Nelarius

Added a quick and dirty VOX importer to my #voxel project. Since I recently played through Monument Valley, I checked out Ephtracy's Monument Valley files first 🏛️

The planetary sunrises and sunsets you get with the Unreal sky model are probably overkill for the #voxel renderer, but makes for nice #screenshotsaturday material 🪐

The new model gives the transmittance at any point in the sky, so the sun turns convincingly red as it approaches the horizon🌗

Integrated the Unreal Engine sky model into the #voxel editor. The sunsets didn't look right in the Hosek-Wilkie model (left). With the new sky model, sunsets are now exactly how I wanted them 🌅

Pardon the fireflies, I need to get proper denoising set up ✨

#raytracing

At a quick glance I thought you had gone down some kind of hardcore atmospheric rendering rabbit hole 😁

The sky is an implementation of Hillaire's model: sebh.github.io/publications...

The atmosphere is rendered into a small 2D angular coordinate lookup table using raymarching integrators from section 3. The LUT is small enough that it can be updated in real-time on the CPU.

The images show a 2D look-up table of scattered light.

The sun position and camera altitude can be played around with in real time. But zooming to space and back just looks so good 😄

Good morning from an altitude of 40 km!

Putting off other tasks in the #voxel project to work on a much nicer ray-marched sky for the ray tracer.

#screenshotsaturday #raymarching #raytracing

One unexpected benefit of the color palette is storing just an offset index in the voxel. Voxels shrank from 4 bytes to a single byte.

Added a simple SIMD optimization in my RLE algorithm, yielding a 6x #voxel chunk compression speed up 🏎️

#screenshotsaturday

Mandatory view of the scene in the #raytracing mode ✨

Adding an editable color palette to the #voxel editor made it feel more like a real tool. I was finally able to actually make something in it 🤓 Perfect playground for making scenes to test #raytracing algorithms!

#indiedev

Experimenting with a face extrusion and retraction brush in my toy #voxel editor. Threw a bit of #raytracing in there while I was at it ✨

YouTube video by I3D Symposium I3D 2025 Chris Wyman's Keynote "ReSTIR: Traveling the Path of Reuse"

Worth watching presentation, also provides some background info on how ReSTIR came to be and where it is heading: "ReSTIR: Traveling the Path of Reuse" www.youtube.com/watch?v=MRg9...

Realized that my bookshelf contains a #programming story 😄

More sliders in the #voxel editor UI! Added okhsl sliders alongside the regular hsl ones. The okhsl color space is much more uniform along its axes (look at the lightness slider).

Björn Ottoson has a great write-up about the colorspace here: bottosson.github.io/posts/colorp...

Basics of the new #voxel UI layout implemented. Apple's RGB sliders are really nice and decided to try implementing those.

#cprogramming

Tried Claude for creating interactive mockups of a #voxel editor UI and color scheme. Pretty happy with how quickly I was able to see and play around with some ideas I had.

Now for the fun part, implementing it all by hand in C 🙂

#claude #anthropic

Went down a rabbit hole comparing my monolithic ray tracer to my wavefront implementation and trying to find performance improvements. Still many things I could do to improve wavefront performance, but sharing notes on progress so far.

nelari.us/post/wavefro...

#raytracing #rendering

Looks like knitted wool 😁

Do you happen to have a write-up about your renderer somewhere? You post all kinds of cool experimental renders, would be cool to learn more about it 🙂

A different perspective of the cornell box ✨

#voxel #raytracing #rendering

Yep, perhaps I should make it impossible to select pure primary colors.

Glad you found a better uintToFloat! And just to be clear, the code is not mine, it belongs to Jakub Boksansky 🙂 It's a great reference that I've also lifted many good code snippets from.

Nice, thanks for the tip!

The cornell box is actually a bit of a pathological scene. With red, white, and green walls, the probability was always one and it is the same as no RR.

But in other scenes p = max(albedo) is definitely an improvement! I'll have to see if I can tweak this a bit 🙂

Added Russian Roulette implementation to my #voxel renderer. Didn't really appreciate before -- it doesn't make the image better, it makes it quicker to render. Left/right: vanilla and russian roulette at 16 spp. Speedup with roulette is 1.5x.

Impl from github.com/boksajak/ref...

#raytracing

Plugged the two-sample estimator into my #voxel project and sampled the sun disk using the cone sampling distribution from a previous post. It yields much better results at 64 spp than brute force method (left image).

Looks close enough to make it a new baseline for the reference renderer 🤞

It appears that one way of implementing "next event estimation" is by just doing multiple importance sampling using two rays instead of one each iteration, with one ray always sampling a light. So instead of the blog post's estimator, using this estimator.

Demystifying multiple importance sampling

I've been trying to wrap my head around "next event estimation" in #raytracing. What exactly is it and how does it differ from the multiple importance sampling technique, presented e.g. here? lisyarus.github.io/blog/posts/m...

The adjustable sun disk radius is added to the cleaned-up C sky model implementation.

Reused the sky and sun integration from my earlier WebGPU renderer: nelari.us/post/pathtra...

The sun disk values are "somewhat in the ballpark", as only a coarse set of sun disk values are interpolated from the original implementation for simplicity 🔭

Continuing with #raytracing in my #voxel project. Integrated the Hosek-Wilkie sky model, with an adjustable solar radius.

A really large sun disk makes it possible to test what the direct sun light contribution looks like in a simple brute-force renderer.

#cprogramming