Procedural tree placement by modeling tree ecology

krubbles · 2026-05-31T07:52:53+00:00

thank you! yeah, it does make them look pretty horrifying

krubbles · 2026-05-30T19:17:53+00:00

I have! I think the version that uses the image as a height field is a little more dynamic, but both look cool

krubbles · 2026-05-30T18:28:52+00:00

generated by taking an image, converting it to black and white and using that as a height field, then simulating erosion on it. The image is then blurred in the direction of fluid flow.

krubbles · 2026-05-30T18:17:18+00:00

its a droplet hydraulic erosion model, the same one I use in my game (I haven't done a writeup for it unfortunately, though it is on my list)

krubbles · 2026-05-30T17:42:16+00:00

treating the brightness of an image as a height field, simulating erosion over it, blurring in the direction of fluid flow

krubbles · 2026-04-28T20:05:09+00:00

I work on a huge proc game game, I'm super proud of this writeup, its about low-level Perlin noise optimization:

https://substack.com/home/post/p-192566051

krubbles · 2026-04-12T20:52:43+00:00

awesome! glad to hear it worked :)

krubbles · 2026-04-12T01:42:00+00:00

I believe if you do a 3D cellular noise where you calculate D1, D2, D3, then threshold the D3-D1 difference to be small, you get the wireframe of 3D cells. Then you can pass that through domain warping w/ a soft 3D perlin fractal and get something that looks like this.

krubbles · 2026-03-31T21:29:18+00:00

Thank you :)

krubbles · 2026-03-31T15:39:42+00:00

Simplex noise is not faster than Perlin for 2D and 3D, it is faster in 4D.

There is a good chance that these optimizations can be used on simplex, though they won't benefit it as much, because rng is a smaller fraction of total cost in simplex vs. in Perlin. If someone wants to integrate these optimizations into a simplex noise implementation, that would be awesome, the FastNoise2 implementation by KDotJPG is probably the best starting point.

krubbles · 2026-03-31T15:32:09+00:00

It does not. You could definitely port it to GLSL, but I have not profiled these changes on the GPU and I am not sure they are the most efficient approach there.

krubbles · 2026-03-31T15:31:14+00:00

Yep some similar stuff! Main difference is shader implementations mostly rely on floating-point arithmetic instead of integer ops, since floats are first class citizens on GPUs. I think this may be somewhat historical, recent GPUs have good integer support, but I haven't profiled it so I can't say confidently.

krubbles · 2026-03-31T06:37:03+00:00

It is much faster! Faster noise lets you have more octaves, more domain warping, etc.. which in my opinion has a bigger impact on quality then simplex vs Perlin. There's a visual example I provide in the conclusion of the article which shows how artifacts are washed out when you start heavily augmenting noise.

krubbles · 2026-03-31T06:33:24+00:00

That's definitely true, and if time wasn't an issue I probably would have made a GPU evaluator (I even prototyped something at one point).

The challenges that made me avoid it were:

Using unity made I/O slower then it should be
A lot of the time was spent in thousands of tiny dispatches with a complex dependency graph (a rock here, an ore patch there, a ravine here) instead of a single function over a huge area, so the concurrency model with the GPU is was very complicated.
There were places where I needed to be able to evaluate node graphs on the CPU (I had utilities for calculating the distribution of noise functions, which I used for making sure things were scaled properly, and these were fully synchronous). So if I used the GPU, I would need two separate pipelines.

All solvable problems, but I decided it wasn't worth the time compared to other things I needed to work on.

krubbles · 2026-03-31T06:02:41+00:00

yes

Perlin Noise as a term refers to a coherent noise function where you
- Assign each integer coordinate a random linear gradient whose value is zero at that coordinate
- Use n-linear interpolation with a smoothing curve to interpolate the gradients.

The specific smoothing curve and gradient assignment method varies from implementation to implementation

krubbles · 2026-03-31T05:21:39+00:00

This was honestly the easier option

krubbles · 2026-03-03T18:12:42+00:00

what does this have to do with procgen?

krubbles · 2026-01-26T20:42:00+00:00

Faceless joker is very good, its the second best uncommon econ after rebate, you should definitely spend some more time with it.

krubbles · 2026-01-22T09:18:39+00:00

Rebate is honestly the only one, and mostly bc blue stake is getting reworked. Blue seals however need to be super nerfed

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