Object.assign(pc, function () {
'use strict';
var SoundInstance;
var STATE_PLAYING = 0;
var STATE_PAUSED = 1;
var STATE_STOPPED = 2;
// Return time % duration but always return a number
// instead of NaN when duration is 0
var capTime = function (time, duration) {
return (time % duration) || 0;
};
if (pc.SoundManager.hasAudioContext()) {
/**
* @constructor
* @name pc.SoundInstance
* @classdesc A pc.SoundInstance plays a {@link pc.Sound}
* @param {pc.SoundManager} manager The sound manager
* @param {pc.Sound} sound The sound to play
* @param {Object} options Options for the instance
* @param {Number} [options.volume=1] The playback volume, between 0 and 1.
* @param {Number} [options.pitch=1] The relative pitch, default of 1, plays at normal pitch.
* @param {Boolean} [options.loop=false] Whether the sound should loop when it reaches the end or not.
* @param {Number} [options.startTime=0] The time from which the playback will start in seconds. Default is 0 to start at the beginning.
* @param {Number} [options.duration=null] The total time after the startTime in seconds when playback will stop or restart if loop is true.
* @param {Function} [options.onPlay=null] Function called when the instance starts playing.
* @param {Function} [options.onPause=null] Function called when the instance is paused.
* @param {Function} [options.onResume=null] Function called when the instance is resumed.
* @param {Function} [options.onStop=null] Function called when the instance is stopped.
* @param {Function} [options.onEnd=null] Function called when the instance ends.
* @property {Number} volume The volume modifier to play the sound with. In range 0-1.
* @property {Number} pitch The pitch modifier to play the sound with. Must be larger than 0.01
* @property {Number} startTime The start time from which the sound will start playing.
* @property {Number} currentTime Gets or sets the current time of the sound that is playing. If the value provided is bigger than the duration of the instance it will wrap from the beginning.
* @property {Number} duration The duration of the sound that the instance will play starting from startTime.
* @property {Boolean} loop If true the instance will restart when it finishes playing
* @property {Boolean} isPlaying Returns true if the instance is currently playing.
* @property {Boolean} isPaused Returns true if the instance is currently paused.
* @property {Boolean} isStopped Returns true if the instance is currently stopped.
* @property {Boolean} isSuspended Returns true if the instance is currently suspended because the window is not focused.
* @property {AudioBufferSourceNode} source Gets the source that plays the sound resource. If the Web Audio API is not supported the type of source is <a href="https://developer.mozilla.org/en-US/docs/Web/HTML/Element/audio" target="_blank">Audio</a>. Source is only available after calling play.
* @property {pc.Sound} sound The sound resource that the instance will play.
*/
SoundInstance = function (manager, sound, options) {
pc.events.attach(this);
options = options || {};
this._volume = options.volume !== undefined ? pc.math.clamp(Number(options.volume) || 0, 0, 1) : 1;
this._pitch = options.pitch !== undefined ? Math.max(0.01, Number(options.pitch) || 0) : 1;
this._loop = !!(options.loop !== undefined ? options.loop : false);
this._sound = sound;
// start at 'stopped'
this._state = STATE_STOPPED;
// true if the manager was suspended
this._suspended = false;
// true if we want to suspend the event handled to the 'onended' event
this._suspendEndEvent = false;
// true if we want to suspend firing instance events
this._suspendInstanceEvents = false;
this._startTime = Math.max(0, Number(options.startTime) || 0);
this._duration = Math.max(0, Number(options.duration) || 0);
this._startedAt = 0;
this._startOffset = null;
// manually keep track of the playback position
// because the Web Audio API does not provide a way to do this
// accurately if the playbackRate is not 1
this._currentTime = 0;
this._currentOffset = 0;
// if true then the instance will start playing its source
// when its created
this._playWhenLoaded = true;
this._manager = manager;
// The input node is the one that is connected to the source.
this._inputNode = null;
// the connected node is the one that is connected to the destination (speakers). Any
// external nodes will be connected to this node.
