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saumilsingh
08-17-08, 01:50 PM
I saw a lot more AA types listed in RivaTuner than in the nVidia control panel.
So what's the different between the following?

2x1
1x2
2x2
4x4
4x 9-tap
4xS
6xS
8xS

As I understand the xS levels are supposed to be SSAA modes. But Googling around showed me that those are infact Hybrid modes and the real SSAA modes are the 2x2, 4x4 levels.
And that has got me all confused...

Also if anybody could list them in ascending order with respect to IQ, that would be great :).

fivefeet8
08-18-08, 01:29 AM
I saw a lot more AA types listed in RivaTuner than in the nVidia control panel.
So what's the different between the following?

2x1
1x2
2x2
4x4
4x 9-tap
4xS
6xS
8xS

As I understand the xS levels are supposed to be SSAA modes. But Googling around showed me that those are infact Hybrid modes and the real SSAA modes are the 2x2, 4x4 levels.
And that has got me all confused...

Also if anybody could list them in ascending order with respect to IQ, that would be great :).

2x1 SS = 2x Pure SSAA OGSS (2xAA horizontal + 0xAA vertical)
1x2 SS = 2x Pure SSAA OGSS (0xAA horizontal + 2xAA vertical)
2x2 SS = 4x Pure SSAA OGSS (2xAA horizontal + 2xAA vertical)
4x4 SS = 16x Pure SSAA OGSS
4x 9-tap = 4x MSAA(RGMS) + slight blur filter
4xS Mixed = 2x SSAA + 4x MSAA(RGMS)
8xS Mixed = 2x SSAA + 8x MSAA(RGMS)

There are other modes, but genarally, mixxed modes are a mixture of supersampling AA with multisampling AA. The pure Super sampling modes are simply that. In recent drivers, using enhancer also opens up higher levels of Mixxed modes.

Generally, the more sampling you have, the better the IQ. But the AA sampling grid pattern also affects it. RGMS is known to be better than OGMS and OGSS on near vertical and near horizontal edges. Supersampling will affect edges within geometric boundaries and alpha textures. Multisampling will not, but there are Transparency AA modes to deal with alpha textures.

saumilsingh
08-18-08, 10:21 AM
Thanks, I think I got it perfectly now :).
Just one question; are 2x1 and 1x2 SSAA better than 2x MSAA?

hemmy
08-18-08, 11:15 AM
NVM, I got em working.

4x4 = 54 fps in cs:s @ 1680
16xQ=204fps at same settings

No difference in quality I could see after examination of screens

walterman
08-18-08, 11:55 AM
With SSAA, you also enjoy better texture filtering. SSAA 2x2 + AF 16x equals to AF 64x.

SSAA is also virtually compatible with any rendering technique (including deferred shading).

If you want to play with the AA modes, try nHancer. It unlocks more modes, like 8xSQ (SSAA 2x2 + MSAA 2x).

nekrosoft13
08-18-08, 12:10 PM
Thanks, I think I got it perfectly now :).
Just one question; are 2x1 and 1x2 SSAA better than 2x MSAA?

SSAA is the best deal, performance hit sometimes is huge, but if you can keep the specific game in playable frame rate, use SSAA when ever possible.

Burnt_Ram
08-19-08, 07:02 PM
what about coverage sampling AA? i use 16xCSAA, and from what i know, when you use 16xCSAA you only get a 4xAA performance hit roughly? how does CSAA compare to other modes IQ wise? it looks really good to me.

walterman
08-19-08, 07:16 PM
CSAA is another form of MSAA, but with different number of samples in the buffers. You only calculate the extra fragments in the edges of the polys. With SSAA, you calculate all the fragments for all the pixels in the scene.

Bman212121
08-19-08, 09:30 PM
:headexplode:

I understand some of it, but all of the different AA options really have me confused most of the time. The other thing that is supposed to be around is transparency AA. From what I understood before if you're using 8x or higher it's automatically enabled on certain cards that support it.

walterman
08-19-08, 09:44 PM
MSAA only works in the edges of the polys, but, if you enable Transparency AA, the gpu will apply AA to all the pixels of a texture with transparency. This is not needed with SSAA, cause all the pixels are AA'ed.

Medion
08-20-08, 12:35 AM
2x1 SS = 2x Pure SSAA OGSS (2xAA horizontal + 0xAA vertical)
1x2 SS = 2x Pure SSAA OGSS (0xAA horizontal + 2xAA vertical)
2x2 SS = 4x Pure SSAA OGSS (2xAA horizontal + 2xAA vertical)
4x4 SS = 16x Pure SSAA OGSS
4x 9-tap = 4x MSAA(RGMS) + slight blur filter
4xS Mixed = 2x SSAA + 4x MSAA(RGMS)
8xS Mixed = 2x SSAA + 8x MSAA(RGMS)



If I remember correctly, 4xS = 2xSSAA + 2xMSAA, and 8xS = 2xSSAA + 4xMSAA. The cards that could do 8xS were not capable of doing 8xMSAA in any form, only 4x. Now 16xS is 2xSSAA + 8xMSAA. That's available (via Rivatuner and nHancer) on G80+.

walterman
08-20-08, 06:36 AM
You can check the description of the combines modes in nHancer:

4xS = 1x2 SS + 2x MS
8xS = 1x2 SS + 4x MS
8xSQ = 2x2 SS + 2x MS
16xS = 2x2 SS + 4x MS
32xS = 2x2 SS + 8x MS

16xS is playable in Half-Life 2, even with the Cinematic MOD, which is awesome :)

saumilsingh
08-20-08, 10:25 AM
^ Yep. nHancer descriptions cleared most of the confusion.

