(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.WebVRPolyfill = f()}})(function(){var define,module,exports;return (function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(_dereq_,module,exports){
'use strict';

var has = Object.prototype.hasOwnProperty
  , prefix = '~';

/**
 * Constructor to create a storage for our `EE` objects.
 * An `Events` instance is a plain object whose properties are event names.
 *
 * @constructor
 * @api private
 */
function Events() {}

//
// We try to not inherit from `Object.prototype`. In some engines creating an
// instance in this way is faster than calling `Object.create(null)` directly.
// If `Object.create(null)` is not supported we prefix the event names with a
// character to make sure that the built-in object properties are not
// overridden or used as an attack vector.
//
if (Object.create) {
  Events.prototype = Object.create(null);

  //
  // This hack is needed because the `__proto__` property is still inherited in
  // some old browsers like Android 4, iPhone 5.1, Opera 11 and Safari 5.
  //
  if (!new Events().__proto__) prefix = false;
}

/**
 * Representation of a single event listener.
 *
 * @param {Function} fn The listener function.
 * @param {Mixed} context The context to invoke the listener with.
 * @param {Boolean} [once=false] Specify if the listener is a one-time listener.
 * @constructor
 * @api private
 */
function EE(fn, context, once) {
  this.fn = fn;
  this.context = context;
  this.once = once || false;
}

/**
 * Minimal `EventEmitter` interface that is molded against the Node.js
 * `EventEmitter` interface.
 *
 * @constructor
 * @api public
 */
function EventEmitter() {
  this._events = new Events();
  this._eventsCount = 0;
}

/**
 * Return an array listing the events for which the emitter has registered
 * listeners.
 *
 * @returns {Array}
 * @api public
 */
EventEmitter.prototype.eventNames = function eventNames() {
  var names = []
    , events
    , name;

  if (this._eventsCount === 0) return names;

  for (name in (events = this._events)) {
    if (has.call(events, name)) names.push(prefix ? name.slice(1) : name);
  }

  if (Object.getOwnPropertySymbols) {
    return names.concat(Object.getOwnPropertySymbols(events));
  }

  return names;
};

/**
 * Return the listeners registered for a given event.
 *
 * @param {String|Symbol} event The event name.
 * @param {Boolean} exists Only check if there are listeners.
 * @returns {Array|Boolean}
 * @api public
 */
EventEmitter.prototype.listeners = function listeners(event, exists) {
  var evt = prefix ? prefix + event : event
    , available = this._events[evt];

  if (exists) return !!available;
  if (!available) return [];
  if (available.fn) return [available.fn];

  for (var i = 0, l = available.length, ee = new Array(l); i < l; i++) {
    ee[i] = available[i].fn;
  }

  return ee;
};

/**
 * Calls each of the listeners registered for a given event.
 *
 * @param {String|Symbol} event The event name.
 * @returns {Boolean} `true` if the event had listeners, else `false`.
 * @api public
 */
EventEmitter.prototype.emit = function emit(event, a1, a2, a3, a4, a5) {
  var evt = prefix ? prefix + event : event;

  if (!this._events[evt]) return false;

  var listeners = this._events[evt]
    , len = arguments.length
    , args
    , i;

  if (listeners.fn) {
    if (listeners.once) this.removeListener(event, listeners.fn, undefined, true);

    switch (len) {
      case 1: return listeners.fn.call(listeners.context), true;
      case 2: return listeners.fn.call(listeners.context, a1), true;
      case 3: return listeners.fn.call(listeners.context, a1, a2), true;
      case 4: return listeners.fn.call(listeners.context, a1, a2, a3), true;
      case 5: return listeners.fn.call(listeners.context, a1, a2, a3, a4), true;
      case 6: return listeners.fn.call(listeners.context, a1, a2, a3, a4, a5), true;
    }

    for (i = 1, args = new Array(len -1); i < len; i++) {
      args[i - 1] = arguments[i];
    }

    listeners.fn.apply(listeners.context, args);
  } else {
    var length = listeners.length
      , j;

    for (i = 0; i < length; i++) {
      if (listeners[i].once) this.removeListener(event, listeners[i].fn, undefined, true);

      switch (len) {
        case 1: listeners[i].fn.call(listeners[i].context); break;
        case 2: listeners[i].fn.call(listeners[i].context, a1); break;
        case 3: listeners[i].fn.call(listeners[i].context, a1, a2); break;
        case 4: listeners[i].fn.call(listeners[i].context, a1, a2, a3); break;
        default:
          if (!args) for (j = 1, args = new Array(len -1); j < len; j++) {
            args[j - 1] = arguments[j];
          }

          listeners[i].fn.apply(listeners[i].context, args);
      }
    }
  }

  return true;
};

/**
 * Add a listener for a given event.
 *
 * @param {String|Symbol} event The event name.
 * @param {Function} fn The listener function.
 * @param {Mixed} [context=this] The context to invoke the listener with.
 * @returns {EventEmitter} `this`.
 * @api public
 */
EventEmitter.prototype.on = function on(event, fn, context) {
  var listener = new EE(fn, context || this)
    , evt = prefix ? prefix + event : event;

  if (!this._events[evt]) this._events[evt] = listener, this._eventsCount++;
  else if (!this._events[evt].fn) this._events[evt].push(listener);
  else this._events[evt] = [this._events[evt], listener];

  return this;
};

/**
 * Add a one-time listener for a given event.
 *
 * @param {String|Symbol} event The event name.
 * @param {Function} fn The listener function.
 * @param {Mixed} [context=this] The context to invoke the listener with.
 * @returns {EventEmitter} `this`.
 * @api public
 */
EventEmitter.prototype.once = function once(event, fn, context) {
  var listener = new EE(fn, context || this, true)
    , evt = prefix ? prefix + event : event;

  if (!this._events[evt]) this._events[evt] = listener, this._eventsCount++;
  else if (!this._events[evt].fn) this._events[evt].push(listener);
  else this._events[evt] = [this._events[evt], listener];

  return this;
};

/**
 * Remove the listeners of a given event.
 *
 * @param {String|Symbol} event The event name.
 * @param {Function} fn Only remove the listeners that match this function.
 * @param {Mixed} context Only remove the listeners that have this context.
 * @param {Boolean} once Only remove one-time listeners.
 * @returns {EventEmitter} `this`.
 * @api public
 */
EventEmitter.prototype.removeListener = function removeListener(event, fn, context, once) {
  var evt = prefix ? prefix + event : event;

  if (!this._events[evt]) return this;
  if (!fn) {
    if (--this._eventsCount === 0) this._events = new Events();
    else delete this._events[evt];
    return this;
  }

  var listeners = this._events[evt];

  if (listeners.fn) {
    if (
         listeners.fn === fn
      && (!once || listeners.once)
      && (!context || listeners.context === context)
    ) {
      if (--this._eventsCount === 0) this._events = new Events();
      else delete this._events[evt];
    }
  } else {
    for (var i = 0, events = [], length = listeners.length; i < length; i++) {
      if (
           listeners[i].fn !== fn
        || (once && !listeners[i].once)
        || (context && listeners[i].context !== context)
      ) {
        events.push(listeners[i]);
      }
    }

    //
    // Reset the array, or remove it completely if we have no more listeners.
    //
    if (events.length) this._events[evt] = events.length === 1 ? events[0] : events;
    else if (--this._eventsCount === 0) this._events = new Events();
    else delete this._events[evt];
  }

  return this;
};

/**
 * Remove all listeners, or those of the specified event.
 *
 * @param {String|Symbol} [event] The event name.
 * @returns {EventEmitter} `this`.
 * @api public
 */
EventEmitter.prototype.removeAllListeners = function removeAllListeners(event) {
  var evt;

  if (event) {
    evt = prefix ? prefix + event : event;
    if (this._events[evt]) {
      if (--this._eventsCount === 0) this._events = new Events();
      else delete this._events[evt];
    }
  } else {
    this._events = new Events();
    this._eventsCount = 0;
  }

  return this;
};

//
// Alias methods names because people roll like that.
//
EventEmitter.prototype.off = EventEmitter.prototype.removeListener;
EventEmitter.prototype.addListener = EventEmitter.prototype.on;

//
// This function doesn't apply anymore.
//
EventEmitter.prototype.setMaxListeners = function setMaxListeners() {
  return this;
};

//
// Expose the prefix.
//
EventEmitter.prefixed = prefix;

//
// Allow `EventEmitter` to be imported as module namespace.
//
EventEmitter.EventEmitter = EventEmitter;

//
// Expose the module.
//
if ('undefined' !== typeof module) {
  module.exports = EventEmitter;
}

},{}],2:[function(_dereq_,module,exports){
'use strict';
/* eslint-disable no-unused-vars */
var hasOwnProperty = Object.prototype.hasOwnProperty;
var propIsEnumerable = Object.prototype.propertyIsEnumerable;

function toObject(val) {
	if (val === null || val === undefined) {
		throw new TypeError('Object.assign cannot be called with null or undefined');
	}

	return Object(val);
}

function shouldUseNative() {
	try {
		if (!Object.assign) {
			return false;
		}

		// Detect buggy property enumeration order in older V8 versions.

		// https://bugs.chromium.org/p/v8/issues/detail?id=4118
		var test1 = new String('abc');  // eslint-disable-line
		test1[5] = 'de';
		if (Object.getOwnPropertyNames(test1)[0] === '5') {
			return false;
		}

		// https://bugs.chromium.org/p/v8/issues/detail?id=3056
		var test2 = {};
		for (var i = 0; i < 10; i++) {
			test2['_' + String.fromCharCode(i)] = i;
		}
		var order2 = Object.getOwnPropertyNames(test2).map(function (n) {
			return test2[n];
		});
		if (order2.join('') !== '0123456789') {
			return false;
		}

		// https://bugs.chromium.org/p/v8/issues/detail?id=3056
		var test3 = {};
		'abcdefghijklmnopqrst'.split('').forEach(function (letter) {
			test3[letter] = letter;
		});
		if (Object.keys(Object.assign({}, test3)).join('') !==
				'abcdefghijklmnopqrst') {
			return false;
		}

		return true;
	} catch (e) {
		// We don't expect any of the above to throw, but better to be safe.
		return false;
	}
}

module.exports = shouldUseNative() ? Object.assign : function (target, source) {
	var from;
	var to = toObject(target);
	var symbols;

	for (var s = 1; s < arguments.length; s++) {
		from = Object(arguments[s]);

		for (var key in from) {
			if (hasOwnProperty.call(from, key)) {
				to[key] = from[key];
			}
		}

		if (Object.getOwnPropertySymbols) {
			symbols = Object.getOwnPropertySymbols(from);
			for (var i = 0; i < symbols.length; i++) {
				if (propIsEnumerable.call(from, symbols[i])) {
					to[symbols[i]] = from[symbols[i]];
				}
			}
		}
	}

	return to;
};

},{}],3:[function(_dereq_,module,exports){
/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var Util = _dereq_('./util.js');
var WakeLock = _dereq_('./wakelock.js');

// Start at a higher number to reduce chance of conflict.
var nextDisplayId = 1000;
var hasShowDeprecationWarning = false;

var defaultLeftBounds = [0, 0, 0.5, 1];
var defaultRightBounds = [0.5, 0, 0.5, 1];

/**
 * The base class for all VR frame data.
 */

function VRFrameData() {
  this.leftProjectionMatrix = new Float32Array(16);
  this.leftViewMatrix = new Float32Array(16);
  this.rightProjectionMatrix = new Float32Array(16);
  this.rightViewMatrix = new Float32Array(16);
  this.pose = null;
};

/**
 * The base class for all VR displays.
 */
function VRDisplay() {
  this.isPolyfilled = true;
  this.displayId = nextDisplayId++;
  this.displayName = 'webvr-polyfill displayName';

  this.depthNear = 0.01;
  this.depthFar = 10000.0;

  this.isConnected = true;
  this.isPresenting = false;
  this.capabilities = {
    hasPosition: false,
    hasOrientation: false,
    hasExternalDisplay: false,
    canPresent: false,
    maxLayers: 1
  };
  this.stageParameters = null;

  // "Private" members.
  this.waitingForPresent_ = false;
  this.layer_ = null;

  this.fullscreenElement_ = null;
  this.fullscreenWrapper_ = null;
  this.fullscreenElementCachedStyle_ = null;

  this.fullscreenEventTarget_ = null;
  this.fullscreenChangeHandler_ = null;
  this.fullscreenErrorHandler_ = null;

  this.wakelock_ = new WakeLock();
}

VRDisplay.prototype.getFrameData = function(frameData) {
  // TODO: Technically this should retain it's value for the duration of a frame
  // but I doubt that's practical to do in javascript.
  return Util.frameDataFromPose(frameData, this.getPose(), this);
};

VRDisplay.prototype.getPose = function() {
  // TODO: Technically this should retain it's value for the duration of a frame
  // but I doubt that's practical to do in javascript.
  return this.getImmediatePose();
};

VRDisplay.prototype.requestAnimationFrame = function(callback) {
  return window.requestAnimationFrame(callback);
};

VRDisplay.prototype.cancelAnimationFrame = function(id) {
  return window.cancelAnimationFrame(id);
};

VRDisplay.prototype.wrapForFullscreen = function(element) {
  // Don't wrap in iOS.
  if (Util.isIOS()) {
    return element;
  }
  if (!this.fullscreenWrapper_) {
    this.fullscreenWrapper_ = document.createElement('div');
    var cssProperties = [
      'height: ' + Math.min(screen.height, screen.width) + 'px !important',
      'top: 0 !important',
      'left: 0 !important',
      'right: 0 !important',
      'border: 0',
      'margin: 0',
      'padding: 0',
      'z-index: 999999 !important',
      'position: fixed',
    ];
    this.fullscreenWrapper_.setAttribute('style', cssProperties.join('; ') + ';');
    this.fullscreenWrapper_.classList.add('webvr-polyfill-fullscreen-wrapper');
  }

  if (this.fullscreenElement_ == element) {
    return this.fullscreenWrapper_;
  }

  // Remove any previously applied wrappers
  this.removeFullscreenWrapper();

  this.fullscreenElement_ = element;
  var parent = this.fullscreenElement_.parentElement;
  parent.insertBefore(this.fullscreenWrapper_, this.fullscreenElement_);
  parent.removeChild(this.fullscreenElement_);
  this.fullscreenWrapper_.insertBefore(this.fullscreenElement_, this.fullscreenWrapper_.firstChild);
  this.fullscreenElementCachedStyle_ = this.fullscreenElement_.getAttribute('style');

  var self = this;
  function applyFullscreenElementStyle() {
    if (!self.fullscreenElement_) {
      return;
    }

    var cssProperties = [
      'position: absolute',
      'top: 0',
      'left: 0',
      'width: ' + Math.max(screen.width, screen.height) + 'px',
      'height: ' + Math.min(screen.height, screen.width) + 'px',
      'border: 0',
      'margin: 0',
      'padding: 0',
    ];
    self.fullscreenElement_.setAttribute('style', cssProperties.join('; ') + ';');
  }

  applyFullscreenElementStyle();

  return this.fullscreenWrapper_;
};