this._connectorNode = null;
// The first external node set by a user
this._firstNode = null;
// The last external node set by a user
this._lastNode = null;
this._initializeNodes();
// external event handlers
this._onPlayCallback = options.onPlay;
this._onPauseCallback = options.onPause;
this._onResumeCallback = options.onResume;
this._onStopCallback = options.onStop;
this._onEndCallback = options.onEnd;
// bind internal event handlers to 'this'
this._endedHandler = this._onEnded.bind(this);
// source is initialized when play() is called
this.source = null;
};
Object.assign(SoundInstance.prototype, {
/**
* @function
* @private
* @name pc.SoundInstance#_initializeNodes
* @description Creates internal audio nodes and connects them
*/
_initializeNodes: function () {
// create gain node for volume control
this.gain = this._manager.context.createGain();
this._inputNode = this.gain;
// the gain node is also the connector node for 2D sound instances
this._connectorNode = this.gain;
this._connectorNode.connect(this._manager.context.destination);
},
/**
* @function
* @name pc.SoundInstance#play
* @description Begins playback of sound. If the sound is not loaded this will return false.
* If the sound is already playing this will restart the sound.
* @returns {Boolean} True if the sound was started.
*/
play: function () {
if (this._state !== STATE_STOPPED) {
this.stop();
}
if (!this.source) {
this._createSource();
}
// calculate start offset
var offset = capTime(this._startOffset, this.duration);
offset = capTime(this._startTime + offset, this._sound.duration);
// reset start offset now that we started the sound
this._startOffset = null;
// start source with specified offset and duration
if (this._duration) {
this.source.start(0, offset, this._duration);
} else {
this.source.start(0, offset);
}
// reset times
this._startedAt = this._manager.context.currentTime;
this._currentTime = 0;
this._currentOffset = offset;
// set state to playing
this._state = STATE_PLAYING;
// no need for this anymore
this._playWhenLoaded = false;
// Initialize volume and loop - note moved to be after start() because of Chrome bug
this.volume = this._volume;
this.loop = this._loop;
this.pitch = this._pitch;
// handle suspend events / volumechange events
this._manager.on('volumechange', this._onManagerVolumeChange, this);
this._manager.on('suspend', this._onManagerSuspend, this);
this._manager.on('resume', this._onManagerResume, this);
this._manager.on('destroy', this._onManagerDestroy, this);
// suspend immediately if manager is suspended
if (this._manager.suspended) {
this._onManagerSuspend();
}
if (!this._suspendInstanceEvents)
this._onPlay();
return true;
},
/**
* @function
* @name pc.SoundInstance#pause
* @description Pauses playback of sound. Call resume() to resume playback from the same position.
* @returns {Boolean} Returns true if the sound was paused
*/
pause: function () {
if (this._state !== STATE_PLAYING || !this.source)
return false;
// store current time
this._updateCurrentTime();
// set state to paused
this._state = STATE_PAUSED;
// Stop the source and re-create it because we cannot reuse the same source.
// Suspend the end event as we are manually stopping the source
this._suspendEndEvent = true;
this.source.stop(0);
this.source = null;
// no need for this anymore
this._playWhenLoaded = false;
// reset user-set start offset
this._startOffset = null;
if (!this._suspendInstanceEvents)
this._onPause();
return true;
},
/**
* @function
* @name pc.SoundInstance#resume
* @description Resumes playback of the sound. Playback resumes at the point that the audio was paused
* @returns {Boolean} Returns true if the sound was resumed.
*/
resume: function () {
if (this._state !== STATE_PAUSED) {
return false;
}
if (!this.source) {
this._createSource();
}
// start at point where sound was paused
var offset = this.currentTime;
// if the user set the 'currentTime' property while the sound
// was paused then use that as the offset instead
if (this._startOffset !== null) {
offset = capTime(this._startOffset, this.duration);
offset = capTime(this._startTime + offset, this._sound.duration);
// reset offset
this._startOffset = null;
}
// start source
if (this._duration) {
this.source.start(0, offset, this._duration);
} else {
this.source.start(0, offset);
}
// set state back to playing
this._state = STATE_PLAYING;
this._startedAt = this._manager.context.currentTime;
this._currentOffset = offset;
// Initialize parameters
this.volume = this._volume;
this.loop = this._loop;
this.pitch = this._pitch;
this._playWhenLoaded = false;
if (!this._suspendInstanceEvents)
this._onResume();
return true;
},
/**
* @function
* @name pc.SoundInstance#stop
* @description Stops playback of sound. Calling play() again will restart playback from the beginning of the sound.
* @returns {Boolean} Returns true if the sound was stopped.
