GITHub is here [0], and this is under an MIT license - which I couldn't find on the documentation site.

[0] https://github.com/nmwsharp/geometry-central

I'm looking for a good half-edge mesh library to use with Unity. In theory anything with C bindings should work. Only issue is I'll need a dll or equivalent for Windows, Linux, MacOS (including Apple Silicon) and Android.

Anyone tried compiling this for Android? I'm a C++ dummy so it needs to be trivially easy. I usually waste an entire afternoon every time I tackle trying to compile native code.

You could try open3d

https://github.com/pezcode/open3d-core-android

http://open3d.org/docs/0.16.0/python_api/open3d.geometry.Hal...

If you're open to writing your own, I found https://fgiesen.wordpress.com/2012/02/21/half-edge-based-mes... and https://fgiesen.wordpress.com/2012/03/24/half-edge-based-mes... to be good resources.

I've actually got my own (partly - the core halfedge stuff is from another C# project).

But it's performance I'm after. I have three options: 1. Burst compilation 2. Offload to the GPU (not sure if this is even a good use case for GPU compute) 3. Find a native library.

(3) is potentially a quick fix but might limit my ability to add functionality. But it also offers the tempting possibility of getting a ton of functionality for "free".

A more detailed comparison to CGAL would be helpful...

Check out libigl too

https://libigl.github.io/

Behind the confusing name, it's a C++ code library, not a document library.

Why would there be a document library of data structures and algorithms?

We usually call this a "book".