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From: dripton@netcom.com (David Ripton)
Subject: Re: GPL-Anti Aliasing
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References: <728al2$6re$1@plug.news.pipex.net> <72bb4c$fst$1@news.mel.aone.net.au> <72d5u3$2jf$1@news.clarkson.edu> <72dav9$94e$1@news.mel.aone.net.au>
Date: Mon, 16 Nov 1998 16:07:36 GMT
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In article <72dav9$94e$1@news.mel.aone.net.au>,
David Mocnay <david@datatask.com.au> wrote:
>That would be AA, If you're right, then N2 des have anti-aliasing in game (or 
>part of it). GPL has antialiasing though Voodoo to a degree as well - in the 
>mirrors. I haven't seen a full screen anti-aias in a 3dfx game .... N2 could 
>be THE one, but I haven't seen it so I can't comment. Can you tell be if 
>N2 though 3dfx has anti-alisong on:
>- side of the road,
>- the lines on the road
>- skid maks on the rad
>- outside of the cars
>- trackside ojects

Bilinear filtering: Anti-aliasing of textures within a polygon
Edge anti-aliasing: Anti-aliasing of polygon edges

Pretty much all 3Dfx games do bilinear filtering, but edge AA
is rare on 3Dfx for two reasons.  One, it requires an extra
pass, which affects frame rate.  Two, it's incompatible with 
Z-buffering, which is used in many games for fast depth 
culling.  Edge AA is more common for Rendition games because
with that architecture it doesn't kill speed, and Rendition
doesn't support hardware Z-buffering anyway.

The latest Tomb Raider 1 3Dfx patch does full-screen AA when
you hit a function key.  (I forget which one; try 'em all.)
TR1 is limited to 30 fps, so with a modern CPU you can leave 
it on for the full game without noticing a frame rate hit.

The market has mostly followed the 3Dfx architecture, which
means lots of games using Z-buffering and not many using edge 
AA.  As resolutions increase, edge AA matters less, though 
it's still nice except when it's applied indiscriminately
and blurs text.

-- 
David Ripton    dripton@netcom.com
spamgard(tm): To email me, put "geek" in your Subject line.
