Future of MSAA?

[Jerry Cornelius]

super sampling is neat, but in an ideal world texture aliasing problems should be solved at the texturing stage. Still, some kind of properly patterned 4x fsaa will probably be just the ticket to smooth out the ultra high res systems everyone will probably have in a few years.

 

[Simon F]

Thats what i'd like to see in hardware
http://www.cs.uaf.edu/~genetti/Research/Papers/CGF98/ASOS.html
Unfortunately, its raytracing by its very nature.

Pyramidal rays? In my first job I wrote a ray tracer that used conic rays as suggested by Amantides. Great for AA because it's very hard for something to "slip through the gaps" between rays.

 

[Fox5]

Why? It might be a matter of taste. I don't like bluriness, and at 1600x1200 I don't really see any benefits. At whatever multiple of that, there'll be no difference IMHO.

Anti-aliasing cannot be equated to blurriness. And yes, there will be a difference. One of the things that has cropped up in this thread, for example, is texture aliasing.

For years we've had simple texture filtering methods to get rid of (for the most part) texture aliasing. This has reduced a great deal of the need for FSAA. But, we are now moving into a time when we're no longer using basic textures for all surfaces, and thus the old techniques of texture filtering are breaking down. There are very significant artifacts involved with texture aliasing that cannot simply be done away with by increasing the resolution.

Anyway, aliasing will always depend upon the resolution and the game, but yes, even at 4096x3072, there will still be visible aliasing in specific in-game scenarios. The most obvious will be high-contrast geometry, such as is often seen in City of Heroes.

Hmm...I dunno, 1856x1392 in cs:source creates a very nice result, and I can't imagine what 4096x3072 would look like. Certainly 1856x1392 is superior in image quality to a lower res with MSAA, and in doom 3 too.(though 1600x1200 is aobut what I max out in that game, and not at very nice framerates)

Why can't high resolution solve everything? It reduces jaggies which I think are the only things MSAA effects, and it makes textures much sharper which is why people like SSAA.(though didn't 3dfx's method improve color accuracy or something?)

Well, it seems to me that micropolygon rendering is sort of a method in and of itself to do anti-aliasing. And if you're going to be doing micropolygon rendering, multisampling won't really make a whole lot of sense.

I thought I remembered someone complaining that if Ps3 did micropolygon rendering then it would have hideious aliasing, while xbox 2 using pixel shaders to accomplish the same effects would look much better.

 

[KimB]

Hmm...I dunno, 1856x1392 in cs:source creates a very nice result, and I can't imagine what 4096x3072 would look like. Certainly 1856x1392 is superior in image quality to a lower res with MSAA, and in doom 3 too.(though 1600x1200 is aobut what I max out in that game, and not at very nice framerates)

This may have been true back in the days with supersampling, where you could play at 1600x1200 without FSAA at the same performance as 800x600 with FSAA. But today the performance hit is much, much less, and therefore there is much less reason to play without it.

And don't forget that at very high resolutions, few monitors are really crystal-clear anymore (many video cards also have problems with very high res), meaning that you'll get anti-aliasing at very high resolutions just through the blurring.

Why can't high resolution solve everything? It reduces jaggies which I think are the only things MSAA effects, and it makes textures much sharper which is why people like SSAA.(though didn't 3dfx's method improve color accuracy or something?)

It's simple: FSAA doesn't just reduce jaggies. It removes harsh patterns that are obvious to our eyes. This is what aliasing is at its heart. It's an ordered pattern (that shouldn't be there) that arises from the discreet sampling of the data.

 

[db]

Aliases are reduced to less objectionable noise with a stochastic spatially-varying sample pattern. A fixed sample pattern produces a fixed alias pattern which may be more noticeable. Spatially varying sample patterns with a small number of samples can generate other artifacts when multipassing or with animation. (or so i've been told).

signals often have components that fall off as 1/freq. Increasing resolution changes the frequency cutoff, but never completely solves the problem. There is a tradeoff between increasing resolution and some potentially cheaper antialiasing technique (insert technique here).

 

[Fox5]

Hmm...I dunno, 1856x1392 in cs:source creates a very nice result, and I can't imagine what 4096x3072 would look like. Certainly 1856x1392 is superior in image quality to a lower res with MSAA, and in doom 3 too.(though 1600x1200 is aobut what I max out in that game, and not at very nice framerates)

This may have been true back in the days with supersampling, where you could play at 1600x1200 without FSAA at the same performance as 800x600 with FSAA. But today the performance hit is much, much less, and therefore there is much less reason to play without it.

And don't forget that at very high resolutions, few monitors are really crystal-clear anymore (many video cards also have problems with very high res), meaning that you'll get anti-aliasing at very high resolutions just through the blurring.

