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From: dripton@netcom.com (David Ripton)
Subject: Re: GPL, Voodoo cards, and anti-aliasing...
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Date: Thu, 15 Oct 1998 14:50:45 GMT
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In article <7044dm$opv$1@news.mel.aone.net.au>,
David Mocnay <david@datatask.com.au> wrote:
>In article <36251EDC.3805@mordor.com>, gollum@mordor.com wrote:
>>webster, @, dnai, ., co, m wrote:
>Papyrus is not too far off when they say 3dfx can't do antialiasing. It can do 
>it, but your framerate will practically half (if not even more). Unlike 
>Rendition cards, 3dfx cards do not have a secondary video buffer (this is 
>where the the programmers would do the antialiasing). What you have to do with 
>the 3dfx in order to antialias is display your image (with no antialising), 
>then read it back to RAM, do the antialiasing, and then display it again on 
>the 3dfx card. As you can see, you could have displayed another frame in 
>between if you were not doing antialiasing.
>
>All in all, more corect way of saying it is "that anialiasing is not feasable 
>on 3dfx). Damn shame, if you ask me.

While you're correct about AA requiring an extra pass on 3Dfx cards, a
Voodoo 2 should have enough muscle to handle it at 640x480 and still 
give good frame rates.  Most people would probably prefer running at
higher resolution, so I can understand Papy's decision not to code it.

>ps. TR 2 does not have antiasing. Maybe you mean 'bilinear filtering". 
>Antialising concorns blending of the edges, while "bilinear filtering" has to 
>do with blending of the inside of the polygon.

Dunno about TR2, but the later 3Dfx patches for Tomb Raider 1 do 
indeed support edge antialiasing.  Improved the look of things quite 
a bit (except for an occasional artifact white line around Laura's 
left pistol), but it significantly hurt frame rate.  Of course, 
that was almost two years ago; with a modern CPU the game would stay 
locked at 30 fps (its limit) even with AA on.  I should go back and 
finish that game one of these days...

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