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Buffering of notes has been introduced to reduce RAM usage and allow …
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…for an unlimited number of notes.
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@meenie
meenie committed Sep 5, 2013
1 parent 834f11f commit 10265ea
Showing 1 changed file with 142 additions and 81 deletions.
223 changes: 142 additions & 81 deletions src/band.js
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Expand Up @@ -51,11 +51,13 @@
notes = packs.rhythm[rhythm],
tempo,
instruments = [],
sounds = [],
allSounds = [],
currentPlayTime,
totalPlayTime = 0,
totalDuration = 0,
currentSeconds = 0,
defaultBufferSize = 50,
bufferTimeout,
tickerCallback,
paused = false,
playing = false,
Expand Down Expand Up @@ -107,7 +109,7 @@
currentTime = 0,
lastRepeatCount = 0,
volumeLevel = 0.25,
notesBuffer = [],
soundsBuffer = [],
instrument = packs.instrument[pack](name, ac)
;

Expand Down Expand Up @@ -149,7 +151,7 @@
});
}

notesBuffer.push({
soundsBuffer.push({
pitch: pitch,
duration: duration,
articulationGap: articulationGap,
Expand All @@ -174,7 +176,7 @@

var duration = getDuration(rhythm);

notesBuffer.push({
soundsBuffer.push({
pitch: false,
duration: duration,
articulationGap: 0,
Expand All @@ -191,7 +193,7 @@
* Place where a repeat section should start
*/
this.repeatStart = function() {
lastRepeatCount = notesBuffer.length;
lastRepeatCount = soundsBuffer.length;

return self;
};
Expand All @@ -212,16 +214,16 @@
*/
this.repeat = function(numOfRepeats) {
numOfRepeats = typeof numOfRepeats === 'undefined' ? 1 : numOfRepeats;
var copyNotesBuffer = notesBuffer.slice(lastRepeatCount);
var soundsBufferCopy = soundsBuffer.slice(lastRepeatCount);
for (var r = 0; r < numOfRepeats; r++) {
copyNotesBuffer.forEach(function(note) {
var noteCopy = clone(note);
soundsBufferCopy.forEach(function(sound) {
var soundCopy = clone(sound);

noteCopy.startTime = currentTime;
noteCopy.stopTime = currentTime + noteCopy.duration - noteCopy.articulationGap;
soundCopy.startTime = currentTime;
soundCopy.stopTime = currentTime + soundCopy.duration - soundCopy.articulationGap;

notesBuffer.push(noteCopy);
currentTime += noteCopy.duration;
soundsBuffer.push(soundCopy);
currentTime += soundCopy.duration;
});
}

Expand All @@ -233,13 +235,18 @@
* of each instrument.
*/
this.finish = function() {
var totalDuration = 0;
notesBuffer.forEach(function(note) {
totalDuration += note.duration;
var duration = 0;
soundsBuffer.forEach(function(sound) {
duration += sound.duration;
});
// Figure out longest duration out of all the instruments
if (duration > totalDuration) {
totalDuration = duration;
}
instruments.push({
instrument: instrument,
notes: notesBuffer,
sounds: soundsBuffer,
bufferPosition: 0,
totalDuration: totalDuration,
volumeLevel: volumeLevel
});
Expand Down Expand Up @@ -340,7 +347,9 @@
};

/**
* Stop playing all music and reset the Oscillators
* Stop playing all music and reset the song
*
* @param fadeOut boolean - should the song fade out?
*/
this.stop = function(fadeOut) {
playing = false;
Expand All @@ -352,26 +361,29 @@
if (fadeOut && ! muted) {
fade('down', function() {
totalPlayTime = 0;
// Reset the sound back to it's master volume level
self.setMasterVolume(masterVolumeLevel);
reset();
faded = false;
tickerCallback(currentSeconds);
});
// Make callback asynchronous
setTimeout(function() {
tickerCallback(currentSeconds);
}, 1);
}, true);
} else {
totalPlayTime = 0;
reset();
// Make callback asynchronous
setTimeout(function() {
tickerCallback(currentSeconds);
}, 1)
}, 1);
}
};

/**
* Set Master Volume
*/
this.setMasterVolume = function(newVolume) {
if (newVolume > 1) {
newVolume = newVolume / 100;
}
masterVolumeLevel = newVolume;
masterVolume.gain.value = masterVolumeLevel;
};
Expand Down Expand Up @@ -416,58 +428,82 @@
};

/**
* Create all the sound nodes
* Needs to be called after all the instruments have been marked off as
* finished.
*
* Buffers up the initial sounds so they can be instantly played.
*/
this.end = function() {
sounds = [];
totalDuration = 0;
for (var i = 0; i < instruments.length; i++) {
// Find the highest duration of all of the instruments
if (totalDuration < instruments[i].totalDuration) {
totalDuration = instruments[i].totalDuration;
}
// Reset the buffer position of all instruments
instruments.forEach(function(instrument) {
instrument.bufferPosition = 0;
});
// Setup initials sounds
allSounds = this.bufferSounds();
};

var theseNotes = instruments[i].notes,
instrument = instruments[i].instrument,
// Create volume for this instrument
volume = ac.createGain();
/**
* Grabs a set of sounds based on the current time and what the Buffer Size is.
* It will also skip any sounds that have a start time less than the
* total play time.
*/
this.bufferSounds = function(bufferSize) {
// Default buffer amount to 50 notes
if (! bufferSize) {
bufferSize = defaultBufferSize;
}

var sounds = [];
instruments.forEach(function(instrument) {
// Create volume for this instrument
var volume = ac.createGain(),
bufferCount = bufferSize;

