Tracks

src/lib.rs

@@ -6,37 +6,133 @@ use std::fs::File;
 use std::io::{self, BufWriter};
 
 use note::notes::*;
-use piece::{NoteEvent, Piece};
+use piece::{NoteEvent, Piece, Track, Wave};
 
 #[rustfmt::skip]
-pub fn main() -> io::Result<()> {
+pub fn crazy_train() -> Piece {
     let mut piece = Piece::new(120);
+    let mut main_track = Track::new(Wave::Square, 0.1);
     let mut time = 0.0;
 
     for _ in 0..4 {
-        piece.notes.push(NoteEvent::new(FS3, time, 0.5)); time += 0.5;
+        main_track.notes.push(NoteEvent::new(FS3, time, 0.5)); time += 0.5;
-        piece.notes.push(NoteEvent::new(FS3, time, 0.5)); time += 0.5;
+        main_track.notes.push(NoteEvent::new(FS3, time, 0.5)); time += 0.5;
-        piece.notes.push(NoteEvent::new(CS4, time, 0.5)); time += 0.5;
+        main_track.notes.push(NoteEvent::new(CS4, time, 0.5)); time += 0.5;
-        piece.notes.push(NoteEvent::new(FS3, time, 0.5)); time += 0.5;
+        main_track.notes.push(NoteEvent::new(FS3, time, 0.5)); time += 0.5;
-        piece.notes.push(NoteEvent::new(D4,  time, 0.5)); time += 0.5;
+        main_track.notes.push(NoteEvent::new(D4,  time, 0.5)); time += 0.5;
-        piece.notes.push(NoteEvent::new(FS3, time, 0.5)); time += 0.5;
+        main_track.notes.push(NoteEvent::new(FS3, time, 0.5)); time += 0.5;
-        piece.notes.push(NoteEvent::new(CS4, time, 0.5)); time += 0.5;
+        main_track.notes.push(NoteEvent::new(CS4, time, 0.5)); time += 0.5;
-        piece.notes.push(NoteEvent::new(FS3, time, 0.5)); time += 0.5;
+        main_track.notes.push(NoteEvent::new(FS3, time, 0.5)); time += 0.5;
-        piece.notes.push(NoteEvent::new(B4,  time, 0.5)); time += 0.5;
+        main_track.notes.push(NoteEvent::new(B4,  time, 0.5)); time += 0.5;
-        piece.notes.push(NoteEvent::new(A4,  time, 0.5)); time += 0.5;
+        main_track.notes.push(NoteEvent::new(A4,  time, 0.5)); time += 0.5;
-        piece.notes.push(NoteEvent::new(GS3, time, 0.5)); time += 0.5;
+        main_track.notes.push(NoteEvent::new(GS3, time, 0.5)); time += 0.5;
-        piece.notes.push(NoteEvent::new(A4,  time, 0.5)); time += 0.5;
+        main_track.notes.push(NoteEvent::new(A4,  time, 0.5)); time += 0.5;
-        piece.notes.push(NoteEvent::new(B4,  time, 0.5)); time += 0.5;
+        main_track.notes.push(NoteEvent::new(B4,  time, 0.5)); time += 0.5;
-        piece.notes.push(NoteEvent::new(A4,  time, 0.5)); time += 0.5;
+        main_track.notes.push(NoteEvent::new(A4,  time, 0.5)); time += 0.5;
-        piece.notes.push(NoteEvent::new(GS3, time, 0.5)); time += 0.5;
+        main_track.notes.push(NoteEvent::new(GS3, time, 0.5)); time += 0.5;
-        piece.notes.push(NoteEvent::new(E3,  time, 0.5)); time += 0.5;
+        main_track.notes.push(NoteEvent::new(E3,  time, 0.5)); time += 0.5;
     }
 
-    piece.notes.push(NoteEvent::new(FS3, time, 0.5));
+    main_track.notes.push(NoteEvent::new(FS3, time, 0.5));
 