Why can't high resolution solve everything? It reduces jaggies which I think are the only things MSAA effects, and it makes textures much sharper which is why people like SSAA.(though didn't 3dfx's method improve color accuracy or something?)

It's simple: FSAA doesn't just reduce jaggies. It removes harsh patterns that are obvious to our eyes. This is what aliasing is at its heart. It's an ordered pattern (that shouldn't be there) that arises from the discreet sampling of the data.

My monitor + vid card don't seem to lose too much clarity at high res, perhaps just enough to add a slight soft look that basically eliminates the limited jaggies left.(the 3d picture seems to fair better than 2d though, but I'm not sure if it's just more noticable with 2d pictures and text or if the 3d part of the radeon can handle higher res than the 2d)

BTW, does MSAA remove the harsh patterns? I'm assuming you're talking about texture aliasing, which isn't dealt with by MSAA but is by high resolution.(or at least I don't think it is)
I dunno, I can see how you could argue that the performance edge of using AA over higher res, but higher res seems to be overall better assuming you can reach it, more detail, less texture aliasing, sharper picture, and smaller jaggies. Super sampling has no performance advantage and doesn't give you more detail(and might be blurrier, but I'm not sure), and MSAA only handles jaggies I think and blurs the image.

BTW, I think a blur filter should be added as an alternative to anti aliasing. It can completely eliminate jaggies at a much lower performance hit than FSAA, and while it of course blurs the image it is still better than a tv(which benefits from blurriness for reduction of jaggies). ATI has several opengl smartshaders that blur the image to varying degrees and they're not too bad, at least not to me, though I am used to having very poor vision so the blur filter just makes it more like how I really see.

 

[KimB]

My monitor + vid card don't seem to lose too much clarity at high res, perhaps just enough to add a slight soft look that basically eliminates the limited jaggies left.(the 3d picture seems to fair better than 2d though, but I'm not sure if it's just more noticable with 2d pictures and text or if the 3d part of the radeon can handle higher res than the 2d)

If they're producing a "soft" look, then it's obviously because your monitor (or the signal to the monitor) is degrading the final picture. That will reduce aliasing.

BTW, does MSAA remove the harsh patterns? I'm assuming you're talking about texture aliasing, which isn't dealt with by MSAA but is by high resolution.(or at least I don't think it is)

Aliasing takes many different forms. MSAA obviously only takes care of the aliasing seen on the edges of triangles. For the harsh patterns, I'm talking about, well, if you've played City of Heroes it'd be obvious. These patterns are typically made extremely visible when, say, you have stairs made out of geometry and are far enough away that the (typically vertical) width of the stairs is approximately one pixel. You'll get bad moire patterns here without any FSAA. Of course, as db pointed out, current sample patterns really aren't as good as they could possibly be at removing aliasing. But they are better than ordered-grid patterns, and therefore do reduce aliasing by more than just doubling the resolution, while being at much higher performance.

BTW, I think a blur filter should be added as an alternative to anti aliasing. It can completely eliminate jaggies at a much lower performance hit than FSAA, and while it of course blurs the image it is still better than a tv(which benefits from blurriness for reduction of jaggies). ATI has several opengl smartshaders that blur the image to varying degrees and they're not too bad, at least not to me, though I am used to having very poor vision so the blur filter just makes it more like how I really see.

nVidia allows this with their Quincunx and 4x9 modes. I don't personally like them (since they make text hard to read, and I play a lot of RPG's).

 

[Fox5]

My monitor + vid card don't seem to lose too much clarity at high res, perhaps just enough to add a slight soft look that basically eliminates the limited jaggies left.(the 3d picture seems to fair better than 2d though, but I'm not sure if it's just more noticable with 2d pictures and text or if the 3d part of the radeon can handle higher res than the 2d)

If they're producing a "soft" look, then it's obviously because your monitor (or the signal to the monitor) is degrading the final picture. That will reduce aliasing.

BTW, does MSAA remove the harsh patterns? I'm assuming you're talking about texture aliasing, which isn't dealt with by MSAA but is by high resolution.(or at least I don't think it is)

Aliasing takes many different forms. MSAA obviously only takes care of the aliasing seen on the edges of triangles. For the harsh patterns, I'm talking about, well, if you've played City of Heroes it'd be obvious. These patterns are typically made extremely visible when, say, you have stairs made out of geometry and are far enough away that the (typically vertical) width of the stairs is approximately one pixel. You'll get bad moire patterns here without any FSAA. Of course, as db pointed out, current sample patterns really aren't as good as they could possibly be at removing aliasing. But they are better than ordered-grid patterns, and therefore do reduce aliasing by more than just doubling the resolution, while being at much higher performance.

