initial start for audio support

index.html

@@ -48,6 +48,7 @@
 	</script>
 	
 	<script src="script/Button.js"></script>
+	<script src="script/audio.js"></script>
 	<script src="script/engine.js"></script>
 	<script src="script/state_manager.js"></script>
 	<script src="script/header.js"></script>

script/audio.js

@@ -0,0 +1,47 @@
+/**
+ * Module that takes care of audio playback
+ */
+var AudioEngine = {
+    AUDIO_BUFFER_CACHE: {},
+    audioContext: null,
+    output: null,
+	init: function(options) {
+        // for legacy browsers
+        this.audioContext = new (window.AudioContext || window.webkitAudioContext);
+        this.output = this.audioContext.createGain();
+        this.output.connect(this.audioContext.destination);
+	},
+	options: {}, // Nothing for now
+    _playAudioBuffer: function(buffer, loop) {
+        var source = this.audioContext.createBufferSource();
+        source.buffer = buffer;
+        source.connect(this.output);
+        source.loop = loop || false;
+        source.start(0);
+    },
+	playSound: function(src, loop) {
+        var self = this;
+        this.loadAudioFile(src)
+            .then(function (buffer) {
+                self._playAudioBuffer(buffer, loop);
+            });
+    },
+    loadAudioFile(src) {
+        var self = this;
+        if (self.AUDIO_BUFFER_CACHE[src]) {
+            return new Promise(function (resolve, reject) {
+                resolve(self.AUDIO_BUFFER_CACHE[src]);
+            });
+        } else {
+            var request = new Request(src);
+            return fetch(request).then(function(response) {
+                return response.arrayBuffer();
+              }).then(function(buffer) {
+                return self.audioContext.decodeAudioData(buffer, function(decodedData) {
+                    self.AUDIO_BUFFER_CACHE[src] = decodedData;
+                    return self.AUDIO_BUFFER_CACHE[src];
+                });
+              });
+        }
+      }
+};

script/engine.js

@@ -200,6 +200,7 @@
 			$.Dispatch('stateUpdate').subscribe(Engine.handleStateUpdates);
 
 			$SM.init();
+			AudioEngine.init();
 			Notifications.init();
 			Events.init();
 			Room.init();