I just found this stale note in my reader:
> As far as "free" texture mapping, take a look at Doom running on
> a PC sometime. Software renderers are much better at doing that kind of
> stuff than current SGI hardware. I've got an indy and a pentium on my
> desk. Using commercially available software renderers, the pentium kills
> the indy on texture performance (ie: it can do it without a problem), and
> is pretty close to polygon performance. This is without specialized 3D
> hardware. For the most part I think that a lot of the specialized 3D
> hardware will just make OpenGL tolerable on a PC, because right now it's
> horrible.
I am very concerned about the tone that this note is taking. This is an
apples-to-oranges comparison. OpenGL texture mapping is "general",
where the texture can be strecthed, shrank, oriented in whatever way on
whatever shape, while DOOM only works on "traps" (trapezoids -- quads
with horizontal or vertical edges (or degenerate triangles), with textures
aligned to match. The quality of the image is far different -- get close
to a wall in DOOM, and tell me that's high-quality texture mapping. Then
there's the age-old argument about sorting polygons vs. depth-buffering.
It's just a different class of features/functions, and the resulting
performance is (very) different.
The point is that no serious CAD/CAM vendor would even think of using DOOM
for thier engineering drawings -- its too broke, and too feature-limitied
in too many ways. OpenGL was/is designed to be a very general-purpose,
do-it-all, easy-to-use, h/w-acclerated 3D API. DOOM was designed to be
a cut-corners, never-mind-the-hacks, who-cares-if-looks-wiggy-if-its-fast
game application. It's kind of a mistake to point at DOOM and say, "do
that", and "ohh, do that in a general-purpose way".
-- on a diffenret note -- maybe you have a really bad implementation of
OpenGL on the pentium. The one I have cranks.
--linas