Game development presentations - a useful reference

Discussion in 'Rendering Technology and APIs' started by liolio, Sep 16, 2009.

  1. chris1515

    Legend Regular

    Joined:
    Jul 24, 2005
    Messages:
    6,009
    Likes Received:
    6,120
    Location:
    Barcelona Spain
  2. OlegSH

    Regular Newcomer

    Joined:
    Jan 10, 2010
    Messages:
    475
    Likes Received:
    596
  3. Lurkmass

    Newcomer

    Joined:
    Mar 3, 2020
    Messages:
    231
    Likes Received:
    226
    ReSTIR may not be as robust or easily extensible as I thought ...

    Only useful in conjunction with shadow rays, high noise involving near disocclusion/lighting discontinuities/high geometric complexity/high-speed light sources/etc and the algorithm reuses primary rays so it can't be used for global illumination beyond the first hit from the camera ...
     
  4. chris1515

    Legend Regular

    Joined:
    Jul 24, 2005
    Messages:
    6,009
    Likes Received:
    6,120
    Location:
    Barcelona Spain
  5. DegustatoR

    Veteran

    Joined:
    Mar 12, 2002
    Messages:
    1,962
    Likes Received:
    1,113
    Location:
    msk.ru/spb.ru
  6. JoeJ

    Veteran Newcomer

    Joined:
    Apr 1, 2018
    Messages:
    1,060
    Likes Received:
    1,241
    You have tried it out?
    I did only skim over the paper, and my impression was it's very promising. I assume we can not really avoid to organize many lights for large worlds in some spatial data structure, which we then have to traverse for each ray hit.
    But i would hope we could throw a large set of lights into one node, and use reservoir sampling to minimize the set to something practical?
     
  7. Lurkmass

    Newcomer

    Joined:
    Mar 3, 2020
    Messages:
    231
    Likes Received:
    226
    I haven't tried it out myself but if you look at algorithm 5 in the paper, they basically state that their prior reservoirs come from the previous frames screen space image. It's conceptually similar to those other massive screen space and temporal rendering hacks. A good portion of the speed up is based on the fact that they didn't have to rely on more complex data structures beyond the previous frames screen space image to do temporal reuse ...

    Their RTXDI video itself demonstrates quite a few examples of robustness issues. They make it abundantly clear that if you have sources of poor samples then ReSTIR has a low capacity to reduce that noise but if you have relatively good quality samples then ReSTIR can significantly help the noise reduction ...

    You can get around the robustness problems by doing less temporal reuse but then ReSTIR becomes less effective at reducing the noise. Consequently, you can increase the sample reuse so that ReSTIR can more effectively reduce the noise but temporal reuse brings it's own host of problems like reducing overall image details. Alternatively, we could try extending ReSTIR with more complex data structures which could potentially open us up to higher quality temporal reuse or allow us to apply the algorithm beyond just shadow rays but the performance gains wouldn't be anywhere near as convincing since the paper explicitly mentions the higher cost of maintaining this data structure. ReSTIR is far from being an elegant solution as people are hyping it up to be ...
     
  8. JoeJ

    Veteran Newcomer

    Joined:
    Apr 1, 2018
    Messages:
    1,060
    Likes Received:
    1,241
    Of course - the paper is about an alternative to this, so they present results where this alternative is better. But there is no way around it, so we need to solve it. (Or we wait for extended RT cores which also support point and range queries on BVH, not just rays.)
    I tend to be 'too optimistic' about acceleration structures in general, but:
    If we can use many lights per node, a simple multi level grid might be good enough even for large city night scenes. If not, one or two levels of sparse grid should help, eventually also with scrolling the grid around the moving camera. Most lights won't move quickly, which can reduce this cost a lot.
    To reduce traversals while shading, we can make bounding box per screen space tile (or world space clusters) and traverse only once for that to get a list of many lights.

    Though, that's ideas about the future, not sure if this makes sense already now. Missed the video, will watch...
     
    jlippo and BRiT like this.
  9. chris1515

    Legend Regular

    Joined:
    Jul 24, 2005
    Messages:
    6,009
    Likes Received:
    6,120
    Location:
    Barcelona Spain
  10. chris1515

    Legend Regular

    Joined:
    Jul 24, 2005
    Messages:
    6,009
    Likes Received:
    6,120
    Location:
    Barcelona Spain
  11. chris1515

    Legend Regular

    Joined:
    Jul 24, 2005
    Messages:
    6,009
    Likes Received:
    6,120
    Location:
    Barcelona Spain


    Godot Engine uses SDFGI
     
Loading...

Share This Page

  • About Us

    Beyond3D has been around for over a decade and prides itself on being the best place on the web for in-depth, technically-driven discussion and analysis of 3D graphics hardware. If you love pixels and transistors, you've come to the right place!

    Beyond3D is proudly published by GPU Tools Ltd.
Loading...