Binary STL support

[tanqci]

Your project is wonderful!

As I know, stl file have Binary and Ascii two type , does your parser support both of them?

[heyvito]

Glad to know it is useful for someone else. Currently, this library only supports ASCII-based STL files, although the binary version can be easily implemented using a simple finite state machine.

I'll try to add support to the binary format in the next week or so.

[epologee]

Here too: cudos on the project!

I was wondering if there's anything we can do to help with the binary format? Cheers, EP

[heyvito]

Hi @epologee! Sorry taking so long to answer your question.

Implementing the binary format should be quite straightforward, and you can even reuse the current implementation. A simple finite state machine should be enough to parse the structure documented here and here. After reading the normal vector, vertexes, and discarding any defined attributes¹, it would then just be a matter of instantiating SCNVector3s and dealing with SceneKit's oddities (SCNGeometrySource & friends).

Sadly I don't have enough time to work on this right now. PRs are super welcome! ✨

Best wishes!

[1] - No one should be using it, but we might want to be extra-cautious with binary formats.

[epologee]

Thanks for the links, @victorgama! The binary STL spec looks easier than the ascii one :)

I can't really make a PR on your repository, because I decided to parse the binary STL with Swift. Your HxSTLParser code was very essential in recreating this with Swift, even though I didn't go the state machine way for simplicity. Let me at least share it here, so maybe @tanqci can benefit from it as well:

https://gist.github.com/epologee/7373ea371812e8facd5a7a00e6b80d70