VRDisplay.prototype.removeFullscreenWrapper = function() {
  if (!this.fullscreenElement_) {
    return;
  }

  var element = this.fullscreenElement_;
  if (this.fullscreenElementCachedStyle_) {
    element.setAttribute('style', this.fullscreenElementCachedStyle_);
  } else {
    element.removeAttribute('style');
  }
  this.fullscreenElement_ = null;
  this.fullscreenElementCachedStyle_ = null;

  var parent = this.fullscreenWrapper_.parentElement;
  this.fullscreenWrapper_.removeChild(element);
  parent.insertBefore(element, this.fullscreenWrapper_);
  parent.removeChild(this.fullscreenWrapper_);

  return element;
};

VRDisplay.prototype.requestPresent = function(layers) {
  var wasPresenting = this.isPresenting;
  var self = this;

  if (!(layers instanceof Array)) {
    if (!hasShowDeprecationWarning) {
      console.warn("Using a deprecated form of requestPresent. Should pass in an array of VRLayers.");
      hasShowDeprecationWarning = true;
    }
    layers = [layers];
  }

  return new Promise(function(resolve, reject) {
    if (!self.capabilities.canPresent) {
      reject(new Error('VRDisplay is not capable of presenting.'));
      return;
    }

    if (layers.length == 0 || layers.length > self.capabilities.maxLayers) {
      reject(new Error('Invalid number of layers.'));
      return;
    }

    var incomingLayer = layers[0];
    if (!incomingLayer.source) {
      /*
      todo: figure out the correct behavior if the source is not provided.
      see https://github.com/w3c/webvr/issues/58
      */
      resolve();
      return;
    }

    var leftBounds = incomingLayer.leftBounds || defaultLeftBounds;
    var rightBounds = incomingLayer.rightBounds || defaultRightBounds;
    if (wasPresenting) {
      // Already presenting, just changing configuration
      var layer = self.layer_;
      if (layer.source !== incomingLayer.source) {
        layer.source = incomingLayer.source;
      }

      for (var i = 0; i < 4; i++) {
        if (layer.leftBounds[i] !== leftBounds[i]) {
          layer.leftBounds[i] = leftBounds[i];
        }
        if (layer.rightBounds[i] !== rightBounds[i]) {
          layer.rightBounds[i] = rightBounds[i];
        }
      }

      resolve();
      return;
    }

    // Was not already presenting.
    self.layer_ = {
      predistorted: incomingLayer.predistorted,
      source: incomingLayer.source,
      leftBounds: leftBounds.slice(0),
      rightBounds: rightBounds.slice(0)
    };

    self.waitingForPresent_ = false;
    if (self.layer_ && self.layer_.source) {
      var fullscreenElement = self.wrapForFullscreen(self.layer_.source);

      function onFullscreenChange() {
        var actualFullscreenElement = Util.getFullscreenElement();

        self.isPresenting = (fullscreenElement === actualFullscreenElement);
        if (self.isPresenting) {
          if (screen.orientation && screen.orientation.lock) {
            screen.orientation.lock('landscape-primary').catch(function(error){
                    console.error('screen.orientation.lock() failed due to', error.message)
            });
          }
          self.waitingForPresent_ = false;
          self.beginPresent_();
          resolve();
        } else {
          if (screen.orientation && screen.orientation.unlock) {
            screen.orientation.unlock();
          }
          self.removeFullscreenWrapper();
          self.wakelock_.release();
          self.endPresent_();
          self.removeFullscreenListeners_();
        }
        self.fireVRDisplayPresentChange_();
      }
      function onFullscreenError() {
        if (!self.waitingForPresent_) {
          return;
        }

        self.removeFullscreenWrapper();
        self.removeFullscreenListeners_();

        self.wakelock_.release();
        self.waitingForPresent_ = false;
        self.isPresenting = false;

        reject(new Error('Unable to present.'));
      }

      self.addFullscreenListeners_(fullscreenElement,
          onFullscreenChange, onFullscreenError);

      if (Util.requestFullscreen(fullscreenElement)) {
        self.wakelock_.request();
        self.waitingForPresent_ = true;
      } else if (Util.isIOS()) {
        // *sigh* Just fake it.
        self.wakelock_.request();
        self.isPresenting = true;
        self.beginPresent_();
        self.fireVRDisplayPresentChange_();
        resolve();
      }
    }

    if (!self.waitingForPresent_ && !Util.isIOS()) {
      Util.exitFullscreen();
      reject(new Error('Unable to present.'));
    }
  });
};

VRDisplay.prototype.exitPresent = function() {
  var wasPresenting = this.isPresenting;
  var self = this;
  this.isPresenting = false;
  this.layer_ = null;
  this.wakelock_.release();

  return new Promise(function(resolve, reject) {
    if (wasPresenting) {
      if (!Util.exitFullscreen() && Util.isIOS()) {
        self.endPresent_();
        self.fireVRDisplayPresentChange_();
      }

      resolve();
    } else {
      reject(new Error('Was not presenting to VRDisplay.'));
    }
  });
};

VRDisplay.prototype.getLayers = function() {
  if (this.layer_) {
    return [this.layer_];
  }
  return [];
};

VRDisplay.prototype.fireVRDisplayPresentChange_ = function() {
  var event = new CustomEvent('vrdisplaypresentchange', {detail: {display: this}});
  window.dispatchEvent(event);
};

VRDisplay.prototype.addFullscreenListeners_ = function(element, changeHandler, errorHandler) {
  this.removeFullscreenListeners_();

  this.fullscreenEventTarget_ = element;
  this.fullscreenChangeHandler_ = changeHandler;
  this.fullscreenErrorHandler_ = errorHandler;

  if (changeHandler) {
    if (document.fullscreenEnabled) {
      element.addEventListener('fullscreenchange', changeHandler, false);
    } else if (document.webkitFullscreenEnabled) {
      element.addEventListener('webkitfullscreenchange', changeHandler, false);
    } else if (document.mozFullScreenEnabled) {
      document.addEventListener('mozfullscreenchange', changeHandler, false);
    } else if (document.msFullscreenEnabled) {
      element.addEventListener('msfullscreenchange', changeHandler, false);
    }
  }

  if (errorHandler) {
    if (document.fullscreenEnabled) {
      element.addEventListener('fullscreenerror', errorHandler, false);
    } else if (document.webkitFullscreenEnabled) {
      element.addEventListener('webkitfullscreenerror', errorHandler, false);
    } else if (document.mozFullScreenEnabled) {
      document.addEventListener('mozfullscreenerror', errorHandler, false);
    } else if (document.msFullscreenEnabled) {
      element.addEventListener('msfullscreenerror', errorHandler, false);
    }
  }
};

VRDisplay.prototype.removeFullscreenListeners_ = function() {
  if (!this.fullscreenEventTarget_)
    return;

  var element = this.fullscreenEventTarget_;

  if (this.fullscreenChangeHandler_) {
    var changeHandler = this.fullscreenChangeHandler_;
    element.removeEventListener('fullscreenchange', changeHandler, false);
    element.removeEventListener('webkitfullscreenchange', changeHandler, false);
    document.removeEventListener('mozfullscreenchange', changeHandler, false);
    element.removeEventListener('msfullscreenchange', changeHandler, false);
  }

  if (this.fullscreenErrorHandler_) {
    var errorHandler = this.fullscreenErrorHandler_;
    element.removeEventListener('fullscreenerror', errorHandler, false);
    element.removeEventListener('webkitfullscreenerror', errorHandler, false);
    document.removeEventListener('mozfullscreenerror', errorHandler, false);
    element.removeEventListener('msfullscreenerror', errorHandler, false);
  }

  this.fullscreenEventTarget_ = null;
  this.fullscreenChangeHandler_ = null;
  this.fullscreenErrorHandler_ = null;
};

VRDisplay.prototype.beginPresent_ = function() {
  // Override to add custom behavior when presentation begins.
};

VRDisplay.prototype.endPresent_ = function() {
  // Override to add custom behavior when presentation ends.
};

VRDisplay.prototype.submitFrame = function(pose) {
  // Override to add custom behavior for frame submission.
};

VRDisplay.prototype.getEyeParameters = function(whichEye) {
  // Override to return accurate eye parameters if canPresent is true.
  return null;
};

/*
 * Deprecated classes
 */

/**
 * The base class for all VR devices. (Deprecated)
 */
function VRDevice() {
  this.isPolyfilled = true;
  this.hardwareUnitId = 'webvr-polyfill hardwareUnitId';
  this.deviceId = 'webvr-polyfill deviceId';
  this.deviceName = 'webvr-polyfill deviceName';
}

/**
 * The base class for all VR HMD devices. (Deprecated)
 */
function HMDVRDevice() {
}
HMDVRDevice.prototype = new VRDevice();

/**
 * The base class for all VR position sensor devices. (Deprecated)
 */
function PositionSensorVRDevice() {
}
PositionSensorVRDevice.prototype = new VRDevice();

module.exports.VRFrameData = VRFrameData;
module.exports.VRDisplay = VRDisplay;
module.exports.VRDevice = VRDevice;
module.exports.HMDVRDevice = HMDVRDevice;
module.exports.PositionSensorVRDevice = PositionSensorVRDevice;

},{"./util.js":22,"./wakelock.js":24}],4:[function(_dereq_,module,exports){
/*
 * Copyright 2016 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var CardboardUI = _dereq_('./cardboard-ui.js');
var Util = _dereq_('./util.js');
var WGLUPreserveGLState = _dereq_('./deps/wglu-preserve-state.js');

var distortionVS = [
  'attribute vec2 position;',
  'attribute vec3 texCoord;',

  'varying vec2 vTexCoord;',

  'uniform vec4 viewportOffsetScale[2];',

  'void main() {',
  '  vec4 viewport = viewportOffsetScale[int(texCoord.z)];',
  '  vTexCoord = (texCoord.xy * viewport.zw) + viewport.xy;',
  '  gl_Position = vec4( position, 1.0, 1.0 );',
  '}',
].join('\n');

var distortionFS = [
  'precision mediump float;',
  'uniform sampler2D diffuse;',

  'varying vec2 vTexCoord;',

  'void main() {',
  '  gl_FragColor = texture2D(diffuse, vTexCoord);',
  '}',
].join('\n');

/**
 * A mesh-based distorter.
 */
function CardboardDistorter(gl) {
  this.gl = gl;
  this.ctxAttribs = gl.getContextAttributes();

  this.meshWidth = 20;
  this.meshHeight = 20;

  this.bufferScale = WebVRConfig.BUFFER_SCALE;

  this.bufferWidth = gl.drawingBufferWidth;
  this.bufferHeight = gl.drawingBufferHeight;

  // Patching support
  this.realBindFramebuffer = gl.bindFramebuffer;
  this.realEnable = gl.enable;
  this.realDisable = gl.disable;
  this.realColorMask = gl.colorMask;
  this.realClearColor = gl.clearColor;
  this.realViewport = gl.viewport;

  if (!Util.isIOS()) {
    this.realCanvasWidth = Object.getOwnPropertyDescriptor(gl.canvas.__proto__, 'width');
    this.realCanvasHeight = Object.getOwnPropertyDescriptor(gl.canvas.__proto__, 'height');
  }

  this.isPatched = false;

  // State tracking
  this.lastBoundFramebuffer = null;
  this.cullFace = false;
  this.depthTest = false;
  this.blend = false;
  this.scissorTest = false;
  this.stencilTest = false;
  this.viewport = [0, 0, 0, 0];
  this.colorMask = [true, true, true, true];
  this.clearColor = [0, 0, 0, 0];

  this.attribs = {
    position: 0,
    texCoord: 1
  };
  this.program = Util.linkProgram(gl, distortionVS, distortionFS, this.attribs);
  this.uniforms = Util.getProgramUniforms(gl, this.program);

  this.viewportOffsetScale = new Float32Array(8);
  this.setTextureBounds();

  this.vertexBuffer = gl.createBuffer();
  this.indexBuffer = gl.createBuffer();
  this.indexCount = 0;

  this.renderTarget = gl.createTexture();
  this.framebuffer = gl.createFramebuffer();

  this.depthStencilBuffer = null;
  this.depthBuffer = null;
  this.stencilBuffer = null;

  if (this.ctxAttribs.depth && this.ctxAttribs.stencil) {
    this.depthStencilBuffer = gl.createRenderbuffer();
  } else if (this.ctxAttribs.depth) {
    this.depthBuffer = gl.createRenderbuffer();
  } else if (this.ctxAttribs.stencil) {
    this.stencilBuffer = gl.createRenderbuffer();
  }

  this.patch();

  this.onResize();

  if (!WebVRConfig.CARDBOARD_UI_DISABLED) {
    this.cardboardUI = new CardboardUI(gl);
  }
};

/**
 * Tears down all the resources created by the distorter and removes any
 * patches.
 */
CardboardDistorter.prototype.destroy = function() {
  var gl = this.gl;

  this.unpatch();

  gl.deleteProgram(this.program);
  gl.deleteBuffer(this.vertexBuffer);
  gl.deleteBuffer(this.indexBuffer);
  gl.deleteTexture(this.renderTarget);
  gl.deleteFramebuffer(this.framebuffer);
  if (this.depthStencilBuffer) {
    gl.deleteRenderbuffer(this.depthStencilBuffer);
  }
  if (this.depthBuffer) {
    gl.deleteRenderbuffer(this.depthBuffer);
  }
  if (this.stencilBuffer) {
    gl.deleteRenderbuffer(this.stencilBuffer);
  }

  if (this.cardboardUI) {
    this.cardboardUI.destroy();
  }
};


/**
 * Resizes the backbuffer to match the canvas width and height.
 */
CardboardDistorter.prototype.onResize = function() {
  var gl = this.gl;
  var self = this;

  var glState = [
    gl.RENDERBUFFER_BINDING,
    gl.TEXTURE_BINDING_2D, gl.TEXTURE0
  ];

  WGLUPreserveGLState(gl, glState, function(gl) {
    // Bind real backbuffer and clear it once. We don't need to clear it again
    // after that because we're overwriting the same area every frame.
    self.realBindFramebuffer.call(gl, gl.FRAMEBUFFER, null);

    // Put things in a good state
    if (self.scissorTest) { self.realDisable.call(gl, gl.SCISSOR_TEST); }
    self.realColorMask.call(gl, true, true, true, true);
    self.realViewport.call(gl, 0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight);
    self.realClearColor.call(gl, 0, 0, 0, 1);

    gl.clear(gl.COLOR_BUFFER_BIT);

