init, load multiple files and merge into one audio stream

.gitignore

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+/target

Cargo.toml

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+[package]
+name = "snoud"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+rodio = { version = "0.16.0", default_features = false, features = ["mp3"] }

src/main.rs

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+use rodio::source::{Repeat, Source};
+use rodio::{Decoder, OutputStream};
+use std::fs::File;
+use std::time::Duration;
+
+type Volume = f32;
+
+fn main() {
+	let files: Vec<String> = vec![
+		"sound/rain.mp3".into(),
+		"sound/thunder.mp3".into(),
+		"sound/wind.mp3".into(),
+	];
+	let source = Snoud::new(&files);
+
+	let (_stream, stream_handle) = OutputStream::try_default().unwrap();
+
+	stream_handle.play_raw(source.convert_samples()).unwrap();
+
+	// let sink = Sink::try_new(&stream_handle).unwrap();
+	// sink.append(source);
+	// sink.play();
+	loop {
+		std::thread::sleep(Duration::from_millis(200));
+	}
+}
+
+struct Snoud {
+	channels: Vec<SoundChannel>,
+	sample_rate: u32,
+}
+
+struct SoundChannel {
+	source: Repeat<Decoder<File>>,
+	paused: bool,
+	volume: Volume,
+}
+
+impl SoundChannel {
+	fn new(name: &String) -> Self {
+		let file = File::open(name).expect("File not found");
+		let source = Decoder::new(file)
+			.expect("Could not decode file")
+			.repeat_infinite();
+		Self {
+			source,
+			paused: false,
+			volume: 1.0,
+		}
+	}
+}
+
+impl Iterator for Snoud {
+	type Item = i16;
+
+	fn next(&mut self) -> Option<Self::Item> {
+		let mut out: Self::Item = 0;
+		for c in &mut self.channels {
+			if c.paused {
+				continue;
+			}
+			let mut sample: Self::Item = c.source.next().unwrap();
+			sample = (f32::from(sample) * c.volume) as Self::Item;
+			out = out.saturating_add(sample);
+		}
+		Some(out)
+	}
+}
+
+impl Source for Snoud {
+	fn channels(&self) -> u16 {
+		2
+	}
+
+	fn sample_rate(&self) -> u32 {
+		self.sample_rate
+	}
+
+	fn current_frame_len(&self) -> Option<usize> {
+		None
+	}
+
+	fn total_duration(&self) -> Option<Duration> {
+		None
+	}
+}
+
+impl Snoud {
+	fn new(filenames: &[String]) -> Self {
+		let channels = filenames.iter().map(SoundChannel::new).collect();
+
+		Self {
+			sample_rate: 48000,
+			channels,
+		}
+	}
+}