speechsong.js

var spawn = require('child_process').spawn;
var EventEmitter = require('events').EventEmitter;

///////////
// Sound //
///////////

function Sound(str, lang, amplitude, speed) {
  EventEmitter.apply(this);
  
  this.str = str;
  this.lang = lang || 'english';
  this.amplitude = (amplitude == undefined) ? 0.5 : amplitude;
  this.speed = speed || 160;
}
Sound.prototype.__proto__ = EventEmitter.prototype;

Sound.prototype.play = function() {
  var amplitude = Math.round(20*this.amplitude);
  var process = spawn('espeak', [
    '-v', this.lang,
    '-a', amplitude,
    '-s', this.speed,
    '"'+this.str.replace(/\"/, '\\"')+'"'
  ]);
  
  var self = this;
  process.on('exit', function() {
    self.emit('said');
  });
};

Sound.prototype.startLoop = function(interval) {
  this.endLoop(); // Make sure no loop is running
  this.interval = setInterval(this.play.bind(this), interval);
};
Sound.prototype.endLoop = function() {
  clearInterval(this.interval);
};

Sound.prototype.times = function(times, delay) {
  var self = this;
  function f() {
    self.play();
    times--;
    if (times) {
      setTimeout(f, delay);
    } else {
      self.emit('times_end');
    }
  }
  f();
};

Sound.prototype.startBackground = function() {
  this.backgroundCallback = this.play.bind(this);
  this.on('said', this.backgroundCallback);
  this.play();
};
Sound.prototype.stopBackground = function() {
  this.removeListener('said', this.backgroundCallback);
};
Sound.prototype.clone = function() {
  return new Sound(this.str, this.lang, this.amplitude, this.speed);
};


//////////
// Song //
//////////

function Song(tact, speed) {
  EventEmitter.apply(this);
  this.tact = tact || 16;
  this.speed = speed || 1;
  
  this.boundNote = this.note.bind(this);
}

Song.prototype.__proto__ = EventEmitter.prototype;

Song.prototype.note = function() {
  var count = this.count;
  var note_values = ['sixteenth'];
  if (count % 2 == 0) note_values.push('eighth');
  if (count % 4 == 0) note_values.push('quarter');
  if (count % 8 == 0) note_values.push('half');
  if (count     == 0) note_values.push('whole');
  //console.log(note_values);
  for (var i = 0, l = note_values.length; i < l; i++) {
    var note_value = note_values[i];
    this.emit(note_value);
    this.emit('tact_'+this.currTact+'_'+note_value);
  }
  if (count == 0) {
    this.emit('tact');
    this.emit('tact_'+this.currTact);
  }
  
  this.emit('tact_'+this.currTact+'_'+count);
  
  this.count = (this.count + 1) % this.tact;
  if (this.count == 0) {
    this.currTact++;
  }
};

Song.prototype.play = function() {
  this.stop();
  this.resume();
};
Song.prototype.stop = function() {
  this.pause();
  this.currTact = 0;
  this.count = 0;
};
Song.prototype.pause = function() {
  clearInterval(this.boundNote);
};
Song.prototype.resume = function() {
  setInterval(this.boundNote, this.speed*(1e3/this.tact));
};


//////////
// Test //
//////////


// Bg
/*var sound = new Sound('oui', 'english', 0, 250);
sound.on('said', function() {
  sound.amplitude += (1-sound.amplitude)/4;
});
sound.startBackground();
setTimeout(function() {
  sound.stopBackground();
}, 10000);*/

// Fg
var sound2 = new Sound('je suis un parisien', 'french', .8, 50);
//sound2.startBackground();
//sound2.times(10, 1000);

var aaa = new Sound('aaaaaaaaaaaa');

var song = new Song(16, 1);
function on(evt, sound) {
  if (typeof sound == 'string') {
    sound = new Sound(sound);
  }
  song.on(String(evt), sound.play.bind(sound));
};

on('quarter', 'b');
on('half', 'a');
on('tact', new Sound('annanannananna', 'french'));
//on('tact', aaa);
//on('tact_5', sound2);

song.play();