comparison core.js @ 656:0a401224660b

Added dev-main branch warning at top of files

+/**
+ * core.js
+ * 
+ * Main script to run, calls all other core functions and manages loading/store to backend.
+ * Also contains all global variables.
+ */
+
+
+/*
+ * 
+ * WARNING!!!
+ * 
+ * 	YOU ARE VIEWING THE DEV VERSION. THERE IS NO GUARANTEE THIS WILL BE FULLY FUNCTIONAL
+ * 
+ * WARNING!!!
+ * 
+ */
+
+
+
+
+/* create the web audio API context and store in audioContext*/
+var audioContext;
+var projectXML;
+var audioEngineContext;
+var projectReturn;
+var preTestQuestions = document.createElement('PreTest');
+var postTestQuestions = document.createElement('PostTest');
+
+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");
+	}
+	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);
+	}
+}
+
+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 store for new audioObjects
+	this.audioObjects = [];
+	
+	this.play = function() {
+		// Send play command to all playback buffers for synchronised start
+		// Also start timer callbacks to detect if playback has finished
+		if (this.status == 0) {
+			// First get current clock
+			var timer = audioContext.currentTime;
+			// Add 3 seconds
+			timer += 3.0;
+			
+			// Send play to all tracks
+			for (var i=0; i<this.audioObjects.length; i++)
+			{
+				this.audioObjects[i].play(timer);
+			}
+			this.status = 1;
+		}
+	};
+	
+	this.stop = function() {
+		// Send stop and reset command to all playback buffers
+		if (this.status == 1) {
+			for (var i=0; i<this.audioObjects.length; i++)
+			{
+				this.audioObjects[i].stop();
+			}
+			this.status = 0;
+		}
+	};
+	
+	this.selectedTrack = function(id) {
+		for (var i=0; i<this.audioObjects.length; i++)
+		{
+			if (id == i) {
+				this.audioObjects[i].outputGain.gain.value = 1.0;
+			} else {
+				this.audioObjects[i].outputGain.gain.value = 0.0;
+			}
+		}
+	};
+	
+	
+	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.
+	
+	// Create a buffer and external gain control to allow internal patching of effects and volume leveling.
+	this.bufferNode = audioContext.createBufferSource();
+	this.outputGain = audioContext.createGain();
+	
+	// Default output gain to be zero
+	this.outputGain.gain.value = 0.0;
+	
+	// Connect buffer to the audio graph
+	this.bufferNode.connect(this.outputGain);
+	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.start(startTime);
+	};
+	
+	this.stop = function() {
+		this.bufferNode.stop(0);
+		this.bufferNode = audioContext.createBufferSource();
+		this.bufferNode.connect(this.outputGain);
+		this.bufferNode.buffer = this.buffer;
+		this.bufferNode.loop = true;
+	};
+
+	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.bufferNode.buffer = audioObj.buffer;
+				audioObj.bufferNode.loop = true;
+				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();
+	};
+	
+}