path: root/src/library_browser.js

//"use strict";

// Utilities for browser environments
mergeInto(LibraryManager.library, {
  $Browser__deps: ['$PATH'],
  $Browser__postset: 'Module["requestFullScreen"] = function Module_requestFullScreen(lockPointer, resizeCanvas) { Browser.requestFullScreen(lockPointer, resizeCanvas) };\n' + // exports
                     'Module["requestAnimationFrame"] = function Module_requestAnimationFrame(func) { Browser.requestAnimationFrame(func) };\n' +
                     'Module["setCanvasSize"] = function Module_setCanvasSize(width, height, noUpdates) { Browser.setCanvasSize(width, height, noUpdates) };\n' +
                     'Module["pauseMainLoop"] = function Module_pauseMainLoop() { Browser.mainLoop.pause() };\n' +
                     'Module["resumeMainLoop"] = function Module_resumeMainLoop() { Browser.mainLoop.resume() };\n' +
                     'Module["getUserMedia"] = function Module_getUserMedia() { Browser.getUserMedia() }',
  $Browser: {
    mainLoop: {
      scheduler: null,
      method: '',
      shouldPause: false,
      paused: false,
      queue: [],
      pause: function() {
        Browser.mainLoop.shouldPause = true;
      },
      resume: function() {
        if (Browser.mainLoop.paused) {
          Browser.mainLoop.paused = false;
          Browser.mainLoop.scheduler();
        }
        Browser.mainLoop.shouldPause = false;
      },
      updateStatus: function() {
        if (Module['setStatus']) {
          var message = Module['statusMessage'] || 'Please wait...';
          var remaining = Browser.mainLoop.remainingBlockers;
          var expected = Browser.mainLoop.expectedBlockers;
          if (remaining) {
            if (remaining < expected) {
              Module['setStatus'](message + ' (' + (expected - remaining) + '/' + expected + ')');
            } else {
              Module['setStatus'](message);
            }
          } else {
            Module['setStatus']('');
          }
        }
      },
      runIter: function(func) {
        if (ABORT) return;
        if (Module['preMainLoop']) {
          var preRet = Module['preMainLoop']();
          if (preRet === false) {
            return; // |return false| skips a frame
          }
        }
        try {
          func();
        } catch (e) {
          if (e instanceof ExitStatus) {
            return;
          } else {
            if (e && typeof e === 'object' && e.stack) Module.printErr('exception thrown: ' + [e, e.stack]);
            throw e;
          }
        }
        if (Module['postMainLoop']) Module['postMainLoop']();
      }
    },
    isFullScreen: false,
    pointerLock: false,
    moduleContextCreatedCallbacks: [],
    workers: [],

    init: function() {
      if (!Module["preloadPlugins"]) Module["preloadPlugins"] = []; // needs to exist even in workers

      if (Browser.initted || ENVIRONMENT_IS_WORKER) return; // workers do not support Image and Audio elements
      Browser.initted = true;

      try {
        new Blob();
        Browser.hasBlobConstructor = true;
      } catch(e) {
        Browser.hasBlobConstructor = false;
        console.log("warning: no blob constructor, cannot create blobs with mimetypes");
      }
      Browser.BlobBuilder = typeof MozBlobBuilder != "undefined" ? MozBlobBuilder : (typeof WebKitBlobBuilder != "undefined" ? WebKitBlobBuilder : (!Browser.hasBlobConstructor ? console.log("warning: no BlobBuilder") : null));
      Browser.URLObject = typeof window != "undefined" ? (window.URL ? window.URL : window.webkitURL) : undefined;
      if (!Module.noImageDecoding && typeof Browser.URLObject === 'undefined') {
        console.log("warning: Browser does not support creating object URLs. Built-in browser image decoding will not be available.");
        Module.noImageDecoding = true;
      }

      // Support for plugins that can process preloaded files. You can add more of these to
      // your app by creating and appending to Module.preloadPlugins.
      //
      // Each plugin is asked if it can handle a file based on the file's name. If it can,
      // it is given the file's raw data. When it is done, it calls a callback with the file's
      // (possibly modified) data. For example, a plugin might decompress a file, or it
      // might create some side data structure for use later (like an Image element, etc.).

      var imagePlugin = {};
      imagePlugin['canHandle'] = function imagePlugin_canHandle(name) {
        return !Module.noImageDecoding && /\.(jpg|jpeg|png|bmp)$/i.test(name);
      };
      imagePlugin['handle'] = function imagePlugin_handle(byteArray, name, onload, onerror) {
        var b = null;
        if (Browser.hasBlobConstructor) {
          try {
            b = new Blob([byteArray], { type: Browser.getMimetype(name) });
            if (b.size !== byteArray.length) { // Safari bug #118630
              // Safari's Blob can only take an ArrayBuffer
              b = new Blob([(new Uint8Array(byteArray)).buffer], { type: Browser.getMimetype(name) });
            }
          } catch(e) {
            Runtime.warnOnce('Blob constructor present but fails: ' + e + '; falling back to blob builder');
          }
        }
        if (!b) {
          var bb = new Browser.BlobBuilder();
          bb.append((new Uint8Array(byteArray)).buffer); // we need to pass a buffer, and must copy the array to get the right data range
          b = bb.getBlob();
        }
        var url = Browser.URLObject.createObjectURL(b);
#if ASSERTIONS
        assert(typeof url == 'string', 'createObjectURL must return a url as a string');
#endif
        var img = new Image();
        img.onload = function img_onload() {
          assert(img.complete, 'Image ' + name + ' could not be decoded');
          var canvas = document.createElement('canvas');
          canvas.width = img.width;
          canvas.height = img.height;
          var ctx = canvas.getContext('2d');
          ctx.drawImage(img, 0, 0);
          Module["preloadedImages"][name] = canvas;
          Browser.URLObject.revokeObjectURL(url);
          if (onload) onload(byteArray);
        };
        img.onerror = function img_onerror(event) {
          console.log('Image ' + url + ' could not be decoded');
          if (onerror) onerror();
        };
        img.src = url;
      };
      Module['preloadPlugins'].push(imagePlugin);

