Lionel Lemarié's Avatar

Lionel Lemarié

@hikey.org

Rendering, ray tracing, Metal API.

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08.01.2024
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Latest posts by Lionel Lemarié @hikey.org

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That looks amazing!
I wanted to try to replicate it. This is the closest I've got so far.

28.02.2026 02:16 👍 1 🔁 0 💬 0 📌 0
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The #WebGPU global illumination engine is getting somewhere, now with volumetric light shafts (00:58) and fully destructible environments. Sorry about the mouse cursor, that's how you know it's real, AI would _never_.

19.02.2026 23:35 👍 24 🔁 1 💬 0 📌 0
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Got some time to spend on the pathtracer denoiser. It's getting there, and the next step is to fix those disocclusion artefacts.

I will start working more and more on this project, and share more info hopefully soon!

#rust #webgpu

18.02.2026 22:51 👍 12 🔁 1 💬 1 📌 0
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For contrast, here's a naive attempt in my renderer.
I'd say it clearly demonstrates how amazingly clean yours is...

15.02.2026 22:21 👍 6 🔁 0 💬 1 📌 0

Wow that looks amazing!
Each time I'm still blown away by how responsive the lighting is in your renderer.

15.02.2026 20:12 👍 1 🔁 0 💬 1 📌 0
Preview
On macOS there's a system beep each time a key is pressed · Issue #5 · Atrix256/Thirteen Repro on macOS: Run a sample, press a key: there's a system beep. The app does receive and process the key press, but the beep is unwanted. That's because sendEvent: is called after the app process...

Hey Fran @carucci.photography (: Here's another report for you: github.com/Atrix256/Thi...

14.02.2026 19:52 👍 1 🔁 0 💬 1 📌 0

Linux support works really well! Superb job.
Keyboard support is a tricky one, though.
bsky.app/profile/hike...

14.02.2026 15:55 👍 2 🔁 0 💬 1 📌 0
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They work now! thirteen.h and tinybvh.h make for quick and easy multiplatform ray tracing (:
Here's Ubuntu and macOS.

14.02.2026 15:49 👍 12 🔁 2 💬 0 📌 1

Sorry, I wasn't clear. When it's realtime at 1spp, it's super noisy. This video has lots of accumulated samples and took overnight to render. Very minimal denoising here.

14.02.2026 15:34 👍 1 🔁 0 💬 0 📌 0

That's on my Metal ray tracing renderer, using GPU hardware acceleration. So it only took overnight to render...
Rendering 1spp is pretty fast (easily realtime), but there's plenty of room to improve convergence and denoising.

14.02.2026 15:15 👍 1 🔁 0 💬 1 📌 0
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The final boss for this mini-renderer. Zorah and a (minified) Moana island.
TinyBVH makes it almost too easy.

14.02.2026 15:02 👍 10 🔁 2 💬 1 📌 0

It's the other way around: I normally shrink a thing to voxel size and build a Sponza scene out of it! bsky.app/profile/hike...

14.02.2026 14:53 👍 11 🔁 1 💬 1 📌 0
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Unbelievable but true: this renderer also works with non-Sponza scenes!

14.02.2026 04:55 👍 11 🔁 2 💬 2 📌 0

Ah oops, I created my own threads like a noob (:

14.02.2026 04:52 👍 1 🔁 0 💬 1 📌 0
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thirteen.h + tinybvh.h = easy pt

14.02.2026 04:44 👍 18 🔁 1 💬 2 📌 0
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It takes no time to use the week-end code with thirteen.h! 🤣

13.02.2026 01:40 👍 10 🔁 1 💬 2 📌 0
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It's hard to make it look good, but it's pretty easy to make it look weird...
ShaderToy Wcd3W2 by Shane.

11.02.2026 04:48 👍 1 🔁 0 💬 0 📌 0
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Live interaction: it reacts pretty quickly in a nice open scene like this.

10.02.2026 13:37 👍 4 🔁 0 💬 1 📌 0
Path traced scene with a shader as the sky. Shader from Xor: https://www.shadertoy.com/view/3fKSzc

Path traced scene with a shader as the sky. Shader from Xor: https://www.shadertoy.com/view/3fKSzc

Nice, it worked easily in a quick test.

10.02.2026 03:49 👍 5 🔁 0 💬 1 📌 0

That looks amazing! And the lighting is incredibly reactive. Nice one.
Inspires me to add it to my renderer too, although it won't look nearly as good.

09.02.2026 22:21 👍 3 🔁 0 💬 1 📌 0
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I think most raytracing effects and denoisers don't really think about needs of fast games like shooters.

For my RTGI denoiser, i put in a lot of care to get an immediately readable and stable image from the first frame after dis-occlusion.

its very satisfying.

04.02.2026 01:50 👍 32 🔁 1 💬 1 📌 0
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New post on how to do real-time diffuse global illumination using surfels and #WebGPU: juretriglav.si/surfel-based... #threejs

29.01.2026 12:22 👍 164 🔁 30 💬 1 📌 2
Original: an old photo I took in the forest

Original: an old photo I took in the forest

3D voxelized scene in the day.

3D voxelized scene in the day.

3D voxelized scene in the night.

3D voxelized scene in the night.

3D voxelized scene in the day with volumetric fog.

3D voxelized scene in the day with volumetric fog.

This was a fun quick experiment:
Using an old photo I took in the forest, I used ml-sharp to generate gaussian splats from it, voxelized it in my toy renderer, relit the scene dramatically.
#rendeting #metalrt

22.01.2026 13:37 👍 24 🔁 4 💬 0 📌 0
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Switched from ImGui to SwiftUI

20.01.2026 16:44 👍 17 🔁 2 💬 3 📌 0

Looks amazing!

20.01.2026 17:18 👍 3 🔁 0 💬 0 📌 0
Path-traced render of an off-white folded fractal.

Path-traced render of an off-white folded fractal.

Path-traced render of a colorful folded fractal.

Path-traced render of a colorful folded fractal.

Coloring a fractal is interesting in itself. Finding good colors is tricky. Applying them to the "right parts" is tricky.
Here's a comparison of off-white vs a value that's displaced relative to the folding for each iteration (then mapped to a color ramp).
#fractals #rendering #metalrt

20.01.2026 15:44 👍 16 🔁 0 💬 0 📌 0
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Ok, so I'm completely stuck trying to debug this.

Left is pathtraced reference, right is my realtime renderer. Top row are metals, bottom row are dielectrics, and roughness goes from 0 to 1 left to right.

19.01.2026 02:01 👍 19 🔁 2 💬 1 📌 0
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Render a fractal in 2 easy steps.
1. Render a sphere.
2. Render the rest of the... fractal.
#rendering #metalrt

16.01.2026 12:32 👍 15 🔁 0 💬 1 📌 0

No, this is classic ray marching IFS. In the distance function, take your position: mirror with abs(), rotate a bit, offset a bit, repeat for a few iterations.

16.01.2026 11:55 👍 1 🔁 0 💬 0 📌 0
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How to render a fractal in two easy steps:
1. Render a fractal.
2. Fold it into a fractal.
#rendering #metalrt

16.01.2026 05:48 👍 14 🔁 1 💬 1 📌 0