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var bkcore = bkcore || {};
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bkcore.Audio = {};
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bkcore.Audio.sounds = {};
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bkcore.Audio.init = function(){
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	if(window.AudioContext||window.webkitAudioContext){
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		bkcore.Audio._ctx = new (window.AudioContext||window.webkitAudioContext)();
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		bkcore.Audio._panner = bkcore.Audio._ctx.createPanner();
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		bkcore.Audio._panner.connect(bkcore.Audio._ctx.destination);
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	}
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	else {
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		bkcore.Audio._ctx = null;
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	}
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	bkcore.Audio.posMultipler = 1.5;
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};
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bkcore.Audio.init();
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bkcore.Audio.addSound = function(src, id, loop, callback, usePanner){
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	var ctx = bkcore.Audio._ctx;
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	var audio = new Audio();
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	if(ctx){
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		var audio = { src: null, gainNode: null, bufferNode: null, loop: loop };
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		var xhr = new XMLHttpRequest();
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		xhr.responseType = 'arraybuffer';
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		xhr.onload = function(){
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			ctx.decodeAudioData(xhr.response, function(b){
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				// Create Gain Node
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				var gainNode = ctx.createGain();
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				if(usePanner === true){
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					gainNode.connect(bkcore.Audio._panner);
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				}
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				else {
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					gainNode.connect(ctx.destination);
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				}
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				// Add the audio source
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				audio.src = b;
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				//Remember the gain node
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				audio.gainNode = gainNode;
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				callback();
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			}, function(e){
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				console.error('Audio decode failed!', e);
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			});
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		};
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		xhr.open('GET', src, true);
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		xhr.send(null);
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	}
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	else {
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		// Workaround for old Safari
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		audio.addEventListener('canplay', function(){
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			audio.pause();
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			audio.currentTime = 0;
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			callback();
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		}, false);
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		audio.autoplay = true;
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		audio.loop = loop;
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		audio.src = src;
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	}
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	bkcore.Audio.sounds[id] = audio;
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};
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bkcore.Audio.play = function(id){
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	var ctx = bkcore.Audio._ctx;
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	if(ctx){
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		var sound = ctx.createBufferSource();
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		sound.connect(bkcore.Audio.sounds[id].gainNode);
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		sound.buffer = bkcore.Audio.sounds[id].src;
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		sound.loop = bkcore.Audio.sounds[id].loop;
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		bkcore.Audio.sounds[id].gainNode.gain.value = 1;
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		bkcore.Audio.sounds[id].bufferNode = sound;
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		sound.start ? sound.start(0) : sound.noteOn(0);
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	}
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	else {
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		if(bkcore.Audio.sounds[id].currentTime > 0){
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			bkcore.Audio.sounds[id].pause();
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			bkcore.Audio.sounds[id].currentTime = 0;
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		}
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		bkcore.Audio.sounds[id].play();
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	}
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};
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bkcore.Audio.stop = function(id){
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	var ctx = bkcore.Audio._ctx;
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	if(ctx){
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		if(bkcore.Audio.sounds[id].bufferNode !== null){
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			var bufferNode = bkcore.Audio.sounds[id].bufferNode;
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			bufferNode.stop ? bufferNode.stop(ctx.currentTime) : bufferNode.noteOff(ctx.currentTime);
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		}
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	}
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	else {
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		bkcore.Audio.sounds[id].pause();
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		bkcore.Audio.sounds[id].currentTime = 0;
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	}
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};
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bkcore.Audio.volume = function(id, volume){
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	var ctx = bkcore.Audio._ctx;
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	if(ctx){
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		bkcore.Audio.sounds[id].gainNode.gain.value = volume;
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	}
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	else {
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		bkcore.Audio.sounds[id].volume = volume;
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	}
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};
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bkcore.Audio.setListenerPos = function(vec){
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	if(bkcore.Audio._ctx){
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		var panner = bkcore.Audio._panner;
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		var vec2 = vec.normalize();
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		panner.setPosition(
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			vec2.x * bkcore.Audio.posMultipler,
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			vec2.y * bkcore.Audio.posMultipler,
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			vec2.z * bkcore.Audio.posMultipler
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		);
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	}
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};
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bkcore.Audio.setListenerVelocity = function(vec){
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	if(bkcore.Audio._ctx){
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		var panner = bkcore.Audio._panner;
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		//panner.setVelocity(vec.x, vec.y, vec.z);
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	}
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};
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