From fd946107df157ef51821921b6047b14b4dc9bea1 Mon Sep 17 00:00:00 2001
From: "Jade (Rose) Rowland" <jaderowlanddev@gmail.com>
Date: Thu, 14 Mar 2024 20:35:56 -0400
Subject: [PATCH] use lerp

---
 packages/core/controls.mjs       |  2 +-
 packages/superdough/synth.mjs    |  4 ++--
 packages/superdough/worklets.mjs | 23 +++++++++++++++++------
 3 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/packages/core/controls.mjs b/packages/core/controls.mjs
index 213839e1..b75d7606 100644
--- a/packages/core/controls.mjs
+++ b/packages/core/controls.mjs
@@ -890,7 +890,7 @@ export const { lock } = registerControl('lock');
  * @param {number | Pattern} amount
  * @synonyms det
  * @example
- * note("d f a a# a d3").fast(2).s("supersaw").detune("<.4 1 3 200>")
+ * note("d f a a# a d3").fast(2).s("supersaw").detune("<.1 .2 .5 24.1>")
  *
  */
 export const { detune, det } = registerControl('detune', 'det');
diff --git a/packages/superdough/synth.mjs b/packages/superdough/synth.mjs
index 0734b581..0df098e1 100644
--- a/packages/superdough/synth.mjs
+++ b/packages/superdough/synth.mjs
@@ -64,8 +64,8 @@ export function registerSynthSounds() {
     'supersaw',
     (begin, value, onended) => {
       const ac = getAudioContext();
-      let { duration, n, unison = 6, spread = 0.3, detune } = value;
-      detune = detune ?? n ?? 2;
+      let { duration, n, unison = 5, spread = 0.6, detune } = value;
+      detune = detune ?? n ?? 0.18;
       const frequency = getFrequencyFromValue(value);
 
       const [attack, decay, sustain, release] = getADSRValues(
diff --git a/packages/superdough/worklets.mjs b/packages/superdough/worklets.mjs
index ea9eb9ed..744ca301 100644
--- a/packages/superdough/worklets.mjs
+++ b/packages/superdough/worklets.mjs
@@ -161,10 +161,21 @@ const saw = (phase, dt) => {
   return v - polyBlep(phase, dt);
 };
 
+function lerp(a, b, n) {
+  return n * (b - a) + a;
+}
+
+function getUnisonDetune(unison, detune, voiceIndex) {
+  if (unison < 2) {
+    return 0;
+  }
+  return lerp(-detune, detune, voiceIndex / (unison - 1));
+}
 class SuperSawOscillatorProcessor extends AudioWorkletProcessor {
   constructor() {
     super();
     this.phase = [];
+    this.logged = 0;
   }
   static get parameterDescriptors() {
     return [
@@ -207,7 +218,7 @@ class SuperSawOscillatorProcessor extends AudioWorkletProcessor {
 
       {
         name: 'voices',
-        defaultValue: 6,
+        defaultValue: 5,
         min: 1,
       },
     ];
@@ -233,13 +244,13 @@ class SuperSawOscillatorProcessor extends AudioWorkletProcessor {
     const gain2 = Math.sqrt(panspread);
 
     for (let n = 0; n < voices; n++) {
-      let adj = 0;
       const isOdd = (n & 1) == 1;
-      //adjust the detune amount for each voice
-      if (n > 0) {
-        adj = isOdd ? n * freqspread : -((n - 1) * freqspread);
+
+      if (this.logged < 10) {
+        this.logged += 1;
       }
-      const freq = Math.min(16744, Math.max(1, frequency + adj * 0.01 * frequency));
+      //applies unison "spread" detune in semitones
+      const freq = frequency * Math.pow(2, getUnisonDetune(voices, freqspread, n) / 1.2);
       let gainL = gain1;
       let gainR = gain2;
       // invert right and left gain