Future of MSAA?

[tEd]

I don't really wanna talk about the quality as it gotten really good in that area in the last 2years IMHO but i'm more interested about combatibility issuses rising on the horizon.

There were some combatibility problems with MSAA which led to many games in the last 15month couldn't support MSAA mainly because of the lack of API support with certain rendering techniques(render to texture). It looks much better now as many games have support for it but it seems the next problem for MSAA is already coming in the near future. More and more games next year probably gonna use fp render targets for HDR or other things (deffered lighting). AFAIK no graphiccard currently available supports MSAA on fp render targets/framebuffer.

I think i already heard a comment from tim sweeney that you won't see AA in UE3 games because it uses HDR.

Anyway i would like to know how are the odds that next years GPU's will have MSAA support for fp render targets/framebuffer and if it even would make sense for IHV to support this or are costs to implement it too high(transistors , performance)?

 

[ChrisRay]

Many games that have issues with multisampling you can generally just shut the effect off, Probably going to remain similar in the coming future.

 

[Guden Oden]

Turning off AA isn't much of a solution though because then we'll be without AA...

MSAA has always struck me as a particulary hackish solution, it uses as much memory and fillrate as SSAA but doesn't deal with texture aliasing and can't handle 'stippled' textures either. And these textures are getting more and more use these days with heavy foliage on the ground, leaves on trees etc, thus making the problem worse.

 

[Dave Baumann]

I think i already heard a comment from tim sweeney that you won't see AA in UE3 games because it uses HDR.

Thats only becuase HDR isn't fully orthogonal in current solutions. That should be the case in future solutions.

 

[ChrisRay]

Eh? I didnt say turn off anti aliasing. I said turn off the effect thats disabling it

In about 3 recent games Anti aliasing hasnt worked by default that I have played. Everquest 2 and World of Warcraft being 2 of them. EQ2 doesnt even support anti aliasing but if you configure the game properly you can get it working. Same with WoW. Disabling certain effects can usually get anti aliasing working again. Not all games have this option but generally most do that seem to have issues with multisampling.

 

[AlNom]

pffft.. back in the good ol' days, we aint no need thems anti ballistic multiple sampling gosh darn business to enjoy a game.




Although, it would be nice to use a feature that the card uses.

So what other types of AA are there? ( Is temporal a form of MSAA )

 

[tEd]

I think i already heard a comment from tim sweeney that you won't see AA in UE3 games because it uses HDR.

Thats only becuase HDR isn't fully orthogonal in current solutions. That should be the case in future solutions.

How far away you think this future is away? R5xx/NV5x or later?

 

[OpenGL guy]

MSAA has always struck me as a particulary hackish solution, it uses as much memory and fillrate as SSAA

Sounds like you are unclear on what the differences between MSAA and SSAA are. MSAA does not impact fillrate: Drawing a 1024x1024 buffer with and without MSAA takes the same number of pixel shader cycles. SSAA does affect fillrate: Drawing a 1024x1024 buffer with, say, 4x SSAA requires 4x as many pixels to be filled which means the pixel shader cost will be about 4x as large.

but doesn't deal with texture aliasing and can't handle 'stippled' textures either. And these textures are getting more and more use these days with heavy foliage on the ground, leaves on trees etc, thus making the problem worse.

You can do supersampling in the shader when the shader is likely to produce aliasing. This will likely be cheaper than supersampling the whole buffer as only the pixels that need supersampling will be supersampled.

 

[AlNom]

You can do supersampling in the shader when the shader is likely to produce aliasing. This will likely be cheaper than supersampling the whole buffer as only the pixels that need supersampling will be supersampled.

Anyone doing that right now or in a game that is out?

 

[KimB]

You can do supersampling in the shader when the shader is likely to produce aliasing. This will likely be cheaper than supersampling the whole buffer as only the pixels that need supersampling will be supersampled.

What I'd really like to see for this is the option to select between supersampling and multisampling on a per-triangle basis. Either this or more access to the hardware-accelerated options that would make supersampling in the shader faster.

Regardless, there are methods of getting around texture aliasing in many scenarios without resorting to supersampling. Normal texture filtering does a good job for color textures. PCF works well for shadow maps. There are methods of anti-aliasing normal maps, and you can elect not to use alpha tests at all in some cases (if, for example, the portion of alpha textures is small, you can just do simple sorting on the alpha textures, render them last, and use alpha blending instead. If the objects are procedural in nature, such as foliage or trees, there may be reasonably-good algorithms to do the sorting more efficiently for many objects).

 

[MfA]

Would be nice to use multisampling for that anyway, you could still switch to supersampling when needed. If you arent using any tricky texturing it is a shame to use supersampling for edges. Bandwith wise it makes little difference due to compression, and storage wise you need to have the same amount of memory in both cases.

 

[KimB]

If you arent using any tricky texturing it is a shame to use supersampling for edges.

Huh? Multisampling is very similar to supersampling in terms of performance constraints at edges.

 

[MfA]

Shading once, or shading X times ... a slight difference.

 

[_xxx_]

Future of AA? In 10 years or so, displays with res. 4096x4096, no AA needed

 

[KimB]

Shading once, or shading X times ... a slight difference.

You still shade multiple times at triangle edges with multisampling....

 

[KimB]

Future of AA? In 10 years or so, displays with res. 4096x4096, no AA needed

Anti-aliasing is needed at any resolution.

 

[MfA]

Shading once, or shading X times ... a slight difference.

You still shade multiple times at triangle edges with multisampling....

Only once per primitive.

 

[_xxx_]

Future of AA? In 10 years or so, displays with res. 4096x4096, no AA needed

Anti-aliasing is needed at any resolution.

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.

 

[trinibwoy]

Future of AA? In 10 years or so, displays with res. 4096x4096, no AA needed

Anti-aliasing is needed at any resolution.

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.

In 10 years the resolution will be higher but the screens will be bigger!!

 

[Gunhead]

Is temporal a form of MSAA?

MultiSampling and SuperSampling both are forms of Spatial (space) AA. Temporal (time) AA is a different thing altogether, using different techniques, tackling different problems, correcting different errors.

Thanks ATI again for calling a special Spatial AA method "Temporal AA" and messing up the terms apparently for good