      var audioPlugin = {};
      audioPlugin['canHandle'] = function audioPlugin_canHandle(name) {
        return !Module.noAudioDecoding && name.substr(-4) in { '.ogg': 1, '.wav': 1, '.mp3': 1 };
      };
      audioPlugin['handle'] = function audioPlugin_handle(byteArray, name, onload, onerror) {
        var done = false;
        function finish(audio) {
          if (done) return;
          done = true;
          Module["preloadedAudios"][name] = audio;
          if (onload) onload(byteArray);
        }
        function fail() {
          if (done) return;
          done = true;
          Module["preloadedAudios"][name] = new Audio(); // empty shim
          if (onerror) onerror();
        }
        if (Browser.hasBlobConstructor) {
          try {
            var b = new Blob([byteArray], { type: Browser.getMimetype(name) });
          } catch(e) {
            return fail();
          }
          var url = Browser.URLObject.createObjectURL(b); // XXX we never revoke this!
#if ASSERTIONS
          assert(typeof url == 'string', 'createObjectURL must return a url as a string');
#endif
          var audio = new Audio();
          audio.addEventListener('canplaythrough', function() { finish(audio) }, false); // use addEventListener due to chromium bug 124926
          audio.onerror = function audio_onerror(event) {
            if (done) return;
            console.log('warning: browser could not fully decode audio ' + name + ', trying slower base64 approach');
            function encode64(data) {
              var BASE = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
              var PAD = '=';
              var ret = '';
              var leftchar = 0;
              var leftbits = 0;
              for (var i = 0; i < data.length; i++) {
                leftchar = (leftchar << 8) | data[i];
                leftbits += 8;
                while (leftbits >= 6) {
                  var curr = (leftchar >> (leftbits-6)) & 0x3f;
                  leftbits -= 6;
                  ret += BASE[curr];
                }
              }
              if (leftbits == 2) {
                ret += BASE[(leftchar&3) << 4];
                ret += PAD + PAD;
              } else if (leftbits == 4) {
                ret += BASE[(leftchar&0xf) << 2];
                ret += PAD;
              }
              return ret;
            }
            audio.src = 'data:audio/x-' + name.substr(-3) + ';base64,' + encode64(byteArray);
            finish(audio); // we don't wait for confirmation this worked - but it's worth trying
          };
          audio.src = url;
          // workaround for chrome bug 124926 - we do not always get oncanplaythrough or onerror
          Browser.safeSetTimeout(function() {
            finish(audio); // try to use it even though it is not necessarily ready to play
          }, 10000);
        } else {
          return fail();
        }
      };
      Module['preloadPlugins'].push(audioPlugin);

      // Canvas event setup

      var canvas = Module['canvas'];
      function pointerLockChange() {
        Browser.pointerLock = document['pointerLockElement'] === canvas ||
                              document['mozPointerLockElement'] === canvas ||
                              document['webkitPointerLockElement'] === canvas ||
                              document['msPointerLockElement'] === canvas;
      }
      if (canvas) {
        // forced aspect ratio can be enabled by defining 'forcedAspectRatio' on Module
        // Module['forcedAspectRatio'] = 4 / 3;
        
        canvas.requestPointerLock = canvas['requestPointerLock'] ||
                                    canvas['mozRequestPointerLock'] ||
                                    canvas['webkitRequestPointerLock'] ||
                                    canvas['msRequestPointerLock'] ||
                                    function(){};
        canvas.exitPointerLock = document['exitPointerLock'] ||
                                 document['mozExitPointerLock'] ||
                                 document['webkitExitPointerLock'] ||
                                 document['msExitPointerLock'] ||
                                 function(){}; // no-op if function does not exist
        canvas.exitPointerLock = canvas.exitPointerLock.bind(document);


        document.addEventListener('pointerlockchange', pointerLockChange, false);
        document.addEventListener('mozpointerlockchange', pointerLockChange, false);
        document.addEventListener('webkitpointerlockchange', pointerLockChange, false);
        document.addEventListener('mspointerlockchange', pointerLockChange, false);

        if (Module['elementPointerLock']) {
          canvas.addEventListener("click", function(ev) {
            if (!Browser.pointerLock && canvas.requestPointerLock) {
              canvas.requestPointerLock();
              ev.preventDefault();
            }
          }, false);
        }
      }
    },

    createContext: function(canvas, useWebGL, setInModule, webGLContextAttributes) {
#if !USE_TYPED_ARRAYS
      if (useWebGL) {
        Module.print('(USE_TYPED_ARRAYS needs to be enabled for WebGL)');
        return null;
      }
#endif
      if (useWebGL && Module.ctx) return Module.ctx; // no need to recreate singleton GL context

      var ctx;
      var errorInfo = '?';
      function onContextCreationError(event) {
        errorInfo = event.statusMessage || errorInfo;
      }
      try {
        if (useWebGL) {
          var contextAttributes = {
            antialias: false,
            alpha: false
          };

          if (webGLContextAttributes) {
            for (var attribute in webGLContextAttributes) {
              contextAttributes[attribute] = webGLContextAttributes[attribute];
            }
          }

#if GL_TESTING
          contextAttributes.preserveDrawingBuffer = true;
#endif

          canvas.addEventListener('webglcontextcreationerror', onContextCreationError, false);
          try {
            ['experimental-webgl', 'webgl'].some(function(webglId) {
              return ctx = canvas.getContext(webglId, contextAttributes);
            });
          } finally {
            canvas.removeEventListener('webglcontextcreationerror', onContextCreationError, false);
          }
        } else {
          ctx = canvas.getContext('2d');
        }
        if (!ctx) throw ':(';
      } catch (e) {
        Module.print('Could not create canvas: ' + [errorInfo, e]);
        return null;
      }
      if (useWebGL) {
#if GL_DEBUG
        function wrapDebugGL(ctx) {

          var printObjectList = [];

