custom rodio source for audio

[tarkah]

This is very much an early draft and in need of feedback.

I've made AudioOuput able to play anything Decodable. Decodable has been implemented on AudioSource and is the concrete type used for creating the AudioOutput in the AudioPlugin. Decodable outputs a Decoder which must implement rodio::Source<Item = rodio::Sample> + Send + Sync to be accepted by AudioOutput.

The downside right now is if someone created their own Decodable, they'd need to setup their own AudioOutput on that type and redo a bunch of the stuff the AudioPlugin sets up on behalf of the user. I've done this at the following test with my Atra3+ decoder and it works. https://github.com/tarkah/bevy-test-custom-audio. Also, users have to specify AudioOutput<AudioSource> out of the box, which is less than ideal, though we could type alias something I'm sure.

I couldn't get dynamic dispatching working in the way I was hoping since rodio::Sample in the associated type for rodio::Source is Sized. I have no idea if it's possible to have a single AudioOutput with a dynamic rodio::Source input without having to define separate instances over the concrete rodio::Source types. I was hoping to be able to do a Box<dyn Decodable> type setup but it just doesn't work. I'm also a little out of my depth here so maybe I am missing something, or maybe I am just tackling this API change completely wrong. Anyway, your feedback would be appreciated!

[tarkah]

Also, I understand if this is super low priority, so no rush on this at all!

[multun]

Can you rebase this on master? Format checking was enabled, and the CI doesn't yet check for it at the commit you're at

[tarkah]

Rebased

[multun]

Awesome, thanks! (the failure isn't yours)

[tarkah]

No problem! I noticed your PR to fix the formatting issue.

[cart]

In general this seem like a reasonable change. It does introduce a bit of complexity and I dont really understand the cases where you would need new Decodables / rodio::Sources. Could you elaborate on that a bit?

[tarkah]

@cart Thanks for taking some time to look at this. I understand this is an edge case, as most people are going to be using MP3, WAV, Vorbis or Flac sources that are supported by the rodio::Decoder. However, if someone wanted to play some other codec, this entire audio module would not work for them. For example, needing to play .at3 that my atrac3-plus decoder handles if you wanted to make an open source port of a PS Vita game using this library.

Since the rodio::Source trait is what enables all the awesome stuff rodio can do with sound, it just seems like a good idea to be able to support playing any rodio::Source and not just what can be decoded by rodio::Decoder.

Anyway, I'm still not in love with where I've landed on this API and I think it's reasonable to hold off on this until we are 100% sure it's a reasonable addition to the audio module. In the meantime I'll go ahead and rebase / make the changes you suggested.

[cart]

I think this is in a good spot to merge. Thanks for your work here!

[tarkah]

Great, thanks @cart!