From b7e0fa06ca5454314f1341a63148001f497ff018 Mon Sep 17 00:00:00 2001
From: JSDurand <mmemmew@gmail.com>
Date: Sat, 27 Aug 2022 15:38:23 +0800
Subject: some new songs and small modifications

---
 src/instruments.rs | 54 ++++++++++++++++++++++++++++++++++++++++++------------
 src/lib.rs         | 13 +++++++++++++
 2 files changed, 55 insertions(+), 12 deletions(-)

(limited to 'src')

diff --git a/src/instruments.rs b/src/instruments.rs
index 15ac7d4..622754c 100644
--- a/src/instruments.rs
+++ b/src/instruments.rs
@@ -192,6 +192,8 @@ impl Instrument for PianoWOver {
 
         let mut result: Vec<Pulse> = vec![];
 
+        let mut current_adsr = 0f64;
+
         for i in 0..nb_samples {
             let mut y = f64::sin(theta);
             // let mut y = 0.6f64 * f64::sin(theta) + 0.4f64 * f64::sin(2f64 * theta);
@@ -201,6 +203,10 @@ impl Instrument for PianoWOver {
 
             y *= *volume;
 
+            current_adsr = adsr(i, nb_samples, current_adsr);
+
+            y *= current_adsr;
+
             result.push(y.into());
 
             theta += step;
@@ -247,6 +253,8 @@ impl Instrument for PianoVideo {
 
         let mut result: Vec<Pulse> = vec![];
 
+        let mut current_adsr = 0f64;
+
         for i in 0..nb_samples {
             let mut y = 0.6f64 * f64::sin(theta) + 0.4f64 * f64::sin(2f64 * theta);
             y *= f64::exp((-0.0015f64) * theta);
@@ -255,6 +263,10 @@ impl Instrument for PianoVideo {
 
             y *= *volume;
 
+            current_adsr = adsr(i, nb_samples, current_adsr);
+
+            y *= current_adsr;
+
             result.push(y.into());
 
             theta += step;
@@ -307,6 +319,8 @@ impl Instrument for PianoStackoverflow {
 
         let mut result: Vec<Pulse> = vec![];
 
+        let mut current_adsr = 0f64;
+
         for i in 0..nb_samples {
             let mut y = f64::sin(theta)
                 + (1f64 / 2f64) * f64::sin(2f64 * theta)
@@ -320,6 +334,10 @@ impl Instrument for PianoStackoverflow {
 
             y *= *volume;
 
+            current_adsr = adsr(i, nb_samples, current_adsr);
+
+            y *= current_adsr;
+
             result.push(y.into());
 
             theta += step;
@@ -329,7 +347,6 @@ impl Instrument for PianoStackoverflow {
     }
 }
 
-#[allow(dead_code)]
 fn adsr(step: usize, total: usize, current: f64) -> f64 {
     if step < 4320 {
         if current <= 1f64 {
@@ -371,6 +388,29 @@ impl Instrument for PianoFromC {
         let duration = duration.into();
         let volume = volume.into();
 
+        let (note_octave, note_rem): (usize, usize) = note.octave();
+
+        let exp_coeff = match note_octave {
+            n if n <= 3 => 0.0015f64,
+            4 => 0.0015f64,
+            5 => 0.001f64,
+            6 => {
+                if note_rem < 9 {
+                    0.0005f64
+                } else {
+                    0.0003f64
+                }
+            }
+            7 => {
+                if note_rem < 5 {
+                    0.0003f64
+                } else {
+                    0.00009f64
+                }
+            }
+            _ => 0.00009f64,
+        };
+
         let bpm = bpm.into();
         let duration_per_beat: Seconds = bpm.into();
         let duration: Seconds = (*duration * *duration_per_beat).into();
@@ -379,9 +419,6 @@ impl Instrument for PianoFromC {
 
         let note_h: Hertz = note.into();
 
-        // dbg!(note);
-        // dbg!(note_h);
-
         let step = *note_h * 2f64 * PI / *rate;
 
         let mut theta = 0f64;
@@ -390,12 +427,11 @@ impl Instrument for PianoFromC {
 
         let mut adsr_factor = 1f64;
 
-        #[allow(unused_variables)]
         for i in 0..nb_samples {
             let mut y = 0.65f64 * f64::sin(theta)
                 + 0.475f64 * f64::sin(2f64 * theta)
                 + 0.05f64 * f64::sin(3f64 * theta);
-            y *= f64::exp((-0.0015f64) * theta);
+            y *= f64::exp((-exp_coeff) * theta);
             y += y * y * y;
             y *= 1f64 + 16f64 * i as f64 * f64::exp((-6f64) * i as f64);
 
@@ -404,12 +440,6 @@ impl Instrument for PianoFromC {
 
             y *= *volume;
 
-            // if y >= 1f64 {
-            //     y = 1f64;
-            // } else if y <= -1f64 {
-            //     y = -1f64;
-            // }
-
             result.push(y.into());
 
             theta += step;
diff --git a/src/lib.rs b/src/lib.rs
index 5fa7e79..23fffe2 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -245,6 +245,19 @@ impl Default for Hertz {
     }
 }
 
+impl Semitones {
+    /// Return the octave of the semitone.
+    fn octave(self) -> (usize, usize) {
+        let translated = *self + 9f64;
+
+        let quotient = translated.div_euclid(12f64) as i64;
+
+        let rem = translated.rem_euclid(12f64) as usize;
+
+        ((quotient + 4) as usize, rem)
+    }
+}
+
 impl From<Semitones> for Hertz {
     fn from(st: Semitones) -> Self {
         (*Self::default() * STD_BASE.powf(*st)).into()
-- 
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