Experimenting more with hybrid probe and per pixel traced gi.

I now use a radiance cache to shade per pixel ray trace hits.

It saves a lot of performance and the quality is very close to proper hit shading.

Roughly saving ~30-70% of performance for rtgi (local lights make this verrry worthwhile).

Started to experiment with raytraced diffuse gi.
My probe GI works well but it just can not represent fine details with good performance/memory usage.

AO helps it a lot i want even more.

Most of the work on RTGI is denoising, very interesting work.

Here the current state: Probes only vs RTGI:

the warping of the octahedral mapping means that this is not an ideal way to sample in all cases as sometimes the texel distances are much shorter than in other areas of the probe.
But generally, this does not seem to cause issues.

this is a color coded debug view showing the debugged depth texel (red) and the weight it assigns to all the trace results (green).

As you can see, the weights become 0 nearly immediately.
Sampling a texel area of 6x6 for this resolution is more than enough to get all valid traces.

One of the biggest changes and optimizations i made to my DDGI impl is how probe texels are updated.
Instead of all texels looping over all rays per probe, each texel only checks out relevant rays.

This is a big performance gain with high ray counts (>256) and good depth resolutions of 16x16.

The current limitation is that i still allocate space for all probes.
Making the memory virtual similar to how VSMs do it might allow me to push the probe count even more.

An update rate of 12.5% of probes a frame as well as detecting and only updating probes that are close to a surface gives a gigantic performance uplift >40x.

Allows me to easily have DDGI run at under 0.3ms even tho i didnt spend more than 30 minutes optimizing.

Next step is virtual probe memory.

First experiments, using DDGI probes for specular.
Made all of bistro super metallic to show the effect.

I think this will work really great for rough indirect specular.
It would be great if DDGI probes could replace dedicated reflection probes to some extent.

I also get beautiful fog at home atm.
So pretty 😍

Love Fog

Automatic Probe Position Refinement :OOO.

Works MUCH better then i expected :D.
It fixes soo many leaks and artifacts with low probe densities.

Really happy with the probes now.

Using shadowmaps to calculate occlusion of probes is painful but necessary for sampling performance.

I finally got rid of most leaks by implementing a bunch of biases and heuristics.

Performance is much greater with shadowmaps as opposed to tracing visibility for probes now.

Working on global illumination is always amazing fun :)