+    piece.tracks.push(main_track);
+    piece
+}
+
+#[rustfmt::skip]
+pub fn technology() -> Piece {
+    let mut piece = Piece::new(100);
+
+    let mut bass_track = Track::new(Wave::Square, 0.05);
+    let mut time = 0.0;
+    for _ in 0..2 {
+        bass_track.notes.push(NoteEvent::new(A1, time, 4.0)); time += 4.0;
+        bass_track.notes.push(NoteEvent::new(G0, time, 2.0)); time += 2.0;
+        bass_track.notes.push(NoteEvent::new(A1, time, 2.0)); time += 2.0;
+
+        bass_track.notes.push(NoteEvent::new(F0, time, 4.0)); time += 4.0;
+        bass_track.notes.push(NoteEvent::new(C1, time, 2.0)); time += 2.0;
+        bass_track.notes.push(NoteEvent::new(G0, time, 2.0)); time += 2.0;
+    }
+    piece.tracks.push(bass_track);
+
+    let mut main_track = Track::new(Wave::Square, 0.1);
+    let mut time = 0.0;
+
+    // Lick 1
+    main_track.notes.push(NoteEvent::new(A4,  time, 0.5 )); time += 0.5;
+    main_track.notes.push(NoteEvent::new(E4,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(A4,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(G3,  time, 0.5 )); time += 0.5;
+    main_track.notes.push(NoteEvent::new(E4,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(G3,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(E3,  time, 1.0 )); time += 1.0;
+
+    time += 0.5;
+    main_track.notes.push(NoteEvent::new(A4,  time, 1.0 )); time += 1.0;
+    main_track.notes.push(NoteEvent::new(G3,  time, 1.0 )); time += 1.0;
+    main_track.notes.push(NoteEvent::new(E3,  time, 0.5 )); time += 0.5;
+    main_track.notes.push(NoteEvent::new(E3,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(F3,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(E3,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(D3,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(E3,  time, 0.5 )); time += 0.5;
+
+    main_track.notes.push(NoteEvent::new(C3,  time, 0.5 )); time += 0.5;
+    main_track.notes.push(NoteEvent::new(E3,  time, 1.0 )); time += 1.0;
+    main_track.notes.push(NoteEvent::new(C3,  time, 0.33)); time += 0.33;
+    main_track.notes.push(NoteEvent::new(D3,  time, 0.42)); time += 0.42;
+    main_track.notes.push(NoteEvent::new(E3,  time, 1.75)); time += 1.75;
+
+    main_track.notes.push(NoteEvent::new(C3,  time, 0.5 )); time += 0.5;
+    main_track.notes.push(NoteEvent::new(E3,  time, 1.0 )); time += 1.0;
+    main_track.notes.push(NoteEvent::new(C3,  time, 0.33)); time += 0.33;
+    main_track.notes.push(NoteEvent::new(E2,  time, 0.42)); time += 0.42;
+    main_track.notes.push(NoteEvent::new(D2,  time, 1.5 )); time += 1.5;
+
+    main_track.notes.push(NoteEvent::new(G2,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(C3,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(G3,  time, 0.25)); time += 0.25;
+
+    // Lick 2
+    main_track.notes.push(NoteEvent::new(A4,  time, 0.5 )); time += 0.5;
+    main_track.notes.push(NoteEvent::new(E4,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(A4,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(G3,  time, 0.5 )); time += 0.5;
+    main_track.notes.push(NoteEvent::new(E4,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(G3,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(E3,  time, 1.0 )); time += 1.0;
+
+    time += 0.5;
+    main_track.notes.push(NoteEvent::new(A4,  time, 1.0 )); time += 1.0;
+    main_track.notes.push(NoteEvent::new(G3,  time, 1.0 )); time += 1.0;
+    main_track.notes.push(NoteEvent::new(E3,  time, 0.5 )); time += 0.5;
+    main_track.notes.push(NoteEvent::new(B4,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(C4,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(B4,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(A4,  time, 0.25)); time += 0.25;
+    main_track.notes.push(NoteEvent::new(B4,  time, 0.5 )); time += 0.5;
+
+    main_track.notes.push(NoteEvent::new(C3,  time, 0.5 )); time += 0.5;
+    main_track.notes.push(NoteEvent::new(E3,  time, 1.0 )); time += 1.0;
+    main_track.notes.push(NoteEvent::new(C3,  time, 0.33)); time += 0.33;
+    main_track.notes.push(NoteEvent::new(D3,  time, 0.42)); time += 0.42;
+    main_track.notes.push(NoteEvent::new(E3,  time, 1.75)); time += 1.75;
+
+    main_track.notes.push(NoteEvent::new(C3,  time, 0.5 )); time += 0.5;
+    main_track.notes.push(NoteEvent::new(E3,  time, 1.0 )); time += 1.0;
+    main_track.notes.push(NoteEvent::new(C3,  time, 0.33)); time += 0.33;
+    main_track.notes.push(NoteEvent::new(A3,  time, 0.42)); time += 0.42;
+    main_track.notes.push(NoteEvent::new(G2,  time, 2.25)); time += 2.25;
+    piece.tracks.push(main_track);
+
+    piece
+}
+
+pub fn main() -> io::Result<()> {
     let file = File::create("output.wav")?;
     let mut writer = BufWriter::new(file);
-    piece.generate_wav(&mut writer)?;
+    technology().generate_wav(&mut writer)?;
 
