Arseny Kapoulkine

Independent. Previously: TF@Roblox

meshoptimizer, pugixml, volk, calm, niagara, qgrep, Luau

GitHub: http://github.com/zeux
Blog: https://zeux.io

Last Notes

2026-09-14 21:35:17 GMT

So I was doing profiling on Windows yesterday night. Then Windows Update installed and rebooted. Today I am testing the same executable and it’s 30% slower.
The executable uses 16 threads on a 16 core 32 thread machine. Today it looks like the scheduler usually schedules two threads per physical core. Settings an affinity mask to exclude odd numbered cores fixes it.
I also never asked for the reboot in the first place. Honestly at this point Windows is a liability.

2026-07-28 16:57:20 GMT

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units are msec, so around a second total

2026-07-28 16:30:30 GMT

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Used to take ~15 seconds end to end 😅
https://cdn.masto.host/mastodongamedevplace/media_attachments/files/116/998/551/591/103/295/original/6c93f3fd649454c3.png

2026-07-28 16:22:50 GMT

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Alright whatever I will just merge all textures in an array. 256 textures at 1K resolution is just ~1.4GB VRAM, and VRAM is cheap these days!

2026-07-27 21:04:24 GMT

There’s still no support for indexing arrays of textures in WebGPU right?
I found that many of my JS perf issues can be worked around by “just” running code on GPU ;) but I need access to textures and it’s difficult to do that with just uniforms…

2026-06-17 16:07:33 GMT

New blog post! In "Zigzag decoding with AVX-512", we look at two different ways to possibly (caveat emptor) speed up various forms of zigzag decoding with AVX-512 functionality that isn't just "wider registers".
Boosts appreciated!
https://zeux.io/2026/06/17/zigzag-decoding-avx512/

2026-02-18 18:15:43 GMT

I don’t fully understand the motivation to use LLMs to write blog posts. The loss of personal voice is so striking that it immediately rings alarm bells in my head. You can fact check the output although even that is spotty but you can’t inject the soul back.
And if you stop writing yourself, what makes you think you still can? And what is it that makes you - you?

2026-01-06 03:37:16 GMT

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Congrats!

2025-12-10 19:23:00 GMT

fun
https://cdn.masto.host/mastodongamedevplace/media_attachments/files/115/696/898/857/775/075/original/0fb95098ab0d4dd7.jpeg

2025-10-01 18:06:33 GMT

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You can set the error to be higher in theory. I think it depends on the particulars of your TAA; and also because actual Nanite does micropoly rasterization in compute for small triangles, I would imagine the performance depends on rendered triangle count in a non-trivial way. Note that unlike discrete LOD, under camera motion you’d expect many cluster transitions every frame in different parts of the screen… so single pixel cutoff is much safer.

2025-09-30 17:39:47 GMT

New blog post! In "Billions of triangles in minutes" we'll walk through hierarchical cluster level of detail generation of, well, billions of triangles in minutes. Retoots welcome!
https://zeux.io/2025/09/30/billions-of-triangles-in-minutes/
https://cdn.masto.host/mastodongamedevplace/media_attachments/files/115/294/467/861/286/476/original/44ba883e92d0c392.jpg

2025-04-25 20:12:51 GMT

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Classic, alongside "we support vertex texture fetch but the list of formats is empty", and I think was another one like this that I'm blanking on...

2025-04-01 04:49:22 GMT

New blog post! "Measuring acceleration structures", in which we will compare BVH costs on various GPU architectures and drivers and attempt to understand the details enough on AMD hardware to make sense of the numbers!
Boosts appreciated :)
https://zeux.io/2025/03/31/measuring-acceleration-structures/

2025-03-14 16:04:08 GMT

meshoptimizer 0.23 is out! Featuring vertex codec v1 (increased compression ratio, faster decompression), even faster decompression on Apple Silicon, improvements to meshlet builder with fewer disconnected clusters and more options for clustered raytracing and hierarchical clusterization, new algorithms for hierarchical clusterization, simplification quality improvements and more.
Thanks to Valve for sponsoring most of the work on the core library in this release!

2024-08-14 16:56:36 GMT

Apparently the current state of the art in developer tooling is write it in Rust (cool), render it with Vulkan (ok) and write a custom UI framework (oh) that no other tool uses.