*/
stop: function () {
if (this._state === STATE_STOPPED || !this.source)
return false;
// unsubscribe from manager events
this._manager.off('volumechange', this._onManagerVolumeChange, this);
this._manager.off('suspend', this._onManagerSuspend, this);
this._manager.off('resume', this._onManagerResume, this);
this._manager.off('destroy', this._onManagerDestroy, this);
// reset stored times
this._startedAt = 0;
this._currentTime = 0;
this._currentOffset = 0;
this._startOffset = null;
this._playWhenLoaded = false;
this._suspendEndEvent = true;
if (this._state === STATE_PLAYING) {
this.source.stop(0);
}
this.source = null;
// set the state to stopped
this._state = STATE_STOPPED;
if (!this._suspendInstanceEvents)
this._onStop();
return true;
},
/**
* @function
* @name pc.SoundInstance#setExternalNodes
* @description Connects external Web Audio API nodes. You need to pass
* the first node of the node graph that you created externally and the last node of that graph. The first
* node will be connected to the audio source and the last node will be connected to the destination of the
* AudioContext (e.g. speakers). Requires Web Audio API support.
* @param {AudioNode} firstNode The first node that will be connected to the audio source of sound instances.
* @param {AudioNode} [lastNode] The last node that will be connected to the destination of the AudioContext.
* If unspecified then the firstNode will be connected to the destination instead.
* @example
* var context = app.systems.sound.context;
* var analyzer = context.createAnalyzer();
* var distortion = context.createWaveShaper();
* var filter = context.createBiquadFilter();
* analyzer.connect(distortion);
* distortion.connect(filter);
* instance.setExternalNodes(analyzer, filter);
*/
setExternalNodes: function (firstNode, lastNode) {
if (!firstNode) {
console.error('The firstNode must be a valid Audio Node');
return;
}
if (!lastNode) {
lastNode = firstNode;
}
// connections are:
// source -> inputNode -> connectorNode -> [firstNode -> ... -> lastNode] -> speakers
var speakers = this._manager.context.destination;
if (this._firstNode !== firstNode) {
if (this._firstNode) {
// if firstNode already exists means the connector node
// is connected to it so disconnect it
this._connectorNode.disconnect(this._firstNode);
} else {
// if firstNode does not exist means that its connected
// to the speakers so disconnect it
this._connectorNode.disconnect(speakers);
}
// set first node and connect with connector node
this._firstNode = firstNode;
this._connectorNode.connect(firstNode);
}
if (this._lastNode !== lastNode) {
if (this._lastNode) {
// if last node exists means it's connected to the speakers so disconnect it
this._lastNode.disconnect(speakers);
}
// set last node and connect with speakers
this._lastNode = lastNode;
this._lastNode.connect(speakers);
}
},
/**
* @function
* @name pc.SoundInstance#clearExternalNodes
* @description Clears any external nodes set by {@link pc.SoundInstance#setExternalNodes}.
*/
clearExternalNodes: function () {
var speakers = this._manager.context.destination;
// break existing connections
if (this._firstNode) {
this._connectorNode.disconnect(this._firstNode);
this._firstNode = null;
}
if (this._lastNode) {
this._lastNode.disconnect(speakers);
this._lastNode = null;
}
// reset connect to speakers
this._connectorNode.connect(speakers);
},
/**
* @function
* @name pc.SoundInstance#getExternalNodes
* @description Gets any external nodes set by {@link pc.SoundInstance#setExternalNodes}.
* @returns {AudioNode[]} Returns an array that contains the two nodes set by {@link pc.SoundInstance#setExternalNodes}.
*/
getExternalNodes: function () {
return [this._firstNode, this._lastNode];
},
/**
* @private
* @function
* @description Creates the source for the instance
*/
_createSource: function () {
if (!this._sound) {
return null;
}
var context = this._manager.context;
if (this._sound.buffer) {
this.source = context.createBufferSource();
this.source.buffer = this._sound.buffer;
// Connect up the nodes
this.source.connect(this._inputNode);
// set events
this.source.onended = this._endedHandler;
// set loopStart and loopEnd so that the source starts and ends at the correct user-set times
this.source.loopStart = capTime(this._startTime, this.source.buffer.duration);
if (this._duration) {
this.source.loopEnd = Math.max(this.source.loopStart, capTime(this._startTime + this._duration, this.source.buffer.duration));
}
}
return this.source;
},
/**
* @private
* @function
* @name pc.SoundInstance#_updateCurrentTime
* @description Sets the current time taking into account the time the instance started playing, the current pitch and the current time offset.
