Can someone please explain AA to me

[Kippa]

In a previous thread someone mentioned that you loose a lot of detail using TXAA over FXAA. I can understand the principle of AA, getting rid of jagged edge. Could some please explain in laymans the different types of AA and what would be ideal to choose. I don't want a flame war between people about which is best, just a general description to inform me which one I would choose in a game.

 

[bystander36]

I'm not sure about TXAA, as it is almost never used and very new to begin with.

FXAA, SMAA, MLAA and even partially TXAA (if I understand correctly on TXAA) are all post process, and tend to blur the whole picture, as they don't target edges, and instead try to fix any jaggy on the screen.

SSAA communicates with the software and fixes aliasing on the entire screen as well, but does a much better job than the above post process versions. It too causes some blurring.

MSAA, CSAA and QSAA are about the only types of AA that do not cause blurring, as they only target the edges of objects.

 

[BallaTheFeared]

Every option is a compromise of something, nothing hits every point of important and succeeds at them.

 

[cmdrdredd]

SSAA should never blur. It renders the game at a higher resolution and then downsamples. The result is a much larger peroformance hit.

 

[bystander36]

SSAA should never blur. It renders the game at a higher resolution and then downsamples. The result is a much larger peroformance hit.

It does more than that, and it clearly blurs, at least part of the time.

http://naturalviolence.webs.com/sgssaa.htm

If you goggle: ssaa blurry, you'll get a lot of people who experience the same thing.

 

[Black Octagon]

Never heard of SSAA causing blurring. Interesting

 

[bystander36]

I never found it distracting, but I did when I was playing Dragon Age Origins with 4x SGSSAA with the monitor less than a foot away. I was seeing how it would feel to have my peripheral vision being taken up by the screen and I found that SGSSAA caused a very distracting blur that went away when disabled.

If viewed at a little distance, it doesn't pop out at me.

Edit: according to the link I posted, at least some of the time, or maybe they mean all the time, if it blurs with SGSSAA it won't with OGSSAA and visa versa.

 

[Tempered81]

you can also fix ssaa blur with a Negative LOD offset

 

[RussianSensation]

Never heard of SSAA causing blurring. Interesting

SSAA without LOD causes blur/loss of detail.

http://www.computerbase.de/artikel/grafikkarten/2012/nvidia-geforce-310.33-beta/2/

 

[boxleitnerb]

SGSSAA to be exact. OGSSAA doesn't blur (unless you apply a filter afterwards like Tomb Raider does) and doesn't need LOD adjustment. This is exactly why one should distinguish between these terms and not just write SSAA.

 

[Black Octagon]

^Ok thanks, but for those of us on AMD setups the choice is simply 'supersampling' on or off. I don't know if AMD uses SGSSAA or OGSSAA. If it's SGSSAA (someone please confirm) how does one enable a 'Negative LOD offset'? Perhaps by setting Texture LOD to zero in RadeonPro?

 

[boxleitnerb]

AMDs solution is SGSSAA. LOD adjustment is automatic with AMD and Nvidia, although with Nvidia you can adjust manually on top of that if you want a sharper or smoother image.
OGSSAA is simply rendering the image in a higher resolution and then downscaling it. It is very inefficient in terms of performance and image quality, but it is much more compatible with current rendering engines since it doesn't require MSAA as a prerequisite. SGSSAA can conflict with many post processing effects and blur even with LOD adjustment. In older games it is the better solution imo, in newer games it highly depends on the game in question.

 

[Black Octagon]

LOD adjustment is automatic with AMD...does this mean that you do NOT have to manually set it to zero then? Wouldn't this then mean that blur from SGSSAA is automatically removed? (scratches head)

 

[boxleitnerb]

You don't want zero, zero is without SGSSAA.
Normally you would go with this formula:
bias = -0.5 * log2(samples)

no SGSSAA -> 0
2x SGSSAA -> ~ -0.5
4x SGSSAA -> ~ -1.0 (automatic adjustment value -0.8)
8x SGSSAA -> ~ -1.5 (automatic adjustment value -1.2)

But yes, the blur is automatically removed - to an extent. Due to the lower value that AMD and Nvidia use (compared to the mathematically "correct" solution) and due to conflicts with certain game effects, a manual adjustment could be beneficial in some cases.

 

[Grooveriding]

Games like Metro:LL and Tomb Raider are using SSAA where the image is being rendered at a higher resolution and downsampled, for example if your resolution is 2560x1600 and you run 2xSSAA the game is actually rendering at 3584x2240.

It looks great and there is no blur, but man is the performance hit heavy.

