Direct3D feature levels discussion

Discussion in 'Rendering Technology and APIs' started by DmitryKo, Feb 20, 2015.

  1. DmitryKo

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    Trim the variable name to something like VPAndRTArrayIndexToRasterizerWithoutGSEmulation and strip ending Supported from the all other capability bits as well...
     
  2. pharma

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    http://www.hardwareluxx.com/index.p...ture-to-offer-full-level-directx-support.html
     
  3. DmitryKo

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    This picture originates from a Brazilian forum and copies a table posted on a Hungarian forum with no attributed source of information (could as well be this thread on Anandtech forum).

    It's wrong on several important counts, for example: none of GCN chips support rasterizer ordered views, conservative rasterization, or tiled resources tier 3 (ie. "volume tiled resources" with Texture3D support), as shown by the D3D12 feature checking tool. GCN 1.1/1.2 cards support tiled resourced tier 2 (with Texture2D support) and feature level 12_0, GCN 1.0 "only" supports tiled resources tier 1 and feature level 11_1. Double precision floats are supported across the entire GCN range.

    Kepler and Maxwell-1 do support resource binding tier 2, and do not support typed UAV load for additional texture formats - this leaves them at feature level 11_0. Maxwell-2 is currently the only card which supports feature level 12_1.

    Conservative depth, SAD4 or dedicated atomic counter are not part of the latest SDK, neither is "emulated" tier 3 for tiled resources, whatever that means.


    As for the complete list of Direct3D 12 compatible GPUs and APUs, AMD revealed it on their blog nearly a month ago.
     
    #203 DmitryKo, Jun 2, 2015
    Last edited: Jun 3, 2015
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  4. Metal_Spirit

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    AMD's GCN does seem to support rasterizer order views!
    As already discussed raster ordered views is just a fancy way to rename Intel's pixelsync, and the feature's name in OpenGL is Intel_fragment_shader_ordering.

    Now check this Tweet from Nathan Reed!

    https://twitter.com/Reedbeta/status/478271158693801984
     
  5. willardjuice

    willardjuice super willyjuice
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    But is that extension usable? The performance on previous drivers made it impractical even for simple cases (if I remember Andrew correctly). I mean my cpu can support feature level 12_1 too, but that's not really saying much. :razz:
     
  6. Andrew Lauritzen

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    Yeah it was ridiculously bad when I briefly tested it... like turn it on even with a trivial pixel shader and no actual synchronization going on and your frame takes 300ms+. Hopefully that was just a bug or some sort of test implementation, but suffice it to say I'll believe they can support it efficiently when I see it :) Hopefully Fiji supports it natively in any case; the sooner ROV support is ubiquitous the sooner games can start relying on OIT and similar things that you can do with it without having to have engine fallbacks.

    And yeah, that table is utterly wrong on almost every count. You could probably invert all the values and it would be just as close to correct. Some of the things don't even really make sense as to what they are noting from an API point of view.
     
    #206 Andrew Lauritzen, Jun 3, 2015
    Last edited: Jun 3, 2015
  7. pharma

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    http://www.pcper.com/reviews/Graphi...view-Matching-TITAN-X-650/DX12-Support-GameWo
     
    #207 pharma, Jun 3, 2015
    Last edited: Jun 3, 2015
  8. Metal_Spirit

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    Well, apparently, for what I see AMD does support ROV even if what you tested was very slow! And it was stated above GCN did not supported it!

    But honestly... i would doubt AMD (or any other) would show support for something if performances were that bad... So unless someone tells me otherwise I would be tempted to believe what you tested was premature? Any more recent testing?

    As for the atomic counter... Check this and this! Is it related?
     
  9. MDolenc

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    It's not that he tested and it was slow. AMD Direct3D 12 driver at the moment does not report support for ROV. This means you can't use it period. This has nothing to do with OpenGL.

    Again this is OpenGL extension. Most of operations mentioned in this extension is already included in D3D 11. What that "dedicated atomic counter" is supposed to be we can't tell because it's not in D3D 12 specs.
     
  10. pharma

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  11. willardjuice

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  12. silent_guy

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  13. Kaotik

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    Unless Fiji does 12_1 :wink:
     
  14. Locuza

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    Which seems very unlikely and it's very unfortunate that AMD isn't contributing to an modern Feature-Level.
    Nvidia does since November 2014 and Intel at least supports ROVs.
     
  15. pharma

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    If it does it will be for a very small user base ...
     
  16. silent_guy

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    FWIW: I don't think supporting 12_1 or not don't matter a whole lot...
     
  17. Rikimaru

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    Level 12_0 mostly leverages on GCN features. Nvidia cards before Maxwell 2 will emulate some features in software.

    12.1 was created for Maxwell 2. Of course AMD is behind on those.
     
  18. pjbliverpool

    pjbliverpool B3D Scallywag
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    Guess...
    sebbbi has had lots of high praise for the 12_1 features. I don't think this is a DX9.3 situation.
     
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  19. Ethatron

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    silent_guy used tripple negation (well, 2.5 really). Intentional? I don't think this isn't no DX9.3 situation. LOL
     
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  20. silent_guy

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    "I think it doesn't matter a great deal. " better? :wink:

    Not that sebbi is wrong about it being very useful, but there's a difference between useful and necessary. I assume most games will do things the hard way...
     
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