*/
_updateCurrentTime: function () {
this._currentTime = capTime((this._manager.context.currentTime - this._startedAt) * this._pitch + this._currentOffset, this.duration);
},
/**
* @private
* @function
* @name pc.SoundInstance#_onManagerDestroy
* @description Handle the manager's 'destroy' event.
*/
_onManagerDestroy: function () {
if (this.source && this._state === STATE_PLAYING) {
this.source.stop(0);
this.source = null;
}
}
});
Object.defineProperty(SoundInstance.prototype, 'volume', {
get: function () {
return this._volume;
},
set: function (volume) {
volume = pc.math.clamp(volume, 0, 1);
this._volume = volume;
if (this.gain) {
this.gain.gain.value = volume * this._manager.volume;
}
}
});
Object.defineProperty(SoundInstance.prototype, 'pitch', {
get: function () {
return this._pitch;
},
set: function (pitch) {
// set offset to current time so that
// we calculate the rest of the time with the new pitch
// from now on
this._currentOffset = this.currentTime;
this._startedAt = this._manager.context.currentTime;
this._pitch = Math.max(Number(pitch) || 0, 0.01);
if (this.source) {
this.source.playbackRate.value = this._pitch;
}
}
});
Object.defineProperty(SoundInstance.prototype, 'loop', {
get: function () {
return this._loop;
},
set: function (loop) {
this._loop = !!loop;
if (this.source) {
this.source.loop = this._loop;
}
}
});
Object.defineProperty(SoundInstance.prototype, 'sound', {
get: function () {
return this._sound;
},
set: function (value) {
this._sound = value;
if (this._state !== STATE_STOPPED) {
this.stop();
} else {
this._createSource();
}
}
});
Object.defineProperty(SoundInstance.prototype, 'currentTime', {
get: function () {
// if the user has set the currentTime and we have not used it yet
// then just return that
if (this._startOffset !== null) {
return this._startOffset;
}
// if the sound is paused return the currentTime calculated when
// pause() was called
if (this._state === STATE_PAUSED) {
return this._currentTime;
}
// if the sound is stopped or we don't have a source
// return 0
if (this._state === STATE_STOPPED || !this.source) {
return 0;
}
// recalculate current time
this._updateCurrentTime();
return this._currentTime;
},
set: function (value) {
if (value < 0) return;
if (this._state === STATE_PLAYING) {
// stop first which will set _startOffset to null
this.stop();
var suspend = this._suspendInstanceEvents;
this._suspendInstanceEvents = true;
// set _startOffset and play
this._startOffset = value;
this.play();
this._suspendInstanceEvents = suspend;
} else {
// set _startOffset which will be used when the instance will start playing
this._startOffset = value;
// set _currentTime
this._currentTime = value;
}
}
});
} else if (pc.SoundManager.hasAudio()) {
SoundInstance = function (manager, resource, options) {
pc.events.attach(this);
options = options || {};
this._volume = options.volume !== undefined ? pc.math.clamp(Number(options.volume) || 0, 0, 1) : 1;
this._pitch = options.pitch !== undefined ? Math.max(0.01, Number(options.pitch) || 0) : 1;
this._loop = !!(options.loop !== undefined ? options.loop : false);
this._sound = resource;
this._state = STATE_STOPPED;
this._suspended = false;
this._suspendEndEvent = false;
this._suspendInstanceEvents = false;
this._playWhenLoaded = true;
this._startTime = Math.max(0, Number(options.startTime) || 0);
this._duration = Math.max(0, Number(options.duration) || 0);
this._startOffset = null;
this._isReady = false;
this._manager = manager;
this._loadedMetadataHandler = this._onLoadedMetadata.bind(this);
this._timeUpdateHandler = this._onTimeUpdate.bind(this);
this._endedHandler = this._onEnded.bind(this);
// external event handlers
this._onPlayCallback = options.onPlay;
this._onPauseCallback = options.onPause;
this._onResumeCallback = options.onResume;
