require sharedarraybuffer support

We use it for sharing low latency buffer metrics.

user_scripts/IodineGBACoreGlueCode.js

@@ -62,9 +62,13 @@ window.onload = function () {
 }
 function registerIodineHandler() {
     try {
+        if (!window.SharedInt32Array) {
+            //Audio synchronization is much better with shared array memory:
+            throw null;
+        }
         //Try starting Iodine in a webworker:
         IodineGUI.Iodine = new IodineGBAWorkerShim();
-        addEvent("onbeforeunload", window, registerBeforeUnloadHandler);
+        addEvent("beforeunload", window, registerBeforeUnloadHandler);
     }
     catch (e) {
         //Otherwise just run on-thread:
@@ -73,12 +77,12 @@ function registerIodineHandler() {
 }
 function registerBeforeUnloadHandler(e) {
     IodineGUI.Iodine.pause();
-    this.style.display = "none";
+    document.getElementById("play").style.display = "none";
     document.getElementById("play").style.display = "inline";
     if (e.preventDefault) {
         e.preventDefault();
     }
-    removeEvent("onbeforeunload", window, registerBeforeUnloadHandler);
+    removeEvent("beforeunload", window, registerBeforeUnloadHandler);
     return "IodineGBA needs to process your save data, leaving now may result in not saving current data.";
 }
 function registerTimerHandler() {

user_scripts/IodineGBAWorkerGlueCode.js

@@ -11,10 +11,12 @@
 function IodineGBAWorkerShim() {
     this.gfx = null;
     this.audio = null;
+    this.audioInitialized = false;
     this.speed = null;
     this.saveExport = null;
     this.saveImport = null;
     this.worker = null;
+    this.shared = null;
     this.initialize();
 }
 var tempvar = document.getElementsByTagName("script");
@@ -25,6 +27,10 @@ IodineGBAWorkerShim.prototype.initialize = function () {
     this.worker.onmessage = function (event) {
         parentObj.decodeMessage(event.data);
     }
+    if (window.SharedInt32Array) {
+        this.shared = new SharedInt32Array(1);
+        this.sendBufferBack(25, this.shared);
+    }
 }
 IodineGBAWorkerShim.prototype.sendMessageSingle = function (eventCode) {
     eventCode = eventCode | 0;
@@ -53,7 +59,14 @@ IodineGBAWorkerShim.prototype.setIntervalRate = function (rate) {
 }
 IodineGBAWorkerShim.prototype.timerCallback = function (timestamp) {
     timestamp = +timestamp;
-    this.sendMessageDouble(23, this.audio.remainingBuffer());
+    if (this.audio && this.audioInitialized) {
+        if (this.shared) {
+            this.shared[0] = this.audio.remainingBuffer() | 0;
+        }
+        else {
+            this.sendMessageDouble(23, this.audio.remainingBuffer() | 0);
+        }
+    }
     this.sendMessageDouble(4, +timestamp);
 }
 IodineGBAWorkerShim.prototype.attachGraphicsFrameHandler = function (gfx) {
@@ -154,6 +167,7 @@ IodineGBAWorkerShim.prototype.audioInitialize = function (channels, sampleRate,
             //Disable audio in the callback here:
             parentObj.disableAudio();
         });
+        this.audioInitialized = true;
     }
 }
 IodineGBAWorkerShim.prototype.audioRegister = function () {

user_scripts/IodineGBAWorkerGlueCodeWorker.js

@@ -54,8 +54,10 @@ importScripts("../IodineGBA/core/cartridge/EEPROM.js");
 var Iodine = new GameBoyAdvanceEmulator();
 //Spare audio buffers:
 var audioBufferPool = [];
+var audioBufferPassCount = 0;
 //Spare graphics buffers:
 var graphicsBufferPool = [];
+var graphicsBufferPassCount = 0;
 //Save callbacks waiting to be satisfied:
 var saveImportPool = [];
 //Cached timestamp:
@@ -139,19 +141,29 @@ self.onmessage = function (event) {
             break;
         case 24:
             processSaveImportFail();
+            break;
+        case 25:
+            attachAudioMetricHook(data.payload);
     }
 }
 function graphicsFrameHandler(swizzledFrame) {
-    var buffer = getFreeGraphicsBuffer(swizzledFrame.length);
-    buffer.set(swizzledFrame);
-    postMessage({messageID:4, graphicsBuffer:buffer}, [buffer.buffer]);
+    if ((graphicsBufferPassCount | 0) < 2) {
+        var buffer = getFreeGraphicsBuffer(swizzledFrame.length);
+        buffer.set(swizzledFrame);
+        graphicsBufferPassCount = ((graphicsBufferPassCount | 0) + 1) | 0;
+        postMessage({messageID:4, graphicsBuffer:buffer}, [buffer.buffer]);
+    }
 }
 //Shim for our audio api:
 var audioHandler = {
+    shared:null,
     push:function (audioBuffer, amountToSend) {
-        var buffer = getFreeAudioBuffer(amountToSend | 0);
-        buffer.set(audioBuffer);
-        postMessage({messageID:3, audioBuffer:buffer, audioNumSamplesTotal:amountToSend | 0}, [buffer.buffer]);
+        if ((audioBufferPassCount | 0) < 10) {
+            var buffer = getFreeAudioBuffer(amountToSend | 0);
+            buffer.set(audioBuffer);
+            audioBufferPassCount = ((audioBufferPassCount | 0) + 1) | 0;
+            postMessage({messageID:3, audioBuffer:buffer, audioNumSamplesTotal:amountToSend | 0}, [buffer.buffer]);
+        }
     },
     register:function () {
         postMessage({messageID:1});
@@ -166,10 +178,16 @@ var audioHandler = {
         postMessage({messageID:0, channels:channels, sampleRate:sampleRate, bufferLimit:bufferLimit});
     },
     remainingBuffer:function () {
+        if (this.shared) {
+            return this.shared[0];
+        }
         return this.remainingBufferCache;
     },
     remainingBufferCache:0
 };
+function attachAudioMetricHook(buffer) {
+    audioHandler.shared = new SharedInt32Array(buffer.buffer);
+}
 function speedHandler(speed) {
      postMessage({messageID:5, speed:speed});
 }
@@ -187,9 +205,11 @@ function processSaveImportFail() {
     saveImportPool.shift()[1]();
 }
 function repoolAudioBuffer(buffer) {
+    audioBufferPassCount = ((audioBufferPassCount | 0) - 1) | 0;
     audioBufferPool.push(buffer);
 }
 function repoolGraphicsBuffer(buffer) {
+    graphicsBufferPassCount = ((graphicsBufferPassCount | 0) - 1) | 0;
     graphicsBufferPool.push(buffer);
 }
 function getFreeGraphicsBuffer(amountToSend) {