How would I use libxmp in Unity?

[RenegadeScooter]

I'm a beginner developer, currently learning how to develop a game in Unity by developing a simple project that I plan to build upon later.

I really wanted to use some Creative-Commons-licensed tracker music composed by Andreas Viklund for my Unity project, and I decided to give this library a try because of its simple API. However, this library is coded in C and Unity uses C#, so I have to build the library into a .dll and then somehow get that running in Unity. Unity treats the .dll as a "native plugin," and the library contains several custom functions and data types.

How do I make this work?

[sezero]

You need to write your own C# bindings, I guess. (I don't know anything about C#, so I can't help.)

[AliceLR]

First off, I've never used C#, so I don't know what I'm talking about. I have marginal experience with the Java equivalent of this.

Right, you're going to have to add native function declarations to your class that interfaces with libxmp as described here: https://docs.unity3d.com/Manual/NativePlugins.html (note: don't statically link libxmp unless your software is GPL or LGPL or you're using libxmp-lite. This seems to only matter for iOS.)

Unfortunately, they don't provide much in terms of examples of how to do this, but they link to this MSDN document that seems like it should be useful: https://docs.microsoft.com/en-us/dotnet/framework/interop/marshalling-data-with-platform-invoke?redirectedfrom=MSDN

The C# native interface and libxmp's API makes this a little obnoxious because it seems that C# chars are 16-bits. The xmp_context used by most libxmp function calls is a char * typedef instead of void * (??), and the native interface maps C char * to C# string. You might have to force 8-bit char strings here.

This could be completely wrong, though, as it seems like there's some separate handling for unmanaged pointers, which is what you'd actually want for xmp_context. I asked in the MZX Discord server to see if anyone who actually knows what they're doing can help.

[RenegadeScooter]

I asked in the MZX Discord server to see if anyone who actually knows what they're doing can help.

Hear back from them yet? @AliceLR

[AliceLR]

No one responded either time I asked, sorry. :(

[sezero]

I think this can be closed now.