Game development presentations - a useful reference

Comparing to 1spp PT does not make much sense, but with DDGI does. (Both methods provide a cache to lookup lighting instead accumulating many paths to get it.)

Very promising: They can provide high frequency details in the cache. No other caching method can do this in realtime and with practical memory costs.
Though, the video shows heavy temporal fluctuations in motion, even on static scene. I expect further progress on ML denoising to address this, but i doubt we could use that in a action game (where stability is more important than realism) anytime soon.

I think the most promising approach would be to have another caching system which is temporally stable but less detailed, and world space to handle disocclusion (e.g. DDGI). If combining strengths of both is possible, temporal issues might become acceptable.
Likely that's not so easy, otherwise they might have shown this as well.

 

When we take a look at the error metrics (lower is better) in the interactive results, most of the time (PT+ReSTIR+DDGI) manages to come out on top of (PT+ReSTIR+NRC) in the 1spp case ...

 

You can cache a spherical basis function instead of just a normal texture to increase detail versus memory. Just take this example and flip from storing irradiance to radiance. Further, it supports glossy reflections and is incredibly stable. H-basis lightmaps have been popular for a while, since you're doing final gather from a cache, other than the tracing step the idea is pretty much the same, as is all the benefits. Example of what kind of detail you can get with using an h-basis lightmap for specular approximation, just flip that and you'll get the same detail for outgoing light:

 

But this never gives you such high frequencies closely to what's shown.


(See the lights reflections which are pretty sharp.)

 

Just lumen software alone, with it's low res flat cache, can get pretty close to that, but not perfect of course. Mostly I was thinking about how to best trade-off memory for detail for a surface cache.

For really smooth reflections you'd probably want shade on hit no matter what else you're doing, and all the divergence that entails.

 

Dori Arazi is director of photography at Sony Santa Monica very funny why they use chromatic aberration, film grain.

 

Maybe we don't need to do this everywhere.
As a human, looking at the scifi image, i can immediately see the reflections of the lights are a bad guess at the boundary of the lights shape.
So ML approach should be able to detect such obvious error in a similar way, and spend expensive rays only at this boundary to fix it efficiently.
Other remaining errors which are not obvious to perception might not even need a fix.

That's kinda the stuff where i can imagine ML makes sense for realtime graphics.
Another example would be with TAA: A moving object over noisy background (a bush) leaves a trail of ghosting object color. Once it's in the history, we can't get rid of this visually obvious error.
I assume ML has better chances here than human engineering. But lacking understanding of ML, that's just a personal guess ofc.

 

https://highperformancegraphics.org/slides20/monday_gruen.pdf

Open problem with current raytracing @JoeJ



Find it searching Brian Karis tweet explaining current raytracing is not ideal for Nanite.

 

Yay, nice numbers to give me ammo for my repetive BVH and LOD arguments

The stuff in the red box could go down to less than a millisecond if we had both.

 

Visibility Buffer Rendering with Material Graphs by John Hable

 

Perhaps you've just read John Hable's paper referenced by jlippo?

There appears to be nothing in Hable's implementation that wouldn't run on a HD 6970 or GTX 580. Sure you'd have to code around the limitations of compute from back in the early D3D11 days, but nothing in the article looks impossible on that 10-ish year-old hardware.

Sure, the performance may be underwhelming. But 10-pixel triangles at 1080p back in 2010 would look better than pretty much every game that was around back then.

 

http://c0de517e.blogspot.com/2016/08/the-real-time-rendering-continuum.html

Yes but I think the idea of hybridizing deferred shading with visibility buffers was first theorized in one of Angelo Pesce's posts behind section "Cutting the pipeline "early"".

I think of Hable's post as an extension to Pesce's hypothetical scenario raised at the time.

 

Was surprised at how fast the visibility buffer caught up, surely hardware fastpath has to be faster until the worst case scenarios right? Well, turns out that happens much faster than one might anticipate.

Maybe UE5 will switch to all visibility buffer after this test, as this implies both that this should cut down on overall render times even for non nanite geo, and that it should help artists worry less about their material cost regardless of the geometry type. Hypothetically one could keep a visibility only renderer for translucency as well, after all you're not using traditional deferred features like SSR for translucency anyway; at most you're keeping some sort of proxy card. Then you'd get complex materials on translucency as well, though one can imagine artists quickly trying to do some sort of refraction shader worst case scenario like he mentioned.

 

Seems entirely reasonable.

And Pesce also mentions texture space lighting, which when temporally cached with ray-traced results for static scene surfaces seems viable as another performance win.

 

https://www.4a-games.com.mt/4a-dna/...upgrade-for-playstation-5-and-xbox-series-x-s

 

https://substance3d.adobe.com/magazine/bluepoint-games-the-masters-of-remasters/

Interview about texture and material creation of Demon's souls remake

 

Raytracing tidbits.
https://interplayoflight.wordpress.com/2021/07/10/raytracing-tidbits/

 

EDIT: