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Question URP on Quest 2 Depth Texture enable Destroys the framerate

Discussion in 'Universal Render Pipeline' started by HRDev, Aug 5, 2022.

  1. HRDev

    HRDev

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    Hello everybody. I am developing a VR game with quest 2 using Vulkan as Graphics api. I need to activate the Depth Txture in the URP settings to do some fog effects. But when I activate this Depth Texture the framerate goes from 90 to 45/50... without doing anything else, without adding anything to the scene, just activating DepthTexture... it's normal? is there a way to optimize it?

    I noticed that with OpenGLES3 it is better, should I make the switch to OpenGLES3? I prefer to avoid...
     
    HRDev, Aug 5, 2022
    #1
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  2. DevDunk

    DevDunk

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    There indeed is an issue with vulkan and depth which is really annoying. I assume you are using Unity 2021? (2020 doesn't have this issue afaik)
    If so, have you updated to the latest release already?
    OpenGLES can definitely have better performance, so if your game does run with all your requirements on it definitely use it. Oculus is pushing vulkan with new features like phase sync, but it's not required
     
    DevDunk, Aug 5, 2022
    #2

  3. rjonaitis

    rjonaitis

    Unity Technologies

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    The issue is known and already being worked on, the Vulkan's performance drop is caused by URP's depth copy pass if MSAA is enabled.
     
    rjonaitis, Aug 10, 2022
    #3
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  4. DevDunk

    DevDunk

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    I think in the past someone already found the PR causing the issue. Is there any ETA for it? Will it be fixed in the 2021 LTS or will ot just be 2022?
     
    DevDunk, Aug 10, 2022
    #4

  5. rjonaitis

    rjonaitis

    Unity Technologies

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    The issue was caused by optimization change preferring depth copy instead of depth prepass, fix already passed testing and waiting for code merge. I can't give you ETA or backport promises, I'm not working on this case.
     
    rjonaitis, Aug 10, 2022
    #5
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  6. joshuacwilde

    joshuacwilde

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    So the testing shows that just regenerating the depth buffer is faster than copying it in the general cases the team tested?
     
    joshuacwilde, Aug 13, 2022
    #6

  7. Koboct-Denis

    Koboct-Denis

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    Hello, any news on the fix?
     
    Koboct-Denis, Sep 9, 2022
    #7
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  8. funkyCoty

    funkyCoty

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    On quest 2, the gpu is using a tiled deferred rendering architecture. To copy the depth buffer you need to resolve this texture. Depending on your resolution and MSAA level this can take several ms per copy. If generating a new one costs less than that, it's worth it. Really though, you should avoid needing the depth buffer at all on quest.
     
    Last edited: Oct 2, 2022
    funkyCoty, Sep 10, 2022
    #8

  9. D3m0n

    D3m0n

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    Same problem.
     
    D3m0n, Oct 2, 2022
    #9

  10. trojant

    trojant

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    @rjonaitis
    Hi,
    Has this 2021 URP MSAA problem been solved? Is there a link? Where is the progress now? Thanks
     
    trojant, Jan 13, 2023
    #10

  11. DevDunk

    DevDunk

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    I think it has been fixed yes
     
    DevDunk, Jan 13, 2023
    #11

  12. trojant

    trojant

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    trojant, Jan 13, 2023
    #12

  13. trojant

    trojant

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    trojant, Jan 13, 2023
    #13

  14. trojant

    trojant

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    I tested 2021.3.16 and didn't feel any performance improvement,With 2021 URP and MSAA 4X problem.
     
    trojant, Jan 13, 2023
    #14

  15. DevDunk

    DevDunk

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    Yes, it was a noticeable improvement for me.

    If you have a project which performs more than 5% faster on the latest 2020lts vs 2021lts with the same settings etc make a bug report including both projects so they can fix it.
     
    DevDunk, Jan 14, 2023
    #15

  16. Rustamovich

    Rustamovich

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    Same here. Let's stay in touch. I want to have a nice fog in the game. But I can't. Maybe 2022 version solved the problem?
     
    Rustamovich, Jan 20, 2023
    #16

  17. funkyCoty

    funkyCoty

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    You can have fog on quest 2 hardware, you just need to do it in your fragment shader.

    upload_2023-1-20_10-11-47.png

    Here's a screenshot of our recent game (minus the shadows and bloom, it looks the same on quest). Fog and a few other "post process"-like effects are possible, but you'll need to be writing HLSL.
     
    funkyCoty, Jan 20, 2023
    #17

  18. ManueleB

    ManueleB

    Unity Technologies

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    if you are having performance issues on Quest 2 due to the extra Copy Depth pass which was introduced in 21, replacing the old default depth prepass, the suggested setup to still force the prepass (which is cheaper on that specific platform most of the time, depending on your scene complexity) is to select "force prepass" as "Depth Texture Mode":

    upload_2023-1-23_10-7-13.png
     
    ManueleB, Jan 23, 2023
    #18
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  19. Rustamovich

    Rustamovich

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    I've tried this one, but it didn't help me. But thanks anyway.

    My setup is as follows:
    Unity 2021.3.16f1
    URP 12.1.8
    XR Plugin 4.2.1

    I would love to hear your thoughts about my setup
     
    Rustamovich, Jan 27, 2023
    #19

  20. ManueleB

    ManueleB

    Unity Technologies

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    Unfortunately without knowing the details of your application it's not possible to figure out what the problem is.

    My previous post is specifically for users that upgraded to 21 and found an extra copy depth pass in the frame.

    The reason for that is that, before 21.2, URP always did a depth prepass when a depth texture was required. This caused performance issues in vertex bound applications and was reported by users, so we decided to remove the costly depth prepass and copy the depth instead.
    But while removing the depth prepass improved perf in vertex bound situations (lot of geometry to draw), it caused regressions in fragment bound ones.
    Quest 2 games are more often fragment bound than vertex bound, so this is the most likely cause of regressions when upgrading to 21.

    Because of the wide range of platforms and possible application types URP supports, we decided to now give the option to force the prepass vs the copy depth, because only users will know after profiling what is best for their specific use case. So that is the suggested best practice for (most) Quest 2 and VR games, unless they are vertex bound because of unoptimized content.

    So to go back to your issue: without profiling and frame captures it is impossible to know what is your bottleneck. It could be a depth prepass vs depth copy issue, too many post processing passes, wrong quality settings, etc

    If you know what the specific issue is and if URP doesn't provide ways to optimize your frame then we would be happy to know what the issue is and consider a fix if possible
     
    ManueleB, Jan 27, 2023
    #20