    // Now bind and resize the fake backbuffer
    self.realBindFramebuffer.call(gl, gl.FRAMEBUFFER, self.framebuffer);

    gl.bindTexture(gl.TEXTURE_2D, self.renderTarget);
    gl.texImage2D(gl.TEXTURE_2D, 0, self.ctxAttribs.alpha ? gl.RGBA : gl.RGB,
        self.bufferWidth, self.bufferHeight, 0,
        self.ctxAttribs.alpha ? gl.RGBA : gl.RGB, gl.UNSIGNED_BYTE, null);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
    gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, self.renderTarget, 0);

    if (self.ctxAttribs.depth && self.ctxAttribs.stencil) {
      gl.bindRenderbuffer(gl.RENDERBUFFER, self.depthStencilBuffer);
      gl.renderbufferStorage(gl.RENDERBUFFER, gl.DEPTH_STENCIL,
          self.bufferWidth, self.bufferHeight);
      gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_STENCIL_ATTACHMENT,
          gl.RENDERBUFFER, self.depthStencilBuffer);
    } else if (self.ctxAttribs.depth) {
      gl.bindRenderbuffer(gl.RENDERBUFFER, self.depthBuffer);
      gl.renderbufferStorage(gl.RENDERBUFFER, gl.DEPTH_COMPONENT16,
          self.bufferWidth, self.bufferHeight);
      gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT,
          gl.RENDERBUFFER, self.depthBuffer);
    } else if (self.ctxAttribs.stencil) {
      gl.bindRenderbuffer(gl.RENDERBUFFER, self.stencilBuffer);
      gl.renderbufferStorage(gl.RENDERBUFFER, gl.STENCIL_INDEX8,
          self.bufferWidth, self.bufferHeight);
      gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.STENCIL_ATTACHMENT,
          gl.RENDERBUFFER, self.stencilBuffer);
    }

    if (!gl.checkFramebufferStatus(gl.FRAMEBUFFER) === gl.FRAMEBUFFER_COMPLETE) {
      console.error('Framebuffer incomplete!');
    }

    self.realBindFramebuffer.call(gl, gl.FRAMEBUFFER, self.lastBoundFramebuffer);

    if (self.scissorTest) { self.realEnable.call(gl, gl.SCISSOR_TEST); }

    self.realColorMask.apply(gl, self.colorMask);
    self.realViewport.apply(gl, self.viewport);
    self.realClearColor.apply(gl, self.clearColor);
  });

  if (this.cardboardUI) {
    this.cardboardUI.onResize();
  }
};

CardboardDistorter.prototype.patch = function() {
  if (this.isPatched) {
    return;
  }

  var self = this;
  var canvas = this.gl.canvas;
  var gl = this.gl;

  if (!Util.isIOS()) {
    canvas.width = Util.getScreenWidth() * this.bufferScale;
    canvas.height = Util.getScreenHeight() * this.bufferScale;

    Object.defineProperty(canvas, 'width', {
      configurable: true,
      enumerable: true,
      get: function() {
        return self.bufferWidth;
      },
      set: function(value) {
        self.bufferWidth = value;
        self.realCanvasWidth.set.call(canvas, value);
        self.onResize();
      }
    });

    Object.defineProperty(canvas, 'height', {
      configurable: true,
      enumerable: true,
      get: function() {
        return self.bufferHeight;
      },
      set: function(value) {
        self.bufferHeight = value;
        self.realCanvasHeight.set.call(canvas, value);
        self.onResize();
      }
    });
  }

  this.lastBoundFramebuffer = gl.getParameter(gl.FRAMEBUFFER_BINDING);

  if (this.lastBoundFramebuffer == null) {
    this.lastBoundFramebuffer = this.framebuffer;
    this.gl.bindFramebuffer(gl.FRAMEBUFFER, this.framebuffer);
  }

  this.gl.bindFramebuffer = function(target, framebuffer) {
    self.lastBoundFramebuffer = framebuffer ? framebuffer : self.framebuffer;
    // Silently make calls to bind the default framebuffer bind ours instead.
    self.realBindFramebuffer.call(gl, target, self.lastBoundFramebuffer);
  };

  this.cullFace = gl.getParameter(gl.CULL_FACE);
  this.depthTest = gl.getParameter(gl.DEPTH_TEST);
  this.blend = gl.getParameter(gl.BLEND);
  this.scissorTest = gl.getParameter(gl.SCISSOR_TEST);
  this.stencilTest = gl.getParameter(gl.STENCIL_TEST);

  gl.enable = function(pname) {
    switch (pname) {
      case gl.CULL_FACE: self.cullFace = true; break;
      case gl.DEPTH_TEST: self.depthTest = true; break;
      case gl.BLEND: self.blend = true; break;
      case gl.SCISSOR_TEST: self.scissorTest = true; break;
      case gl.STENCIL_TEST: self.stencilTest = true; break;
    }
    self.realEnable.call(gl, pname);
  };

  gl.disable = function(pname) {
    switch (pname) {
      case gl.CULL_FACE: self.cullFace = false; break;
      case gl.DEPTH_TEST: self.depthTest = false; break;
      case gl.BLEND: self.blend = false; break;
      case gl.SCISSOR_TEST: self.scissorTest = false; break;
      case gl.STENCIL_TEST: self.stencilTest = false; break;
    }
    self.realDisable.call(gl, pname);
  };

  this.colorMask = gl.getParameter(gl.COLOR_WRITEMASK);
  gl.colorMask = function(r, g, b, a) {
    self.colorMask[0] = r;
    self.colorMask[1] = g;
    self.colorMask[2] = b;
    self.colorMask[3] = a;
    self.realColorMask.call(gl, r, g, b, a);
  };

  this.clearColor = gl.getParameter(gl.COLOR_CLEAR_VALUE);
  gl.clearColor = function(r, g, b, a) {
    self.clearColor[0] = r;
    self.clearColor[1] = g;
    self.clearColor[2] = b;
    self.clearColor[3] = a;
    self.realClearColor.call(gl, r, g, b, a);
  };

  this.viewport = gl.getParameter(gl.VIEWPORT);
  gl.viewport = function(x, y, w, h) {
    self.viewport[0] = x;
    self.viewport[1] = y;
    self.viewport[2] = w;
    self.viewport[3] = h;
    self.realViewport.call(gl, x, y, w, h);
  };

  this.isPatched = true;
  Util.safariCssSizeWorkaround(canvas);
};

CardboardDistorter.prototype.unpatch = function() {
  if (!this.isPatched) {
    return;
  }

  var gl = this.gl;
  var canvas = this.gl.canvas;

  if (!Util.isIOS()) {
    Object.defineProperty(canvas, 'width', this.realCanvasWidth);
    Object.defineProperty(canvas, 'height', this.realCanvasHeight);
  }
  canvas.width = this.bufferWidth;
  canvas.height = this.bufferHeight;

  gl.bindFramebuffer = this.realBindFramebuffer;
  gl.enable = this.realEnable;
  gl.disable = this.realDisable;
  gl.colorMask = this.realColorMask;
  gl.clearColor = this.realClearColor;
  gl.viewport = this.realViewport;

  // Check to see if our fake backbuffer is bound and bind the real backbuffer
  // if that's the case.
  if (this.lastBoundFramebuffer == this.framebuffer) {
    gl.bindFramebuffer(gl.FRAMEBUFFER, null);
  }

  this.isPatched = false;

  setTimeout(function() {
    Util.safariCssSizeWorkaround(canvas);
  }, 1);
};

CardboardDistorter.prototype.setTextureBounds = function(leftBounds, rightBounds) {
  if (!leftBounds) {
    leftBounds = [0, 0, 0.5, 1];
  }

  if (!rightBounds) {
    rightBounds = [0.5, 0, 0.5, 1];
  }

  // Left eye
  this.viewportOffsetScale[0] = leftBounds[0]; // X
  this.viewportOffsetScale[1] = leftBounds[1]; // Y
  this.viewportOffsetScale[2] = leftBounds[2]; // Width
  this.viewportOffsetScale[3] = leftBounds[3]; // Height

  // Right eye
  this.viewportOffsetScale[4] = rightBounds[0]; // X
  this.viewportOffsetScale[5] = rightBounds[1]; // Y
  this.viewportOffsetScale[6] = rightBounds[2]; // Width
  this.viewportOffsetScale[7] = rightBounds[3]; // Height
};

/**
 * Performs distortion pass on the injected backbuffer, rendering it to the real
 * backbuffer.
 */
CardboardDistorter.prototype.submitFrame = function() {
  var gl = this.gl;
  var self = this;

  var glState = [];

  if (!WebVRConfig.DIRTY_SUBMIT_FRAME_BINDINGS) {
    glState.push(
      gl.CURRENT_PROGRAM,
      gl.ARRAY_BUFFER_BINDING,
      gl.ELEMENT_ARRAY_BUFFER_BINDING,
      gl.TEXTURE_BINDING_2D, gl.TEXTURE0
    );
  }

  WGLUPreserveGLState(gl, glState, function(gl) {
    // Bind the real default framebuffer
    self.realBindFramebuffer.call(gl, gl.FRAMEBUFFER, null);

    // Make sure the GL state is in a good place
    if (self.cullFace) { self.realDisable.call(gl, gl.CULL_FACE); }
    if (self.depthTest) { self.realDisable.call(gl, gl.DEPTH_TEST); }
    if (self.blend) { self.realDisable.call(gl, gl.BLEND); }
    if (self.scissorTest) { self.realDisable.call(gl, gl.SCISSOR_TEST); }
    if (self.stencilTest) { self.realDisable.call(gl, gl.STENCIL_TEST); }
    self.realColorMask.call(gl, true, true, true, true);
    self.realViewport.call(gl, 0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight);

    // If the backbuffer has an alpha channel clear every frame so the page
    // doesn't show through.
    if (self.ctxAttribs.alpha || Util.isIOS()) {
      self.realClearColor.call(gl, 0, 0, 0, 1);
      gl.clear(gl.COLOR_BUFFER_BIT);
    }

    // Bind distortion program and mesh
    gl.useProgram(self.program);

    gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, self.indexBuffer);

    gl.bindBuffer(gl.ARRAY_BUFFER, self.vertexBuffer);
    gl.enableVertexAttribArray(self.attribs.position);
    gl.enableVertexAttribArray(self.attribs.texCoord);
    gl.vertexAttribPointer(self.attribs.position, 2, gl.FLOAT, false, 20, 0);
    gl.vertexAttribPointer(self.attribs.texCoord, 3, gl.FLOAT, false, 20, 8);

    gl.activeTexture(gl.TEXTURE0);
    gl.uniform1i(self.uniforms.diffuse, 0);
    gl.bindTexture(gl.TEXTURE_2D, self.renderTarget);

    gl.uniform4fv(self.uniforms.viewportOffsetScale, self.viewportOffsetScale);

    // Draws both eyes
    gl.drawElements(gl.TRIANGLES, self.indexCount, gl.UNSIGNED_SHORT, 0);

    if (self.cardboardUI) {
      self.cardboardUI.renderNoState();
    }

    // Bind the fake default framebuffer again
    self.realBindFramebuffer.call(self.gl, gl.FRAMEBUFFER, self.framebuffer);

    // If preserveDrawingBuffer == false clear the framebuffer
    if (!self.ctxAttribs.preserveDrawingBuffer) {
      self.realClearColor.call(gl, 0, 0, 0, 0);
      gl.clear(gl.COLOR_BUFFER_BIT);
    }

    if (!WebVRConfig.DIRTY_SUBMIT_FRAME_BINDINGS) {
      self.realBindFramebuffer.call(gl, gl.FRAMEBUFFER, self.lastBoundFramebuffer);
    }

    // Restore state
    if (self.cullFace) { self.realEnable.call(gl, gl.CULL_FACE); }
    if (self.depthTest) { self.realEnable.call(gl, gl.DEPTH_TEST); }
    if (self.blend) { self.realEnable.call(gl, gl.BLEND); }
    if (self.scissorTest) { self.realEnable.call(gl, gl.SCISSOR_TEST); }
    if (self.stencilTest) { self.realEnable.call(gl, gl.STENCIL_TEST); }

    self.realColorMask.apply(gl, self.colorMask);
    self.realViewport.apply(gl, self.viewport);
    if (self.ctxAttribs.alpha || !self.ctxAttribs.preserveDrawingBuffer) {
      self.realClearColor.apply(gl, self.clearColor);
    }
  });

  // Workaround for the fact that Safari doesn't allow us to patch the canvas
  // width and height correctly. After each submit frame check to see what the
  // real backbuffer size has been set to and resize the fake backbuffer size
  // to match.
  if (Util.isIOS()) {
    var canvas = gl.canvas;
    if (canvas.width != self.bufferWidth || canvas.height != self.bufferHeight) {
      self.bufferWidth = canvas.width;
      self.bufferHeight = canvas.height;
      self.onResize();
    }
  }
};

/**
 * Call when the deviceInfo has changed. At this point we need
 * to re-calculate the distortion mesh.
 */
CardboardDistorter.prototype.updateDeviceInfo = function(deviceInfo) {
  var gl = this.gl;
  var self = this;

  var glState = [gl.ARRAY_BUFFER_BINDING, gl.ELEMENT_ARRAY_BUFFER_BINDING];
  WGLUPreserveGLState(gl, glState, function(gl) {
    var vertices = self.computeMeshVertices_(self.meshWidth, self.meshHeight, deviceInfo);
    gl.bindBuffer(gl.ARRAY_BUFFER, self.vertexBuffer);
    gl.bufferData(gl.ARRAY_BUFFER, vertices, gl.STATIC_DRAW);

    // Indices don't change based on device parameters, so only compute once.
    if (!self.indexCount) {
      var indices = self.computeMeshIndices_(self.meshWidth, self.meshHeight);
      gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, self.indexBuffer);
      gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, indices, gl.STATIC_DRAW);
      self.indexCount = indices.length;
    }
  });
};

/**
 * Build the distortion mesh vertices.
 * Based on code from the Unity cardboard plugin.
 */
CardboardDistorter.prototype.computeMeshVertices_ = function(width, height, deviceInfo) {
  var vertices = new Float32Array(2 * width * height * 5);

  var lensFrustum = deviceInfo.getLeftEyeVisibleTanAngles();
  var noLensFrustum = deviceInfo.getLeftEyeNoLensTanAngles();
  var viewport = deviceInfo.getLeftEyeVisibleScreenRect(noLensFrustum);
  var vidx = 0;
  var iidx = 0;
  for (var e = 0; e < 2; e++) {
    for (var j = 0; j < height; j++) {
      for (var i = 0; i < width; i++, vidx++) {
        var u = i / (width - 1);
        var v = j / (height - 1);

        // Grid points regularly spaced in StreoScreen, and barrel distorted in
        // the mesh.
        var s = u;
        var t = v;
        var x = Util.lerp(lensFrustum[0], lensFrustum[2], u);
        var y = Util.lerp(lensFrustum[3], lensFrustum[1], v);
        var d = Math.sqrt(x * x + y * y);
        var r = deviceInfo.distortion.distortInverse(d);
        var p = x * r / d;
        var q = y * r / d;
        u = (p - noLensFrustum[0]) / (noLensFrustum[2] - noLensFrustum[0]);
        v = (q - noLensFrustum[3]) / (noLensFrustum[1] - noLensFrustum[3]);

        // Convert u,v to mesh screen coordinates.
        var aspect = deviceInfo.device.widthMeters / deviceInfo.device.heightMeters;

