Lightnews — Scholar-powered news

Andrew Helmer @andrewhelmer.bsky.social · 2d

My first 3D software!

Andrew Helmer @andrewhelmer.bsky.social · 4d

For anyone who's tried to use spherical harmonics for lighting and found the notation- and terminology- heavy definitions confusing, highly recommend this classic: grahamhazel.com/blog/2017/12...

I think Graham Hazel's blog was down for a long time, years maybe, but works now!

Alternative definition of Spherical Harmonics for Lighting – Graham Hazel

grahamhazel.com

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Reposted by Andrew Helmer

Baptiste GENEST @baptiste-genest.bsky.social · 7d

Computing the exact bijection of the optimal transport (OT) problem between very large point sets is completely untractable…

In our SIGGRAPH Asia 2025 paper: “BSP-OT: Sparse transport plans between discrete measures in log-linear time” we get one with typically 1% of error in a few seconds on CPU!

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Reposted by Andrew Helmer

mjp @mjp123.bsky.social · Sep 8

I've got a new blog post for all of you fine folks! It runs through the additions to D3D12 since it was released, and finishes up with some of the things that have changed for me personally in my code.

(And yes it's really been 10 years 👴).

therealmjp.github.io/posts/ten-ye...

Ten Years of D3D12

For those of us that have been using it from the start, it can be hard to believe that Direct3D 12 has been around for nearly ten years now. Windows 10 was released on July 29th 2015, and D3D12 has be...

therealmjp.github.io

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Andrew Helmer @andrewhelmer.bsky.social · Aug 22

That wouldn't surprise me, or at least Pixel chips haven't improved nearly as much as QC (and definitely not Apple). The Pixels have 50% more RAM than comparable iPhones though.

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Andrew Helmer @andrewhelmer.bsky.social · Aug 22

It's not a regression though, the 10XL is still faster than the 9XL according to Geekbench. Just that Pixels were never near Apple perf, which isn't new.

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Andrew Helmer @andrewhelmer.bsky.social · Aug 19

Paper here: diglib.eg.org/bitstream/ha...

diglib.eg.org

Andrew Helmer @andrewhelmer.bsky.social · Aug 19

Highly recommend Peter Shirley's presentation of "Spherical Harmonic Exponentials for Efficient Glossy Reflections". As always, he makes notation-heavy math way more accessible, and it's an amazing technique: youtu.be/jN7FX5COASM?...

Spherical Harmonic Exponentials for Efficient Glossy Reflections

YouTube video by High-Performance Graphics

youtu.be

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Reposted by Andrew Helmer

Kostas Anagnostou @kostasanagnostou.bsky.social · Aug 14

Great Siggraph 2025 presentation of Gran Turismo's tonemapping pipeline, which also includes a fantastic introduction to light perception and tonemapping, its origins and how it evolved over the years with display technology, recommended read: blog.selfshadow.com/publications...

blog.selfshadow.com

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Reposted by Andrew Helmer

Kostas Anagnostou @kostasanagnostou.bsky.social · Jul 13

"Hallucinations on the future of real-time rendering", High Performance Graphics 2025 keynote: c0de517e.com/023_hpg.htm

Hallucinations on the future of real-time rendering.

Angelo Pesce's homepage & blog on computers, graphics and other things.

c0de517e.com

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Andrew Helmer @andrewhelmer.bsky.social · Jul 9

Your cone solid angle sampling post reminded me of this!

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Andrew Helmer @andrewhelmer.bsky.social · Jul 9

Always a great reference for generating an orthonormal basis from a unit vector: jcgt.org/published/00...

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Reposted by Andrew Helmer

Yining Karl Li @yiningkarlli.bsky.social · Jul 7

At SIGGRAPH 2025, Intel, Disney, & Chaos are doing a course on the nitty gritty details of implementing path guiding methods in 3 production renderers: Cycles, Hyperion, and Corona. I helped write the course notes: 80 pages of great stuff! Coming soon.

s2025.conference-schedule.org/presentation...

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Andrew Helmer @andrewhelmer.bsky.social · Jul 3

There are a bunch of follow-ups, and the libdivide library to do this at runtime:

ridiculousfish.com/blog/posts.h...

libdivide.com

Announcing a port of Angband running entirely in-browser. Angband is a venerable roguelike dungeon-crawler set in the Tolkien universe.

ridiculousfish.com

Andrew Helmer @andrewhelmer.bsky.social · Jul 3

Or maybe do precomputation on a CPU and give the values to the GPU for the divisions? Maybe good for finding cells in a uniform grid that is not a power-of-two size.

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Andrew Helmer @andrewhelmer.bsky.social · Jul 3

Found this cool blog post explaining one way to optimize integer divisions by a constant divisor: ridiculousfish.com/blog/posts/l...

Could be useful for a lot of things. Eg hash-map with a prime number of entries, do the precomputation on initialization.

Labor of Division (Episode I)

ridiculousfish.com

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Andrew Helmer @andrewhelmer.bsky.social · Jul 1

I don't think this is bad at all. In addition to being well documented, it's well contained. Hacks like these are often necessary, what really becomes problematic is when they're spread all over the place through the codebase and make other code brittle.

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Andrew Helmer @andrewhelmer.bsky.social · Jun 26

Oh this looks great! I've been looking for an easy-to-use C++ library parser.

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Reposted by Andrew Helmer

Christoph Peters @momentsingraphics.bsky.social · Jun 21

All HPG 2025 papers are now available on the EG digital library.
CGF papers: diglib.eg.org/handle/10.23...
Conference papers: diglib.eg.org/handle/10.23...
It has been a huge honor to act as HPG papers chair and guest editor and I look forward to an exciting program in Copenhagen.

44-Issue 8

High-Performance Graphics 2025

diglib.eg.org

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Andrew Helmer @andrewhelmer.bsky.social · Jun 20

Yeah, me too. But that still doesn't support their statement that someone is interrupted "every 2 minutes". That's the most extreme assumption - that every message is an interruption. The opposite extreme is that only one single message each day is an interruption. Both extremes are wrong.

Andrew Helmer @andrewhelmer.bsky.social · Jun 20

By their metric, one 30 minute conversation with 50 messages is the same amount of interruption as a unique message every ~10 minutes throughout the 8 hour workday. In one of these cases you get 7.5 hours of uninterrupted focused work, and in the other you get interrupted every 10 minutes.

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Andrew Helmer @andrewhelmer.bsky.social · Jun 20

Of course many async threads is terrible. But if I'm in an active conversation with a person (whether it's messaging, or in real life), yes it can be a distraction, but it's wrong to refer to every single statement that person makes as a unique "interruption".

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Andrew Helmer @andrewhelmer.bsky.social · Jun 20

Hmm looking at their absolute numbers, it seems like they are not distinguishing.

None of this takes away from your high level point at all, distractions have gotten way worse. But the "average 2 minutes" looks like a very misleading, arguably incorrect stat.

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Andrew Helmer @andrewhelmer.bsky.social · Jun 20

The mean time between receiving emails for me is probably a few minutes, and probably shorter for the mean time between Slack messages (DMs or tags). But the vast majority of those aren't interruptions.

It's totally possible MS is actually classifying which ones are interruptions in a sensible way.

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Andrew Helmer @andrewhelmer.bsky.social · Jun 20

I'm curious about a lot of these metrics. I get an email for every CL submitted into our codebase, but it goes directly into an archived label. Does this count as an "interruption by an email"? If I've already started a conversation with someone, does each new message count as an interruption?

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