It's surprisingly detailed considering the low probe density.
It's also practically completely free as its trivial to calculate the radiance in the same shader as the irradiance per texel.

perf is not too great now, probes take around 500us to update, 600us to eval screen irradiance.
Rtgi replaces the eval screen irradiance but takes around 2-3ms now.

Goal is to shoot short traces from pixels (up to maybe 15 meters).

On miss the ray would read the probe volume radiance in the rays direction.

The shorter raylength improves performance immensly.

This hybrid RTGI/probe GI is something that i believe could be very performant and pretty.

Great stuff 😍

firefox + duckduckgo is pretty solid

somehow, i know that this is correct

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.

The trick is to trace rays into a octahedral trace result texture per probe.
The texel update threads can then narrow the area of the trace result texture to consider. For visibility updates, a texel area of only 6x6 contains all relevant samples. 6x6 is 7 times less loop iterations compared to 256.

out of curiosity how do you even do sfinae in hlsl, i thought the templates arent powerful enough to do it?

atm its just the raw ddgi probes where i reduce the cos weight for ray directions per sample to a narrow angle.

I wanna play with sh but didnt come to that yet.

The sampling cost of sh seems kinda hefty considering i interpolate 8 probes per pixel