Creating custom signals is kinda unergonomic

[harudagondi]

According to the noise example:

(1) Create a Noise struct to and derive TypeUuid

bevy_oddio/examples/noise.rs

Lines 13 to 15 in 2e98c5f

	#[derive(TypeUuid)]
	#[uuid = "7cc24057-b499-4f7a-8f8a-e37dfa64be32"]
	struct Noise;

(2) Create a NoiseSignal struct and implement Signal (the actual code that creates sound).

bevy_oddio/examples/noise.rs

Lines 16 to 28 in 2e98c5f

	struct NoiseSignal;
	impl Signal for NoiseSignal {
	type Frame = Stereo;
	fn sample(&self, _interval: f32, out: &mut [Self::Frame]) {
	for out_frame in out {
	let mono = fastrand::f32();
	out_frame[0] = mono;
	out_frame[1] = mono;
	}
	}
	}

(3) Implement ToSignal for Noise.

bevy_oddio/examples/noise.rs

Lines 30 to 37 in 2e98c5f

	impl ToSignal for Noise {
	type Settings = ();
	type Signal = NoiseSignal;
	fn to_signal(&self, _settings: Self::Settings) -> Self::Signal {
	NoiseSignal
	}
	}

(4) Add the Noise struct as an audio source (also indicating the number of channels it uses).

bevy_oddio/examples/noise.rs

Line 43 in 2e98c5f

.add_audio_source::<2, _, Noise>()

(5) Create a noise handle and noise sink type to easily hold the sink as a resource.

bevy_oddio/examples/noise.rs

Lines 49 to 52 in 2e98c5f

	#[derive(Deref)]
	struct NoiseHandle(Handle<Noise>);
	struct NoiseSink(Handle<AudioHandle<Noise>>, Handle<AudioSink<Noise>>);

(6) Add Noise as an asset.

bevy_oddio/examples/noise.rs

Lines 54 to 57 in 2e98c5f

	fn init_assets(mut commands: Commands, mut assets: ResMut<Assets<Noise>>) {
	let handle = assets.add(Noise);
	commands.insert_resource(NoiseHandle(handle));
	}

(7) Play the audio.

bevy_oddio/examples/noise.rs

Lines 59 to 66 in 2e98c5f

	fn play_noise(
	mut commands: Commands,
	mut audio: ResMut<Audio<Stereo, Noise>>,
	noise: Res<NoiseHandle>,
	) {
	let handles = audio.play(noise.clone(), ());
	commands.insert_resource(NoiseSink(handles.0, handles.1));
	}

Ergonomics

This is a lot of code for just adding a custom signal. Here are the things I would love to see to improve this.

• Collapse steps (1) to (3) into a single step.
• (Probably allow closures that return frames to implement Signal, and things that return those closures to implement ToSignal)
• Ideally remove the second generic in (4) to reduce noise and confusion.
• ToSignal implementing types that also implement FromWorld should already be added as an asset to remove step (6).

Related Issues:

• Allow Audio to accept Handle<S> where S: Signal #2
• Add support for oddio signals where it accepts other signals #6