          function prettyPrint(arg) {
            if (typeof arg == 'undefined') return '!UNDEFINED!';
            if (typeof arg == 'boolean') arg = arg + 0;
            if (!arg) return arg;
            var index = printObjectList.indexOf(arg);
            if (index >= 0) return '<' + arg + '|'; // + index + '>';
            if (arg.toString() == '[object HTMLImageElement]') {
              return arg + '\n\n';
            }
            if (arg.byteLength) {
              return '{' + Array.prototype.slice.call(arg, 0, Math.min(arg.length, 400)) + '}'; // Useful for correct arrays, less so for compiled arrays, see the code below for that
              var buf = new ArrayBuffer(32);
              var i8buf = new Int8Array(buf);
              var i16buf = new Int16Array(buf);
              var f32buf = new Float32Array(buf);
              switch(arg.toString()) {
                case '[object Uint8Array]':
                  i8buf.set(arg.subarray(0, 32));
                  break;
                case '[object Float32Array]':
                  f32buf.set(arg.subarray(0, 5));
                  break;
                case '[object Uint16Array]':
                  i16buf.set(arg.subarray(0, 16));
                  break;
                default:
                  alert('unknown array for debugging: ' + arg);
                  throw 'see alert';
              }
              var ret = '{' + arg.byteLength + ':\n';
              var arr = Array.prototype.slice.call(i8buf);
              ret += 'i8:' + arr.toString().replace(/,/g, ',') + '\n';
              arr = Array.prototype.slice.call(f32buf, 0, 8);
              ret += 'f32:' + arr.toString().replace(/,/g, ',') + '}';
              return ret;
            }
            if (typeof arg == 'object') {
              printObjectList.push(arg);
              return '<' + arg + '|'; // + (printObjectList.length-1) + '>';
            }
            if (typeof arg == 'number') {
              if (arg > 0) return '0x' + arg.toString(16) + ' (' + arg + ')';
            }
            return arg;
          }

          var wrapper = {};
          for (var prop in ctx) {
            (function(prop) {
              switch (typeof ctx[prop]) {
                case 'function': {
                  wrapper[prop] = function gl_wrapper() {
                    var printArgs = Array.prototype.slice.call(arguments).map(prettyPrint);
                    dump('[gl_f:' + prop + ':' + printArgs + ']\n');
                    var ret = ctx[prop].apply(ctx, arguments);
                    if (typeof ret != 'undefined') {
                      dump('[     gl:' + prop + ':return:' + prettyPrint(ret) + ']\n');
                    }
                    return ret;
                  }
                  break;
                }
                case 'number': case 'string': {
                  wrapper.__defineGetter__(prop, function() {
                    //dump('[gl_g:' + prop + ':' + ctx[prop] + ']\n');
                    return ctx[prop];
                  });
                  wrapper.__defineSetter__(prop, function(value) {
                    dump('[gl_s:' + prop + ':' + value + ']\n');
                    ctx[prop] = value;
                  });
                  break;
                }
              }
            })(prop);
          }
          return wrapper;
        }
#endif
        // possible GL_DEBUG entry point: ctx = wrapDebugGL(ctx);

        // Set the background of the WebGL canvas to black
        canvas.style.backgroundColor = "black";
      }
      if (setInModule) {
        if (!useWebGL) assert(typeof GLctx === 'undefined', 'cannot set in module if GLctx is used, but we are a non-GL context that would replace it');
        Module.ctx = ctx;
        if (useWebGL) GLctx = ctx;
        Module.useWebGL = useWebGL;
        Browser.moduleContextCreatedCallbacks.forEach(function(callback) { callback() });
        Browser.init();
      }
      return ctx;
    },

    destroyContext: function(canvas, useWebGL, setInModule) {},

    fullScreenHandlersInstalled: false,
    lockPointer: undefined,
    resizeCanvas: undefined,
    requestFullScreen: function(lockPointer, resizeCanvas) {
      Browser.lockPointer = lockPointer;
      Browser.resizeCanvas = resizeCanvas;
      if (typeof Browser.lockPointer === 'undefined') Browser.lockPointer = true;
      if (typeof Browser.resizeCanvas === 'undefined') Browser.resizeCanvas = false;

      var canvas = Module['canvas'];
      function fullScreenChange() {
        Browser.isFullScreen = false;
        var canvasContainer = canvas.parentNode;
        if ((document['webkitFullScreenElement'] || document['webkitFullscreenElement'] ||
             document['mozFullScreenElement'] || document['mozFullscreenElement'] ||
             document['fullScreenElement'] || document['fullscreenElement'] ||
             document['msFullScreenElement'] || document['msFullscreenElement'] ||
             document['webkitCurrentFullScreenElement']) === canvasContainer) {
          canvas.cancelFullScreen = document['cancelFullScreen'] ||
                                    document['mozCancelFullScreen'] ||
                                    document['webkitCancelFullScreen'] ||
                                    document['msExitFullscreen'] ||
                                    document['exitFullscreen'] ||
                                    function() {};
          canvas.cancelFullScreen = canvas.cancelFullScreen.bind(document);
          if (Browser.lockPointer) canvas.requestPointerLock();
          Browser.isFullScreen = true;
          if (Browser.resizeCanvas) Browser.setFullScreenCanvasSize();
        } else {
          
          // remove the full screen specific parent of the canvas again to restore the HTML structure from before going full screen
          canvasContainer.parentNode.insertBefore(canvas, canvasContainer);
          canvasContainer.parentNode.removeChild(canvasContainer);
          
          if (Browser.resizeCanvas) Browser.setWindowedCanvasSize();
        }
        if (Module['onFullScreen']) Module['onFullScreen'](Browser.isFullScreen);
        Browser.updateCanvasDimensions(canvas);
      }

      if (!Browser.fullScreenHandlersInstalled) {
        Browser.fullScreenHandlersInstalled = true;
        document.addEventListener('fullscreenchange', fullScreenChange, false);
        document.addEventListener('mozfullscreenchange', fullScreenChange, false);
        document.addEventListener('webkitfullscreenchange', fullScreenChange, false);
        document.addEventListener('MSFullscreenChange', fullScreenChange, false);
      }

      // create a new parent to ensure the canvas has no siblings. this allows browsers to optimize full screen performance when its parent is the full screen root
      var canvasContainer = document.createElement("div");
      canvas.parentNode.insertBefore(canvasContainer, canvas);
      canvasContainer.appendChild(canvas);
      
