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Intel Details Handling Anti-Aliasing On CPUs

MojoKid writes "When AMD launched their Barts GPU that powers the Radeon 6850 and 6870, they added support for a new type of anti-aliasing called Morphological AA (MLAA). However, Intel originally developed MLAA in 2009 and they have released a follow-up paper on the topic--including a discussion of how the technique could be handled by the CPU. Supersampling is much more computationally and bandwidth intensive than multisampling, but both techniques are generally too demanding of more horsepower than modern consoles or mobile devices are able to provide. Morphological Anti-aliasing, in contrast, is performed on an already-rendered image. The technique is embarrassingly parallel and, unlike traditional hardware anti-aliasing, can be effectively handled by the CPU in real time. MLAA is also equally compatible with ray tracing or rasterized graphics."

15 of 190 comments (clear)

  1. Re:Bah, humbug, tech writers need help by windwalkr · · Score: 5, Informative
  2. Re:Bah, humbug, tech writers need help by MojoKid · · Score: 4, Informative

    I think you need to do your research before being critical... embarrassingly critical it appears.

  3. Why not leave it on the GPU? by Tr3vin · · Score: 4, Insightful

    If it is "embarrassingly parallel", why not leave it on the GPU? Makes more sense to have it running on dozens to potentially hundreds of stream processors than a couple "free" cores on the CPU.

  4. Rain dances around Shannon by Anonymous Coward · · Score: 3, Insightful

    If your signal is aliased during sampling, you are toasted.
    No voodoo will help you if your spectrum folded on itself.
    So super-sample it or shut up.
    Everything else is a snake oil for unwashed masses.
    And yes, MPLAA still looks like crap in comparison to SS.

  5. You sure GPU's aren't better? by guruevi · · Score: 3, Interesting

    If the system is 'embarrassingly parallel' and simple then the GPU would be a better use case. GPU's typically have a lot (200-400) cores that are optimized for embarrassingly simple calculations. Sure you could render everything on a CPU these days, simpler games could even run with an old school SVGA (simple frame buffer) card and let all the graphics be handled by the CPU as used to be the case in the 90's and is evidenced by the 'game emulators in JavaScript' we've been seeing lately but GPU's are usually fairly unused except for the ultramodern 3D shooters which also tax a CPU pretty hard.

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  6. Blur by Baloroth · · Score: 5, Insightful

    So, it basically blurs the image around areas of high contrast? Sounds like thats whats going on. Looks like it, too. I can understand why they are targeting this at mobile and lower powered devices: it kinda looks crappy. I might even say that no antialiasing looks better, but I'd really have to see more samples, especially contrasting this with regular MSAA. I suspect, however, that normal antialiasing will always look considerably better. For instance, normal AA would not blur the edge between two high-contrast textures on a wall (I think, since it is actually aware that it is processing polygon edges), while I suspect MLAA will, since it only sees an area of high contrast. Look at the sample image they post in the article: the white snow on the black rock looks blurred in the MLAA processed picture, while it has no aliasing artifacts at all in the unprocessed image. Its pretty slight, but its definitely there. Like I say, need to see more real world renders to really tell if its a problem at all or simply a minor thing no one will ever notice. I'll stick to my 4X MSAA, TYVM.

    --
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    1. Re:Blur by djdanlib · · Score: 5, Informative

      It's different from a Gaussian blur or median filter because it attempts to be selective about which edges it blurs, and how it blurs those edges.

      This technique really wrecks text and GUI elements, though. When I first installed my 6950, I turned it on just to see what it was like, and it really ruined the readability of my games' GUIs. So, while it may be an effective AA technique, applications may need to be rewritten to take advantage of it.

  7. So, it is not anti-aliasing at all... by LanceUppercut · · Score: 5, Informative

    Anti-aliasing, by definition, must be performed in object space or, possibly, in picture space. But it cannot be possibly carried out on an already rendered image. They must be trying to market some glorified blur technique under the anti-aliasing moniker. Nothing new here...

  8. Re:Bah, humbug, tech writers need help by PhrostyMcByte · · Score: 5, Informative

    "Embarrassingly parallel" refers to a problem made up of many isolated tasks -- such as running a fragment (pixel) shader on millions of different fragments, or a HTTP server handling thousands of clients -- that can all be run concurrently without any communication between them.

    It's odd that they use that term here, because the other anti-aliasing techniques are embarrassingly parallel as well.

    SSAA (super-sampling) always renders each pixel n times at various locations within the pixel, and blends them together.

    MSAA (multi-sampling) is basically the same as SSAA, but only works on polygon edges and is very dependant on proper mipmapping to reduce aliasing introduced when scaling textures.

  9. Re:Bah, humbug, tech writers need help by Kjella · · Score: 4, Funny

    This is Slashdot. Many here would be happy to admit to having an SO with whom they are having regular sex.

    So would a lot of the people with SOs...

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  10. Re:Bah, humbug, tech writers need help by nedlohs · · Score: 4, Insightful

    It's a term of art commonly used in the field for a very long time. That you don't like it really doesn't matter at all to anyone but you.

  11. FXAA is a better choice by dicobalt · · Score: 5, Interesting

    It can work on any DX9 GPU without dedicated support. http://hardocp.com/article/2011/07/18/nvidias_new_fxaa_antialiasing_technology/1

  12. Re:Bah, humbug, tech writers need help by MightyMartian · · Score: 3, Funny

    Translation: Damn, I was revealed as an ignoramus. How can I swing this back in my favor?

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  13. decent phones don't need AA by bored · · Score: 3, Interesting

    AA is a crutch to get around a lack of DPI. Take the iphone 4 at 326 DPI, it is 3 to 4x the DPI of the average craptasic "HD" computer monitor. I have a laptop with a 15" 1920x1200 screen. At that DPI Seeing the "jaggies" is pretty difficult compared with the same resolution on my 24". On the 15" can turn AA on/off and its pretty difficult to discern the difference. That monitor is only ~150DPI. I challenge you to see the affects of anti-aliasing on a screen with a DPI equivalent to the iphone 4.

    The playstation/xbox on the other-hand are often used on TV's with DPI's approaching 30. If you get within a couple feet of those things the current generation of game machines look like total crap. Of course the game machines have AC power, so there really isn't an excuse. I've often wondered why sony/MS haven't added AA to one of the respun versions of their consoles.

    1. Re:decent phones don't need AA by thegarbz · · Score: 3, Informative

      Seeing jaggies is not the only purpose of AA. The idea is also to be able to render objects that are smaller than the spatial resolution of the view. Think a long distance away you're looking at a guywire of a comms tower. You may see a row of appearing / disappearing pixels as on average the wire is rendered as smaller than a pixel width. AA takes care of this, which is far more annoying than simply a resolution issue of sharp edges on objects.

      This glorified blurring algorithm however doesn't fix this.