this._onStopCallback = options.onStop;
this._onEndCallback = options.onEnd;
this.source = null;
this._createSource();
};
Object.assign(SoundInstance.prototype, {
play: function () {
if (this._state !== STATE_STOPPED) {
this.stop();
}
if (!this.source) {
if (!this._createSource()) {
return false;
}
}
this.volume = this._volume;
this.pitch = this._pitch;
this.loop = this._loop;
this.source.play();
this._state = STATE_PLAYING;
this._playWhenLoaded = false;
this._manager.on('volumechange', this._onManagerVolumeChange, this);
this._manager.on('suspend', this._onManagerSuspend, this);
this._manager.on('resume', this._onManagerResume, this);
this._manager.on('destroy', this._onManagerDestroy, this);
// suspend immediately if manager is suspended
if (this._manager.suspended)
this._onManagerSuspend();
if (!this._suspendInstanceEvents)
this._onPlay();
return true;
},
pause: function () {
if (!this.source || this._state !== STATE_PLAYING)
return false;
this._suspendEndEvent = true;
this.source.pause();
this._playWhenLoaded = false;
this._state = STATE_PAUSED;
this._startOffset = null;
if (!this._suspendInstanceEvents)
this._onPause();
return true;
},
resume: function () {
if (!this.source || this._state !== STATE_PAUSED)
return false;
this._state = STATE_PLAYING;
this._playWhenLoaded = false;
if (this.source.paused) {
this.source.play();
if (!this._suspendInstanceEvents)
this._onResume();
}
return true;
},
stop: function () {
if (!this.source || this._state === STATE_STOPPED)
return false;
this._manager.off('volumechange', this._onManagerVolumeChange, this);
this._manager.off('suspend', this._onManagerSuspend, this);
this._manager.off('resume', this._onManagerResume, this);
this._manager.off('destroy', this._onManagerDestroy, this);
this._suspendEndEvent = true;
this.source.pause();
this._playWhenLoaded = false;
this._state = STATE_STOPPED;
this._startOffset = null;
if (!this._suspendInstanceEvents)
this._onStop();
return true;
},
setExternalNodes: function () {
// not supported
},
clearExternalNodes: function () {
// not supported
},
getExternalNodes: function () {
// not supported but return same type of result
return [null, null];
},
// Sets start time after loadedmetadata is fired which is required by most browsers
_onLoadedMetadata: function () {
this.source.removeEventListener('loadedmetadata', this._loadedMetadataHandler);
this._isReady = true;
// calculate start time for source
var offset = capTime(this._startOffset, this.duration);
offset = capTime(this._startTime + offset, this._sound.duration);
// reset currentTime
this._startOffset = null;
// set offset on source
this.source.currentTime = offset;
},
_createSource: function () {
if (this._sound && this._sound.audio) {
this._isReady = false;
this.source = this._sound.audio.cloneNode(true);
// set events
this.source.addEventListener('loadedmetadata', this._loadedMetadataHandler);
this.source.addEventListener('timeupdate', this._timeUpdateHandler);
this.source.onended = this._endedHandler;
}
return this.source;
},
// called every time the 'currentTime' is changed
_onTimeUpdate: function () {
if (!this._duration)
return;
// if the currentTime passes the end then if looping go back to the beginning
// otherwise manually stop
if (this.source.currentTime > capTime(this._startTime + this._duration, this.source.duration)) {
if (this.loop) {
this.source.currentTime = capTime(this._startTime, this.source.duration);
} else {
// remove listener to prevent multiple calls
this.source.removeEventListener('timeupdate', this._timeUpdateHandler);
this.source.pause();
// call this manually because it doesn't work in all browsers in this case
this._onEnded();
}
}
},
/**
* @private
* @function
* @name pc.SoundInstance#_onManagerDestroy
* @description Handle the manager's 'destroy' event.
