Optimizations of PC Titles *spawn*

Discussion in 'Architecture and Products' started by pjbliverpool, Nov 16, 2020.

  1. OlegSH

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    lol, no, that's not how games work, neither coherent secondary mirror reflections will provide any benefit to somebody.
    Reflections rays can be heavy not because they are simply secondary or whatever, that's not important.
    Glossy reflections are heavy because the more diffuse material is - the larger rays dispersion is and such reflections are the largest portion of reflections in real world since glossy materials are everywhere.
    In modern games, there are PBR materials for every object, reflections are applied for all PBR materials, roughness texture defines the roughness of any surface in game.
    Instead of fetching reflections data from cube maps, RT reflections can be used for any surface in a game scene, no need for any mirrors:roll:
    Hence the roughness cutoff parameter in config files, this parameter defines for which surfaces RT will be used.
    Actually, specular occlusion on rough surfaces provides the most visual benefit in most scenes because otherwise there are tons of light/reflections leaks, glowing objects everywhere and other artifacts which make modern games look so "gamey".
    Take a look at these screens for reference:
    https://screenshotcomparison.com/comparison/8300
    https://screenshotcomparison.com/comparison/8294
    https://screenshotcomparison.com/comparison/8299
    https://screenshotcomparison.com/comparison/8295
    https://screenshotcomparison.com/comparison/8296
    https://screenshotcomparison.com/comparison/8297
    https://screenshotcomparison.com/comparison/8298
    https://screenshotcomparison.com/comparison/8293
    https://screenshotcomparison.com/comparison/8292
    https://screenshotcomparison.com/comparison/8288
    https://screenshotcomparison.com/comparison/8289
    https://screenshotcomparison.com/comparison/8290
    https://screenshotcomparison.com/comparison/8291
     
  2. OlegSH

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    Yes, they were emulated via slow global memory atomics

    This doesn't matter, there obviously will be triangles in between pixels, lots of them actually since pixels can't be perfectly aligned with raster pixel grid.
    GCN simply lacked subpixel culling units before Polaris and that's the main reason why it was bad at subpixel triangles.

    How can you prove that there are subpixel triangles with hairworks?
    Played Metro Exodus recently, have not seen anything subpixel unfortunately, there were just quite visible triangles:-(

    Yet, they still use traditional HW path on PS5 instead of compute shaders for subpixel rasterization, so I guess it all comes down to subpixel triangles culling rates in the end, on some platforms it might be cheaper to do in HW, on others in SW.
     
    #102 OlegSH, Nov 24, 2020
    Last edited by a moderator: Nov 24, 2020
  3. ToTTenTranz

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    @OlegSH would you please use the multi-quote system instead of posting 4 times in a row?
    There'd be less useless screen space that way, which would improve reading conditions for forum users.


    I'm not sure why you felt the need to make a general description on what raytracing can be used for, followed by a battery of screenshots of watch dog legions..

    I was specifically referring to @Dictator 's statements about developers telling him AMD's RT implementation is 4x slower than nvidia's on processing incoherent rays.
    Incoherent rays have very low performance on all architectures, difference being it's even lower on AMD cards.


    By halving the tessellation factor and the screen showing the exact same pixels on the hair.
    See the Witcher 3 explanation above, on Robert Hallock's video.


    UE5 developers, regarding the PS5 demo, very specifically said they're using the console's geometry engine together with primitive shaders.
    I'm not sure what you mean by "subpixel rasterization" as there is no such thing. There's subpixel accuracy but at this point I wonder if you know what it means.
     
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  4. Jay

    Jay
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  5. OlegSH

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    "incoherent rays would mean devs starting to put unnecessary mirrors and mirrored surfaces" is an utter nonsense, that's why I provided a general description for you on what RT reflections are actually used for in reply on the nonsense with mirrors.
    Incoherent rays are simply glossy reflections on surfaces with high roughness, once again - no need to put the ridiculous unnecessary mirrors and mirrored surfaces.
    The most incoherent rays are AO and GI ones since ray's direction is selected in a random fashion in a hemisphere centered around normal vector in a screen pixel.
    Yet, RX 6800 XT performance in Metro Exodus is bad, but not as bad as in games with multiple RT effects.

    Thanks, but rather than watching 15 minutes video, I would rather prefer looking at high resolution screenshots with different tesselation factors.
    Then you should explain how that's different to Tress FX, open sourcing it won't magically fix any issues and give access to developer's code, unless developers and their contracts allow to do so.
    Other than that, I don't see why this argument is used as an excuse for recent AMD games being slow on nvidia gpus for no visible reason.

    GCN and RDNA primitive shaders are SW based culling and shader merging wrapper for standard pipeline, it can replace HW based subpixel triangles culling when it makes sense, but it obviously doesn't replace HW rasterization.

    Now you are being picky about words after the nonsence with mirrors? How clever, but it's too late pretending to be an expert for you:lol:
    I talked about rasterization of subpixel triangles, obviously:roll: And subpixel rasterization exists, have you heard about MSAA?:roll:
     
    #105 OlegSH, Nov 24, 2020
    Last edited: Nov 24, 2020
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  6. chris1515

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    They use the Geometry engine and primitive shader for bigger triangle when they have small triangle they use compute and a software based rasterizer.
     
  7. CarstenS

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    I truly wish, someone would have the time to re-test those titles on RX6800 XT vs. 3080.
     
  8. ToTTenTranz

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    You mean instead of watching the proof you specifically asked for and were presented with, you prefer to be kept in willful ignorance so that you can keep your fake feeling of righteousness.


