GARTX: Games and Applications using RTX

Discussion in 'Rendering Technology and APIs' started by BRiT, Jan 1, 2019.

  1. pharma

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    GI from the artist's point of view (Metro Exodus)
     
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  2. del42sa

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    I thought, that Nvidia implementation of ray tracing RTX (not DXR) uses OptiX https://developer.nvidia.com/optix-denoiser
     
  3. pharma

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    Real Time Path-Tracing and Denoising in Quake II RTX
     
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  4. Rootax

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    I believed it's a possibility (not a technical obligation), but devs haven't used it in games for now. My guess is their are reasons for it.
     
  5. JoeJ

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    Pretty sure it's not, because this aims for interactive updates but not realtime for games.

    For games they did manual work, as presented here:


    This is about things like using an elliptic kernel to denoise shadows from an area light for example.
    This also results in specialized denoising passes per effect or even per light, so it can sum up and become expensive. (I leave it to you to watch it and listen if they mention tensor cores :) IIRC they do not, but not sure.)

    The denoising done in Quake2 RTX is very different from that, as it works on the whole lighting at once. That's faster but may miss low frequency details.
    Here i'm sure it's regular compute shader code becuse it's open source.


    I can't remember where the initial assumption tensor cores would do denoising came from (i thought the same at first). Was it misleading marketing, or just everyone getting all this new stuff wrong?
    However - IMO the existanse of tensor cores in gaming GPUs remains questionable. Likely the shrinked units on GTX 1660 would be enough. There has shown no killer application yet.
    But maybe DirectML will change this... (Actually Cuda is the only way to fully utilize tensors - not sure.)

    To come back on thread topic,
    somebody here mentioned Navi has low precision dot product instructions. If true, i would guess that's part of the new specialized function units, and functionality should be similar to NV tensor cores (Make your matrix multiply from some dot products).
    I would further guess performance is slower than NV but less chip area is taken, so more general purpose performance on the other hand. (Common assumption seems tensor cores take much more area than RT cores?)
    That's quite interesting, seems a similar situation than with RT.

    Edit: Damn - i need to find how to enable spelling auto correction in my browser again... :D
     
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  6. Davros

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    Agreed i thought the whole point of raytracing was you got things like reflection and occlusion for free
     
  7. del42sa

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    Yes you ´re right. I wasn´t aware about that they doing handcrafted denoising in current games. And maybe my initial thought about using Tensor Cores AI for denoising came from prior Nvidia presentation about OptiX and Turing arch. because they talked about it like it was done that way. It will be interesting how the future implementation of AI denoising will work. Someone mentioned needs of interactive updates and not realtime for games, but DLSS is working that way too in realtime games, right ?

    Anyway thanks guys for your input, I must admit I didn´t dive much into real implementation of RTX in games, so I thought denoising works the same way as DLSS (via Tensor Cores)
     
  8. DavidGraham

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  9. iroboto

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    I think it's inevitable. Just need to wait a year or 2. DirectML should be the tool that they need to customize their own NN denoising but would be applicable to all GPU vendors and low level enough to remove most of the overhead in NN libraries. I'll be watching this space to see when this finally happens.
     
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  10. del42sa

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    I agree, it´s the original plan and I don´t think Nvidia will drop Tensor Cores from their GPU ....
     
  11. hughJ

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    Specifically I was thinking more in terms of taking old games that have a lot of normal mapped low-poly assets (something like Doom 3 comes to mind) and using the info from existing materials to behave as a displacement map, as ray intersections are pretty flexible and granular (in a software render pipeline, anyways). I guess another big question would be how destructive the original high poly asset -> normal map generation was, and whether there'd be a ton of discontinuities at the polygon edges if you tried to interpret a surface from the base mesh and texture offset, or clipping artifacts caused from animation and skinning. But yeah, if one were to need to rerig and animate the assets then you may as well just pay artists to manually refine and retop the meshes as well.
     
  12. pharma

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    KitGuru: Control GamePlay
    July 22, 2019
    https://www.kitguru.net/components/...sions-for-control-on-pc-with-rtx-ray-tracing/
     
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