feat: modularize sin wave generator

raust-cli/src/main.rs

@@ -1,6 +1,6 @@
 use clap::Parser;
 use cpal::traits::DeviceTrait;
-use raust_engine::{AudioPlayer, Note};
+use raust_engine::{AudioPlayer, Note, generators::Generator};
 
 /// Play a single tone through the default audio output device.
 #[derive(Parser, Debug)]
@@ -24,16 +24,8 @@ fn main() -> anyhow::Result<()> {
     let (device, config) = raust_engine::get_device_and_config()?;
     println!("Output device: {}", device.id()?);
     println!("Default output config: {config:?}");
-    let mut clock = 0f32;
-    // Sample rates are a few hundred kHz at most, nowhere near f32's
-    // 24-bit exact-integer range, so this cast never loses precision.
-    #[allow(clippy::cast_precision_loss, clippy::as_conversions)]
-    let sample_rate = config.sample_rate() as f32;
-    let generator = move || {
-        clock = (clock + 1.0) % sample_rate;
-        (clock * note.pitch * 2.0 * std::f32::consts::PI / sample_rate).sin()
-    };
-    let audio_player = AudioPlayer::try_new(&device, config, Box::new(generator))?;
+    let mut sin = raust_engine::generators::SinWave::new(config.sample_rate(), note.pitch);
+    let audio_player = AudioPlayer::try_new(&device, config, Box::new(move || sin.generate()))?;
 
     audio_player.play()?;
     std::thread::sleep(std::time::Duration::from_millis(note.length));