adding sound emulation in browser

sim/libmbit.ts

@@ -332,13 +332,69 @@ namespace ks.rt.micro_bit {
     export function servoSetPulse(pin: Pin, micros:number) {        
     }
         
+    module AudioContextManager {
+        var _context : any; // AudioContext
+        var _vco : any; //OscillatorNode;
+        var _vca: any; // GainNode;
+        
+        function context() : any {
+            if (!_context) _context = freshContext();
+            return _context;
+        }
+        
+        function freshContext() : any {
+            (<any>window).AudioContext = (<any>window).AudioContext || (<any>window).webkitAudioContext;
+            if ((<any>window).AudioContext) {
+                try {
+                    // this call my crash.
+                    // SyntaxError: audio resources unavailable for AudioContext construction
+                    return  new (<any>window).AudioContext();
+                } catch(e) {}
+             }
+            return undefined;
+        }
+        
+        export function stop() {
+            if (_vca) _vca.gain.value = 0;
+        }
+        
+        export function tone(frequency: number, gain: number) { 
+            if (frequency <= 0) return;            
+            var ctx = context();
+            if (!ctx) return;
+            
+            gain = Math.max(0, Math.min(1, gain));            
+            if (!_vco) {
+                try {
+                    _vco = ctx.createOscillator();
+                    _vca = ctx.createGain();
+                    _vco.connect(_vca);
+                    _vca.connect(ctx.destination);
+                    _vca.gain.value = gain;
+                    _vco.start(0);
+                } catch(e) {
+                    _vco = undefined;
+                    _vca = undefined;
+                    return;
+                }
+            }
+            
+            _vco.frequency.value = frequency;
+            _vca.gain.value = gain;
+        }
+    }
+    
     export function enablePitch(pin: Pin) {
         pin.mode = PinMode.Analog | PinMode.Output;
     }
     
     export function pitch(frequency: number, ms: number) {
         let cb = getResume();
-        setTimeout(() => { cb() }, ms);
+        AudioContextManager.tone(frequency, 1);
+        setTimeout(() => {
+            if (ms > 0) AudioContextManager.stop();            
+            cb() 
+        }, ms);
     }
     
     

sim/state.ts

@@ -18,28 +18,28 @@ namespace ks.rt.micro_bit {
     }
 
     export class Pin {
-        constructor(public id: number) {}
+        constructor(public id: number) { }
         touched = false;
         value = 0;
         mode = PinMode.Unused;
 
-        isTouched() : boolean {
+        isTouched(): boolean {
             this.mode = PinMode.Touch;
             return this.touched;
         }
     }
 
     export class Button {
-        constructor(public id : number) {}
+        constructor(public id: number) { }
         pressed: boolean;
     }
 
     export class EventBus {
-        private queues : Map<EventQueue<number>> = {};
+        private queues: Map<EventQueue<number>> = {};
 
-        constructor(private runtime : Runtime) { }
+        constructor(private runtime: Runtime) { }
 
-        listen(id:number, evid:number, handler: RefAction) {
+        listen(id: number, evid: number, handler: RefAction) {
             let k = id + ':' + evid;
             let queue = this.queues[k];
             if (!queue) queue = this.queues[k] = new EventQueue<number>(this.runtime);
@@ -54,21 +54,21 @@ namespace ks.rt.micro_bit {
     }
 
     export interface PacketBuffer {
-        data:number[];
+        data: number[];
-        rssi?:number;
+        rssi?: number;
     }
 
     export class RadioDatagram {
         datagram: PacketBuffer[] = [];
         lastReceived: PacketBuffer = {
-            data:[0,0,0,0], 
+            data: [0, 0, 0, 0],
             rssi: -1
         };
 
-        constructor(private runtime : Runtime) { 
+        constructor(private runtime: Runtime) {
         }
 
-        queue(packet : PacketBuffer) {
+        queue(packet: PacketBuffer) {
             if (this.datagram.length < 5) {
                 this.datagram.push(packet);
                 let ens = enums();
@@ -76,17 +76,17 @@ namespace ks.rt.micro_bit {
             }
         }
 
-        send(buffer : number[]) {
+        send(buffer: number[]) {
             Runtime.postMessage(<SimulatorRadioPacketMessage>{
-                type:'radiopacket',
+                type: 'radiopacket',
                 data: buffer.slice(0, 8)
             })
         }
 
