comparison core.js @ 1608:a21deccefe7d

Currently playing sample red.

+/**
+ * core.js
+ * 
+ * Main script to run, calls all other core functions and manages loading/store to backend.
+ * Also contains all global variables.
+ */
+
+/* create the web audio API context and store in audioContext*/
+var audioContext; // Hold the browser web audio API
+var projectXML; // Hold the parsed setup XML
+
+var testXMLSetups = []; // Hold the parsed test instances
+var testResultsHolders =[]; // Hold the results from each test for publishing to XML
+var currentTrackOrder = []; // Hold the current XML tracks in their (randomised) order
+var currentTestHolder; // Hold any intermediate results during test - metrics
+var audioEngineContext; // The custome AudioEngine object
+var projectReturn; // Hold the URL for the return
+var preTestQuestions = document.createElement('PreTest'); // Store any pre-test question response
+var postTestQuestions = document.createElement('PostTest'); // Store any post-test question response
+
+// Add a prototype to the bufferSourceNode to reference to the audioObject holding it
+AudioBufferSourceNode.prototype.owner = undefined;
+
+window.onload = function() {
+	// Function called once the browser has loaded all files.
+	// This should perform any initial commands such as structure / loading documents
+	
+	// Create a web audio API context
+	// Fixed for cross-browser support
+	var AudioContext = window.AudioContext || window.webkitAudioContext;
+	audioContext = new AudioContext;
+	
+	// Create the audio engine object
+	audioEngineContext = new AudioEngine();
+};
+
+function loadProjectSpec(url) {
+	// Load the project document from the given URL, decode the XML and instruct audioEngine to get audio data
+	// If url is null, request client to upload project XML document
+	var r = new XMLHttpRequest();
+	r.open('GET',url,true);
+	r.onload = function() {
+		loadProjectSpecCallback(r.response);
+	};
+	r.send();
+};
+
+function loadProjectSpecCallback(response) {
+	// Function called after asynchronous download of XML project specification
+	var decode = $.parseXML(response);
+	projectXML = $(decode);
+	
+	// Now extract the setup tag
+	var xmlSetup = projectXML.find('setup');
+	// Detect the interface to use and load the relevant javascripts.
+	var interfaceType = xmlSetup[0].attributes['interface'];
+	var interfaceJS = document.createElement('script');
+	interfaceJS.setAttribute("type","text/javascript");
+	if (interfaceType.value == 'APE') {
+		interfaceJS.setAttribute("src","ape.js");
+		
+		// APE comes with a css file
+		var css = document.createElement('link');
+		css.rel = 'stylesheet';
+		css.type = 'text/css';
+		css.href = 'ape.css';
+		
+		document.getElementsByTagName("head")[0].appendChild(css);
+	}
+	document.getElementsByTagName("head")[0].appendChild(interfaceJS);
+}
+
+function createProjectSave(destURL) {
+	// Save the data from interface into XML and send to destURL
+	// If destURL is null then download XML in client
+	// Now time to render file locally
+	var xmlDoc = interfaceXMLSave();
+	if (destURL == "null" || destURL == undefined) {
+		var parent = document.createElement("div");
+		parent.appendChild(xmlDoc);
+		var file = [parent.innerHTML];
+		var bb = new Blob(file,{type : 'application/xml'});
+		var dnlk = window.URL.createObjectURL(bb);
+		var a = document.createElement("a");
+		a.hidden = '';
+		a.href = dnlk;
+		a.download = "save.xml";
+		a.textContent = "Save File";
+		
+		var submitDiv = document.getElementById('download-point');
+		submitDiv.appendChild(a);
+	}
+	return submitDiv;
+}
+
+function AudioEngine() {
+	
+	// Create two output paths, the main outputGain and fooGain.
+	// Output gain is default to 1 and any items for playback route here
+	// Foo gain is used for analysis to ensure paths get processed, but are not heard
+	// because web audio will optimise and any route which does not go to the destination gets ignored.
+	this.outputGain = audioContext.createGain();
+	this.fooGain = audioContext.createGain();
+	this.fooGain.gain = 0;
+	
+	// Use this to detect playback state: 0 - stopped, 1 - playing
+	this.status = 0;
+	
+	// Connect both gains to output
+	this.outputGain.connect(audioContext.destination);
+	this.fooGain.connect(audioContext.destination);
+	
+	// Create the timer Object
+	this.timer = new timer();
+	// Create session metrics
+	this.metric = new sessionMetrics(this);
+	
+	this.loopPlayback = false;
+	
+	// Create store for new audioObjects
+	this.audioObjects = [];
+	
+	this.play = function(){};
+	
+	this.stop = function(){};
+	
+	
+	this.newTrack = function(url) {
+		// Pull data from given URL into new audio buffer
+		// URLs must either be from the same source OR be setup to 'Access-Control-Allow-Origin'
+		
+		// Create the audioObject with ID of the new track length;
+		audioObjectId = this.audioObjects.length;
+		this.audioObjects[audioObjectId] = new audioObject(audioObjectId);
+
+		// AudioObject will get track itself.
