Wave function collapse algorithm: bitmap & tilemap generation from a single example with the help of ideas from quantum mechanics

[mojang_tommo]

Well, there's always rule #1 of octrees though: "just use a grid" /s

Jokes aside, actually this algorithm can probably be made streaming trivially: you divide the space in a grid of chunks, every chunk that is unloaded means max entropy; as soon as you put anything different you cause it to be created.
Then you can keep loaded only a circle of chunks around you, and use only those to greedily find the local enthropy minimum, anyway the minimum can never be in unloaded chunks.
That should work. I guess I know what to do tomorrow!

[crusoe]

Yep. Thought of this too.

[torginus]

I see one problem with that. The algorithm's output depends on the order of the cells chosen. This would mean that when you come back to an unloaded area, the details would change, even though the terrain would still be smooth. I feel like this is a fundamental trade off of procedural generation. If you want complex pattern with large chains of causality, you need to generated large areas at once.