      // use parent of canvas as full screen root to allow aspect ratio correction (Firefox stretches the root to screen size)
      canvasContainer.requestFullScreen = canvasContainer['requestFullScreen'] ||
                                          canvasContainer['mozRequestFullScreen'] ||
                                          canvasContainer['msRequestFullscreen'] ||
                                         (canvasContainer['webkitRequestFullScreen'] ? function() { canvasContainer['webkitRequestFullScreen'](Element['ALLOW_KEYBOARD_INPUT']) } : null);
      canvasContainer.requestFullScreen();
    },

    nextRAF: 0,

    fakeRequestAnimationFrame: function(func) {
      // try to keep 60fps between calls to here
      var now = Date.now();
      if (Browser.nextRAF === 0) {
        Browser.nextRAF = now + 1000/60;
      } else {
        while (now + 2 >= Browser.nextRAF) { // fudge a little, to avoid timer jitter causing us to do lots of delay:0
          Browser.nextRAF += 1000/60;
        }
      }
      var delay = Math.max(Browser.nextRAF - now, 0);
      setTimeout(func, delay);
    },

    requestAnimationFrame: function requestAnimationFrame(func) {
      if (typeof window === 'undefined') { // Provide fallback to setTimeout if window is undefined (e.g. in Node.js)
        Browser.fakeRequestAnimationFrame(func);
      } else {
        if (!window.requestAnimationFrame) {
          window.requestAnimationFrame = window['requestAnimationFrame'] ||
                                         window['mozRequestAnimationFrame'] ||
                                         window['webkitRequestAnimationFrame'] ||
                                         window['msRequestAnimationFrame'] ||
                                         window['oRequestAnimationFrame'] ||
                                         Browser.fakeRequestAnimationFrame;
        }
        window.requestAnimationFrame(func);
      }
    },

    // generic abort-aware wrapper for an async callback
    safeCallback: function(func) {
      return function() {
        if (!ABORT) return func.apply(null, arguments);
      };
    },

    // abort-aware versions
    safeRequestAnimationFrame: function(func) {
      return Browser.requestAnimationFrame(function() {
        if (!ABORT) func();
      });
    },
    safeSetTimeout: function(func, timeout) {
      Module['noExitRuntime'] = true;
      return setTimeout(function() {
        if (!ABORT) func();
      }, timeout);
    },
    safeSetInterval: function(func, timeout) {
      Module['noExitRuntime'] = true;
      return setInterval(function() {
        if (!ABORT) func();
      }, timeout);
    },

    getMimetype: function(name) {
      return {
        'jpg': 'image/jpeg',
        'jpeg': 'image/jpeg',
        'png': 'image/png',
        'bmp': 'image/bmp',
        'ogg': 'audio/ogg',
        'wav': 'audio/wav',
        'mp3': 'audio/mpeg'
      }[name.substr(name.lastIndexOf('.')+1)];
    },
    
    getUserMedia: function(func) {
      if(!window.getUserMedia) {
        window.getUserMedia = navigator['getUserMedia'] ||
                              navigator['mozGetUserMedia'];
      }
      window.getUserMedia(func);
    },


    getMovementX: function(event) {
      return event['movementX'] ||
             event['mozMovementX'] ||
             event['webkitMovementX'] ||
             0;
    },

    getMovementY: function(event) {
      return event['movementY'] ||
             event['mozMovementY'] ||
             event['webkitMovementY'] ||
             0;
    },

    getMouseWheelDelta: function(event) {
      var delta = 0;
      switch (event.type) {
        case 'DOMMouseScroll': 
          delta = event.detail;
          break;
        case 'mousewheel': 
          delta = -event.wheelDelta;
          break;
        case 'wheel': 
          delta = event.deltaY;
          break;
        default:
          throw 'unrecognized mouse wheel event: ' + event.type;
      }
      return Math.max(-1, Math.min(1, delta));
    },

    mouseX: 0,
    mouseY: 0,
    mouseMovementX: 0,
    mouseMovementY: 0,
    touches: {},
    lastTouches: {},

    calculateMouseEvent: function(event) { // event should be mousemove, mousedown or mouseup
      if (Browser.pointerLock) {
        // When the pointer is locked, calculate the coordinates
        // based on the movement of the mouse.
        // Workaround for Firefox bug 764498
        if (event.type != 'mousemove' &&
            ('mozMovementX' in event)) {
          Browser.mouseMovementX = Browser.mouseMovementY = 0;
        } else {
          Browser.mouseMovementX = Browser.getMovementX(event);
          Browser.mouseMovementY = Browser.getMovementY(event);
        }
        
        // check if SDL is available
        if (typeof SDL != "undefined") {
        	Browser.mouseX = SDL.mouseX + Browser.mouseMovementX;
        	Browser.mouseY = SDL.mouseY + Browser.mouseMovementY;
        } else {
        	// just add the mouse delta to the current absolut mouse position
        	// FIXME: ideally this should be clamped against the canvas size and zero
        	Browser.mouseX += Browser.mouseMovementX;
        	Browser.mouseY += Browser.mouseMovementY;
        }        
      } else {
        // Otherwise, calculate the movement based on the changes
        // in the coordinates.
        var rect = Module["canvas"].getBoundingClientRect();
        var cw = Module["canvas"].width;
        var ch = Module["canvas"].height;

        // Neither .scrollX or .pageXOffset are defined in a spec, but
        // we prefer .scrollX because it is currently in a spec draft.
        // (see: http://www.w3.org/TR/2013/WD-cssom-view-20131217/)
        var scrollX = ((typeof window.scrollX !== 'undefined') ? window.scrollX : window.pageXOffset);
        var scrollY = ((typeof window.scrollY !== 'undefined') ? window.scrollY : window.pageYOffset);
#if ASSERTIONS
        // If this assert lands, it's likely because the browser doesn't support scrollX or pageXOffset
        // and we have no viable fallback.
        assert((typeof scrollX !== 'undefined') && (typeof scrollY !== 'undefined'), 'Unable to retrieve scroll position, mouse positions likely broken.');
#endif

        if (event.type === 'touchstart' || event.type === 'touchend' || event.type === 'touchmove') {
          var touch = event.touch;
          if (touch === undefined) {
            return; // the "touch" property is only defined in SDL