+		this.audioObjects[audioObjectId].constructTrack(url);
+	};
+	
+}
+
+function audioObject(id) {
+	// The main buffer object with common control nodes to the AudioEngine
+	
+	this.id = id;
+	this.state = 0; // 0 - no data, 1 - ready
+	this.url = null; // Hold the URL given for the output back to the results.
+	this.metric = new metricTracker();
+	
+	// Create a buffer and external gain control to allow internal patching of effects and volume leveling.
+	this.bufferNode = undefined;
+	this.outputGain = audioContext.createGain();
+	
+	// Default output gain to be zero
+	this.outputGain.gain.value = 0.0;
+	
+	// Connect buffer to the audio graph
+	this.outputGain.connect(audioEngineContext.outputGain);
+	
+	// the audiobuffer is not designed for multi-start playback
+	// When stopeed, the buffer node is deleted and recreated with the stored buffer.
+	this.buffer;
+	
+	this.play = function(startTime) {
+		this.bufferNode = audioContext.createBufferSource();
+		this.bufferNode.connect(this.outputGain);
+		this.bufferNode.buffer = this.buffer;
+		this.bufferNode.loop = audioEngineContext.loopPlayback;
+		this.bufferNode.start(startTime);
+	};
+	
+	this.stop = function() {
+		this.bufferNode.stop(0);
+		this.bufferNode = undefined;
+	};
+
+	this.constructTrack = function(url) {
+		var request = new XMLHttpRequest();
+		this.url = url;
+		request.open('GET',url,true);
+		request.responseType = 'arraybuffer';
+		
+		var audioObj = this;
+		
+		// Create callback to decode the data asynchronously
+		request.onloadend = function() {
+			audioContext.decodeAudioData(request.response, function(decodedData) {
+				audioObj.buffer = decodedData;
+				audioObj.state = 1;
+			}, function(){
+				// Should only be called if there was an error, but sometimes gets called continuously
+				// Check here if the error is genuine
+				if (audioObj.state == 0 || audioObj.buffer == undefined) {
+					// Genuine error
+					console.log('FATAL - Error loading buffer on '+audioObj.id);
+				}
+			});
+		};
+		request.send();
+	};
+	
+}
+
+function timer()
+{
+	/* Timer object used in audioEngine to keep track of session timings
+	 * Uses the timer of the web audio API, so sample resolution
+	 */
+	this.testStarted = false;
+	this.testStartTime = 0;
+	this.testDuration = 0;
+	this.minimumTestTime = 0; // No minimum test time
+	this.startTest = function()
+	{
+		if (this.testStarted == false)
+		{
+			this.testStartTime = audioContext.currentTime;
+			this.testStarted = true;
+			this.updateTestTime();
+			audioEngineContext.metric.initialiseTest();
+		}
+	};
+	this.stopTest = function()
+	{
+		if (this.testStarted)
+		{
+			this.testDuration = this.getTestTime();
+			this.testStarted = false;
+		} else {
+			console.log('ERR: Test tried to end before beginning');
+		}
+	};
+	this.updateTestTime = function()
+	{
+		if (this.testStarted)
+		{
+			this.testDuration = audioContext.currentTime - this.testStartTime;
+		}
+	};
+	this.getTestTime = function()
+	{
+		this.updateTestTime();
+		return this.testDuration;
+	};
+}
+
+function sessionMetrics(engine)
+{
+	/* Used by audioEngine to link to audioObjects to minimise the timer call timers;
+	 */
+	this.engine = engine;
+	this.lastClicked = -1;
+	this.data = -1;
+	this.initialiseTest = function(){};
+}
+
+function metricTracker()
+{
+	/* Custom object to track and collect metric data
+	 * Used only inside the audioObjects object.
+	 */
+	
+	this.listenedTimer = 0;
+	this.listenStart = 0;
+	this.initialPosition = -1;
+	this.movementTracker = [];
+	this.wasListenedTo = false;
+	this.wasMoved = false;
+	this.hasComments = false;
+	
+	this.initialised = function(position)
+	{
+		if (this.initialPosition == -1) {
+			this.initialPosition = position;
+		}
+	};
+	
+	this.moved = function(time,position)
+	{
+		this.wasMoved = true;
+		this.movementTracker[this.movementTracker.length] = [time, position];
+	};
+	
+	this.listening = function(time)
+	{
+		if (this.listenStart == 0)
+		{
+			this.wasListenedTo = true;
+			this.listenStart = time;
+		} else {
+			this.listenedTimer += (time - this.listenStart);
+			this.listenStart = 0;
+		}
+	};
+}
+
+function randomiseOrder(input)
+{
+	// This takes an array of information and randomises the order
+	var N = input.length;
+	var K = N;
+	var holdArr = [];
+	for (var n=0; n<N; n++)
+	{
+		// First pick a random number
+		var r = Math.random();
+		// Multiply and floor by the number of elements left
+		r = Math.floor(r*input.length);
+		// Pick out that element and delete from the array
+		holdArr.push(input.splice(r,1)[0]);
+	}
+	return holdArr;
+}