WaveFunctionCollapse in Common Lisp

Anish Moorthy [email protected]

This is a Common Lisp "Implementation" of Maxim Gumin's WaveFunction Collapse.

As far as I know, this code correctly implements the "overlap" mode of the WFC algorithm. However it's just an "implementation" because it's missing a lot of features as compared to the original repo, and is too slow to use in practice :|

Also its not structured well at all: for example, there are still some hardcoded paths to files that I used for testing on my system, etc. Despite that, I hope that the code is at least understandable. It is my first nontrivial project in Common Lisp, so although I strove to keep the code of decent quality I'm sure that there are some issues.

Regarding performance

As I said, the code is too slow to use in practice: but I don't think it needs to be. Significant speedups could be achieved by tackling the following areas.

1. I :use the generic-cl package, when the only things I really need from it ire elt, equalp, and its hash-maps. I'm not sure what the performance penaly is here (hopefully small, but I have no idea), but selective imports would probably eliminate a ton of unnecessary dynamic dispatch.

2. There's a lot of unnecessary consing going on. The range and product functions are particularly egrigious offenders due to how often they're called, but the set operations could use some redoing too.

   The performance issues of range and product could be easily solved with a proper range function and itertools package. I'll probably try my hand at polishing and/or implementing these soon.

License

MIT