          }
          var adjustedX = touch.pageX - (scrollX + rect.left);
          var adjustedY = touch.pageY - (scrollY + rect.top);

          adjustedX = adjustedX * (cw / rect.width);
          adjustedY = adjustedY * (ch / rect.height);

          var coords = { x: adjustedX, y: adjustedY };
          
          if (event.type === 'touchstart') {
            Browser.lastTouches[touch.identifier] = coords;
            Browser.touches[touch.identifier] = coords;
          } else if (event.type === 'touchend' || event.type === 'touchmove') {
            Browser.lastTouches[touch.identifier] = Browser.touches[touch.identifier];
            Browser.touches[touch.identifier] = { x: adjustedX, y: adjustedY };
          } 
          return;
        }

        var x = event.pageX - (scrollX + rect.left);
        var y = event.pageY - (scrollY + rect.top);

        // the canvas might be CSS-scaled compared to its backbuffer;
        // SDL-using content will want mouse coordinates in terms
        // of backbuffer units.
        x = x * (cw / rect.width);
        y = y * (ch / rect.height);

        Browser.mouseMovementX = x - Browser.mouseX;
        Browser.mouseMovementY = y - Browser.mouseY;
        Browser.mouseX = x;
        Browser.mouseY = y;
      }
    },

    xhrLoad: function(url, onload, onerror) {
      var xhr = new XMLHttpRequest();
      xhr.open('GET', url, true);
      xhr.responseType = 'arraybuffer';
      xhr.onload = function xhr_onload() {
        if (xhr.status == 200 || (xhr.status == 0 && xhr.response)) { // file URLs can return 0
          onload(xhr.response);
        } else {
          onerror();
        }
      };
      xhr.onerror = onerror;
      xhr.send(null);
    },

    asyncLoad: function(url, onload, onerror, noRunDep) {
      Browser.xhrLoad(url, function(arrayBuffer) {
        assert(arrayBuffer, 'Loading data file "' + url + '" failed (no arrayBuffer).');
        onload(new Uint8Array(arrayBuffer));
        if (!noRunDep) removeRunDependency('al ' + url);
      }, function(event) {
        if (onerror) {
          onerror();
        } else {
          throw 'Loading data file "' + url + '" failed.';
        }
      });
      if (!noRunDep) addRunDependency('al ' + url);
    },

    resizeListeners: [],

    updateResizeListeners: function() {
      var canvas = Module['canvas'];
      Browser.resizeListeners.forEach(function(listener) {
        listener(canvas.width, canvas.height);
      });
    },

    setCanvasSize: function(width, height, noUpdates) {
      var canvas = Module['canvas'];
      Browser.updateCanvasDimensions(canvas, width, height);
      if (!noUpdates) Browser.updateResizeListeners();
    },

    windowedWidth: 0,
    windowedHeight: 0,
    setFullScreenCanvasSize: function() {
      // check if SDL is available   
      if (typeof SDL != "undefined") {
      	var flags = {{{ makeGetValue('SDL.screen+Runtime.QUANTUM_SIZE*0', '0', 'i32', 0, 1) }}};
      	flags = flags | 0x00800000; // set SDL_FULLSCREEN flag
      	{{{ makeSetValue('SDL.screen+Runtime.QUANTUM_SIZE*0', '0', 'flags', 'i32') }}}
      }
      Browser.updateResizeListeners();
    },

    setWindowedCanvasSize: function() {
      // check if SDL is available       
      if (typeof SDL != "undefined") {
      	var flags = {{{ makeGetValue('SDL.screen+Runtime.QUANTUM_SIZE*0', '0', 'i32', 0, 1) }}};
      	flags = flags & ~0x00800000; // clear SDL_FULLSCREEN flag
      	{{{ makeSetValue('SDL.screen+Runtime.QUANTUM_SIZE*0', '0', 'flags', 'i32') }}}
      }
      Browser.updateResizeListeners();
    },

    updateCanvasDimensions : function(canvas, wNative, hNative) {
      if (wNative && hNative) {
        canvas.widthNative = wNative;
        canvas.heightNative = hNative;
      } else {
        wNative = canvas.widthNative;
        hNative = canvas.heightNative;
      }
      var w = wNative;
      var h = hNative;
      if (Module['forcedAspectRatio'] && Module['forcedAspectRatio'] > 0) {
        if (w/h < Module['forcedAspectRatio']) {
          w = Math.round(h * Module['forcedAspectRatio']);
        } else {
          h = Math.round(w / Module['forcedAspectRatio']);
        }
      }
      if (((document['webkitFullScreenElement'] || document['webkitFullscreenElement'] ||
           document['mozFullScreenElement'] || document['mozFullscreenElement'] ||
           document['fullScreenElement'] || document['fullscreenElement'] ||
           document['msFullScreenElement'] || document['msFullscreenElement'] ||
           document['webkitCurrentFullScreenElement']) === canvas.parentNode) && (typeof screen != 'undefined')) {
         var factor = Math.min(screen.width / w, screen.height / h);
         w = Math.round(w * factor);
         h = Math.round(h * factor);
      }
      if (Browser.resizeCanvas) {
        if (canvas.width  != w) canvas.width  = w;
        if (canvas.height != h) canvas.height = h;
        if (typeof canvas.style != 'undefined') {
          canvas.style.removeProperty( "width");
          canvas.style.removeProperty("height");
        }
      } else {
        if (canvas.width  != wNative) canvas.width  = wNative;
        if (canvas.height != hNative) canvas.height = hNative;
        if (typeof canvas.style != 'undefined') {
          if (w != wNative || h != hNative) {
            canvas.style.setProperty( "width", w + "px", "important");
            canvas.style.setProperty("height", h + "px", "important");
          } else {
            canvas.style.removeProperty( "width");
            canvas.style.removeProperty("height");
          }
        }
      }
    }
  },

