extract polygons in a depth-sorted order (Thus, BSP trees
were suitable for rendering with painters algorithm, avoiding the need for
a Z-buffer -- back in the "doom" timeframe, I guess)

Entities might have their polys sorted each frame, or not be antialiased
at all.

Anyone know of a reason not to spend some time trying to implement this?

Jeff