        // FIXME: The original Unity plugin multiplied U by the aspect ratio
        // and didn't multiply either value by 2, but that seems to get it
        // really close to correct looking for me. I hate this kind of "Don't
        // know why it works" code though, and wold love a more logical
        // explanation of what needs to happen here.
        u = (viewport.x + u * viewport.width - 0.5) * 2.0; //* aspect;
        v = (viewport.y + v * viewport.height - 0.5) * 2.0;

        vertices[(vidx * 5) + 0] = u; // position.x
        vertices[(vidx * 5) + 1] = v; // position.y
        vertices[(vidx * 5) + 2] = s; // texCoord.x
        vertices[(vidx * 5) + 3] = t; // texCoord.y
        vertices[(vidx * 5) + 4] = e; // texCoord.z (viewport index)
      }
    }
    var w = lensFrustum[2] - lensFrustum[0];
    lensFrustum[0] = -(w + lensFrustum[0]);
    lensFrustum[2] = w - lensFrustum[2];
    w = noLensFrustum[2] - noLensFrustum[0];
    noLensFrustum[0] = -(w + noLensFrustum[0]);
    noLensFrustum[2] = w - noLensFrustum[2];
    viewport.x = 1 - (viewport.x + viewport.width);
  }
  return vertices;
}

/**
 * Build the distortion mesh indices.
 * Based on code from the Unity cardboard plugin.
 */
CardboardDistorter.prototype.computeMeshIndices_ = function(width, height) {
  var indices = new Uint16Array(2 * (width - 1) * (height - 1) * 6);
  var halfwidth = width / 2;
  var halfheight = height / 2;
  var vidx = 0;
  var iidx = 0;
  for (var e = 0; e < 2; e++) {
    for (var j = 0; j < height; j++) {
      for (var i = 0; i < width; i++, vidx++) {
        if (i == 0 || j == 0)
          continue;
        // Build a quad.  Lower right and upper left quadrants have quads with
        // the triangle diagonal flipped to get the vignette to interpolate
        // correctly.
        if ((i <= halfwidth) == (j <= halfheight)) {
          // Quad diagonal lower left to upper right.
          indices[iidx++] = vidx;
          indices[iidx++] = vidx - width - 1;
          indices[iidx++] = vidx - width;
          indices[iidx++] = vidx - width - 1;
          indices[iidx++] = vidx;
          indices[iidx++] = vidx - 1;
        } else {
          // Quad diagonal upper left to lower right.
          indices[iidx++] = vidx - 1;
          indices[iidx++] = vidx - width;
          indices[iidx++] = vidx;
          indices[iidx++] = vidx - width;
          indices[iidx++] = vidx - 1;
          indices[iidx++] = vidx - width - 1;
        }
      }
    }
  }
  return indices;
};

CardboardDistorter.prototype.getOwnPropertyDescriptor_ = function(proto, attrName) {
  var descriptor = Object.getOwnPropertyDescriptor(proto, attrName);
  // In some cases (ahem... Safari), the descriptor returns undefined get and
  // set fields. In this case, we need to create a synthetic property
  // descriptor. This works around some of the issues in
  // https://github.com/borismus/webvr-polyfill/issues/46
  if (descriptor.get === undefined || descriptor.set === undefined) {
    descriptor.configurable = true;
    descriptor.enumerable = true;
    descriptor.get = function() {
      return this.getAttribute(attrName);
    };
    descriptor.set = function(val) {
      this.setAttribute(attrName, val);
    };
  }
  return descriptor;
};

module.exports = CardboardDistorter;

},{"./cardboard-ui.js":5,"./deps/wglu-preserve-state.js":7,"./util.js":22}],5:[function(_dereq_,module,exports){
/*
 * Copyright 2016 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var Util = _dereq_('./util.js');
var WGLUPreserveGLState = _dereq_('./deps/wglu-preserve-state.js');

var uiVS = [
  'attribute vec2 position;',

  'uniform mat4 projectionMat;',

  'void main() {',
  '  gl_Position = projectionMat * vec4( position, -1.0, 1.0 );',
  '}',
].join('\n');

var uiFS = [
  'precision mediump float;',

  'uniform vec4 color;',

  'void main() {',
  '  gl_FragColor = color;',
  '}',
].join('\n');

var DEG2RAD = Math.PI/180.0;

// The gear has 6 identical sections, each spanning 60 degrees.
var kAnglePerGearSection = 60;

// Half-angle of the span of the outer rim.
var kOuterRimEndAngle = 12;

// Angle between the middle of the outer rim and the start of the inner rim.
var kInnerRimBeginAngle = 20;

// Distance from center to outer rim, normalized so that the entire model
// fits in a [-1, 1] x [-1, 1] square.
var kOuterRadius = 1;

// Distance from center to depressed rim, in model units.
var kMiddleRadius = 0.75;

// Radius of the inner hollow circle, in model units.
var kInnerRadius = 0.3125;

// Center line thickness in DP.
var kCenterLineThicknessDp = 4;

// Button width in DP.
var kButtonWidthDp = 28;

// Factor to scale the touch area that responds to the touch.
var kTouchSlopFactor = 1.5;

var Angles = [
  0, kOuterRimEndAngle, kInnerRimBeginAngle,
  kAnglePerGearSection - kInnerRimBeginAngle,
  kAnglePerGearSection - kOuterRimEndAngle
];

/**
 * Renders the alignment line and "options" gear. It is assumed that the canvas
 * this is rendered into covers the entire screen (or close to it.)
 */
function CardboardUI(gl) {
  this.gl = gl;

  this.attribs = {
    position: 0
  };
  this.program = Util.linkProgram(gl, uiVS, uiFS, this.attribs);
  this.uniforms = Util.getProgramUniforms(gl, this.program);

  this.vertexBuffer = gl.createBuffer();
  this.gearOffset = 0;
  this.gearVertexCount = 0;
  this.arrowOffset = 0;
  this.arrowVertexCount = 0;

  this.projMat = new Float32Array(16);

  this.listener = null;

  this.onResize();
};

/**
 * Tears down all the resources created by the UI renderer.
 */
CardboardUI.prototype.destroy = function() {
  var gl = this.gl;

  if (this.listener) {
    gl.canvas.removeEventListener('click', this.listener, false);
  }

  gl.deleteProgram(this.program);
  gl.deleteBuffer(this.vertexBuffer);
};

/**
 * Adds a listener to clicks on the gear and back icons
 */
CardboardUI.prototype.listen = function(optionsCallback, backCallback) {
  var canvas = this.gl.canvas;
  this.listener = function(event) {
    var midline = canvas.clientWidth / 2;
    var buttonSize = kButtonWidthDp * kTouchSlopFactor;
    // Check to see if the user clicked on (or around) the gear icon
    if (event.clientX > midline - buttonSize &&
        event.clientX < midline + buttonSize &&
        event.clientY > canvas.clientHeight - buttonSize) {
      optionsCallback(event);
    }
    // Check to see if the user clicked on (or around) the back icon
    else if (event.clientX < buttonSize && event.clientY < buttonSize) {
      backCallback(event);
    }
  };
  canvas.addEventListener('click', this.listener, false);
};

/**
 * Builds the UI mesh.
 */
CardboardUI.prototype.onResize = function() {
  var gl = this.gl;
  var self = this;

  var glState = [
    gl.ARRAY_BUFFER_BINDING
  ];

  WGLUPreserveGLState(gl, glState, function(gl) {
    var vertices = [];

    var midline = gl.drawingBufferWidth / 2;

    // Assumes your canvas width and height is scaled proportionately.
    // TODO(smus): The following causes buttons to become huge on iOS, but seems
    // like the right thing to do. For now, added a hack. But really, investigate why.
    var dps = (gl.drawingBufferWidth / (screen.width * window.devicePixelRatio));
    if (!Util.isIOS()) {
      dps *= window.devicePixelRatio;
    }

    var lineWidth = kCenterLineThicknessDp * dps / 2;
    var buttonSize = kButtonWidthDp * kTouchSlopFactor * dps;
    var buttonScale = kButtonWidthDp * dps / 2;
    var buttonBorder = ((kButtonWidthDp * kTouchSlopFactor) - kButtonWidthDp) * dps;

    // Build centerline
    vertices.push(midline - lineWidth, buttonSize);
    vertices.push(midline - lineWidth, gl.drawingBufferHeight);
    vertices.push(midline + lineWidth, buttonSize);
    vertices.push(midline + lineWidth, gl.drawingBufferHeight);

    // Build gear
    self.gearOffset = (vertices.length / 2);

    function addGearSegment(theta, r) {
      var angle = (90 - theta) * DEG2RAD;
      var x = Math.cos(angle);
      var y = Math.sin(angle);
      vertices.push(kInnerRadius * x * buttonScale + midline, kInnerRadius * y * buttonScale + buttonScale);
      vertices.push(r * x * buttonScale + midline, r * y * buttonScale + buttonScale);
    }

    for (var i = 0; i <= 6; i++) {
      var segmentTheta = i * kAnglePerGearSection;

      addGearSegment(segmentTheta, kOuterRadius);
      addGearSegment(segmentTheta + kOuterRimEndAngle, kOuterRadius);
      addGearSegment(segmentTheta + kInnerRimBeginAngle, kMiddleRadius);
      addGearSegment(segmentTheta + (kAnglePerGearSection - kInnerRimBeginAngle), kMiddleRadius);
      addGearSegment(segmentTheta + (kAnglePerGearSection - kOuterRimEndAngle), kOuterRadius);
    }

    self.gearVertexCount = (vertices.length / 2) - self.gearOffset;

    // Build back arrow
    self.arrowOffset = (vertices.length / 2);

    function addArrowVertex(x, y) {
      vertices.push(buttonBorder + x, gl.drawingBufferHeight - buttonBorder - y);
    }

    var angledLineWidth = lineWidth / Math.sin(45 * DEG2RAD);

    addArrowVertex(0, buttonScale);
    addArrowVertex(buttonScale, 0);
    addArrowVertex(buttonScale + angledLineWidth, angledLineWidth);
    addArrowVertex(angledLineWidth, buttonScale + angledLineWidth);

    addArrowVertex(angledLineWidth, buttonScale - angledLineWidth);
    addArrowVertex(0, buttonScale);
    addArrowVertex(buttonScale, buttonScale * 2);
    addArrowVertex(buttonScale + angledLineWidth, (buttonScale * 2) - angledLineWidth);

    addArrowVertex(angledLineWidth, buttonScale - angledLineWidth);
    addArrowVertex(0, buttonScale);

    addArrowVertex(angledLineWidth, buttonScale - lineWidth);
    addArrowVertex(kButtonWidthDp * dps, buttonScale - lineWidth);
    addArrowVertex(angledLineWidth, buttonScale + lineWidth);
    addArrowVertex(kButtonWidthDp * dps, buttonScale + lineWidth);

    self.arrowVertexCount = (vertices.length / 2) - self.arrowOffset;

    // Buffer data
    gl.bindBuffer(gl.ARRAY_BUFFER, self.vertexBuffer);
    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);
  });
};

/**
 * Performs distortion pass on the injected backbuffer, rendering it to the real
 * backbuffer.
 */
CardboardUI.prototype.render = function() {
  var gl = this.gl;
  var self = this;

  var glState = [
    gl.CULL_FACE,
    gl.DEPTH_TEST,
    gl.BLEND,
    gl.SCISSOR_TEST,
    gl.STENCIL_TEST,
    gl.COLOR_WRITEMASK,
    gl.VIEWPORT,

    gl.CURRENT_PROGRAM,
    gl.ARRAY_BUFFER_BINDING
  ];

  WGLUPreserveGLState(gl, glState, function(gl) {
    // Make sure the GL state is in a good place
    gl.disable(gl.CULL_FACE);
    gl.disable(gl.DEPTH_TEST);
    gl.disable(gl.BLEND);
    gl.disable(gl.SCISSOR_TEST);
    gl.disable(gl.STENCIL_TEST);
    gl.colorMask(true, true, true, true);
    gl.viewport(0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight);

    self.renderNoState();
  });
};

CardboardUI.prototype.renderNoState = function() {
  var gl = this.gl;

  // Bind distortion program and mesh
  gl.useProgram(this.program);

  gl.bindBuffer(gl.ARRAY_BUFFER, this.vertexBuffer);
  gl.enableVertexAttribArray(this.attribs.position);
  gl.vertexAttribPointer(this.attribs.position, 2, gl.FLOAT, false, 8, 0);

  gl.uniform4f(this.uniforms.color, 1.0, 1.0, 1.0, 1.0);

  Util.orthoMatrix(this.projMat, 0, gl.drawingBufferWidth, 0, gl.drawingBufferHeight, 0.1, 1024.0);
  gl.uniformMatrix4fv(this.uniforms.projectionMat, false, this.projMat);

  // Draws UI element
  gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
  gl.drawArrays(gl.TRIANGLE_STRIP, this.gearOffset, this.gearVertexCount);
  gl.drawArrays(gl.TRIANGLE_STRIP, this.arrowOffset, this.arrowVertexCount);
};

module.exports = CardboardUI;

},{"./deps/wglu-preserve-state.js":7,"./util.js":22}],6:[function(_dereq_,module,exports){
/*
 * Copyright 2016 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var CardboardDistorter = _dereq_('./cardboard-distorter.js');
var CardboardUI = _dereq_('./cardboard-ui.js');
var DeviceInfo = _dereq_('./device-info.js');
var Dpdb = _dereq_('./dpdb/dpdb.js');
var FusionPoseSensor = _dereq_('./sensor-fusion/fusion-pose-sensor.js');
var RotateInstructions = _dereq_('./rotate-instructions.js');
var ViewerSelector = _dereq_('./viewer-selector.js');
var VRDisplay = _dereq_('./base.js').VRDisplay;
var Util = _dereq_('./util.js');

var Eye = {
  LEFT: 'left',
  RIGHT: 'right'
};

/**
 * VRDisplay based on mobile device parameters and DeviceMotion APIs.
 */
function CardboardVRDisplay() {
  this.displayName = 'Cardboard VRDisplay (webvr-polyfill)';

  this.capabilities.hasOrientation = true;
  this.capabilities.canPresent = true;

  // "Private" members.
  this.bufferScale_ = WebVRConfig.BUFFER_SCALE;
  this.poseSensor_ = new FusionPoseSensor();
  this.distorter_ = null;
  this.cardboardUI_ = null;

  this.dpdb_ = new Dpdb(true, this.onDeviceParamsUpdated_.bind(this));
  this.deviceInfo_ = new DeviceInfo(this.dpdb_.getDeviceParams());

  this.viewerSelector_ = new ViewerSelector();
  this.viewerSelector_.on('change', this.onViewerChanged_.bind(this));

  // Set the correct initial viewer.
  this.deviceInfo_.setViewer(this.viewerSelector_.getCurrentViewer());

  if (!WebVRConfig.ROTATE_INSTRUCTIONS_DISABLED) {
    this.rotateInstructions_ = new RotateInstructions();
  }

  if (Util.isIOS()) {
    // Listen for resize events to workaround this awful Safari bug.
    window.addEventListener('resize', this.onResize_.bind(this));
  }
}
CardboardVRDisplay.prototype = new VRDisplay();