  emscripten_async_wget: function(url, file, onload, onerror) {
    var _url = Pointer_stringify(url);
    var _file = Pointer_stringify(file);
    function doCallback(callback) {
      if (callback) {
        var stack = Runtime.stackSave();
        Runtime.dynCall('vi', callback, [allocate(intArrayFromString(_file), 'i8', ALLOC_STACK)]);
        Runtime.stackRestore(stack);
      }
    }
    FS.createPreloadedFile(
      PATH.dirname(_file),
      PATH.basename(_file),
      _url, true, true,
      function() {
        doCallback(onload);
      },
      function() {
        doCallback(onerror);
      }
    );
  },

  emscripten_async_wget_data: function(url, arg, onload, onerror) {
    Browser.asyncLoad(Pointer_stringify(url), function(byteArray) {
      var buffer = _malloc(byteArray.length);
      HEAPU8.set(byteArray, buffer);
      Runtime.dynCall('viii', onload, [arg, buffer, byteArray.length]);
      _free(buffer);
    }, function() {
      if (onerror) Runtime.dynCall('vi', onerror, [arg]);
    }, true /* no need for run dependency, this is async but will not do any prepare etc. step */ );
  },

  emscripten_async_wget2: function(url, file, request, param, arg, onload, onerror, onprogress) {
    var _url = Pointer_stringify(url);
    var _file = Pointer_stringify(file);
    var _request = Pointer_stringify(request);
    var _param = Pointer_stringify(param);
    var index = _file.lastIndexOf('/');

    var http = new XMLHttpRequest();
    http.open(_request, _url, true);
    http.responseType = 'arraybuffer';

    // LOAD
    http.onload = function http_onload(e) {
      if (http.status == 200) {
        FS.createDataFile( _file.substr(0, index), _file.substr(index + 1), new Uint8Array(http.response), true, true);
        if (onload) {
          var stack = Runtime.stackSave();
          Runtime.dynCall('vii', onload, [arg, allocate(intArrayFromString(_file), 'i8', ALLOC_STACK)]);
          Runtime.stackRestore(stack);
        }
      } else {
        if (onerror) Runtime.dynCall('vii', onerror, [arg, http.status]);
      }
    };

    // ERROR
    http.onerror = function http_onerror(e) {
      if (onerror) Runtime.dynCall('vii', onerror, [arg, http.status]);
    };

    // PROGRESS
    http.onprogress = function http_onprogress(e) {
      if (e.lengthComputable || (e.lengthComputable === undefined && e.total != 0)) {
        var percentComplete = (e.loaded / e.total)*100;
        if (onprogress) Runtime.dynCall('vii', onprogress, [arg, percentComplete]);
      }
    };

    // Useful because the browser can limit the number of redirection
    try {
      if (http.channel instanceof Ci.nsIHttpChannel)
      http.channel.redirectionLimit = 0;
    } catch (ex) { /* whatever */ }

    if (_request == "POST") {
      //Send the proper header information along with the request
      http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
      http.setRequestHeader("Content-length", _param.length);
      http.setRequestHeader("Connection", "close");
      http.send(_param);
    } else {
      http.send(null);
    }
  },

  emscripten_async_wget2_data: function(url, request, param, arg, free, onload, onerror, onprogress) {
    var _url = Pointer_stringify(url);
    var _request = Pointer_stringify(request);
    var _param = Pointer_stringify(param);

    var http = new XMLHttpRequest();
    http.open(_request, _url, true);
    http.responseType = 'arraybuffer';

    // LOAD
    http.onload = function http_onload(e) {
      if (http.status == 200 || _url.substr(0,4).toLowerCase() != "http") {
        var byteArray = new Uint8Array(http.response);
        var buffer = _malloc(byteArray.length);
        HEAPU8.set(byteArray, buffer);
        if (onload) Runtime.dynCall('viii', onload, [arg, buffer, byteArray.length]);
        if (free) _free(buffer);
      } else {
        if (onerror) Runtime.dynCall('viii', onerror, [arg, http.status, http.statusText]);
      }
    };

    // ERROR
    http.onerror = function http_onerror(e) {
      if (onerror) Runtime.dynCall('viii', onerror, [arg, http.status, http.statusText]);
    };

    // PROGRESS
    http.onprogress = function http_onprogress(e) {
      if (onprogress) Runtime.dynCall('viii', onprogress, [arg, e.loaded, e.lengthComputable || e.lengthComputable === undefined ? e.total : 0]);
    };

    // Useful because the browser can limit the number of redirection
    try {
      if (http.channel instanceof Ci.nsIHttpChannel)
      http.channel.redirectionLimit = 0;
    } catch (ex) { /* whatever */ }

    if (_request == "POST") {
      //Send the proper header information along with the request
      http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
      http.setRequestHeader("Content-length", _param.length);
      http.setRequestHeader("Connection", "close");
      http.send(_param);
    } else {
      http.send(null);
    }
  },

  emscripten_async_prepare: function(file, onload, onerror) {
    Module['noExitRuntime'] = true;

    var _file = Pointer_stringify(file);
    var data = FS.analyzePath(_file);
    if (!data.exists) return -1;
    FS.createPreloadedFile(
      PATH.dirname(_file),
      PATH.basename(_file),
      new Uint8Array(data.object.contents), true, true,
      function() {
        if (onload) Runtime.dynCall('vi', onload, [file]);
      },
      function() {
        if (onerror) Runtime.dynCall('vi', onerror, [file]);
      },
      true // don'tCreateFile - it's already there
    );
    return 0;
  },

  emscripten_async_prepare_data: function(data, size, suffix, arg, onload, onerror) {
    Module['noExitRuntime'] = true;

    var _suffix = Pointer_stringify(suffix);
    if (!Browser.asyncPrepareDataCounter) Browser.asyncPrepareDataCounter = 0;
    var name = 'prepare_data_' + (Browser.asyncPrepareDataCounter++) + '.' + _suffix;
    var cname = _malloc(name.length+1);
    writeStringToMemory(name, cname);
    FS.createPreloadedFile(
      '/',
      name,
      {{{ makeHEAPView('U8', 'data', 'data + size') }}},
      true, true,
      function() {
        if (onload) Runtime.dynCall('vii', onload, [arg, cname]);
      },
      function() {
        if (onerror) Runtime.dynCall('vi', onerror, [arg]);
      },
      true // don'tCreateFile - it's already there
    );
    return 0;
  },

  emscripten_async_run_script__deps: ['emscripten_run_script'],
  emscripten_async_run_script: function(script, millis) {
    Module['noExitRuntime'] = true;

