chaos knob

2 files changed, 35 insertions, 18 deletions

diff --git a/src/relabi/canvas.js b/src/relabi/canvas.js
index 2003a5a..fed4f6d 100644
--- a/src/relabi/canvas.js
+++ b/src/relabi/canvas.js
@@ -3,6 +3,8 @@
  * @module src/relabi/canvas.js;
  */
 
+const NOTE_RADIUS = 7;
+
 export default class RelabiCanvas {
   /**
    * Initialize relabi wave renderer
@@ -209,10 +211,10 @@ export default class RelabiCanvas {
         continue;
       }
       ctx.beginPath();
-      ctx.arc(x - 2.5, y, 5, 0, 2 * Math.PI);
+      ctx.arc(x - NOTE_RADIUS / 4, y, NOTE_RADIUS, 0, 2 * Math.PI);
       ctx.fillStyle = direction
-        ? `rgba(255,128,192,${opacity})`
-        : `rgba(192,255,128,${opacity})`;
+        ? `rgba(255,96,128,${opacity})`
+        : `rgba(128,255,96,${opacity})`;
       ctx.fill();
     }
   }
diff --git a/src/relabi/index.js b/src/relabi/index.js
index 8e23d2a..9e649f2 100644
--- a/src/relabi/index.js
+++ b/src/relabi/index.js
@@ -4,6 +4,7 @@
 
 import * as Tone from "tone";
 import RelabiCanvas from "./canvas";
+import * as Instruments from "../lib/instruments";
 
 const TWO_PI = 2 * Math.PI;
 
@@ -19,7 +20,8 @@ const WAVE_SHAPES = {
       ) -
     1,
   square: (time) => (time % TWO_PI < Math.PI ? 1 : -1),
-  saw: (time) => ((time % TWO_PI) - Math.PI) / Math.PI,
+  saw: (time) => (time % TWO_PI) / Math.PI - 1,
+  reverse_saw: (time) => 1 - (time % TWO_PI) / Math.PI,
 };
 
 /**
@@ -29,16 +31,12 @@ export default class Relabi {
   /**
    * Initialize generator
    */
-  constructor({ waves, bounds, parent }) {
+  constructor({ waves, bounds, settings, parent }) {
     this.updateTime = 1;
     this.steps = 50;
-    this.waves = waves || [
-      { shape: "triangle", frequency: randrange(0.5, 1.5) },
-      { shape: "triangle", frequency: randrange(0.75, 2.25) },
-      { shape: "triangle", frequency: randrange(1, 3) },
-      { shape: "triangle", frequency: randrange(2, 4) },
-    ];
+    this.waves = waves;
     this.bounds = bounds;
+    this.settings = settings;
     this.previousValue = null;
     this.canvas = new RelabiCanvas({ relabi: this, parent });
   }
@@ -71,14 +69,17 @@ export default class Relabi {
    * Generate relabi events
    */
   generate(time) {
-    const waveCount = this.waves.length;
     let index;
     let step;
     let value;
     let values = [];
+    let previousWaveValue = this.previousWaveValue || 0;
+
+    // Weight individual waves rather than simply averaging them
+    let totalWeight = this.waves.reduce((sum, wave) => sum + wave.weight, 0.0);
 
     // Overshoot the line slightly each time
-    let stepCount = this.steps + 20;
+    let stepCount = this.steps;
 
     // Generate several events per second
     for (step = 0; step < stepCount; step += 1) {
@@ -89,17 +90,27 @@ export default class Relabi {
       value = 0;
 
       // Compute the wave functions for this event
-      for (index = 0; index < waveCount; index += 1) {
-        const wave = this.waves[index];
-        value += WAVE_SHAPES[wave.shape](timeOffset * wave.frequency);
+      for (const wave of this.waves) {
+        const waveOffset =
+          (wave.offset || 0) +
+          (wave.frequency * this.settings.speed) / this.steps +
+          previousWaveValue * this.settings.feedback;
+
+        const waveValue = WAVE_SHAPES[wave.shape](waveOffset);
+        value += waveValue * wave.weight;
+        previousWaveValue = waveValue;
+        wave.offset = waveOffset;
       }
 
       // Scale to [-1, 1]
-      value /= waveCount;
+      value /= totalWeight;
+      previousWaveValue = value;
 
       values.push([timeOffset, value]);
     }
 
+    this.previousWaveValue = previousWaveValue;
+
     return values;
   }
 
@@ -158,6 +169,10 @@ export default class Relabi {
    */
   trigger(time, sound) {
     // console.log("trigger index", index, time);
-    sound.instrument.play(time, sound);
+    if (sound.instrument in Instruments) {
+      Instruments[sound.instrument].play(time, sound);
+    } else {
+      sound.instrument.play(time, sound);
+    }
   }
 }