> 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.
I am very concerned with the tone of your reply. I think the orginal
poster was referring to Doom to make a point about differences in
performance, not exact comparisons. Doom is obviously a toy. His point is
that even for a toy, it comes close, and it is a very successful product.
Maybe we should think about all those PCs out there that DON'T have extra
special hardware for all this intricate rendering. The average consumer
isn't going to want to buy a hulking SGI box just to do virtual
walkthroughs of the local shopping mall.
> 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".
CAD/CAM? So 3D is reserved only for high minded Visual Engineers doing
animated 3D renderings of jet engines and the Space Shuttle?
Get this: Everything that we do eventually has to have a purpose, or it's
worthless. 3D is going to be a big part of our lives, sooner or later.
Sooner, if we are allowed to free associate and invent, rather than make
revservations, and limitations. I see Doom at one end of a scale. It's the
base line. What a CAD/CAM vendor will produce is at the other end. In the
middle is a Bell curve, around the peak of which are all the products
about to be invented and marketed. Go too high on the curve, and your
limited market won't allow you to make enough money to cover costs. Go too
low, and you're one-upped. Stay in the middle, and you sell good products
to large numbers of people, whose buying patterns then suggest other
advances. It's a process. Look past Doom, to the next step. Think! Don't
throw wet blankets.
It's about time 3D came out of the lab. Doom is that first big step. Give
it credit for sparking the minds of all those little game crazy
teenagers, some of whom will some day join our ranks as top notch
computer scientists and engineers, building what THEY envision.
--- Andrew C. Esh mailto:email@example.com Computer Network Technology firstname.lastname@example.org (finger for PGP key) 6500 Wedgwood Road 612.550.8000 (main) Maple Grove MN 55311 612.550.8229 (direct) <A HREF="http://www.mtn.org/~andrewes">ACE Home Page</A>