    // TODO: cache these to avoid generating garbage
    Browser.safeSetTimeout(function() {
      _emscripten_run_script(script);
    }, millis);
  },

  emscripten_async_load_script: function(url, onload, onerror) {
    Module['noExitRuntime'] = true;

    onload = Runtime.getFuncWrapper(onload, 'v');

    assert(runDependencies === 0, 'async_load_script must be run when no other dependencies are active');
    var script = document.createElement('script');
    script.onload = function script_onload() {
      if (runDependencies > 0) {
        dependenciesFulfilled = onload;
      } else {
        onload();
      }
    };
    script.onerror = onerror;
    script.src = Pointer_stringify(url);
    document.body.appendChild(script);
  },

  emscripten_set_main_loop: function(func, fps, simulateInfiniteLoop, arg) {
    Module['noExitRuntime'] = true;

    assert(!Browser.mainLoop.scheduler, 'there can only be one main loop function at once: call emscripten_cancel_main_loop to cancel the previous one, if you want to');

    Browser.mainLoop.runner = function Browser_mainLoop_runner() {
      if (ABORT) return;
      if (Browser.mainLoop.queue.length > 0) {
        var start = Date.now();
        var blocker = Browser.mainLoop.queue.shift();
        blocker.func(blocker.arg);
        if (Browser.mainLoop.remainingBlockers) {
          var remaining = Browser.mainLoop.remainingBlockers;
          var next = remaining%1 == 0 ? remaining-1 : Math.floor(remaining);
          if (blocker.counted) {
            Browser.mainLoop.remainingBlockers = next;
          } else {
            // not counted, but move the progress along a tiny bit
            next = next + 0.5; // do not steal all the next one's progress
            Browser.mainLoop.remainingBlockers = (8*remaining + next)/9;
          }
        }
        console.log('main loop blocker "' + blocker.name + '" took ' + (Date.now() - start) + ' ms'); //, left: ' + Browser.mainLoop.remainingBlockers);
        Browser.mainLoop.updateStatus();
        setTimeout(Browser.mainLoop.runner, 0);
        return;
      }
      if (Browser.mainLoop.shouldPause) {
        // catch pauses from non-main loop sources
        Browser.mainLoop.paused = true;
        Browser.mainLoop.shouldPause = false;
        return;
      }

      // Signal GL rendering layer that processing of a new frame is about to start. This helps it optimize
      // VBO double-buffering and reduce GPU stalls.
#if FULL_ES2
      GL.newRenderingFrameStarted();
#endif
#if LEGACY_GL_EMULATION
      GL.newRenderingFrameStarted();
#endif

      if (Browser.mainLoop.method === 'timeout' && Module.ctx) {
        Module.printErr('Looks like you are rendering without using requestAnimationFrame for the main loop. You should use 0 for the frame rate in emscripten_set_main_loop in order to use requestAnimationFrame, as that can greatly improve your frame rates!');
        Browser.mainLoop.method = ''; // just warn once per call to set main loop
      }

      Browser.mainLoop.runIter(function() {
        if (typeof arg !== 'undefined') {
          Runtime.dynCall('vi', func, [arg]);
        } else {
          Runtime.dynCall('v', func);
        }
      });

      if (Browser.mainLoop.shouldPause) {
        // catch pauses from the main loop itself
        Browser.mainLoop.paused = true;
        Browser.mainLoop.shouldPause = false;
        return;
      }
      Browser.mainLoop.scheduler();
    }
    if (fps && fps > 0) {
      Browser.mainLoop.scheduler = function Browser_mainLoop_scheduler() {
        setTimeout(Browser.mainLoop.runner, 1000/fps); // doing this each time means that on exception, we stop
      };
      Browser.mainLoop.method = 'timeout';
    } else {
      Browser.mainLoop.scheduler = function Browser_mainLoop_scheduler() {
        Browser.requestAnimationFrame(Browser.mainLoop.runner);
      };
      Browser.mainLoop.method = 'rAF';
    }
    Browser.mainLoop.scheduler();

    if (simulateInfiniteLoop) {
      throw 'SimulateInfiniteLoop';
    }
  },

  emscripten_set_main_loop_arg__deps: ['emscripten_set_main_loop'],
  emscripten_set_main_loop_arg: function(func, arg, fps, simulateInfiniteLoop) {
    _emscripten_set_main_loop(func, fps, simulateInfiniteLoop, arg);
  },

  emscripten_cancel_main_loop: function() {
    Browser.mainLoop.scheduler = null;
    Browser.mainLoop.shouldPause = true;
  },

  emscripten_pause_main_loop: function() {
    Browser.mainLoop.pause();
  },

  emscripten_resume_main_loop: function() {
    Browser.mainLoop.resume();
  },

  _emscripten_push_main_loop_blocker: function(func, arg, name) {
    Browser.mainLoop.queue.push({ func: function() {
      Runtime.dynCall('vi', func, [arg]);
    }, name: Pointer_stringify(name), counted: true });
    Browser.mainLoop.updateStatus();
  },