 

[boxleitnerb]

Tomb Raider certainly blurs because there is something else going on. It's not just downsampling, but there is a filter of some sort applied as well. As for Metro:LL I don't know, but I can check later. Will be difficult to see because their AAA or what they call it is always on, even with SSAA and cannot be deactivated.

 

[cmdrdredd]

Tomb Raider certainly blurs because there is something else going on. It's not just downsampling, but there is a filter of some sort applied as well. As for Metro:LL I don't know, but I can check later. Will be difficult to see because their AAA or what they call it is always on, even with SSAA and cannot be deactivated.

Maybe you can show a couple screenshots of this or something? I have a hard time understand what you see as blur. FXAA is blur to me, but it is free in terms of performance.

 

[Smoblikat]

SGSSAA to be exact. OGSSAA doesn't blur (unless you apply a filter afterwards like Tomb Raider does) and doesn't need LOD adjustment. This is exactly why one should distinguish between these terms and not just write SSAA.

How many letters can we make our AA names?

Heres mine:
RCAENBSSSAAFCK

Really cool and effective no blur super super sampling anti aliasing for cool kids

 

[SirPauly]

Blur is used a lot and some users don't subjectively like a smoother image, while some do!

Third party tools may be the answer!

SweetFX is a nice third party tool that offers flexibility for gamers to make their games sharper; to find the right balance for their subjective taste, tolerance and threshold.

The ability to add negative lod with tools like nVInspector are welcomed as well, may help, too.

In game commands, at times, help as well, for example Crysis 3:

r_Sharpening - Crysis 3

Controls the level of the post-processing image sharpening filter. Higher values give more sharpening, but too high values will create artifacts. A value of 0.0 is off

Default value: 0.25

Anti-aliasing encompasses a great deal from polygon edges, moire, alpha tests and transparencies, pixel popping to shimmering, specular to various shadow and shader methods, etc.. This is why there are so many types of AA methods -- each with their strengths and weaknesses.

Many users may look at image quality differently -- my subjective foundation is quality of the pixel while moving -- why features like SGSSAA, RGSSAA, hybrid mixed modes, flexibility and quality with TRSSAA, higher quality filtering over the years, TXAA are very important.

With the foundation of quality while moving is there -- can add detail to my subjective taste by utilizing thrid party tools!

 

[Black Octagon]

I can't help but think we need higher res monitors and higher res in-game textures to become the standard so we can leave the world of AA behind altogether. It's too much to keep up with without spending some serious time researching all the different methods

 

[boxleitnerb]

Maybe you can show a couple screenshots of this or something? I have a hard time understand what you see as blur. FXAA is blur to me, but it is free in terms of performance.

http://www.hardocp.com/image.html?image=MTM2MzIxNDEyMzR2MlRrVGJQZE1fN18yX2wuanBn
http://www.hardocp.com/image.html?image=MTM2MzIxNDEyMzR2MlRrVGJQZE1fN18zX2wuanBn

I think it's clear

How many letters can we make our AA names?

Heres mine:
RCAENBSSSAAFCK

Really cool and effective no blur super super sampling anti aliasing for cool kids

Sorry, but there is a distinct difference between these modes, you cannot call them by the same term. One has to take into account the sampling grid (sparse, ordered, rotated).

 

[bystander36]

http://www.hardocp.com/image.html?image=MTM2MzIxNDEyMzR2MlRrVGJQZE1fN18yX2wuanBn
http://www.hardocp.com/image.html?image=MTM2MzIxNDEyMzR2MlRrVGJQZE1fN18zX2wuanBn

I think it's clear

The SSAA versions do seem to have a little blur to it, but what you don't get from the still images, is how well SSAA prevents jaggies from moving up and down edges when objects/foliage moves across the screen. That is the part that I like most about SSAA.

 

[boxleitnerb]

^ true, I don't deny that. The blur is definitely there, though. When using driver-based downsampling, there is no blur, but it is also a little less smooth.

 

[TypicalEmiraty]

I think nothing explains this better than real world gaming examples, GeForce experience gives me a fairly good explanation for what is used for what in most of the games I have Installed in my Rig.
So I will post for you some.. =)

 

[Red Hawk]

Tomb Raider certainly blurs because there is something else going on. It's not just downsampling, but there is a filter of some sort applied as well. As for Metro:LL I don't know, but I can check later. Will be difficult to see because their AAA or what they call it is always on, even with SSAA and cannot be deactivated.

I think it's true that Tomb Raider effectively combines FXAA with SSAA when running either of the SSAA settings. The thing about it though is that the FXAA is applied before the downsampling, essentially giving the FXAA a whole lot more sub-pixel information to work with and resulting in much less blur than FXAA without SSAA.