Soetdjuret
08-20-08, 10:32 AM
32xAA is the shiet! and can only be used with geforce 7 series cards in SLI right?

walterman
08-20-08, 02:06 PM
32xAA works also in the G80 & above. It does SSAA 2x2 + MSAA 8x. But, there is SSAA 4x4 too ;)

jlippo
08-21-08, 01:36 AM
One very nice thing about SSAA is that it helps to shader aliasing we see a lot in new games.
Most visible shader aliasing is usually in specular component of shaders and basically all water shaders ever written.
In most cases it just adds to an overall image quality and games end up looking a lot better than with normal MSAA.

one of the nice games I would recommend to test with SSAA is C&C3 as it gets rid of the shadow problems and makes everything look a lot better.
Crysis looks a lot better as well, but one needs to drop resulution to around 800x600 for 3x3 SSAA to be palyable. (Tough it looks amazing.)

Best way as allways for shader aliasing is the proper AA code within shaders, but I have yet to see game where they would have done so.

walterman
08-21-08, 07:50 AM
Yes, SSAA is how the AA should be (excellent IQ & compatibility), but, unluckily, it has a terrible performance hit. Maybe some day in the future with TB/s of memory bandwidth, it will be the standard.

saumilsingh
08-21-08, 04:02 PM
If I use my high resolution sky updates in GTR 2, they shimmer quite a bit with 4x MSAA.
With 8xS AA, it's all picture perfect :).

buicks suck
08-21-08, 06:26 PM
they ought to create a hw bilinear aa mode with adjustable levels of minification.

some emulators use bilinear aa.

Stevedroid
08-21-08, 10:58 PM
I wish they would expose the SSAA modes in the normal driver control panel. I don't understand why they keep them hidden.

If like me, you run a relatively low resolution (1360x768 - 720p HDTV), 2x2 SSAA is within reason for a lot of games and depending on the game can look better than even 8x MSAA.

---update---

I haven't really played around with SSAA in a while and this thread got me to play around with it again. Tried out Mass Effect at 2x2 and it looked bloody amazing. It ran around 35-50fps depending on what was going on, I'd say the average was probably around 45fps. I'm not quite sure it looks good to trade up MSAA for the framerate though. The occasional dips into the 30s are pretty jarring.

Stevedroid
08-21-08, 11:58 PM
they ought to create a hw bilinear aa mode with adjustable levels of minification.

some emulators use bilinear aa.
Huh? What is "bilinear aa"? Bilinear is only form of texture filtering as far as I know.

nekrosoft13
08-22-08, 12:02 AM
I wish they would expose the SSAA modes in the normal driver control panel. I don't understand why they keep them hidden.


for one simple reason, it would confuse most people

fivefeet8
08-22-08, 04:36 PM
If I remember correctly, 4xS = 2xSSAA + 2xMSAA, and 8xS = 2xSSAA + 4xMSAA. The cards that could do 8xS were not capable of doing 8xMSAA in any form, only 4x. Now 16xS is 2xSSAA + 8xMSAA. That's available (via Rivatuner and nHancer) on G80+.

You're correct. I missed that one. :o

walterman
08-22-08, 05:57 PM
Read nHancer descriptions. The combined modes are a mix of SSAA & MSAA.

jolle
08-26-08, 11:49 AM
Thanks, I think I got it perfectly now :).
Just one question; are 2x1 and 1x2 SSAA better than 2x MSAA?
The way SSAA works to my understanding is basicly rendering the image larger and downsample it, so on 2x2 every pixel is a average of 4 pixels (I belive this is what is called a subpixel accuracy of 4).
In this case 2x1 would render the image twice as large on the width and scale it down, and 2x1 on the height, rendering twice as high resolution, while 2x2 (or 4x) renders 4x as high resolution as currently used. (800x600 becomes 1600x1200 performancewise essentially, and my 1680x1050 would be 3360x2100)
(this can often be seen in PR screenshots of games where they took the screen at high resolution and downsized it for publish, where it gets some free SSAA compared to a 1:1 scale screenshot)

I think the 2x1 and 1x2 modes may suffer a bit from the fact that they arent working as well on vertical edges when extending horizontally and vice versa.
Might still look better then 2x MSAA though, even though 2x MSAA is applied more evenly, its still pretty weak and only works on actual geometry edges, not every pixel on screen as SSAA.