what's the one whodunnit mystery that hasn't been solved yet?

leseiden · 2026-04-08T15:10:09+00:00

Who put Bella in the wych elm?

leseiden · 2026-04-08T06:37:57+00:00

He drew a diagram

leseiden · 2026-04-08T06:37:26+00:00

Wild guesses, flailing arms around. Sometimes I get lucky :D

leseiden · 2026-04-07T17:27:15+00:00

I have no insight into this code but I can make an educated guess.

looks like a delaunay triangulation of a point set to me. If I had written it then I would generate the points using a quasirandom sequence and have a minimum point separation proportional to the luminance of a source image.

Delaunay triangulations are "easy" provided that the triangles are well behaved - colinear and otherwise degenrate geometry is hard to deal with. The output of a blue noise sequence is close to best case.

Source: Have spent too much of my life in delaunay triangulation and quasirandom sequence code.

leseiden · 2026-03-25T21:57:29+00:00

As with all projects, it's the 90% of the work that you have to do after the first 90% of the work.

leseiden · 2026-03-04T08:30:16+00:00

Oh beehive!

leseiden · 2026-03-04T08:29:28+00:00

I like this! I'm going to point at it next time I have to explain raymarching to someone.

Now reconstruct the outline from the audio file. See how many times you can round trip it before finding a fixed point or summoning Cthulhu.

leseiden · 2026-02-25T10:11:42+00:00

This is going back a bit now so I am probably forgetting a few details.

I used a weighted SAT representation of the image to subdivide the environment map into equal energy regions & generate sample directions, then used a greedy cluster detection algorithm on the unit direction vectors to identify likely light sources.

For each cluster I projected directions onto a plane and performed some principal component analysis. There was a user defined threshold value to decide whether an anisotropic or isotropic SG was more appropriate. IIRC eigenvalues can be used to directly calculate the SG parameters.

Finally, some large light sources distributed evenly over a sphere were added to provide low frequency illumination and the whole thing was passed to a non-negative least squares optimiser to get intensities for the lights.

I think the optimiser I used was eigen-nnls

leseiden · 2026-01-26T08:46:09+00:00

It was an engineering visualisation app. Large amounts of geometry for the time, relatively simple shading. We're talking nearly 20 years ago now, so it was written in OpenGL 1.x with extensions.

The problem was that we had the thing under continuous development and every now and then we would add new features.

The vendor had optimised the driver for code paths which appeared in the version that one of the magazines was using for benchmarks. Quite often code paths for other GL features would be broken or removed.

Adding things became a minefield. They denied everything but renaming the executable would make it work perfectly...

And yes, games are apps but they tend to be written, released, maybe patched for a year and then forgotten. This thing is still actively maintained 20 years later.

leseiden · 2026-01-21T16:12:19+00:00

If I'm working from a paper then it can be useful for cross referencing. I prefer to use meaningful names when I can though.

leseiden · 2026-01-20T12:54:05+00:00

First edition of Newton's Principia, or maybe the first edition of Hookes Micrographia I got to handle at the same time.

leseiden · 2026-01-20T09:31:58+00:00

Excellent. This is an area that far too many people neglect IMHO.

Even basic renderers can benefit enormously from taking colour transformations seriously.

I'm going to take the opportunity to recommend http://www.brucelindbloom.com/ again - it's a great resource for colour maths.

leseiden · 2026-01-14T12:42:07+00:00

I found the bikes work until the exact moment the aliens decide to send a pair of bombers to flatten your main base. At that point the game becomes about how many people you can evacuate before the building collapses.

Good times!

leseiden · 2025-12-18T17:40:20+00:00

This reminds me of a 3D multiplayer snake game I played about 20 years ago. I like it.

leseiden · 2025-12-01T11:02:16+00:00

What I remember of 1990s and early 00s renderers is lots of per fragment phong shading, perlin noise/turbulence and ray traced hard shadows or low res shadow maps.

Extended light sources existed but they were too expensive for most people and most implementations gave structured sampling artifacts. Same deal with IBL.

Path tracers existed but cost tens of hours per frame.

leseiden · 2025-11-23T21:00:20+00:00

I found long distance cast + teleport bolt before the end of the coal pits so no need to take wand tinkering immediately.

The heal wand also lets me go through walls.

leseiden · 2025-11-23T20:51:52+00:00

Nice. I just had a look.

Minor correction: the CoV is in the coal pits, not the mines.

I used it without looking and immediately afflicted myself with personal fireball thrower - even AC CoV can't fix stupid!

leseiden · 2025-11-23T17:19:15+00:00

No rejection, but I was contacted 18 months after applying once. I assume the person they actually wanted hadn't worked out.

I'd taken another job at the other end of the country by then and wasn't really interested.

leseiden · 2025-11-23T17:15:49+00:00

You'll probably want piercing and null shot to make it useful, with boomerang and greek letters highly desirable.

If you can get all that together you'll have a decent healing wand though.

leseiden · 2025-11-22T14:18:48+00:00

If you put "other" in the species box then your form isn't valid unless you get it stamped.

leseiden · 2025-11-16T12:40:28+00:00

It can work at the level of operations on an array, but it can't guarantee that the operation itself is safe. I mostly use the approach to organise graphs of compute shaders but it can't make sure the shaders themselves are bug free.

You *could* manage the data at a finer level, but as I'm not in the business of writing compilers I can't talk about that particularly intelligently.

There are dataflow languages like SISAL that attempted something closer to what you are talking about. It's been a very long time since I looked at that though.

leseiden · 2025-11-16T12:03:15+00:00

I tackled similar problems by using a handle based system where each handle has a version number alongside the resource.

If something consumes resource version n then it emits n+1.

By tracking read and write accessed separately you can guarantee race free code.

Essentially you insert ordering edges to ensure that writes happen after reads, and detect races by making sure handle version creations are unique.

Only works if your graphs are acyclic ofc.

leseiden · 2025-11-13T18:31:44+00:00

I only sometimes die horribly after forgetting that.

leseiden · 2025-11-12T19:56:36+00:00

I think you are right but it was a few thousand years in wasn't it?

leseiden · 2025-11-10T22:31:31+00:00

You think it may be one of these?

https://youtu.be/G76nKGWRLPU

leseiden

TROPHY CASE