PC Review


Reply
Thread Tools Rate Thread

Antialiasing : How it works on modern cards?

 
 
Asestar
Guest
Posts: n/a
 
      10th Apr 2004
I remember from voodoo5 days that AA filtering was made possible by drawing
an image at high resolution, say 4 times the normal display res. and then
scaling it down, thus eliminating the jaggies and getting smooth picture.
This however was a very slow process.

Can someone tell me is it the same process in current DX9 cards, like 9600,
9700, 9800 and 5700 5900?
Also does radeon8500 uses the same methos?


 
Reply With Quote
 
 
 
 
Tony DiMarzio
Guest
Posts: n/a
 
      10th Apr 2004
Actually, the Voodoo5 used RGSS/JGSS in it's FSAA implementation. Oh..
RGSS=Rotated Grid Super Sampling, JGSS=Jittered Grid Super Sampling. Rather
than render the image at 4 times the resolution (upsample) to the offscreen
buffer and scale it back down (downsample) while averaging the subsample
data around each pixel (this is OGSS or Ordered Grid Super Sampling), RGSS
takes subsample pixel data at points of random rotation around the pixel.

There are religious wars even still over which implementation is better from
a tech standpoint and from a practicality standpoint... RGSS or OGSS.... but
no one will dispute the superior IQ afforded by RGSS.

Anyway... 3dfx used RGSS. All other manufacturers (ATI and Nvidia) used, and
AFAIK still do use, OGSS.

Correct me if I'm wrong, but I'd assume all ATI cards are doing OGSS.

--
Tony DiMarzio
(E-Mail Removed)
(E-Mail Removed)

"Asestar" <a s e s t a r @ s t a r t . n o> wrote in message
news:t1Hdc.78174$(E-Mail Removed)...
> I remember from voodoo5 days that AA filtering was made possible by

drawing
> an image at high resolution, say 4 times the normal display res. and then
> scaling it down, thus eliminating the jaggies and getting smooth picture.
> This however was a very slow process.
>
> Can someone tell me is it the same process in current DX9 cards, like

9600,
> 9700, 9800 and 5700 5900?
> Also does radeon8500 uses the same methos?
>
>



 
Reply With Quote
 
Asestar
Guest
Posts: n/a
 
      10th Apr 2004
Thanks for reply. That does explain it.
However I tought that with this new breed of gpu's everyone is talking about
supperior performance with AA enabled, compaired to previous gen gpu's.

Example: a r8500/gf4ti4200 would perform somewhat same as r9600/Fx5600 in
certain cases, when AA is not enabled. However enbling AA makes newer cards
so much faster than the previous generation.

This led me to believe that there are some revolutionary change in AA
techinique with new DX9 cards. Maybe they use some kind of pixelshader
programming or whatever to do AA? Guess not then.


"Tony DiMarzio" <(E-Mail Removed)> wrote in message
news(E-Mail Removed)...
> Actually, the Voodoo5 used RGSS/JGSS in it's FSAA implementation. Oh..
> RGSS=Rotated Grid Super Sampling, JGSS=Jittered Grid Super Sampling.

Rather
> than render the image at 4 times the resolution (upsample) to the

offscreen
> buffer and scale it back down (downsample) while averaging the subsample
> data around each pixel (this is OGSS or Ordered Grid Super Sampling), RGSS
> takes subsample pixel data at points of random rotation around the pixel.
>
> There are religious wars even still over which implementation is better

from
> a tech standpoint and from a practicality standpoint... RGSS or OGSS....

but
> no one will dispute the superior IQ afforded by RGSS.
>
> Anyway... 3dfx used RGSS. All other manufacturers (ATI and Nvidia) used,

and
> AFAIK still do use, OGSS.
>
> Correct me if I'm wrong, but I'd assume all ATI cards are doing OGSS.
>
> --
> Tony DiMarzio
> (E-Mail Removed)
> (E-Mail Removed)
>
> "Asestar" <a s e s t a r @ s t a r t . n o> wrote in message
> news:t1Hdc.78174$(E-Mail Removed)...
> > I remember from voodoo5 days that AA filtering was made possible by

> drawing
> > an image at high resolution, say 4 times the normal display res. and

then
> > scaling it down, thus eliminating the jaggies and getting smooth

picture.
> > This however was a very slow process.
> >
> > Can someone tell me is it the same process in current DX9 cards, like

> 9600,
> > 9700, 9800 and 5700 5900?
> > Also does radeon8500 uses the same methos?
> >
> >

>
>



 
Reply With Quote
 
Tony DiMarzio
Guest
Posts: n/a
 
      10th Apr 2004
Well.. I'm sure there not doing AA with shaders

I don't know the specifics of how Nvidia and ATI have optimized their FSAA
OGSS implementations. I don't think anything revolutionary has occured. But!
it does seem like there is some magic going on somewhere doesn't it? The
performance hits just aren't what you'd expect.

