added basic stereo-panning support for notes

HISTORY.md

@@ -58,6 +58,7 @@
 * Objects: use AudioContext to play recorded sounds
 * Objects: new audio scheme support for the stage
 * Objects: added basic stereo-panning support for sounds (under construction)
+* Objects, Threads: added basic stereo-panning support for notes
 
 ### 2019-04-01
 * Objects: let the Microphone share the Note prototype's AudioContext

src/objects.js

@@ -1492,6 +1492,7 @@ SpriteMorph.prototype.fullCopy = function (forClone) {
     c.stopTalking();
     c.color = this.color.copy();
     c.gainNode = null;
+    c.panNode = null;
     c.blocksCache = {};
     c.paletteCache = {};
     c.cachedHSV = c.color.hsv();
@@ -8977,7 +8978,7 @@ Note.prototype.getAudioContext = function () {
 
 // Note playing
 
-Note.prototype.play = function (type, gainNode) {
+Note.prototype.play = function (type, gainNode, panNode) {
     this.oscillator = this.audioContext.createOscillator();
     if (!this.oscillator.start) {
         this.oscillator.start = this.oscillator.noteOn;
@@ -8994,7 +8995,8 @@ Note.prototype.play = function (type, gainNode) {
     this.oscillator.frequency.value = isNil(this.frequency) ?
         Math.pow(2, (this.pitch - 69) / 12) * 440 : this.frequency;
     this.oscillator.connect(gainNode);
-    gainNode.connect(this.audioContext.destination);
+    gainNode.connect(panNode);
+    panNode.connect(this.audioContext.destination);
     this.oscillator.start(0);
 };
 

src/threads.js

@@ -4094,12 +4094,13 @@ Process.prototype.doPlayNoteForSecs = function (pitch, secs) {
     // interpolated
     var rcvr = this.blockReceiver();
     if (!this.context.startTime) {
-        rcvr.setVolume(rvr.volume); // b/c Chrome needs lazy initialization
+        rcvr.setVolume(rcvr.volume); // b/c Chrome needs lazy initialization
         this.context.startTime = Date.now();
         this.context.activeNote = new Note(pitch);
         this.context.activeNote.play(
             this.instrument,
-            rcvr.getGainNode()
+            rcvr.getGainNode(),
+            rcvr.getPanNode()
         );
     }
     if ((Date.now() - this.context.startTime) >= (secs * 1000)) {