*/
_onManagerDestroy: function () {
if (this.source) {
this.source.pause();
}
}
});
Object.defineProperty(SoundInstance.prototype, 'volume', {
get: function () {
return this._volume;
},
set: function (volume) {
volume = pc.math.clamp(volume, 0, 1);
this._volume = volume;
if (this.source) {
this.source.volume = volume * this._manager.volume;
}
}
});
Object.defineProperty(SoundInstance.prototype, 'pitch', {
get: function () {
return this._pitch;
},
set: function (pitch) {
this._pitch = Math.max(Number(pitch) || 0, 0.01);
if (this.source) {
this.source.playbackRate = this._pitch;
}
}
});
Object.defineProperty(SoundInstance.prototype, 'loop', {
get: function () {
return this._loop;
},
set: function (loop) {
this._loop = !!loop;
if (this.source) {
this.source.loop = this._loop;
}
}
});
Object.defineProperty(SoundInstance.prototype, 'sound', {
get: function () {
return this._sound;
},
set: function (value) {
this.stop();
this._sound = value;
}
});
Object.defineProperty(SoundInstance.prototype, 'currentTime', {
get: function () {
if (this._startOffset !== null) {
return this._startOffset;
}
if (this._state === STATE_STOPPED || !this.source) {
return 0;
}
return this.source.currentTime - this._startTime;
},
set: function (value) {
if (value < 0) return;
this._startOffset = value;
if (this.source && this._isReady) {
this.source.currentTime = capTime(this._startTime + capTime(value, this.duration), this._sound.duration);
this._startOffset = null;
}
}
});
} else {
SoundInstance = function () { };
}
// Add functions which don't depend on source type
Object.assign(SoundInstance.prototype, {
_onPlay: function () {
this.fire('play');
if (this._onPlayCallback)
this._onPlayCallback(this);
},
_onPause: function () {
this.fire('pause');
if (this._onPauseCallback)
this._onPauseCallback(this);
},
_onResume: function () {
this.fire('resume');
if (this._onResumeCallback)
this._onResumeCallback(this);
},
_onStop: function () {
this.fire('stop');
if (this._onStopCallback)
this._onStopCallback(this);
},
_onEnded: function () {
// the callback is not fired synchronously
// so only reset _suspendEndEvent to false when the
// callback is fired
if (this._suspendEndEvent) {
this._suspendEndEvent = false;
return;
}
this.fire('end');
if (this._onEndCallback)
this._onEndCallback(this);
this.stop();
},
/**
* @private
* @function
* @name pc.SoundInstance#_onManagerVolumeChange
* @description Handle the manager's 'volumechange' event.
*/
_onManagerVolumeChange: function () {
this.volume = this._volume;
},
/**
* @private
* @function
* @name pc.SoundInstance#_onManagerSuspend
* @description Handle the manager's 'suspend' event.
*/
_onManagerSuspend: function () {
if (this._state === STATE_PLAYING && !this._suspended) {
this._suspended = true;
this.pause();
}
},
/**
* @private
* @function
* @name pc.SoundInstance#_onManagerResume
* @description Handle the manager's 'resume' event.
*/
_onManagerResume: function () {
if (this._suspended) {
this._suspended = false;
this.resume();
}
}
});
Object.defineProperty(SoundInstance.prototype, 'startTime', {
get: function () {
return this._startTime;
},
set: function (value) {
this._startTime = Math.max(0, Number(value) || 0);
// restart
var isPlaying = this._state === STATE_PLAYING;
this.stop();
if (isPlaying) {
this.play();
}
}
});
Object.defineProperty(SoundInstance.prototype, 'duration', {
get: function () {
if (!this._sound) {
return 0;
}
if (this._duration) {
return capTime(this._duration, this._sound.duration);
}
return this._sound.duration;
},
set: function (value) {
this._duration = Math.max(0, Number(value) || 0);
// restart
var isPlaying = this._state === STATE_PLAYING;
this.stop();
if (isPlaying) {
this.play();
}
}
});
Object.defineProperty(SoundInstance.prototype, 'isPlaying', {
get: function () {
return this._state === STATE_PLAYING;
}
});
Object.defineProperty(SoundInstance.prototype, 'isPaused', {
get: function () {
return this._state === STATE_PAUSED;
}
});
Object.defineProperty(SoundInstance.prototype, 'isStopped', {
get: function () {
return this._state === STATE_STOPPED;
}
});
Object.defineProperty(SoundInstance.prototype, 'isSuspended', {
get: function () {
return this._suspended;
}
});
return {
SoundInstance: SoundInstance
};
}());
// Events Documentation
/**
* @event
* @name pc.SoundInstance#play
* @description Fired when the instance starts playing its source
*/
/**
* @event
* @name pc.SoundInstance#pause
* @description Fired when the instance is paused.
*/
/**
* @event
* @name pc.SoundInstance#resume
* @description Fired when the instance is resumed.
*/
/**
* @event
* @name pc.SoundInstance#stop
* @description Fired when the instance is stopped.
*/
/**
* @event
* @name pc.SoundInstance#end
* @description Fired when the sound currently played by the instance ends.
*/