  _emscripten_push_uncounted_main_loop_blocker: function(func, arg, name) {
    Browser.mainLoop.queue.push({ func: function() {
      Runtime.dynCall('vi', func, [arg]);
    }, name: Pointer_stringify(name), counted: false });
    Browser.mainLoop.updateStatus();
  },

  emscripten_set_main_loop_expected_blockers: function(num) {
    Browser.mainLoop.expectedBlockers = num;
    Browser.mainLoop.remainingBlockers = num;
    Browser.mainLoop.updateStatus();
  },

  emscripten_async_call: function(func, arg, millis) {
    Module['noExitRuntime'] = true;

    function wrapper() {
      Runtime.getFuncWrapper(func, 'vi')(arg);
    }

    if (millis >= 0) {
      Browser.safeSetTimeout(wrapper, millis);
    } else {
      Browser.safeRequestAnimationFrame(wrapper);
    }
  },

  emscripten_exit_with_live_runtime: function() {
    Module['noExitRuntime'] = true;
    throw 'SimulateInfiniteLoop';
  },

  emscripten_hide_mouse: function() {
    var styleSheet = document.styleSheets[0];
    var rules = styleSheet.cssRules;
    for (var i = 0; i < rules.length; i++) {
      if (rules[i].cssText.substr(0, 6) == 'canvas') {
        styleSheet.deleteRule(i);
        i--;
      }
    }
    styleSheet.insertRule('canvas.emscripten { border: 1px solid black; cursor: none; }', 0);
  },

  emscripten_set_canvas_size: function(width, height) {
    Browser.setCanvasSize(width, height);
  },
  
  emscripten_get_canvas_size: function(width, height, isFullscreen) {
    var canvas = Module['canvas'];
    {{{ makeSetValue('width', '0', 'canvas.width', 'i32') }}};
    {{{ makeSetValue('height', '0', 'canvas.height', 'i32') }}};
    {{{ makeSetValue('isFullscreen', '0', 'Browser.isFullScreen ? 1 : 0', 'i32') }}};
  },

  emscripten_create_worker: function(url) {
    url = Pointer_stringify(url);
    var id = Browser.workers.length;
    var info = {
      worker: new Worker(url),
      callbacks: [],
      awaited: 0,
      buffer: 0,
      bufferSize: 0
    };
    info.worker.onmessage = function info_worker_onmessage(msg) {
      var info = Browser.workers[id];
      if (!info) return; // worker was destroyed meanwhile
      var callbackId = msg.data['callbackId'];
      var callbackInfo = info.callbacks[callbackId];
      if (!callbackInfo) return; // no callback or callback removed meanwhile
      // Don't trash our callback state if we expect additional calls.
      if (msg.data['finalResponse']) {
        info.awaited--;
        info.callbacks[callbackId] = null; // TODO: reuse callbackIds, compress this
      }
      var data = msg.data['data'];
      if (data) {
        if (!data.byteLength) data = new Uint8Array(data);
        if (!info.buffer || info.bufferSize < data.length) {
          if (info.buffer) _free(info.buffer);
          info.bufferSize = data.length;
          info.buffer = _malloc(data.length);
        }
        HEAPU8.set(data, info.buffer);
        callbackInfo.func(info.buffer, data.length, callbackInfo.arg);
      } else {
        callbackInfo.func(0, 0, callbackInfo.arg);
      }
    };
    Browser.workers.push(info);
    return id;
  },

  emscripten_destroy_worker: function(id) {
    var info = Browser.workers[id];
    info.worker.terminate();
    if (info.buffer) _free(info.buffer);
    Browser.workers[id] = null;
  },

  emscripten_call_worker: function(id, funcName, data, size, callback, arg) {
    Module['noExitRuntime'] = true; // should we only do this if there is a callback?

    funcName = Pointer_stringify(funcName);
    var info = Browser.workers[id];
    var callbackId = -1;
    if (callback) {
      callbackId = info.callbacks.length;
      info.callbacks.push({
        func: Runtime.getFuncWrapper(callback, 'viii'),
        arg: arg
      });
      info.awaited++;
    }
    info.worker.postMessage({
      'funcName': funcName,
      'callbackId': callbackId,
      'data': data ? new Uint8Array({{{ makeHEAPView('U8', 'data', 'data + size') }}}) : 0 // XXX copy to a new typed array as a workaround for chrome bug 169705
    });
  },

  emscripten_worker_respond_provisionally: function(data, size) {
    if (!inWorkerCall) throw 'not in worker call!';
    if (workerResponded) throw 'already responded with final response!';
    postMessage({
      'callbackId': workerCallbackId,
      'finalResponse': false,
      'data': data ? new Uint8Array({{{ makeHEAPView('U8', 'data', 'data + size') }}}) : 0 // XXX copy to a new typed array as a workaround for chrome bug 169705
    });
  },

  emscripten_worker_respond: function(data, size) {
    if (!inWorkerCall) throw 'not in worker call!';
    if (workerResponded) throw 'already responded with final response!';
    workerResponded = true;
    postMessage({
      'callbackId': workerCallbackId,
      'finalResponse': true,
      'data': data ? new Uint8Array({{{ makeHEAPView('U8', 'data', 'data + size') }}}) : 0 // XXX copy to a new typed array as a workaround for chrome bug 169705
    });
  },

  emscripten_get_worker_queue_size: function(id) {
    var info = Browser.workers[id];
    if (!info) return -1;
    return info.awaited;
  },

  emscripten_get_preloaded_image_data: function(path, w, h) {
    if (typeof path === "number") {
      path = Pointer_stringify(path);
    }

    path = PATH.resolve(path);

    var canvas = Module["preloadedImages"][path];
    if (canvas) {
      var ctx = canvas.getContext("2d");
      var image = ctx.getImageData(0, 0, canvas.width, canvas.height);
      var buf = _malloc(canvas.width * canvas.height * 4);

      HEAPU8.set(image.data, buf);

      {{{ makeSetValue('w', '0', 'canvas.width', 'i32') }}};
      {{{ makeSetValue('h', '0', 'canvas.height', 'i32') }}};
      return buf;
    }

    return 0;
  },

  emscripten_get_preloaded_image_data_from_FILE__deps: ['emscripten_get_preloaded_image_data'],
  emscripten_get_preloaded_image_data_from_FILE: function(file, w, h) {
    var stream = FS.getStreamFromPtr(file);
    if (stream) {
      return _emscripten_get_preloaded_image_data(stream.path, w, h);
    }

    return 0;
  }
});

/* Useful stuff for browser debugging

function slowLog(label, text) {
  if (!slowLog.labels) slowLog.labels = {};
  if (!slowLog.labels[label]) slowLog.labels[label] = 0;
  var now = Date.now();
  if (now - slowLog.labels[label] > 1000) {
    Module.print(label + ': ' + text);
    slowLog.labels[label] = now;
  }
}

*/