Anti-aliasing Part 1: Supersampling – If it were a perfect world.

[EnJoY]

New blog at TechREACTION by user Randomizer:


Most people can’t stand the sight of aliasing, the staircase effect most noticeable on the edges of objects (or polygons to be more precise). It’s even worse when movement is involved, as the “jaggies” often appear to “crawl.”

A pixel must be only one colour (or no colour at all). To determine the colour of a pixel, a sample is taken from the centre of the pixel, and whatever the colour is at that point, the whole pixel becomes. Full screen anti-aliasing (hereafter called AA) is an evolving method of dealing with this problem. One of the earliest methods for performing AA was supersampling. This is a brute force method for applying AA to the entire screen.

In simple terms, supersampling takes all screen space coordinates (which are generated for a specific screen resolution) and up-samples them, usually by at least a factor of 2. This means that for a frame displayed at 1680×1050, the up-sampled version would be rendered at 3360×2100 in the buffer, and for every pixel of the original frame we now have four; double in each direction.

Now that there’s a high-resolution frame to work with, we need to down-sample it again to fit the screen. The colours of each of the four pixels are averaged (where the sample is taken in each pixel is determined by on of several methods, which are beyond the scope of this post), and this average colour is used to fill a single pixel in the down-sampled frame, which is now the same size as the original; equal to the screen resolution. Going back to the image above, rather than being either black or white, a pixel could be a shade of grey, which “smooths” the edge.

Full Article Here (http://www.techreaction.net/2009/10/16/anti-aliasing-part-1-supersampling-if-it-was-a-perfect-world/)

[SoulsCollective]

Eh, I don't really like SS because it tends to blur everything and reduce the crispness of textures. Good to have the option with my 5870, played with it for a while, but turned it off.

[Blkout]

Eh, I don't really like SS because it tends to blur everything and reduce the crispness of textures. Good to have the option with my 5870, played with it for a while, but turned it off.

2xSS isn't bad at all on the 5800 series. I use it in a lot of games, it's only a slight loss of texture detail, but it's easier on the video card than 8xMS Edge Detect and does a better job too. 4xSS is too much texture blurring for my tastes.

[SoulsCollective]

2xSS isn't bad at all on the 5800 series. I use it in a lot of games, it's only a slight loss of texture detail, but it's easier on the video card than 8xMS Edge Detect and does a better job too. 4xSS is too much texture blurring for my tastes.
That's interesting. It was quite noticeable for me even at 2x. As in, I wondered what was up with the game - then remembered AA. I can see it being useful in older titles where jaggies are more of a problem and textures blurring would be less of an issue, but for modern games with high-res texture packs it's just too much.

This is why we need game-specific profiles with ATi - stop dicking around changing the skin in Cat A.I and get to implementing a decent, per-game profile system! nVidia can do it, it's not that hard.

[Chumbucket843]

i love supersampling. it just eats up my bandwidth like crazy though. MSAA is for n00bs.

[Xello]

Yeah can't beat some supersampling just get ready for your fps to drop from 360 to 60 lol.

[Blkout]

Yeah can't beat some supersampling just get ready for your fps to drop from 360 to 60 lol.

My LCD monitor can only display 60fps anyway with V-sync enabled so I have no use for the remaining 300fps.

2xAA SS on the ATI 5800 series is faster than 8xAA MS and almost as fast as 4xAA MS and provided better IQ than both. It's only at 4xAA SS that performance really starts to drop and IQ takes a hit due to blurring textures, but that should be resolved in a future driver update with negative LOD adjustment.

[Blkout]

With Crossfire 5850's I have the option of 16xAA MS, but I've yet to find a game that can use it without trying to force it in the control panel which gives mixed results, often not even working at all. IN all of my testing, 4xAA SS provides the best AA, but the texture blurring is a little distracting to me so I find 2xAA SS to be the best compromise of IQ and performance. I choose 2xAA SS over any MS, even 8xAA MS edge detect.

[Der_KHAN]

strange, i've never noticed texture blurring back in the days when all video cards did SS only and no MS. could it be that ati does something differently with its SS method now?

[Chumbucket843]

strange, i've never noticed texture blurring back in the days when all video cards did SS only and no MS. could it be that ati does something differently with its SS method now?
you just need to adjust LOD with ATi tray tool. nvidia's ssaa handles that by itself. crysis looks amaing in that shot. the foliage is improved a lot.
http://www.pcgameshardware.com/aid,695689/Radeon-HD-5870-Review-of-the-first-DirectX-11-graphics-card/Reviews/?page=6

[Der_KHAN]

...crysis looks amaing in that shot. the foliage is improved a lot. ...wait, i have discussed that before... *digging through old posts* ... yeah, that was 2 years ago: Crysis and Transparency Anti-Aliasing (http://www.xtremesystems.org/forums/showthread.php?t=164118)

[WrigleyVillain]

This is why we need game-specific profiles with ATi - stop dicking around changing the skin in Cat A.I and get to implementing a decent, per-game profile system! nVidia can do it, it's not that hard.

Seriously.

[Chumbucket843]

wait, i have discussed that before... *digging through old posts* ... yeah, that was 2 years ago: Crysis and Transparency Anti-Aliasing (http://www.xtremesystems.org/forums/showthread.php?t=164118)

thats probably because cryengine2 uses parallax occlusion mapping. it does a really good job of creating depth. this was done with no AF at all.:shocked:
http://img687.imageshack.us/img687/5189/crysis2009111218213392.th.png (http://img687.imageshack.us/i/crysis2009111218213392.png/)

[aNoN_]

Interesting thread. I need to clear up a few things... First of all, ATI's new supersample method is not like the one Nvidia uses along with nHancer. Textures and the image wont get blurry when using SS on NV cards, but it does on radeon's 5series. This as we know can be fixed by negative LOD. Crysis, doesn't really support TAA or transparency-AA but you can activate it if you force TAA via the graphics control panel, activates 4 or 8x regular AA from the crysis ingame options meny, then look up at the Palmleaves above you and swap to your pistol (this pistol thing is the only way to activate TAA in crysis and it's some kind of shaderbugg lol, but am not joking) TAA in crysis doesn't affect the performance much, maybe minus 5 - 10 fps down thats all. And it does look really nice, but this forces you to play crysis with only the pistol(s)

SSAA is alot more nice than both regular MSAA and TAA even together because, it removes the jaggies alot more effective and also totally removes the need for any anisotropic filtering. It also makes the image alot more sharp and detailed, every small details gets a real lift.

Chumbucket, Parallax oc mapping is nice indeed, but it wont work along with AF as AF wont affect textures that are affected by POM. Although, if using supersample AA the pom will look alot better at distance where AF doesnt work.


Now, can someone take a few highres pics in Crysis comparing the radeon 5 series SS modes, and comparing it to regular AA please? Am unsure if TAA will work in crysis using the new radeons, but it does work on nvidia cards as described above.

That's my 2 cents :)

[aNoN_]

bump

[aNoN_]

noob forum... dead forum...

[zshadow]

http://relm.exophase.com/crysis/Crysis64%202010-01-02%2014-40-55-84.png

^ shot of Crysis with 8xSSAA on a 5970. Had to run it in DX9 because ATI's SSAA implementation does not work in DX10.