move audio system to wlx-common, compress audio data, sample player

wlx-common/src/audio.rs

@@ -0,0 +1,97 @@
+use std::{collections::HashMap, io::Cursor};
+
+use rodio::Source;
+
+pub struct AudioSystem {
+	audio_stream: Option<rodio::OutputStream>,
+	first_try: bool,
+}
+
+pub struct AudioSample {
+	buffer: rodio::buffer::SamplesBuffer,
+}
+
+pub struct SamplePlayer {
+	samples: HashMap<String, AudioSample>,
+}
+
+impl SamplePlayer {
+	pub fn new() -> Self {
+		Self {
+			samples: HashMap::new(),
+		}
+	}
+
+	pub fn register_sample(&mut self, sample_name: &str, sample: AudioSample) {
+		self.samples.insert(String::from(sample_name), sample);
+	}
+
+	pub fn play_sample(&mut self, system: &mut AudioSystem, sample_name: &str) {
+		let Some(sample) = self.samples.get(sample_name) else {
+			log::error!("failed to play sample by name {}", sample_name);
+			return;
+		};
+
+		system.play_sample(sample);
+	}
+}
+
+impl Default for SamplePlayer {
+	fn default() -> Self {
+		Self::new()
+	}
+}
+
+impl AudioSystem {
+	pub const fn new() -> Self {
+		Self {
+			audio_stream: None,
+			first_try: true,
+		}
+	}
+
+	fn get_handle(&mut self) -> Option<&rodio::OutputStream> {
+		if self.audio_stream.is_none() && self.first_try {
+			self.first_try = false;
+			if let Ok(stream) = rodio::OutputStreamBuilder::open_default_stream() {
+				self.audio_stream = Some(stream);
+			} else {
+				log::error!("Failed to open audio stream. Audio will not work.");
+				return None;
+			}
+		}
+		self.audio_stream.as_ref()
+	}
+
+	pub fn play_sample(&mut self, sample: &AudioSample) -> Option<()> {
+		let handle = self.get_handle()?;
+		handle.mixer().add(sample.buffer.clone());
+		Some(())
+	}
+}
+
+impl Default for AudioSystem {
+	fn default() -> Self {
+		Self::new()
+	}
+}
+
+impl AudioSample {
+	pub fn from_mp3(encoded_bin: &[u8]) -> anyhow::Result<Self> {
+		// SAFETY: this is safe
+		// rodio requires us to provide 'static data to decode it
+		// we are casting &T into &'static T just to prevent unnecessary memory copy into Vec<u8>.
+		// `encoded_bin` data will be always valid, because we are dropping `decoder` in this scope afterwards.
+		// Compliant and slower version would be: Cursor::new(encoded_bin.to_vec())
+		let cursor = unsafe { Cursor::new(std::mem::transmute::<&[u8], &'static [u8]>(encoded_bin)) };
+
+		let decoder = rodio::Decoder::new_mp3(cursor)?;
+		Ok(Self {
+			buffer: rodio::buffer::SamplesBuffer::new(
+				decoder.channels(),
+				decoder.sample_rate(),
+				decoder.collect::<Vec<rodio::Sample>>(),
+			),
+		})
+	}
+}