    No, I was simply highlighting your blatant use of made-up words (subpixel rasterization <3) as factual proof that you know a crap ton of nothing you're talking about.
     
  9. OlegSH

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    There is no proof in this video. I already said what I would consider to be a proof and that's not babbling about something, but real evidences such as high quality images.

    I already said what I meant. Not going to repeat. Being picky about the obvious typo just shows how desperate you are in trying to find any arguments, which would make any sense, highlighting a typo is not an argument. You failed this.
    Judging by your "overexerting RT functionalities in Cyberpunk was coming over a mile away" and the mirrors you mentioned you have no clue on how RT is being done, so please go and learn something. That silly "made-up words" stuff won't help you.
     
  10. ToTTenTranz

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    There will never be proof of anything to you, at the rate you change your goalposts.
    If you're talking about proof of subpixel triangles in the Witcher 3's Hairworks, then unless you also don't know what a pixel is, you'll find lots of examples showing x64 tessellation showing the exact same detail at pixel level as 16x tessellation (i.e. 1/4th of the geometry showing the same pixels).
    But then again, your goalpost will probably change to something more ridiculous next time.



    Oh yes you wrote "subpixel rasterization" but you actually meant subpixel triangles in Unreal Engine 5, right?

    Which is again wrong because the UE5's Nanite pipeline is engineered to avoid subpixel triangles and the target is to never go below 1 triangle per pixel.
    You actually managed to correct one ignorant mistake with another ignorant mistake on top of it.


    But yeah, feel free to continue dumping tens of subject-unrelated pretty screenshots to try to make across a completely invalid point.
    I'll just get my popcorn ready.
     
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  11. OlegSH

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    I don't change anything. 3D graphics is all about visuals, so if you want to prove there is no IQ difference -- bring on high res screenshots.
    I don't have time to waste on someone's blabbing because it won't prove anything regarding the image quality.

    Of cause I've seen these screenshots, but unless you are blind there is quite a large difference between 8x and 16x even on these overcompressed screenshots.
    Now, let's imagine for a second, that in the story driven game there are tons of scenes where the character stands not away from the camera, but rather up front to it.
    Now, let's imagine somebody would want to play the game in 4K, can you gurantee there won't be any difference between 16x and 64x?
    That's why I am asking for High Res screenshots.

    Even in modern games there are tons of subpixel triangles in many cases and it can be only worse with Nanite.
    Nanite doesn't use tessellation, so you can't adjust the number of triangles per pixel on the fly as with adaptive tessellation.
    Do you imagine they are doing perfect LODs for every possible distance to camera and perfectly aligning triangles with centroids so that there are no triangles in-between pixels? How naive :lol:

    The only thing you've managed so far is to write some nonsense on the stuff you clearly don't understand.

    Instead of writing bullshit like this - "mean devs starting to put unnecessary mirrors and mirrored surfaces that needlessly bounce entire scenes 3 times before reaching the player's POV", try harder next time.
     
  12. ToTTenTranz

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    Next paragraph:
    OMG nvidia's default isn't 8x or 16x, it's 64x! You can't see the difference between 64x and 16x, but here you go changing the goalposts to "b-but I can see difference between 16x and 8x!", both of which are well below the Hairworks default of x64. You didn't even bother to read the article (not that I expected it, to be honest).

    This couldn't get any more hilarious!
    *Popcorn was a good idea.


    Still making stuff up?
    Quotation needed.

    You stated Nanite does subpixel rasterization.. oh sorry it was Nanite does subpixel triangle rasterization. Do provide proof of your (completely made up and ignorant) claims.




    Nonsense stuff like subpixel rasterization? <3
     
  13. PSman1700

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    Yet the UE5 demo ran better on a RTX2080Q.
     
  14. troyan

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    You know that the tessellation factor is responsible for the numbers of strands created from the base geometry? Using 64x means less base geometry (less vertics, less vertex shader calculations, better culling etc.) and more on chip geometry creation.
     
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  15. pharma

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    Are you always going to be ignorant? Try google.
     
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  16. ToTTenTranz

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  17. pharma

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    It's easier if interpret if you were actively involved in the "trade".
    Font not rendering smoothly like screenshot · Issue #101 · alacritty/alacritty · GitHub

    A generalized sub-pixel mapping algorithm for auto-stereoscopic displays using slanted optical plates | Semantic Scholar

    Etc, etc, etc .....
     
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  18. OlegSH

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    Blah, blah
    https://imgsli.com/MzI4ODE
    https://i.imgsli.com/images/b6d7dbc5-feff-4820-802f-0f3ecafda563.png
    Here is the example I was asking you for, did it for you, no need to thank.
    Hopefully, at least you will be able to spot the triangular edges on his hair, so apperently making these edges 4x longer clearly won't have any IQ impact during cut scenes, right?:roll:

    Why should I educate you? It's not my job, sorry
     
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  19. Kaotik

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    You're comparing no tessellation to 64x tessellation. ToTTenTranz point was that you can go down to 16x with no effect on image quality (in Witcher 3), but vastly better performance. Going down to 8x starts to affect results.

    [​IMG]
     
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  20. OlegSH

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    Where is my facepalm emoji?
    How can you go down to 16x with no effect on image quality when you can clearly see long edges up close to camera even with 64x tessellation factor in 1440p?

    As troyan has already explained, the base mesh is quite coarse, so reducing the tessellation by a factor of 4 would make these already quite visible edges in 1440p way more visible.
     
    #120 OlegSH, Dec 11, 2020
    Last edited: Dec 11, 2020
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