CardboardVRDisplay.prototype.getImmediatePose = function() {
  return {
    position: this.poseSensor_.getPosition(),
    orientation: this.poseSensor_.getOrientation(),
    linearVelocity: null,
    linearAcceleration: null,
    angularVelocity: null,
    angularAcceleration: null
  };
};

CardboardVRDisplay.prototype.resetPose = function() {
  this.poseSensor_.resetPose();
};

CardboardVRDisplay.prototype.getEyeParameters = function(whichEye) {
  var offset = [this.deviceInfo_.viewer.interLensDistance * 0.5, 0.0, 0.0];
  var fieldOfView;

  // TODO: FoV can be a little expensive to compute. Cache when device params change.
  if (whichEye == Eye.LEFT) {
    offset[0] *= -1.0;
    fieldOfView = this.deviceInfo_.getFieldOfViewLeftEye();
  } else if (whichEye == Eye.RIGHT) {
    fieldOfView = this.deviceInfo_.getFieldOfViewRightEye();
  } else {
    console.error('Invalid eye provided: %s', whichEye);
    return null;
  }

  return {
    fieldOfView: fieldOfView,
    offset: offset,
    // TODO: Should be able to provide better values than these.
    renderWidth: this.deviceInfo_.device.width * 0.5 * this.bufferScale_,
    renderHeight: this.deviceInfo_.device.height * this.bufferScale_,
  };
};

CardboardVRDisplay.prototype.onDeviceParamsUpdated_ = function(newParams) {
  if (Util.isDebug()) {
    console.log('DPDB reported that device params were updated.');
  }
  this.deviceInfo_.updateDeviceParams(newParams);

  if (this.distorter_) {
    this.distorter_.updateDeviceInfo(this.deviceInfo_);
  }
};

CardboardVRDisplay.prototype.updateBounds_ = function () {
  if (this.layer_ && this.distorter_ && (this.layer_.leftBounds || this.layer_.rightBounds)) {
    this.distorter_.setTextureBounds(this.layer_.leftBounds, this.layer_.rightBounds);
  }
};

CardboardVRDisplay.prototype.beginPresent_ = function() {
  var gl = this.layer_.source.getContext('webgl');
  if (!gl)
    gl = this.layer_.source.getContext('experimental-webgl');
  if (!gl)
    gl = this.layer_.source.getContext('webgl2');

  if (!gl)
    return; // Can't do distortion without a WebGL context.

  // Provides a way to opt out of distortion
  if (this.layer_.predistorted) {
    if (!WebVRConfig.CARDBOARD_UI_DISABLED) {
      gl.canvas.width = Util.getScreenWidth() * this.bufferScale_;
      gl.canvas.height = Util.getScreenHeight() * this.bufferScale_;
      this.cardboardUI_ = new CardboardUI(gl);
    }
  } else {
    // Create a new distorter for the target context
    this.distorter_ = new CardboardDistorter(gl);
    this.distorter_.updateDeviceInfo(this.deviceInfo_);
    this.cardboardUI_ = this.distorter_.cardboardUI;
  }

  if (this.cardboardUI_) {
    this.cardboardUI_.listen(function(e) {
      // Options clicked.
      this.viewerSelector_.show(this.layer_.source.parentElement);
      e.stopPropagation();
      e.preventDefault();
    }.bind(this), function(e) {
      // Back clicked.
      this.exitPresent();
      e.stopPropagation();
      e.preventDefault();
    }.bind(this));
  }

  if (this.rotateInstructions_) {
    if (Util.isLandscapeMode() && Util.isMobile()) {
      // In landscape mode, temporarily show the "put into Cardboard"
      // interstitial. Otherwise, do the default thing.
      this.rotateInstructions_.showTemporarily(3000, this.layer_.source.parentElement);
    } else {
      this.rotateInstructions_.update();
    }
  }

  // Listen for orientation change events in order to show interstitial.
  this.orientationHandler = this.onOrientationChange_.bind(this);
  window.addEventListener('orientationchange', this.orientationHandler);

  // Listen for present display change events in order to update distorter dimensions
  this.vrdisplaypresentchangeHandler = this.updateBounds_.bind(this);
  window.addEventListener('vrdisplaypresentchange', this.vrdisplaypresentchangeHandler);

  // Fire this event initially, to give geometry-distortion clients the chance
  // to do something custom.
  this.fireVRDisplayDeviceParamsChange_();
};

CardboardVRDisplay.prototype.endPresent_ = function() {
  if (this.distorter_) {
    this.distorter_.destroy();
    this.distorter_ = null;
  }
  if (this.cardboardUI_) {
    this.cardboardUI_.destroy();
    this.cardboardUI_ = null;
  }

  if (this.rotateInstructions_) {
    this.rotateInstructions_.hide();
  }
  this.viewerSelector_.hide();

  window.removeEventListener('orientationchange', this.orientationHandler);
  window.removeEventListener('vrdisplaypresentchange', this.vrdisplaypresentchangeHandler);
};

CardboardVRDisplay.prototype.submitFrame = function(pose) {
  if (this.distorter_) {
    this.distorter_.submitFrame();
  } else if (this.cardboardUI_ && this.layer_) {
    // Hack for predistorted: true.
    var canvas = this.layer_.source.getContext('webgl').canvas;
    if (canvas.width != this.lastWidth || canvas.height != this.lastHeight) {
      this.cardboardUI_.onResize();
    }
    this.lastWidth = canvas.width;
    this.lastHeight = canvas.height;

    // Render the Cardboard UI.
    this.cardboardUI_.render();
  }
};

CardboardVRDisplay.prototype.onOrientationChange_ = function(e) {
  // Hide the viewer selector.
  this.viewerSelector_.hide();

  // Update the rotate instructions.
  if (this.rotateInstructions_) {
    this.rotateInstructions_.update();
  }

  this.onResize_();
};

CardboardVRDisplay.prototype.onResize_ = function(e) {
  if (this.layer_) {
    var gl = this.layer_.source.getContext('webgl');
    // Size the CSS canvas.
    // Added padding on right and bottom because iPhone 5 will not
    // hide the URL bar unless content is bigger than the screen.
    // This will not be visible as long as the container element (e.g. body)
    // is set to 'overflow: hidden'.
    var cssProperties = [
      'position: absolute',
      'top: 0',
      'left: 0',
      'width: ' + Math.max(screen.width, screen.height) + 'px',
      'height: ' + Math.min(screen.height, screen.width) + 'px',
      'border: 0',
      'margin: 0',
      'padding: 0 10px 10px 0',
    ];
    gl.canvas.setAttribute('style', cssProperties.join('; ') + ';');

    Util.safariCssSizeWorkaround(gl.canvas);
  }
};

CardboardVRDisplay.prototype.onViewerChanged_ = function(viewer) {
  this.deviceInfo_.setViewer(viewer);

  if (this.distorter_) {
    // Update the distortion appropriately.
    this.distorter_.updateDeviceInfo(this.deviceInfo_);
  }

  // Fire a new event containing viewer and device parameters for clients that
  // want to implement their own geometry-based distortion.
  this.fireVRDisplayDeviceParamsChange_();
};

CardboardVRDisplay.prototype.fireVRDisplayDeviceParamsChange_ = function() {
  var event = new CustomEvent('vrdisplaydeviceparamschange', {
    detail: {
      vrdisplay: this,
      deviceInfo: this.deviceInfo_,
    }
  });
  window.dispatchEvent(event);
};

module.exports = CardboardVRDisplay;

},{"./base.js":3,"./cardboard-distorter.js":4,"./cardboard-ui.js":5,"./device-info.js":8,"./dpdb/dpdb.js":12,"./rotate-instructions.js":16,"./sensor-fusion/fusion-pose-sensor.js":18,"./util.js":22,"./viewer-selector.js":23}],7:[function(_dereq_,module,exports){
/*
Copyright (c) 2016, Brandon Jones.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

/*
Caches specified GL state, runs a callback, and restores the cached state when
done.

Example usage:

var savedState = [
  gl.ARRAY_BUFFER_BINDING,

  // TEXTURE_BINDING_2D or _CUBE_MAP must always be followed by the texure unit.
  gl.TEXTURE_BINDING_2D, gl.TEXTURE0,

  gl.CLEAR_COLOR,
];
// After this call the array buffer, texture unit 0, active texture, and clear
// color will be restored. The viewport will remain changed, however, because
// gl.VIEWPORT was not included in the savedState list.
WGLUPreserveGLState(gl, savedState, function(gl) {
  gl.viewport(0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight);

  gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
  gl.bufferData(gl.ARRAY_BUFFER, ....);

  gl.activeTexture(gl.TEXTURE0);
  gl.bindTexture(gl.TEXTURE_2D, texture);
  gl.texImage2D(gl.TEXTURE_2D, ...);

  gl.clearColor(1, 0, 0, 1);
  gl.clear(gl.COLOR_BUFFER_BIT);
});

Note that this is not intended to be fast. Managing state in your own code to
avoid redundant state setting and querying will always be faster. This function
is most useful for cases where you may not have full control over the WebGL
calls being made, such as tooling or effect injectors.
*/

function WGLUPreserveGLState(gl, bindings, callback) {
  if (!bindings) {
    callback(gl);
    return;
  }

  var boundValues = [];

  var activeTexture = null;
  for (var i = 0; i < bindings.length; ++i) {
    var binding = bindings[i];
    switch (binding) {
      case gl.TEXTURE_BINDING_2D:
      case gl.TEXTURE_BINDING_CUBE_MAP:
        var textureUnit = bindings[++i];
        if (textureUnit < gl.TEXTURE0 || textureUnit > gl.TEXTURE31) {
          console.error("TEXTURE_BINDING_2D or TEXTURE_BINDING_CUBE_MAP must be followed by a valid texture unit");
          boundValues.push(null, null);
          break;
        }
        if (!activeTexture) {
          activeTexture = gl.getParameter(gl.ACTIVE_TEXTURE);
        }
        gl.activeTexture(textureUnit);
        boundValues.push(gl.getParameter(binding), null);
        break;
      case gl.ACTIVE_TEXTURE:
        activeTexture = gl.getParameter(gl.ACTIVE_TEXTURE);
        boundValues.push(null);
        break;
      default:
        boundValues.push(gl.getParameter(binding));
        break;
    }
  }

  callback(gl);

  for (var i = 0; i < bindings.length; ++i) {
    var binding = bindings[i];
    var boundValue = boundValues[i];
    switch (binding) {
      case gl.ACTIVE_TEXTURE:
        break; // Ignore this binding, since we special-case it to happen last.
      case gl.ARRAY_BUFFER_BINDING:
        gl.bindBuffer(gl.ARRAY_BUFFER, boundValue);
        break;
      case gl.COLOR_CLEAR_VALUE:
        gl.clearColor(boundValue[0], boundValue[1], boundValue[2], boundValue[3]);
        break;
      case gl.COLOR_WRITEMASK:
        gl.colorMask(boundValue[0], boundValue[1], boundValue[2], boundValue[3]);
        break;
      case gl.CURRENT_PROGRAM:
        gl.useProgram(boundValue);
        break;
      case gl.ELEMENT_ARRAY_BUFFER_BINDING:
        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, boundValue);
        break;
      case gl.FRAMEBUFFER_BINDING:
        gl.bindFramebuffer(gl.FRAMEBUFFER, boundValue);
        break;
      case gl.RENDERBUFFER_BINDING:
        gl.bindRenderbuffer(gl.RENDERBUFFER, boundValue);
        break;
      case gl.TEXTURE_BINDING_2D:
        var textureUnit = bindings[++i];
        if (textureUnit < gl.TEXTURE0 || textureUnit > gl.TEXTURE31)
          break;
        gl.activeTexture(textureUnit);
        gl.bindTexture(gl.TEXTURE_2D, boundValue);
        break;
      case gl.TEXTURE_BINDING_CUBE_MAP:
        var textureUnit = bindings[++i];
        if (textureUnit < gl.TEXTURE0 || textureUnit > gl.TEXTURE31)
          break;
        gl.activeTexture(textureUnit);
        gl.bindTexture(gl.TEXTURE_CUBE_MAP, boundValue);
        break;
      case gl.VIEWPORT:
        gl.viewport(boundValue[0], boundValue[1], boundValue[2], boundValue[3]);
        break;
      case gl.BLEND:
      case gl.CULL_FACE:
      case gl.DEPTH_TEST:
      case gl.SCISSOR_TEST:
      case gl.STENCIL_TEST:
        if (boundValue) {
          gl.enable(binding);
        } else {
          gl.disable(binding);
        }
        break;
      default:
        console.log("No GL restore behavior for 0x" + binding.toString(16));
        break;
    }

    if (activeTexture) {
      gl.activeTexture(activeTexture);
    }
  }
}

module.exports = WGLUPreserveGLState;
},{}],8:[function(_dereq_,module,exports){
/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var Distortion = _dereq_('./distortion/distortion.js');
var MathUtil = _dereq_('./math-util.js');
var Util = _dereq_('./util.js');

function Device(params) {
  this.width = params.width || Util.getScreenWidth();
  this.height = params.height || Util.getScreenHeight();
  this.widthMeters = params.widthMeters;
  this.heightMeters = params.heightMeters;
  this.bevelMeters = params.bevelMeters;
}


// Fallback Android device (based on Nexus 5 measurements) for use when
// we can't recognize an Android device.
var DEFAULT_ANDROID = new Device({
  widthMeters: 0.110,
  heightMeters: 0.062,
  bevelMeters: 0.004
});

// Fallback iOS device (based on iPhone6) for use when
// we can't recognize an Android device.
var DEFAULT_IOS = new Device({
  widthMeters: 0.1038,
  heightMeters: 0.0584,
  bevelMeters: 0.004
});


var Viewers = {
  CardboardV1: new CardboardViewer({
    id: 'CardboardV1',
    label: 'Cardboard I/O 2014',
    fov: 40,
    interLensDistance: 0.060,
    baselineLensDistance: 0.035,
    screenLensDistance: 0.042,
    distortionCoefficients: [0.441, 0.156],
    inverseCoefficients: [-0.4410035, 0.42756155, -0.4804439, 0.5460139,
      -0.58821183, 0.5733938, -0.48303202, 0.33299083, -0.17573841,
      0.0651772, -0.01488963, 0.001559834]
  }),
  CardboardV2: new CardboardViewer({
    id: 'CardboardV2',
    label: 'Cardboard I/O 2015',
    fov: 60,
    interLensDistance: 0.064,
    baselineLensDistance: 0.035,
    screenLensDistance: 0.039,
    distortionCoefficients: [0.34, 0.55],
    inverseCoefficients: [-0.33836704, -0.18162185, 0.862655, -1.2462051,
      1.0560602, -0.58208317, 0.21609078, -0.05444823, 0.009177956,
      -9.904169E-4, 6.183535E-5, -1.6981803E-6]
  })
};


var DEFAULT_LEFT_CENTER = {x: 0.5, y: 0.5};
var DEFAULT_RIGHT_CENTER = {x: 0.5, y: 0.5};