BTW, I think a blur filter should be added as an alternative to anti aliasing. It can completely eliminate jaggies at a much lower performance hit than FSAA, and while it of course blurs the image it is still better than a tv(which benefits from blurriness for reduction of jaggies). ATI has several opengl smartshaders that blur the image to varying degrees and they're not too bad, at least not to me, though I am used to having very poor vision so the blur filter just makes it more like how I really see.

nVidia allows this with their Quincunx and 4x9 modes. I don't personally like them (since they make text hard to read, and I play a lot of RPG's).

I thought quincunx was something like 4x msaa? I remember when it came out it was advertised as 4x aa removal of jaggies with 2x aa performance hit. Don't know what the 4x9 mode is.

 

[KimB]

Quincunx is 2x AA with a blur filter. 4x9 is 4x AA with a blur filter.

 

[Fox5]

Quincunx is 2x AA with a blur filter. 4x9 is 4x AA with a blur filter.

Oh, I always thought quincunx was just blurry because it was a crappy and early MSAA method and that later cards improved on it.

 

[Arun]

Why can't high resolution solve everything? It reduces jaggies which I think are the only things MSAA effects, and it makes textures much sharper which is why people like SSAA.(though didn't 3dfx's method improve color accuracy or something?)

Don't you think that your screen's size will increase too? I sure as hell hope we aren't going to get 17 inches 4096x3072 displays.
Sure, you won't notice aliasing AS MUCH perhaps... But I suspect (and that's entirely subjective) you'll still notice it quite a bit if screensize grows even just 33% as fast as resolution.

Uttar

 

[Rolf N]

Quincunx is 2x AA with a blur filter. 4x9 is 4x AA with a blur filter.

Oh, I always thought quincunx was just blurry because it was a crappy and early MSAA method and that later cards improved on it.

No. Quincunx was deliberately made crappy.
The Geforce 3 (which is the first offering that can do Quincunx) also has proper 2x rotated grid and 4x ordered grid multisampling. With no blurriness whatsoever, I might add.

Again, Quincunx is 2xRGMS plus blur filter. I.e. you couldn't implement it if you didn't have multisampling.

 

[radar1200gs]

I think Chalnoth exaggerates just a little when it comes to blurring and quincunx.

While its certainly true that on GF3 there was a definite blurring problem, it is barely noticeable on GF4 and up.

I just rechecked Deusex @1600x1200 2xQ. The normal ingame text is perfectly readable. The font used by the talk (console) is very slightly blurry but can still be read (its isn't easy to read at 1600x1200 no matter what your AA options due to the microscopic size).

 

[Unit01]

I think Chalnoth exaggerates just a little when it comes to blurring and quincunx.

While its certainly true that on GF3 there was a definite blurring problem, it is barely noticeable on GF4 and up.

I just rechecked Deusex @1600x1200 2xQ. The normal ingame text is perfectly readable. The font used by the talk (console) is very slightly blurry but can still be read (its isn't easy to read at 1600x1200 no matter what your AA options due to the microscopic size).

And you don't think it depends on the monitor size as well? Your comment that "its isn't easy to read at 1600x1200 no matter what your AA options due to the microscopic size" doesn't last very long. There are monitors beyond 17"

 

[radar1200gs]

Yes, unit01 , I know there are monitors beyond 17 inches.

I use one of them. The Philips 109P20 to be precise. It uses a mitsubishi Diamondtron tube and has professional grade electronics and BNC inputs, which I make use of.

 

[radar1200gs]

Edit by DB: Radar, stop being abusive. Warning 1 of 3.

I sincerely hope Unit01 and quite a few other forum members have recieved the same warning.

I never abuse others unless abused first.

 

[radar1200gs]

Here is a comparison between 4x AA and 2xQ (quincunx) You should view with a screen resolution of 1600x1200 since that is what the images were captured at.

4x AA (Deus Ex)

2xQ AA (Deus Ex)

 

[Basic]

Looking at it at 1600x1200.

4x AA perfectly readable, including the small text.
2xQ AA definitely harder to read, but still possible.

To make a fair comparision to your monitor, I then reduced the screen size in the monitor controls. Changed it from 21" to 19" equivalent:

4x AA still readable.
2xQ AA anoyingly hard to read, but still possible.

Was that what you tried to prove?

 

[radar1200gs]

Just trying to show what quincunx really looks like.

I included the console text in recognition of Unit01's contribution to the thread.

It's also about the worst case (or equivelant to) you'll probably come across for reading text in game. In any case the fault lies with the game engines choice of font, not the AA employed.

 

[DegustatoR]

While its certainly true that on GF3 there was a definite blurring problem, it is barely noticeable on GF4 and up.

It was mostly the same. The only difference was that blur filter was done in RAMDAC in GF4+ so you couldn't capture it with ordinary screen capture utilities.