c_meyer/pxt-calliope
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

adding sound emulation in browser

Browse Source
This commit is contained in:
Peli de Halleux 2016-03-13 21:24:11 -07:00
parent a751be2e97
commit d323995196
2 changed files with 149 additions and 93 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

58
sim/libmbit.ts
View File

@ -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);
}