added "play frequency" primitive to "Sound" category

HISTORY.md

@@ -11,6 +11,7 @@
     * new blocks for setting and changing the stage's background color
     * new "microphone" reporter in Sensing for getting volume, note, pitch signals and frequencies
     * new "object" reporter in the Sensing category for getting a sprite by its name
+    * new "play frequency" command in the Sound category
     * blocks for changing and querying the "flat line ends" setting 
     * selectors for changing and querying "draggable" and "rotation style" settings
     * special context-aware drop-downs for custom blocks
@@ -50,6 +51,7 @@
 
 ### 2019-03-12
 * Threads: changed microphone volume (back) to a scale of 0-100
+* Threads, Objects: added "play frequency" primitive to "Sound" category
 
 ### 2019-03-11
 * added note / hz conversion blocks to audioComp library

snap.html

@@ -8,7 +8,7 @@
         <script type="text/javascript" src="src/widgets.js?version=2018-10-02"></script>
         <script type="text/javascript" src="src/blocks.js?version=2019-03-11"></script>
         <script type="text/javascript" src="src/threads.js?version=2019-03-12"></script>
-        <script type="text/javascript" src="src/objects.js?version=2019-03-11"></script>
+        <script type="text/javascript" src="src/objects.js?version=2019-03-12"></script>
         <script type="text/javascript" src="src/gui.js?version=2019-03-11"></script>
         <script type="text/javascript" src="src/paint.js?version=2019-02-22"></script>
         <script type="text/javascript" src="src/lists.js?version=2019-02-07"></script>

src/objects.js

@@ -84,7 +84,7 @@ BlockEditorMorph, BlockDialogMorph, PrototypeHatBlockMorph, localize,
 TableMorph, TableFrameMorph, normalizeCanvas, BooleanSlotMorph, HandleMorph,
 AlignmentMorph, Process, XML_Element, VectorPaintEditorMorph*/
 
-modules.objects = '2019-March-11';
+modules.objects = '2019-March-12';
 
 var SpriteMorph;
 var StageMorph;
@@ -449,6 +449,12 @@ SpriteMorph.prototype.initBlocks = function () {
             spec: 'play note %note for %n beats',
             defaults: [60, 0.5]
         },
+        doPlayFrequency: {
+            type: 'command',
+            category: 'sound',
+            spec: 'play %n hz for %n secs',
+            defaults: [440, 2]
+        },
         doSetInstrument: {
             type: 'command',
             category: 'sound',
@@ -1951,6 +1957,8 @@ SpriteMorph.prototype.blockTemplates = function (category) {
         blocks.push(block('doSetTempo'));
         blocks.push(watcherToggle('getTempo'));
         blocks.push(block('getTempo'));
+        blocks.push('-');
+        blocks.push(block('doPlayFrequency'));
         blocks.push('=');
         blocks.push(this.makeBlockButton(cat));
 
@@ -7210,6 +7218,8 @@ StageMorph.prototype.blockTemplates = function (category) {
         blocks.push(block('doSetTempo'));
         blocks.push(watcherToggle('getTempo'));
         blocks.push(block('getTempo'));
+        blocks.push('-');
+        blocks.push(block('doPlayFrequency'));
         blocks.push('=');
         blocks.push(this.makeBlockButton(cat));
 
@@ -8786,12 +8796,14 @@ Sound.prototype.toDataURL = function () {
 
 // Note /////////////////////////////////////////////////////////
 
-// I am a single musical note
+// I am a single musical note.
+// alternatively I can be used to play a frequency in hz
 
 // Note instance creation
 
 function Note(pitch) {
     this.pitch = pitch === 0 ? 0 : pitch || 69;
+    this.frequency = null; // alternative for playing a non-note frequency
     this.setupContext();
     this.oscillator = null;
 }
@@ -8841,8 +8853,8 @@ Note.prototype.play = function (type) {
         'sawtooth',
         'triangle'
     ][(type || 1) - 1];
-    this.oscillator.frequency.value =
-        Math.pow(2, (this.pitch - 69) / 12) * 440;
+    this.oscillator.frequency.value = isNil(this.frequency) ?
+        Math.pow(2, (this.pitch - 69) / 12) * 440 : this.frequency;
     this.oscillator.connect(this.gainNode);
     this.gainNode.connect(this.audioContext.destination);
     this.oscillator.start(0);

src/threads.js

@@ -4041,6 +4041,32 @@ Process.prototype.doPlayNoteForSecs = function (pitch, secs) {
     this.pushContext();
 };
 
+Process.prototype.doPlayFrequency = function (hz, secs) {
+    this.doPlayFrequencyForSecs(
+        parseFloat(hz || '0'),
+        parseFloat(secs || '0')
+    );
+};
+
+Process.prototype.doPlayFrequencyForSecs = function (hz, secs) {
+    // interpolated
+    if (!this.context.startTime) {
+        this.context.startTime = Date.now();
+        this.context.activeNote = new Note();
+        this.context.activeNote.frequency = hz;
+        this.context.activeNote.play(this.instrument);
+    }
+    if ((Date.now() - this.context.startTime) >= (secs * 1000)) {
+        if (this.context.activeNote) {
+            this.context.activeNote.stop();
+            this.context.activeNote = null;
+        }
+        return null;
+    }
+    this.pushContext('doYield');
+    this.pushContext();
+};
+
 Process.prototype.doSetInstrument = function (num) {
     this.instrument = +num;
     this.receiver.instrument = +num;