// Connect volume gain to the Master Volume;
volume.connect(masterVolume);
// Set the volume for this note
volume.gain.value = instruments[i].volumeLevel;
volume.gain.value = instrument.volumeLevel;

for (var ii = 0; ii < theseNotes.length; ii++) {
var pitch = theseNotes[ii].pitch,
startTime = theseNotes[ii].startTime,
stopTime = theseNotes[ii].stopTime
for (var i = 0; i < bufferCount; i++) {
var sound = instrument.sounds[instrument.bufferPosition + i];

// If pitch is false, then it's a rest and we don't need a sound
if (false === pitch) {
if (typeof sound === 'undefined') {
break;
}

var pitch = sound.pitch,
startTime = sound.startTime,
stopTime = sound.stopTime;

if (startTime < totalPlayTime) {
bufferCount++;
continue;
}

if (typeof pitch === 'undefined') {
sounds.push({
startTime: startTime,
stopTime: stopTime,
instrument: instrument,
destination: volume,
pitch: false
});
} else {
pitch.forEach(function(p) {
// If pitch is false, then it's a rest and we don't need a sound
if (false !== pitch) {
if (typeof pitch === 'undefined') {
sounds.push({
startTime: startTime,
stopTime: stopTime,
instrument: instrument,
destination: volume,
pitch: pitches[p.trim()]
node: instrument.instrument.createSound(volume)
});
});
} else {
pitch.forEach(function(p) {
sounds.push({
startTime: startTime,
stopTime: stopTime,
node: instrument.instrument.createSound(volume, pitches[p.trim()])
});
});
}
}
}
}
instrument.bufferPosition += bufferCount;
});

// Return array of sounds
return sounds;
};

/**
Expand Down Expand Up @@ -495,32 +531,45 @@
};

/**
* Grabs all the sound nodes and start()/stop()'s them
* Grabs currently buffered sound nodes and calls their start/stop methods.
*
* It then sets up a timer to buffer up the next set of notes based on the
* a set buffer size. This will keep going until the song is stopped or paused.
*
* It will use the total time played so far as an offset so you pause/play the music
*/
this.play = function() {
playing = true;
paused = false;
// Starts calculator which keeps track of total play time
currentPlayTime = ac.currentTime;
requestAnimationFrame(totalPlayTimeCalculator);

var timeOffset = ac.currentTime - totalPlayTime;
sounds.forEach(function(sound) {
var instrument = sound.instrument,
startTime = sound.startTime + timeOffset,
stopTime = sound.stopTime + timeOffset,
destination = sound.destination,
pitch = sound.pitch
;

if (startTime > ac.currentTime) {
sound.node = instrument.createSound(destination, pitch);
sound.node.start(startTime);
sound.node.stop(stopTime);
}
totalPlayTimeCalculator();
var timeOffset = ac.currentTime - totalPlayTime,
playSounds = function(sounds) {
sounds.forEach(function(sound) {
var startTime = sound.startTime + timeOffset,
stopTime = sound.stopTime + timeOffset;
;

sound.node.start(startTime);
sound.node.stop(stopTime);
});
},
bufferUp = function() {
bufferTimeout = setTimeout(function() {
if (playing & ! paused) {
var newSounds = self.bufferSounds();
if (newSounds.length > 0) {
playSounds(newSounds);
allSounds = allSounds.concat(newSounds);
bufferUp();
}
}
}, 5000);
};

});
playSounds(allSounds);
bufferUp();

if (faded && ! muted) {
fade('up');
Expand All @@ -541,7 +590,8 @@
};

/**
* Pauses the music, resets the sound nodes, gets the total time played so far
* Pauses the music, resets the sound nodes,
* and gets the total time played so far
*/
this.pause = function() {
paused = true;
Expand Down Expand Up @@ -573,8 +623,8 @@
*/
this.setTime = function(newTime) {
totalPlayTime = parseInt(newTime);
reset();
if (playing && ! paused) {
reset();
self.play();
}
};
Expand Down Expand Up @@ -612,10 +662,12 @@
}

/**
* Helper function to stop all sound nodes and recreate them
* Helper function to stop all sound nodes
* then call self.end() to re-buffer them
*/
function reset() {
sounds.forEach(function(sound) {
clearTimeout(bufferTimeout);
allSounds.forEach(function(sound) {
if (sound.node) {
sound.node.stop(0);
}
Expand All @@ -628,8 +680,12 @@
*
* @param direction - up or down
* @param [cb] - Callback function fired after the transition is completed
* @param [resetVolume] - Reset the volume back to it's original level
*/
function fade(direction, cb) {
function fade(direction, cb, resetVolume) {
if (typeof resetVolume === 'undefined') {
resetVolume = false;
}
if ('up' !== direction && 'down' !== direction) {
throw new Error('Direction must be either up or down.');
}
Expand All @@ -646,10 +702,15 @@
if (typeof cb === 'function') {
cb();
}

if (resetVolume) {
faded = ! faded;
masterVolume.gain.value = masterVolumeLevel;
}
}
};

requestAnimationFrame(fadeTimer);
fadeTimer();
}
}

Expand Down

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