/**
 * Manages information about the device and the viewer.
 *
 * deviceParams indicates the parameters of the device to use (generally
 * obtained from dpdb.getDeviceParams()). Can be null to mean no device
 * params were found.
 */
function DeviceInfo(deviceParams) {
  this.viewer = Viewers.CardboardV2;
  this.updateDeviceParams(deviceParams);
  this.distortion = new Distortion(this.viewer.distortionCoefficients);
}

DeviceInfo.prototype.updateDeviceParams = function(deviceParams) {
  this.device = this.determineDevice_(deviceParams) || this.device;
};

DeviceInfo.prototype.getDevice = function() {
  return this.device;
};

DeviceInfo.prototype.setViewer = function(viewer) {
  this.viewer = viewer;
  this.distortion = new Distortion(this.viewer.distortionCoefficients);
};

DeviceInfo.prototype.determineDevice_ = function(deviceParams) {
  if (!deviceParams) {
    // No parameters, so use a default.
    if (Util.isIOS()) {
      console.warn('Using fallback iOS device measurements.');
      return DEFAULT_IOS;
    } else {
      console.warn('Using fallback Android device measurements.');
      return DEFAULT_ANDROID;
    }
  }

  // Compute device screen dimensions based on deviceParams.
  var METERS_PER_INCH = 0.0254;
  var metersPerPixelX = METERS_PER_INCH / deviceParams.xdpi;
  var metersPerPixelY = METERS_PER_INCH / deviceParams.ydpi;
  var width = Util.getScreenWidth();
  var height = Util.getScreenHeight();
  return new Device({
    widthMeters: metersPerPixelX * width,
    heightMeters: metersPerPixelY * height,
    bevelMeters: deviceParams.bevelMm * 0.001,
  });
};

/**
 * Calculates field of view for the left eye.
 */
DeviceInfo.prototype.getDistortedFieldOfViewLeftEye = function() {
  var viewer = this.viewer;
  var device = this.device;
  var distortion = this.distortion;

  // Device.height and device.width for device in portrait mode, so transpose.
  var eyeToScreenDistance = viewer.screenLensDistance;

  var outerDist = (device.widthMeters - viewer.interLensDistance) / 2;
  var innerDist = viewer.interLensDistance / 2;
  var bottomDist = viewer.baselineLensDistance - device.bevelMeters;
  var topDist = device.heightMeters - bottomDist;

  var outerAngle = MathUtil.radToDeg * Math.atan(
      distortion.distort(outerDist / eyeToScreenDistance));
  var innerAngle = MathUtil.radToDeg * Math.atan(
      distortion.distort(innerDist / eyeToScreenDistance));
  var bottomAngle = MathUtil.radToDeg * Math.atan(
      distortion.distort(bottomDist / eyeToScreenDistance));
  var topAngle = MathUtil.radToDeg * Math.atan(
      distortion.distort(topDist / eyeToScreenDistance));

  return {
    leftDegrees: Math.min(outerAngle, viewer.fov),
    rightDegrees: Math.min(innerAngle, viewer.fov),
    downDegrees: Math.min(bottomAngle, viewer.fov),
    upDegrees: Math.min(topAngle, viewer.fov)
  };
};

/**
 * Calculates the tan-angles from the maximum FOV for the left eye for the
 * current device and screen parameters.
 */
DeviceInfo.prototype.getLeftEyeVisibleTanAngles = function() {
  var viewer = this.viewer;
  var device = this.device;
  var distortion = this.distortion;

  // Tan-angles from the max FOV.
  var fovLeft = Math.tan(-MathUtil.degToRad * viewer.fov);
  var fovTop = Math.tan(MathUtil.degToRad * viewer.fov);
  var fovRight = Math.tan(MathUtil.degToRad * viewer.fov);
  var fovBottom = Math.tan(-MathUtil.degToRad * viewer.fov);
  // Viewport size.
  var halfWidth = device.widthMeters / 4;
  var halfHeight = device.heightMeters / 2;
  // Viewport center, measured from left lens position.
  var verticalLensOffset = (viewer.baselineLensDistance - device.bevelMeters - halfHeight);
  var centerX = viewer.interLensDistance / 2 - halfWidth;
  var centerY = -verticalLensOffset;
  var centerZ = viewer.screenLensDistance;
  // Tan-angles of the viewport edges, as seen through the lens.
  var screenLeft = distortion.distort((centerX - halfWidth) / centerZ);
  var screenTop = distortion.distort((centerY + halfHeight) / centerZ);
  var screenRight = distortion.distort((centerX + halfWidth) / centerZ);
  var screenBottom = distortion.distort((centerY - halfHeight) / centerZ);
  // Compare the two sets of tan-angles and take the value closer to zero on each side.
  var result = new Float32Array(4);
  result[0] = Math.max(fovLeft, screenLeft);
  result[1] = Math.min(fovTop, screenTop);
  result[2] = Math.min(fovRight, screenRight);
  result[3] = Math.max(fovBottom, screenBottom);
  return result;
};

/**
 * Calculates the tan-angles from the maximum FOV for the left eye for the
 * current device and screen parameters, assuming no lenses.
 */
DeviceInfo.prototype.getLeftEyeNoLensTanAngles = function() {
  var viewer = this.viewer;
  var device = this.device;
  var distortion = this.distortion;

  var result = new Float32Array(4);
  // Tan-angles from the max FOV.
  var fovLeft = distortion.distortInverse(Math.tan(-MathUtil.degToRad * viewer.fov));
  var fovTop = distortion.distortInverse(Math.tan(MathUtil.degToRad * viewer.fov));
  var fovRight = distortion.distortInverse(Math.tan(MathUtil.degToRad * viewer.fov));
  var fovBottom = distortion.distortInverse(Math.tan(-MathUtil.degToRad * viewer.fov));
  // Viewport size.
  var halfWidth = device.widthMeters / 4;
  var halfHeight = device.heightMeters / 2;
  // Viewport center, measured from left lens position.
  var verticalLensOffset = (viewer.baselineLensDistance - device.bevelMeters - halfHeight);
  var centerX = viewer.interLensDistance / 2 - halfWidth;
  var centerY = -verticalLensOffset;
  var centerZ = viewer.screenLensDistance;
  // Tan-angles of the viewport edges, as seen through the lens.
  var screenLeft = (centerX - halfWidth) / centerZ;
  var screenTop = (centerY + halfHeight) / centerZ;
  var screenRight = (centerX + halfWidth) / centerZ;
  var screenBottom = (centerY - halfHeight) / centerZ;
  // Compare the two sets of tan-angles and take the value closer to zero on each side.
  result[0] = Math.max(fovLeft, screenLeft);
  result[1] = Math.min(fovTop, screenTop);
  result[2] = Math.min(fovRight, screenRight);
  result[3] = Math.max(fovBottom, screenBottom);
  return result;
};

/**
 * Calculates the screen rectangle visible from the left eye for the
 * current device and screen parameters.
 */
DeviceInfo.prototype.getLeftEyeVisibleScreenRect = function(undistortedFrustum) {
  var viewer = this.viewer;
  var device = this.device;

  var dist = viewer.screenLensDistance;
  var eyeX = (device.widthMeters - viewer.interLensDistance) / 2;
  var eyeY = viewer.baselineLensDistance - device.bevelMeters;
  var left = (undistortedFrustum[0] * dist + eyeX) / device.widthMeters;
  var top = (undistortedFrustum[1] * dist + eyeY) / device.heightMeters;
  var right = (undistortedFrustum[2] * dist + eyeX) / device.widthMeters;
  var bottom = (undistortedFrustum[3] * dist + eyeY) / device.heightMeters;
  return {
    x: left,
    y: bottom,
    width: right - left,
    height: top - bottom
  };
};

DeviceInfo.prototype.getFieldOfViewLeftEye = function(opt_isUndistorted) {
  return opt_isUndistorted ? this.getUndistortedFieldOfViewLeftEye() :
      this.getDistortedFieldOfViewLeftEye();
};

DeviceInfo.prototype.getFieldOfViewRightEye = function(opt_isUndistorted) {
  var fov = this.getFieldOfViewLeftEye(opt_isUndistorted);
  return {
    leftDegrees: fov.rightDegrees,
    rightDegrees: fov.leftDegrees,
    upDegrees: fov.upDegrees,
    downDegrees: fov.downDegrees
  };
};

/**
 * Calculates undistorted field of view for the left eye.
 */
DeviceInfo.prototype.getUndistortedFieldOfViewLeftEye = function() {
  var p = this.getUndistortedParams_();

  return {
    leftDegrees: MathUtil.radToDeg * Math.atan(p.outerDist),
    rightDegrees: MathUtil.radToDeg * Math.atan(p.innerDist),
    downDegrees: MathUtil.radToDeg * Math.atan(p.bottomDist),
    upDegrees: MathUtil.radToDeg * Math.atan(p.topDist)
  };
};

DeviceInfo.prototype.getUndistortedViewportLeftEye = function() {
  var p = this.getUndistortedParams_();
  var viewer = this.viewer;
  var device = this.device;

  // Distances stored in local variables are in tan-angle units unless otherwise
  // noted.
  var eyeToScreenDistance = viewer.screenLensDistance;
  var screenWidth = device.widthMeters / eyeToScreenDistance;
  var screenHeight = device.heightMeters / eyeToScreenDistance;
  var xPxPerTanAngle = device.width / screenWidth;
  var yPxPerTanAngle = device.height / screenHeight;

  var x = Math.round((p.eyePosX - p.outerDist) * xPxPerTanAngle);
  var y = Math.round((p.eyePosY - p.bottomDist) * yPxPerTanAngle);
  return {
    x: x,
    y: y,
    width: Math.round((p.eyePosX + p.innerDist) * xPxPerTanAngle) - x,
    height: Math.round((p.eyePosY + p.topDist) * yPxPerTanAngle) - y
  };
};

DeviceInfo.prototype.getUndistortedParams_ = function() {
  var viewer = this.viewer;
  var device = this.device;
  var distortion = this.distortion;

  // Most of these variables in tan-angle units.
  var eyeToScreenDistance = viewer.screenLensDistance;
  var halfLensDistance = viewer.interLensDistance / 2 / eyeToScreenDistance;
  var screenWidth = device.widthMeters / eyeToScreenDistance;
  var screenHeight = device.heightMeters / eyeToScreenDistance;

  var eyePosX = screenWidth / 2 - halfLensDistance;
  var eyePosY = (viewer.baselineLensDistance - device.bevelMeters) / eyeToScreenDistance;

  var maxFov = viewer.fov;
  var viewerMax = distortion.distortInverse(Math.tan(MathUtil.degToRad * maxFov));
  var outerDist = Math.min(eyePosX, viewerMax);
  var innerDist = Math.min(halfLensDistance, viewerMax);
  var bottomDist = Math.min(eyePosY, viewerMax);
  var topDist = Math.min(screenHeight - eyePosY, viewerMax);

  return {
    outerDist: outerDist,
    innerDist: innerDist,
    topDist: topDist,
    bottomDist: bottomDist,
    eyePosX: eyePosX,
    eyePosY: eyePosY
  };
};


function CardboardViewer(params) {
  // A machine readable ID.
  this.id = params.id;
  // A human readable label.
  this.label = params.label;

  // Field of view in degrees (per side).
  this.fov = params.fov;

  // Distance between lens centers in meters.
  this.interLensDistance = params.interLensDistance;
  // Distance between viewer baseline and lens center in meters.
  this.baselineLensDistance = params.baselineLensDistance;
  // Screen-to-lens distance in meters.
  this.screenLensDistance = params.screenLensDistance;

  // Distortion coefficients.
  this.distortionCoefficients = params.distortionCoefficients;
  // Inverse distortion coefficients.
  // TODO: Calculate these from distortionCoefficients in the future.
  this.inverseCoefficients = params.inverseCoefficients;
}

// Export viewer information.
DeviceInfo.Viewers = Viewers;
module.exports = DeviceInfo;

},{"./distortion/distortion.js":10,"./math-util.js":14,"./util.js":22}],9:[function(_dereq_,module,exports){
/*
 * Copyright 2016 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
var VRDisplay = _dereq_('./base.js').VRDisplay;
var HMDVRDevice = _dereq_('./base.js').HMDVRDevice;
var PositionSensorVRDevice = _dereq_('./base.js').PositionSensorVRDevice;

/**
 * Wraps a VRDisplay and exposes it as a HMDVRDevice
 */
function VRDisplayHMDDevice(display) {
  this.display = display;

  this.hardwareUnitId = display.displayId;
  this.deviceId = 'webvr-polyfill:HMD:' + display.displayId;
  this.deviceName = display.displayName + ' (HMD)';
}
VRDisplayHMDDevice.prototype = new HMDVRDevice();

VRDisplayHMDDevice.prototype.getEyeParameters = function(whichEye) {
  var eyeParameters = this.display.getEyeParameters(whichEye);

  return {
    currentFieldOfView: eyeParameters.fieldOfView,
    maximumFieldOfView: eyeParameters.fieldOfView,
    minimumFieldOfView: eyeParameters.fieldOfView,
    recommendedFieldOfView: eyeParameters.fieldOfView,
    eyeTranslation: { x: eyeParameters.offset[0], y: eyeParameters.offset[1], z: eyeParameters.offset[2] },
    renderRect: {
      x: (whichEye == 'right') ? eyeParameters.renderWidth : 0,
      y: 0,
      width: eyeParameters.renderWidth,
      height: eyeParameters.renderHeight
    }
  };
};

VRDisplayHMDDevice.prototype.setFieldOfView =
    function(opt_fovLeft, opt_fovRight, opt_zNear, opt_zFar) {
  // Not supported. getEyeParameters reports that the min, max, and recommended
  // FoV is all the same, so no adjustment can be made.
};

// TODO: Need to hook requestFullscreen to see if a wrapped VRDisplay was passed
// in as an option. If so we should prevent the default fullscreen behavior and
// call VRDisplay.requestPresent instead.

