1 files changed, 135 insertions, 0 deletions
diff --git a/beeps.rs b/beeps.rs
new file mode 100644
index 0000000..f3c3ac8
--- /dev/null
+++ b/beeps.rs
@@ -0,0 +1,135 @@
+// Copyright (C) 2024  Tomasz Kramkowski <tomasz@kramkow.ski>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+use std::{
+    env,
+    f64::consts,
+    io::{self, Write},
+    process,
+};
+type Float = f64;
+
+const RATE: f64 = 8000.0;
+
+#[derive(Debug, Copy, Clone)]
+struct Beep {
+    frequency: Float,
+    volume: Float,
+}
+
+impl Beep {
+    fn new(frequency: Float, volume: Float) -> Self {
+        Self { frequency, volume }
+    }
+
+    fn sample_at(&self, time: Float) -> Float {
+        Float::sin(time * consts::TAU * self.frequency) * self.volume
+    }
+}
+
+#[derive(Copy, Clone)]
+struct Beat<'a> {
+    beep: Beep,
+    start: Float,
+    duration: Float,
+    interval: Float,
+    mask: &'a dyn Fn(Float) -> bool,
+}
+
+impl<'a> Beat<'a> {
+    fn new(
+        beep: Beep,
+        start: Float,
+        duration: Float,
+        interval: Option<Float>,
+        mask: Option<&'a dyn Fn(Float) -> bool>,
+    ) -> Self {
+        Self {
+            beep,
+            start,
+            duration,
+            interval: interval.unwrap_or(Float::INFINITY),
+            mask: mask.unwrap_or(&|_| true),
+        }
+    }
+
+    fn rel_time(&self, time: Float) -> Float {
+        (time - self.start) % self.interval
+    }
+
+    fn plays_now(&self, time: Float) -> bool {
+        (self.mask)(time) && time > self.start && self.rel_time(time) < self.duration
+    }
+
+    fn sample_at(&self, time: Float) -> Float {
+        self.beep.sample_at(self.rel_time(time))
+    }
+}
+
+fn sample_at(beats: &[Beat<'_>], time: Float) -> Float {
+    let mut sample = 0.0;
+
+    for beat in beats {
+        if beat.plays_now(time) {
+            sample += beat.sample_at(time)
+        }
+    }
+
+    sample
+}
+
+fn main() {
+    let mut args = env::args();
+    // This is bugged, argv[0] is empty if you exec with an empty or no argv
+    let argv0 = args.next().expect("No argv0");
+    let (Some(duration), None) = (args.next(), args.next()) else {
+        eprintln!("Usage: {argv0} duration");
+        process::exit(1);
+    };
+    let duration: Float = duration.parse().expect("Invalid duration");
+    let mut stdout = io::stdout();
+
+    let endstop = |s| s < duration - 1.0;
+
+    let beats = [
+        Beat::new(Beep::new(500.0, 0.5), 0.0, 0.1, Some(30.0), Some(&endstop)),
+        Beat::new(Beep::new(500.0, 0.5), 14.9, 0.1, Some(30.0), Some(&endstop)),
+        Beat::new(Beep::new(600.0, 0.5), 15.0, 0.1, Some(30.0), Some(&endstop)),
+        Beat::new(Beep::new(600.0, 0.5), -0.1, 0.1, Some(30.0), Some(&endstop)),
+        Beat::new(
+            Beep::new(300.0, 0.3),
+            1.45,
+            0.1,
+            Some(3.0),
+            Some(&|s| (s / 15.0) as u64 % 2 == 0),
+        ),
+        Beat::new(
+            Beep::new(1000.0, 0.4),
+            299.95,
+            0.05,
+            Some(300.0),
+            Some(&endstop),
+        ),
+        Beat::new(
+            Beep::new(1000.0, 0.4),
+            300.05,
+            0.05,
+            Some(300.0),
+            Some(&endstop),
+        ),
+        Beat::new(Beep::new(400.0, 0.5), duration + 0.0, 0.4, None, None),
+        Beat::new(Beep::new(500.0, 0.5), duration + 0.45, 0.4, None, None),
+        Beat::new(Beep::new(600.0, 0.5), duration + 0.9, 0.4, None, None),
+    ];
+
+    let start = -0.1;
+    let end = duration + 1.4;
+
+    for sample_index in 0..((RATE * (end - start)) as u64) {
+        let time = start + sample_index as Float / RATE;
+        let sample = sample_at(&beats, time);
+        stdout
+            .write_all(&[((sample + 1.0) / 2.0 * 256.0).floor().clamp(0.0, 255.0) as u8])
+            .expect("Could not write sample");
+    }
+}