-        recv() : PacketBuffer {
+        recv(): PacketBuffer {
             var r = this.datagram.shift();
             if (!r) r = {
-                data:[0,0,0,0], 
+                data: [0, 0, 0, 0],
                 rssi: -1
             };
             return this.lastReceived = r;
@@ -96,9 +96,9 @@ namespace ks.rt.micro_bit {
     export class RadioBus {
         // uint8_t radioDefaultGroup = MICROBIT_RADIO_DEFAULT_GROUP;
         groupId = 0; // todo
-        datagram : RadioDatagram;
+        datagram: RadioDatagram;
 
-        constructor(private runtime : Runtime) { 
+        constructor(private runtime: Runtime) {
             this.datagram = new RadioDatagram(runtime);
         }
 
@@ -109,7 +109,7 @@ namespace ks.rt.micro_bit {
         broadcast(msg: number) {
             let ens = enums();
             Runtime.postMessage(<SimulatorEventBusMessage>{
-                type:'eventbus',
+                type: 'eventbus',
                 id: ens.MES_BROADCAST_GENERAL_ID,
                 eventid: msg
             })
@@ -123,7 +123,7 @@ namespace ks.rt.micro_bit {
     }
 
     export interface SimulatorSerialMessage extends SimulatorMessage {
-        id:string;
+        id: string;
         data: string;
     }
 
@@ -136,7 +136,7 @@ namespace ks.rt.micro_bit {
         id: string;
 
         // the bus
-        bus : EventBus;
+        bus: EventBus;
         radio: RadioBus;
 
         // display
@@ -147,10 +147,10 @@ namespace ks.rt.micro_bit {
 
         // buttons    
         usesButtonAB: boolean = false;
-        buttons : Button[];
+        buttons: Button[];
 
         // pins
-        pins : Pin[];
+        pins: Pin[];
 
         // serial
         serialIn: string[] = [];
@@ -207,10 +207,10 @@ namespace ks.rt.micro_bit {
         }
 
 
-        initAsync(msg : SimulatorRunMessage) : Promise<void> {
+        initAsync(msg: SimulatorRunMessage): Promise<void> {
             let options = (msg.options || {}) as RuntimeOptions;
-            let theme : micro_bit.IBoardTheme;
+            let theme: micro_bit.IBoardTheme;
-            switch(options.theme) {
+            switch (options.theme) {
                 case 'blue': theme = micro_bit.themes[0]; break;
                 case 'yellow': theme = micro_bit.themes[1]; break;
                 case 'green': theme = micro_bit.themes[2]; break;
@@ -232,7 +232,7 @@ namespace ks.rt.micro_bit {
         receiveMessage(msg: SimulatorMessage) {
             if (!runtime || runtime.dead) return;
 
-            switch(msg.type || "") {
+            switch (msg.type || "") {
                 case 'eventbus':
                     let ev = <SimulatorEventBusMessage>msg;
                     this.bus.queue(ev.id, ev.eventid, ev.value);
@@ -242,7 +242,7 @@ namespace ks.rt.micro_bit {
                     break;
                 case 'radiopacket':
                     let packet = <SimulatorRadioPacketMessage>msg;
-                    this.radio.datagram.queue({ data: packet.data || [], rssi: packet.rssi || 0})
+                    this.radio.datagram.queue({ data: packet.data || [], rssi: packet.rssi || 0 })
                     break;
             }
         }
@@ -253,10 +253,10 @@ namespace ks.rt.micro_bit {
         }
 
         serialOutBuffer: string = '';
-        writeSerial(s : string) {
+        writeSerial(s: string) {
-            for(let i = 0; i < s.length;++i) {
+            for (let i = 0; i < s.length; ++i) {
                 let c = s[i];
-                switch(c) {
+                switch (c) {
                     case '\n':
                         Runtime.postMessage(<SimulatorSerialMessage>{
                             type: 'serial',
@@ -295,8 +295,8 @@ namespace ks.rt.micro_bit {
                 }
             }
         }
-        public clear() : void {
+        public clear(): void {
-            for(var i = 0;i < this.data.length; ++i)
+            for (var i = 0; i < this.data.length; ++i)
                 this.data[i] = 0;
         }
     }