/**
 * Wraps a VRDisplay and exposes it as a PositionSensorVRDevice
 */
function VRDisplayPositionSensorDevice(display) {
  this.display = display;

  this.hardwareUnitId = display.displayId;
  this.deviceId = 'webvr-polyfill:PositionSensor: ' + display.displayId;
  this.deviceName = display.displayName + ' (PositionSensor)';
}
VRDisplayPositionSensorDevice.prototype = new PositionSensorVRDevice();

VRDisplayPositionSensorDevice.prototype.getState = function() {
  var pose = this.display.getPose();
  return {
    position: pose.position ? { x: pose.position[0], y: pose.position[1], z: pose.position[2] } : null,
    orientation: pose.orientation ? { x: pose.orientation[0], y: pose.orientation[1], z: pose.orientation[2], w: pose.orientation[3] } : null,
    linearVelocity: null,
    linearAcceleration: null,
    angularVelocity: null,
    angularAcceleration: null
  };
};

VRDisplayPositionSensorDevice.prototype.resetState = function() {
  return this.positionDevice.resetPose();
};


module.exports.VRDisplayHMDDevice = VRDisplayHMDDevice;
module.exports.VRDisplayPositionSensorDevice = VRDisplayPositionSensorDevice;


},{"./base.js":3}],10:[function(_dereq_,module,exports){
/**
 * TODO(smus): Implement coefficient inversion.
 */
function Distortion(coefficients) {
  this.coefficients = coefficients;
}

/**
 * Calculates the inverse distortion for a radius.
 * </p><p>
 * Allows to compute the original undistorted radius from a distorted one.
 * See also getApproximateInverseDistortion() for a faster but potentially
 * less accurate method.
 *
 * @param {Number} radius Distorted radius from the lens center in tan-angle units.
 * @return {Number} The undistorted radius in tan-angle units.
 */
Distortion.prototype.distortInverse = function(radius) {
  // Secant method.
  var r0 = 0;
  var r1 = 1;
  var dr0 = radius - this.distort(r0);
  while (Math.abs(r1 - r0) > 0.0001 /** 0.1mm */) {
    var dr1 = radius - this.distort(r1);
    var r2 = r1 - dr1 * ((r1 - r0) / (dr1 - dr0));
    r0 = r1;
    r1 = r2;
    dr0 = dr1;
  }
  return r1;
};

/**
 * Distorts a radius by its distortion factor from the center of the lenses.
 *
 * @param {Number} radius Radius from the lens center in tan-angle units.
 * @return {Number} The distorted radius in tan-angle units.
 */
Distortion.prototype.distort = function(radius) {
  var r2 = radius * radius;
  var ret = 0;
  for (var i = 0; i < this.coefficients.length; i++) {
    ret = r2 * (ret + this.coefficients[i]);
  }
  return (ret + 1) * radius;
};

// Functions below roughly ported from
// https://github.com/googlesamples/cardboard-unity/blob/master/Cardboard/Scripts/CardboardProfile.cs#L412

// Solves a small linear equation via destructive gaussian
// elimination and back substitution.  This isn't generic numeric
// code, it's just a quick hack to work with the generally
// well-behaved symmetric matrices for least-squares fitting.
// Not intended for reuse.
//
// @param a Input positive definite symmetrical matrix. Destroyed
//     during calculation.
// @param y Input right-hand-side values. Destroyed during calculation.
// @return Resulting x value vector.
//
Distortion.prototype.solveLinear_ = function(a, y) {
  var n = a.length;

  // Gaussian elimination (no row exchange) to triangular matrix.
  // The input matrix is a A^T A product which should be a positive
  // definite symmetrical matrix, and if I remember my linear
  // algebra right this implies that the pivots will be nonzero and
  // calculations sufficiently accurate without needing row
  // exchange.
  for (var j = 0; j < n - 1; ++j) {
    for (var k = j + 1; k < n; ++k) {
      var p = a[j][k] / a[j][j];
      for (var i = j + 1; i < n; ++i) {
        a[i][k] -= p * a[i][j];
      }
      y[k] -= p * y[j];
    }
  }
  // From this point on, only the matrix elements a[j][i] with i>=j are
  // valid. The elimination doesn't fill in eliminated 0 values.

  var x = new Array(n);

  // Back substitution.
  for (var j = n - 1; j >= 0; --j) {
    var v = y[j];
    for (var i = j + 1; i < n; ++i) {
      v -= a[i][j] * x[i];
    }
    x[j] = v / a[j][j];
  }

  return x;
};

// Solves a least-squares matrix equation.  Given the equation A * x = y, calculate the
// least-square fit x = inverse(A * transpose(A)) * transpose(A) * y.  The way this works
// is that, while A is typically not a square matrix (and hence not invertible), A * transpose(A)
// is always square.  That is:
//   A * x = y
//   transpose(A) * (A * x) = transpose(A) * y   <- multiply both sides by transpose(A)
//   (transpose(A) * A) * x = transpose(A) * y   <- associativity
//   x = inverse(transpose(A) * A) * transpose(A) * y  <- solve for x
// Matrix A's row count (first index) must match y's value count.  A's column count (second index)
// determines the length of the result vector x.
Distortion.prototype.solveLeastSquares_ = function(matA, vecY) {
  var i, j, k, sum;
  var numSamples = matA.length;
  var numCoefficients = matA[0].length;
  if (numSamples != vecY.Length) {
    throw new Error("Matrix / vector dimension mismatch");
  }

  // Calculate transpose(A) * A
  var matATA = new Array(numCoefficients);
  for (k = 0; k < numCoefficients; ++k) {
    matATA[k] = new Array(numCoefficients);
    for (j = 0; j < numCoefficients; ++j) {
      sum = 0;
      for (i = 0; i < numSamples; ++i) {
        sum += matA[j][i] * matA[k][i];
      }
      matATA[k][j] = sum;
    }
  }

  // Calculate transpose(A) * y
  var vecATY = new Array(numCoefficients);
  for (j = 0; j < numCoefficients; ++j) {
    sum = 0;
    for (i = 0; i < numSamples; ++i) {
      sum += matA[j][i] * vecY[i];
    }
    vecATY[j] = sum;
  }

  // Now solve (A * transpose(A)) * x = transpose(A) * y.
  return this.solveLinear_(matATA, vecATY);
};

/// Calculates an approximate inverse to the given radial distortion parameters.
Distortion.prototype.approximateInverse = function(maxRadius, numSamples) {
  maxRadius = maxRadius || 1;
  numSamples = numSamples || 100;
  var numCoefficients = 6;
  var i, j;

  // R + K1*R^3 + K2*R^5 = r, with R = rp = distort(r)
  // Repeating for numSamples:
  //   [ R0^3, R0^5 ] * [ K1 ] = [ r0 - R0 ]
  //   [ R1^3, R1^5 ]   [ K2 ]   [ r1 - R1 ]
  //   [ R2^3, R2^5 ]            [ r2 - R2 ]
  //   [ etc... ]                [ etc... ]
  // That is:
  //   matA * [K1, K2] = y
  // Solve:
  //   [K1, K2] = inverse(transpose(matA) * matA) * transpose(matA) * y
  var matA = new Array(numCoefficients);
  for (j = 0; j < numCoefficients; ++j) {
    matA[j] = new Array(numSamples);
  }
  var vecY = new Array(numSamples);

  for (i = 0; i < numSamples; ++i) {
    var r = maxRadius * (i + 1) / numSamples;
    var rp = this.distort(r);
    var v = rp;
    for (j = 0; j < numCoefficients; ++j) {
      v *= rp * rp;
      matA[j][i] = v;
    }
    vecY[i] = r - rp;
  }

  var inverseCoefficients = this.solveLeastSquares_(matA, vecY);

  return new Distortion(inverseCoefficients);
};

module.exports = Distortion;

},{}],11:[function(_dereq_,module,exports){
/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * DPDB cache.
 */
var DPDB_CACHE = {
  "format": 1,
  "last_updated": "2016-01-20T00:18:35Z",
  "devices": [

  {
    "type": "android",
    "rules": [
      { "mdmh": "asus/*/Nexus 7/*" },
      { "ua": "Nexus 7" }
    ],
    "dpi": [ 320.8, 323.0 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "asus/*/ASUS_Z00AD/*" },
      { "ua": "ASUS_Z00AD" }
    ],
    "dpi": [ 403.0, 404.6 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "HTC/*/HTC6435LVW/*" },
      { "ua": "HTC6435LVW" }
    ],
    "dpi": [ 449.7, 443.3 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "HTC/*/HTC One XL/*" },
      { "ua": "HTC One XL" }
    ],
    "dpi": [ 315.3, 314.6 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "htc/*/Nexus 9/*" },
      { "ua": "Nexus 9" }
    ],
    "dpi": 289.0,
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "HTC/*/HTC One M9/*" },
      { "ua": "HTC One M9" }
    ],
    "dpi": [ 442.5, 443.3 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "HTC/*/HTC One_M8/*" },
      { "ua": "HTC One_M8" }
    ],
    "dpi": [ 449.7, 447.4 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "HTC/*/HTC One/*" },
      { "ua": "HTC One" }
    ],
    "dpi": 472.8,
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "Huawei/*/Nexus 6P/*" },
      { "ua": "Nexus 6P" }
    ],
    "dpi": [ 515.1, 518.0 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "LGE/*/Nexus 5X/*" },
      { "ua": "Nexus 5X" }
    ],
    "dpi": [ 422.0, 419.9 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "LGE/*/LGMS345/*" },
      { "ua": "LGMS345" }
    ],
    "dpi": [ 221.7, 219.1 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "LGE/*/LG-D800/*" },
      { "ua": "LG-D800" }
    ],
    "dpi": [ 422.0, 424.1 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "LGE/*/LG-D850/*" },
      { "ua": "LG-D850" }
    ],
    "dpi": [ 537.9, 541.9 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "LGE/*/VS985 4G/*" },
      { "ua": "VS985 4G" }
    ],
    "dpi": [ 537.9, 535.6 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "LGE/*/Nexus 5/*" },
      { "ua": "Nexus 5 " }
    ],
    "dpi": [ 442.4, 444.8 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "LGE/*/Nexus 4/*" },
      { "ua": "Nexus 4" }
    ],
    "dpi": [ 319.8, 318.4 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "LGE/*/LG-P769/*" },
      { "ua": "LG-P769" }
    ],
    "dpi": [ 240.6, 247.5 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "LGE/*/LGMS323/*" },
      { "ua": "LGMS323" }
    ],
    "dpi": [ 206.6, 204.6 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "LGE/*/LGLS996/*" },
      { "ua": "LGLS996" }
    ],
    "dpi": [ 403.4, 401.5 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "Micromax/*/4560MMX/*" },
      { "ua": "4560MMX" }
    ],
    "dpi": [ 240.0, 219.4 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "Micromax/*/A250/*" },
      { "ua": "Micromax A250" }
    ],
    "dpi": [ 480.0, 446.4 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "Micromax/*/Micromax AQ4501/*" },
      { "ua": "Micromax AQ4501" }
    ],
    "dpi": 240.0,
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "motorola/*/DROID RAZR/*" },
      { "ua": "DROID RAZR" }
    ],
    "dpi": [ 368.1, 256.7 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "motorola/*/XT830C/*" },
      { "ua": "XT830C" }
    ],
    "dpi": [ 254.0, 255.9 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "motorola/*/XT1021/*" },
      { "ua": "XT1021" }
    ],
    "dpi": [ 254.0, 256.7 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "motorola/*/XT1023/*" },
      { "ua": "XT1023" }
    ],
    "dpi": [ 254.0, 256.7 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "motorola/*/XT1028/*" },
      { "ua": "XT1028" }
    ],
    "dpi": [ 326.6, 327.6 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "motorola/*/XT1034/*" },
      { "ua": "XT1034" }
    ],
    "dpi": [ 326.6, 328.4 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "motorola/*/XT1053/*" },
      { "ua": "XT1053" }
    ],
    "dpi": [ 315.3, 316.1 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "motorola/*/XT1562/*" },
      { "ua": "XT1562" }
    ],
    "dpi": [ 403.4, 402.7 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "motorola/*/Nexus 6/*" },
      { "ua": "Nexus 6 " }
    ],
    "dpi": [ 494.3, 489.7 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "motorola/*/XT1063/*" },
      { "ua": "XT1063" }
    ],
    "dpi": [ 295.0, 296.6 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "motorola/*/XT1064/*" },
      { "ua": "XT1064" }
    ],
    "dpi": [ 295.0, 295.6 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "motorola/*/XT1092/*" },
      { "ua": "XT1092" }
    ],
    "dpi": [ 422.0, 424.1 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "motorola/*/XT1095/*" },
      { "ua": "XT1095" }
    ],
    "dpi": [ 422.0, 423.4 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "OnePlus/*/A0001/*" },
      { "ua": "A0001" }
    ],
    "dpi": [ 403.4, 401.0 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "OnePlus/*/ONE E1005/*" },
      { "ua": "ONE E1005" }
    ],
    "dpi": [ 442.4, 441.4 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "OnePlus/*/ONE A2005/*" },
      { "ua": "ONE A2005" }
    ],
    "dpi": [ 391.9, 405.4 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "OPPO/*/X909/*" },
      { "ua": "X909" }
    ],
    "dpi": [ 442.4, 444.1 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/GT-I9082/*" },
      { "ua": "GT-I9082" }
    ],
    "dpi": [ 184.7, 185.4 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-G360P/*" },
      { "ua": "SM-G360P" }
    ],
    "dpi": [ 196.7, 205.4 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/Nexus S/*" },
      { "ua": "Nexus S" }
    ],
    "dpi": [ 234.5, 229.8 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/GT-I9300/*" },
      { "ua": "GT-I9300" }
    ],
    "dpi": [ 304.8, 303.9 ],
    "bw": 5,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-T230NU/*" },
      { "ua": "SM-T230NU" }
    ],
    "dpi": 216.0,
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SGH-T399/*" },
      { "ua": "SGH-T399" }
    ],
    "dpi": [ 217.7, 231.4 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-N9005/*" },
      { "ua": "SM-N9005" }
    ],
    "dpi": [ 386.4, 387.0 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SAMSUNG-SM-N900A/*" },
      { "ua": "SAMSUNG-SM-N900A" }
    ],
    "dpi": [ 386.4, 387.7 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/GT-I9500/*" },
      { "ua": "GT-I9500" }
    ],
    "dpi": [ 442.5, 443.3 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/GT-I9505/*" },
      { "ua": "GT-I9505" }
    ],
    "dpi": 439.4,
    "bw": 4,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-G900F/*" },
      { "ua": "SM-G900F" }
    ],
    "dpi": [ 415.6, 431.6 ],
    "bw": 5,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-G900M/*" },
      { "ua": "SM-G900M" }
    ],
    "dpi": [ 415.6, 431.6 ],
    "bw": 5,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-G800F/*" },
      { "ua": "SM-G800F" }
    ],
    "dpi": 326.8,
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-G906S/*" },
      { "ua": "SM-G906S" }
    ],
    "dpi": [ 562.7, 572.4 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/GT-I9300/*" },
      { "ua": "GT-I9300" }
    ],
    "dpi": [ 306.7, 304.8 ],
    "bw": 5,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-T535/*" },
      { "ua": "SM-T535" }
    ],
    "dpi": [ 142.6, 136.4 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-N920C/*" },
      { "ua": "SM-N920C" }
    ],
    "dpi": [ 515.1, 518.4 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/GT-I9300I/*" },
      { "ua": "GT-I9300I" }
    ],
    "dpi": [ 304.8, 305.8 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/GT-I9195/*" },
      { "ua": "GT-I9195" }
    ],
    "dpi": [ 249.4, 256.7 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SPH-L520/*" },
      { "ua": "SPH-L520" }
    ],
    "dpi": [ 249.4, 255.9 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SAMSUNG-SGH-I717/*" },
      { "ua": "SAMSUNG-SGH-I717" }
    ],
    "dpi": 285.8,
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SPH-D710/*" },
      { "ua": "SPH-D710" }
    ],
    "dpi": [ 217.7, 204.2 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/GT-N7100/*" },
      { "ua": "GT-N7100" }
    ],
    "dpi": 265.1,
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SCH-I605/*" },
      { "ua": "SCH-I605" }
    ],
    "dpi": 265.1,
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/Galaxy Nexus/*" },
      { "ua": "Galaxy Nexus" }
    ],
    "dpi": [ 315.3, 314.2 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-N910H/*" },
      { "ua": "SM-N910H" }
    ],
    "dpi": [ 515.1, 518.0 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-N910C/*" },
      { "ua": "SM-N910C" }
    ],
    "dpi": [ 515.2, 520.2 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-G130M/*" },
      { "ua": "SM-G130M" }
    ],
    "dpi": [ 165.9, 164.8 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-G928I/*" },
      { "ua": "SM-G928I" }
    ],
    "dpi": [ 515.1, 518.4 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-G920F/*" },
      { "ua": "SM-G920F" }
    ],
    "dpi": 580.6,
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-G920P/*" },
      { "ua": "SM-G920P" }
    ],
    "dpi": [ 522.5, 577.0 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-G925F/*" },
      { "ua": "SM-G925F" }
    ],
    "dpi": 580.6,
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "samsung/*/SM-G925V/*" },
      { "ua": "SM-G925V" }
    ],
    "dpi": [ 522.5, 576.6 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "Sony/*/C6903/*" },
      { "ua": "C6903" }
    ],
    "dpi": [ 442.5, 443.3 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "Sony/*/D6653/*" },
      { "ua": "D6653" }
    ],
    "dpi": [ 428.6, 427.6 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "Sony/*/E6653/*" },
      { "ua": "E6653" }
    ],
    "dpi": [ 428.6, 425.7 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "Sony/*/E6853/*" },
      { "ua": "E6853" }
    ],
    "dpi": [ 403.4, 401.9 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "Sony/*/SGP321/*" },
      { "ua": "SGP321" }
    ],
    "dpi": [ 224.7, 224.1 ],
    "bw": 3,
    "ac": 500
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "TCT/*/ALCATEL ONE TOUCH Fierce/*" },
      { "ua": "ALCATEL ONE TOUCH Fierce" }
    ],
    "dpi": [ 240.0, 247.5 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "THL/*/thl 5000/*" },
      { "ua": "thl 5000" }
    ],
    "dpi": [ 480.0, 443.3 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "android",
    "rules": [
      { "mdmh": "ZTE/*/ZTE Blade L2/*" },
      { "ua": "ZTE Blade L2" }
    ],
    "dpi": 240.0,
    "bw": 3,
    "ac": 500
  },