--
Tony DiMarzio
(E-Mail Removed)
(E-Mail Removed)
"Asestar" <a s e s t a r @ s t a r t . n o> wrote in message
news:OyXdc.78234$(E-Mail Removed)...
> Thanks for reply. That does explain it.
> However I tought that with this new breed of gpu's everyone is talking

about
> supperior performance with AA enabled, compaired to previous gen gpu's.
>
> Example: a r8500/gf4ti4200 would perform somewhat same as r9600/Fx5600 in
> certain cases, when AA is not enabled. However enbling AA makes newer

cards
> so much faster than the previous generation.
>
> This led me to believe that there are some revolutionary change in AA
> techinique with new DX9 cards. Maybe they use some kind of pixelshader
> programming or whatever to do AA? Guess not then.
>
>
> "Tony DiMarzio" <(E-Mail Removed)> wrote in message
> news(E-Mail Removed)...
> > Actually, the Voodoo5 used RGSS/JGSS in it's FSAA implementation. Oh..
> > RGSS=Rotated Grid Super Sampling, JGSS=Jittered Grid Super Sampling.

> Rather
> > than render the image at 4 times the resolution (upsample) to the

> offscreen
> > buffer and scale it back down (downsample) while averaging the subsample
> > data around each pixel (this is OGSS or Ordered Grid Super Sampling),

RGSS
> > takes subsample pixel data at points of random rotation around the

pixel.
> >
> > There are religious wars even still over which implementation is better

> from
> > a tech standpoint and from a practicality standpoint... RGSS or OGSS....

> but
> > no one will dispute the superior IQ afforded by RGSS.
> >
> > Anyway... 3dfx used RGSS. All other manufacturers (ATI and Nvidia) used,

> and
> > AFAIK still do use, OGSS.
> >
> > Correct me if I'm wrong, but I'd assume all ATI cards are doing OGSS.
> >
> > --
> > Tony DiMarzio
> > (E-Mail Removed)
> > (E-Mail Removed)
> >
> > "Asestar" <a s e s t a r @ s t a r t . n o> wrote in message
> > news:t1Hdc.78174$(E-Mail Removed)...
> > > I remember from voodoo5 days that AA filtering was made possible by

> > drawing
> > > an image at high resolution, say 4 times the normal display res. and

> then
> > > scaling it down, thus eliminating the jaggies and getting smooth

> picture.
> > > This however was a very slow process.
> > >
> > > Can someone tell me is it the same process in current DX9 cards, like

> > 9600,
> > > 9700, 9800 and 5700 5900?
> > > Also does radeon8500 uses the same methos?
> > >
> > >

> >
> >

>
>



 
Reply With Quote
 
Asestar
Guest
Posts: n/a
 
      10th Apr 2004
> it does seem like there is some magic going on somewhere doesn't it? The
> performance hits just aren't what you'd expect.


Exactly the reason for my first post! I would love to get some more info
about this.. but from where? The old 3dfx site used to be so helpful back
then .. sob


 
Reply With Quote
 
Tony DiMarzio
Guest
Posts: n/a
 
      12th Apr 2004
http://www.beyond3d.com/forum/viewto...&view=previous

this should shed "some" light.

--
Tony DiMarzio
(E-Mail Removed)
(E-Mail Removed)

"Asestar" <a s e s t a r @ s t a r t . n o> wrote in message
news:XsYdc.78240$(E-Mail Removed)...
> > it does seem like there is some magic going on somewhere doesn't it? The
> > performance hits just aren't what you'd expect.

>
> Exactly the reason for my first post! I would love to get some more info
> about this.. but from where? The old 3dfx site used to be so helpful back
> then .. sob
>
>



 
Reply With Quote
 
 
 
Reply

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Microsoft Works Business Cards cmyint Windows XP General 2 3rd Jun 2010 01:51 PM
TV cards (was: Re: I pull my modem and my TV tuner works) Vic Smith Computer Hardware 9 21st Nov 2006 07:33 PM
ATi Control Panel Works on X1900 Cards? First of One ATI Video Cards 6 23rd Apr 2006 01:01 AM
How does 9800 Pro compare with modern cards? Bobby ATI Video Cards 44 24th Jun 2005 05:44 PM
Microsoft Works Greeting Cards =?Utf-8?B?am1zMmpzZg==?= Microsoft Word Document Management 0 24th Apr 2005 05:19 PM


Features
 

Advertising
 

Newsgroups
 


All times are GMT +1. The time now is 01:37 PM.