From:	Tudor <tudor AT cam DOT org>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Allegro perspective-correct texture mapping
Date:	Thu, 06 Mar 1997 09:52:58 -0800
Organization:	Communications Accesibles Montreal
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Message-ID:	<331F047A.271F@cam.org>
References:	<5fg3s0$hob$1 AT troll DOT powertech DOT no>
Reply-To:	tudor AT cam DOT org
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Ove Kaaven wrote:
> 2. The perspective-correct mapping is also somewhat slower than what's
> appropriate for games like Doom or Duke3D. By looking at the Allegro
> sources, it seems to be calculating scanlines the 'traditional' way.
> Are there plans to provide optimized routines for horizontal and
> vertical surfaces, or even better, the method described in zed3d
> (letting the logical scanlines you map onto be slanted themselves) to
> have a very fast perspective mapper?
Games like DOOM or DUKE3D don't use polygons and textures.They use
raytracer engines. If you are talking about Quake, it 'cheats' in the
way it maps textures.It combines affine with perspective correct or
somthin like that.Like it's doing a correction only every 16 pixels. The
result is a faster texture mapper but still 'perspective correct' for
the human eye & mind. 
> 3. What should I give Shawn for his excellent library?
If you make a big game, a copy of it would be nice.. 

-- 
tudor 'at' cam 'dot' org
http://www.cam.org/~tudor
'This is Scott Nudds of the Borg. C is irrelevant.'

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