The radiance cache works by storing another layer of texels on the probe. The new texels store the direct radiance coming into their direction, no cos convolve. When shading rtgi ray hits, i sample the radiance of the 8 closest probes by projecting the radiance back onto the hit ws position.

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:

Yoo, timberdoodle is in there. Great projects all around :)

It’s Timberdoodle time 💛🪶🥔 American Woodcock in Bryant Park, NYC, March 2025

The tech and graphical advancements in Assassin's Creed Shadows are mighty impressive: Micropolygon geometry, fluid wind simulations, ray traced global illumination and so much more. How do they all work and compare to AC games of the past? Find out in my video below! youtu.be/nhFkw5CqMN0

Thread divergence during constant buffer reads can have a big perf impact, this presentation discusses how to detect this on NVidia GPUs using GPU Trace and Shader profiler. Also shows how useful access to ISA is for understanding what the shader does under the hood. www.youtube.com/watch?v=HSsP...

While watching all the trailers from the Sony State of Play I could not help but notice that 90% of the games shown are Unreal Engine games... with each new scene/effect/character shown it is hard not to think "that will probably stutter on PC".

Illume

Thanks to a lot of colleagues' great work, happy to share Vulkan samples for RTX Mega Geometry. They should run on all RTX GPUs using today's new drivers github.com/nvpro-sample... github.com/nvpro-sample... github.com/nvpro-sample... github.com/nvpro-sample...

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.

something I've been thinking about recently: could object-space shading be the key to mitigating artifacts from temporal techniques? accumulating data over time in "shade space" rather than camera frame that flails around. www.oxidegames.com/wp-content/u...

Graphics Programming weekly - Issue 375 - January 19th, 2025 www.jendrikillner.com/post/graphic...

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.

A nice visualisation why using fps as a measure of performance (improvement) should be avoided. The mapping from ms to fps is not linear and the actual impact on frame time (ms) of an fps increase will depend on where in the graph (X axis) you are (from software.intel.com/content/www/...)

Albert Road Middlesbrough, mid afternoon . Life in a Northern Town. #photography #monochrome #monochromephotography #urbanphotography #thephotohour #blackandwhitephotography

Kein Ende in Sicht. ☁️

Your foggy corn

After so many years of real-time GI being a near-impossible “holy grail” of graphics, it’s a bit funny that the RTGI era has finally arrived without much fanfare. It’s also interesting that the main benefit ended up being vastly improved dev workflow as opposed to a visual quality increase.

Love Fog

Enchanted path. Dorset, England. #landscape #woodland #photography #forest #uk

One of the best hobbyist engines out there.

I like this analogy

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 :)

All I want for Christmas is for everyone to please stop sending me links to *those* videos complaining about "modern graphical technique ruins gaming", how graphics were better a decade ago, and how said person complaining is going to build a special team to fix Unreal Engine. Santa please. PLEASE.

In our next Tiny Glade update we'll bump the light limit from 32 to 32k while keeping the cost more or less the same. The small limit has been a cop out, as we didn't quite know how to render huge numbers of (screen-space) shadow-casting lights without severe performance degradation.