     Ok(())
 }

src/piece.rs

@@ -3,6 +3,31 @@ use std::io::{self, Write};
 use crate::note::*;
 use crate::wav;
 
+#[derive(Copy, Clone)]
+pub enum Wave {
+    Square,
+    Triangle,
+}
+
+impl Wave {
+    pub fn sample(self, note: &Note, t: f64) -> f64 {
+        let freq = note.freq();
+        match self {
+            Wave::Square => {
+                if (2.0 * std::f64::consts::PI * freq * t).sin() >= 0.0 {
+                    1.0
+                } else {
+                    -1.0
+                }
+            }
+            Wave::Triangle => {
+                let phase = (freq * t) % 1.0;
+                4.0 * (phase - 0.5).abs() - 1.0
+            }
+        }
+    }
+}
+
 pub struct NoteEvent {
     pub note: Note,
     pub start: f64,
@@ -19,14 +44,33 @@ impl NoteEvent {
     }
 }
 
-pub struct Piece {
+pub struct Track {
+    pub wave: Wave,
+    pub amplitude: f64,
     pub notes: Vec<NoteEvent>,
+}
+
+impl Track {
+    pub fn new(wave: Wave, amplitude: f64) -> Track {
+        Track {
+            wave,
+            amplitude,
+            notes: vec![],
+        }
+    }
+}
+
+pub struct Piece {
+    pub tracks: Vec<Track>,
     pub bpm: u32,
 }
 
 impl Piece {
     pub fn new(bpm: u32) -> Piece {
-        Piece { bpm, notes: vec![] }
+        Piece {
+            bpm,
+            tracks: vec![],
+        }
     }
 
     pub fn generate_wav<W: Write>(&self, writer: &mut W) -> io::Result<()> {
@@ -35,9 +79,15 @@ impl Piece {
         let params = wav::Params::new();
 
         let max_beat = self
-            .notes
+            .tracks
             .iter()
-            .map(|x| x.start + x.duration)
+            .map(|x| {
+                x.notes
+                    .iter()
+                    .map(|x| x.start + x.duration)
+                    .max_by(|x, y| x.total_cmp(y))
+                    .unwrap_or(0.0)
+            })
             .max_by(|x, y| x.total_cmp(y))
             .unwrap_or(0.0);
 
@@ -55,17 +105,17 @@ impl Piece {
         for i in 0..total_samples {
             let t = i as f64 / params.sampling_rate as f64;
             let mut value: f64 = 0.0;
-            for event in &self.notes {
+            for track in &self.tracks {
-                let start_time = event.start * seconds_per_beat;
+                for event in &track.notes {
-                let end_time = start_time + event.duration * seconds_per_beat;
+                    let start_time = event.start * seconds_per_beat;
-                if t >= start_time && t < end_time {
+                    let end_time = start_time + event.duration * seconds_per_beat;
-                    let freq = event.note.freq();
+                    if t >= start_time && t < end_time {
-                    let sin = (std::f64::consts::TAU * freq * (t - start_time)).sin();
+                        value += track.amplitude * track.wave.sample(&event.note, t);
-                    value += if sin >= 0.0 { 1.0 } else { -1.0 };
+                    }
                 }
             }
 
-            let sample = (value * (i16::MAX as f64) * amplitude).round() as i16;
+            let sample = (value * (i16::MAX as f64)).round() as i16;
             writer.write_all(&sample.to_le_bytes())?;
         }