  {
    "type": "ios",
    "rules": [ { "res": [ 640, 960 ] } ],
    "dpi": [ 325.1, 328.4 ],
    "bw": 4,
    "ac": 1000
  },

  {
    "type": "ios",
    "rules": [ { "res": [ 640, 960 ] } ],
    "dpi": [ 325.1, 328.4 ],
    "bw": 4,
    "ac": 1000
  },

  {
    "type": "ios",
    "rules": [ { "res": [ 640, 1136 ] } ],
    "dpi": [ 317.1, 320.2 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "ios",
    "rules": [ { "res": [ 640, 1136 ] } ],
    "dpi": [ 317.1, 320.2 ],
    "bw": 3,
    "ac": 1000
  },

  {
    "type": "ios",
    "rules": [ { "res": [ 750, 1334 ] } ],
    "dpi": 326.4,
    "bw": 4,
    "ac": 1000
  },

  {
    "type": "ios",
    "rules": [ { "res": [ 750, 1334 ] } ],
    "dpi": 326.4,
    "bw": 4,
    "ac": 1000
  },

  {
    "type": "ios",
    "rules": [ { "res": [ 1242, 2208 ] } ],
    "dpi": [ 453.6, 458.4 ],
    "bw": 4,
    "ac": 1000
  },

  {
    "type": "ios",
    "rules": [ { "res": [ 1242, 2208 ] } ],
    "dpi": [ 453.6, 458.4 ],
    "bw": 4,
    "ac": 1000
  }
]};

module.exports = DPDB_CACHE;

},{}],12:[function(_dereq_,module,exports){
/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// Offline cache of the DPDB, to be used until we load the online one (and
// as a fallback in case we can't load the online one).
var DPDB_CACHE = _dereq_('./dpdb-cache.js');
var Util = _dereq_('../util.js');

// Online DPDB URL.
var ONLINE_DPDB_URL = 'https://storage.googleapis.com/cardboard-dpdb/dpdb.json';

/**
 * Calculates device parameters based on the DPDB (Device Parameter Database).
 * Initially, uses the cached DPDB values.
 *
 * If fetchOnline == true, then this object tries to fetch the online version
 * of the DPDB and updates the device info if a better match is found.
 * Calls the onDeviceParamsUpdated callback when there is an update to the
 * device information.
 */
function Dpdb(fetchOnline, onDeviceParamsUpdated) {
  // Start with the offline DPDB cache while we are loading the real one.
  this.dpdb = DPDB_CACHE;

  // Calculate device params based on the offline version of the DPDB.
  this.recalculateDeviceParams_();

  // XHR to fetch online DPDB file, if requested.
  if (fetchOnline) {
    // Set the callback.
    this.onDeviceParamsUpdated = onDeviceParamsUpdated;

    var xhr = new XMLHttpRequest();
    var obj = this;
    xhr.open('GET', ONLINE_DPDB_URL, true);
    xhr.addEventListener('load', function() {
      obj.loading = false;
      if (xhr.status >= 200 && xhr.status <= 299) {
        // Success.
        obj.dpdb = JSON.parse(xhr.response);
        obj.recalculateDeviceParams_();
      } else {
        // Error loading the DPDB.
        console.error('Error loading online DPDB!');
      }
    });
    xhr.send();
  }
}

// Returns the current device parameters.
Dpdb.prototype.getDeviceParams = function() {
  return this.deviceParams;
};

// Recalculates this device's parameters based on the DPDB.
Dpdb.prototype.recalculateDeviceParams_ = function() {
  var newDeviceParams = this.calcDeviceParams_();
  if (newDeviceParams) {
    this.deviceParams = newDeviceParams;
    // Invoke callback, if it is set.
    if (this.onDeviceParamsUpdated) {
      this.onDeviceParamsUpdated(this.deviceParams);
    }
  } else {
    console.error('Failed to recalculate device parameters.');
  }
};

// Returns a DeviceParams object that represents the best guess as to this
// device's parameters. Can return null if the device does not match any
// known devices.
Dpdb.prototype.calcDeviceParams_ = function() {
  var db = this.dpdb; // shorthand
  if (!db) {
    console.error('DPDB not available.');
    return null;
  }
  if (db.format != 1) {
    console.error('DPDB has unexpected format version.');
    return null;
  }
  if (!db.devices || !db.devices.length) {
    console.error('DPDB does not have a devices section.');
    return null;
  }

  // Get the actual user agent and screen dimensions in pixels.
  var userAgent = navigator.userAgent || navigator.vendor || window.opera;
  var width = Util.getScreenWidth();
  var height = Util.getScreenHeight();

  if (!db.devices) {
    console.error('DPDB has no devices section.');
    return null;
  }

  for (var i = 0; i < db.devices.length; i++) {
    var device = db.devices[i];
    if (!device.rules) {
      console.warn('Device[' + i + '] has no rules section.');
      continue;
    }

    if (device.type != 'ios' && device.type != 'android') {
      console.warn('Device[' + i + '] has invalid type.');
      continue;
    }

    // See if this device is of the appropriate type.
    if (Util.isIOS() != (device.type == 'ios')) continue;

    // See if this device matches any of the rules:
    var matched = false;
    for (var j = 0; j < device.rules.length; j++) {
      var rule = device.rules[j];
      if (this.matchRule_(rule, userAgent, width, height)) {
        matched = true;
        break;
      }
    }
    if (!matched) continue;

    // device.dpi might be an array of [ xdpi, ydpi] or just a scalar.
    var xdpi = device.dpi[0] || device.dpi;
    var ydpi = device.dpi[1] || device.dpi;

    return new DeviceParams({ xdpi: xdpi, ydpi: ydpi, bevelMm: device.bw });
  }

  console.warn('No DPDB device match.');
  return null;
};

Dpdb.prototype.matchRule_ = function(rule, ua, screenWidth, screenHeight) {
  // We can only match 'ua' and 'res' rules, not other types like 'mdmh'
  // (which are meant for native platforms).
  if (!rule.ua && !rule.res) return false;

  // If our user agent string doesn't contain the indicated user agent string,
  // the match fails.
  if (rule.ua && ua.indexOf(rule.ua) < 0) return false;

  // If the rule specifies screen dimensions that don't correspond to ours,
  // the match fails.
  if (rule.res) {
    if (!rule.res[0] || !rule.res[1]) return false;
    var resX = rule.res[0];
    var resY = rule.res[1];
    // Compare min and max so as to make the order not matter, i.e., it should
    // be true that 640x480 == 480x640.
    if (Math.min(screenWidth, screenHeight) != Math.min(resX, resY) ||
        (Math.max(screenWidth, screenHeight) != Math.max(resX, resY))) {
      return false;
    }
  }

  return true;
}

function DeviceParams(params) {
  this.xdpi = params.xdpi;
  this.ydpi = params.ydpi;
  this.bevelMm = params.bevelMm;
}

module.exports = Dpdb;

},{"../util.js":22,"./dpdb-cache.js":11}],13:[function(_dereq_,module,exports){
/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
var Util = _dereq_('./util.js');
var WebVRPolyfill = _dereq_('./webvr-polyfill.js').WebVRPolyfill;

// Initialize a WebVRConfig just in case.
window.WebVRConfig = Util.extend({
  // Forces availability of VR mode, even for non-mobile devices.
  FORCE_ENABLE_VR: false,

  // Complementary filter coefficient. 0 for accelerometer, 1 for gyro.
  K_FILTER: 0.98,

  // How far into the future to predict during fast motion (in seconds).
  PREDICTION_TIME_S: 0.040,

  // Flag to enable touch panner. In case you have your own touch controls.
  TOUCH_PANNER_DISABLED: true,

  // Flag to disabled the UI in VR Mode.
  CARDBOARD_UI_DISABLED: false, // Default: false

  // Flag to disable the instructions to rotate your device.
  ROTATE_INSTRUCTIONS_DISABLED: false, // Default: false.

  // Enable yaw panning only, disabling roll and pitch. This can be useful
  // for panoramas with nothing interesting above or below.
  YAW_ONLY: false,

  // To disable keyboard and mouse controls, if you want to use your own
  // implementation.
  MOUSE_KEYBOARD_CONTROLS_DISABLED: false,

  // Prevent the polyfill from initializing immediately. Requires the app
  // to call InitializeWebVRPolyfill() before it can be used.
  DEFER_INITIALIZATION: false,

  // Enable the deprecated version of the API (navigator.getVRDevices).
  ENABLE_DEPRECATED_API: false,

  // Scales the recommended buffer size reported by WebVR, which can improve
  // performance.
  // UPDATE(2016-05-03): Setting this to 0.5 by default since 1.0 does not
  // perform well on many mobile devices.
  BUFFER_SCALE: 0.5,

  // Allow VRDisplay.submitFrame to change gl bindings, which is more
  // efficient if the application code will re-bind its resources on the
  // next frame anyway. This has been seen to cause rendering glitches with
  // THREE.js.
  // Dirty bindings include: gl.FRAMEBUFFER_BINDING, gl.CURRENT_PROGRAM,
  // gl.ARRAY_BUFFER_BINDING, gl.ELEMENT_ARRAY_BUFFER_BINDING,
  // and gl.TEXTURE_BINDING_2D for texture unit 0.
  DIRTY_SUBMIT_FRAME_BINDINGS: false,

  // When set to true, this will cause a polyfilled VRDisplay to always be
  // appended to the list returned by navigator.getVRDisplays(), even if that
  // list includes a native VRDisplay.
  ALWAYS_APPEND_POLYFILL_DISPLAY: false
}, window.WebVRConfig);

if (!window.WebVRConfig.DEFER_INITIALIZATION) {
  new WebVRPolyfill();
} else {
  window.InitializeWebVRPolyfill = function() {
    new WebVRPolyfill();
  }
}

},{"./util.js":22,"./webvr-polyfill.js":25}],14:[function(_dereq_,module,exports){
/*
 * Copyright 2016 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var MathUtil = window.MathUtil || {};

MathUtil.degToRad = Math.PI / 180;
MathUtil.radToDeg = 180 / Math.PI;

// Some minimal math functionality borrowed from THREE.Math and stripped down
// for the purposes of this library.


MathUtil.Vector2 = function ( x, y ) {
  this.x = x || 0;
  this.y = y || 0;
};

MathUtil.Vector2.prototype = {
  constructor: MathUtil.Vector2,

  set: function ( x, y ) {
    this.x = x;
    this.y = y;

    return this;
  },

  copy: function ( v ) {
    this.x = v.x;
    this.y = v.y;

    return this;
  },

  subVectors: function ( a, b ) {
    this.x = a.x - b.x;
    this.y = a.y - b.y;

    return this;
  },
};

MathUtil.Vector3 = function ( x, y, z ) {
  this.x = x || 0;
  this.y = y || 0;
  this.z = z || 0;
};

MathUtil.Vector3.prototype = {
  constructor: MathUtil.Vector3,

  set: function ( x, y, z ) {
    this.x = x;
    this.y = y;
    this.z = z;

    return this;
  },

  copy: function ( v ) {
    this.x = v.x;
    this.y = v.y;
    this.z = v.z;

    return this;
  },

  length: function () {
    return Math.sqrt( this.x * this.x + this.y * this.y + this.z * this.z );
  },

  normalize: function () {
    var scalar = this.length();

    if ( scalar !== 0 ) {
      var invScalar = 1 / scalar;

      this.multiplyScalar(invScalar);
    } else {
      this.x = 0;
      this.y = 0;
      this.z = 0;
    }

    return this;
  },

  multiplyScalar: function ( scalar ) {
    this.x *= scalar;
    this.y *= scalar;
    this.z *= scalar;
  },

  applyQuaternion: function ( q ) {
    var x = this.x;
    var y = this.y;
    var z = this.z;

    var qx = q.x;
    var qy = q.y;
    var qz = q.z;
    var qw = q.w;

    // calculate quat * vector
    var ix =  qw * x + qy * z - qz * y;
    var iy =  qw * y + qz * x - qx * z;
    var iz =  qw * z + qx * y - qy * x;
    var iw = - qx * x - qy * y - qz * z;

    // calculate result * inverse quat
    this.x = ix * qw + iw * - qx + iy * - qz - iz * - qy;
    this.y = iy * qw + iw * - qy + iz * - qx - ix * - qz;
    this.z = iz * qw + iw * - qz + ix * - qy - iy * - qx;

    return this;
  },

  dot: function ( v ) {
    return this.x * v.x + this.y * v.y + this.z * v.z;
  },

  crossVectors: function ( a, b ) {
    var ax = a.x, ay = a.y, az = a.z;
    var bx = b.x, by = b.y, bz = b.z;

    this.x = ay * bz - az * by;
    this.y = az * bx - ax * bz;
    this.z = ax * by - ay * bx;

    return this;
  },
};

MathUtil.Quaternion = function ( x, y, z, w ) {
  this.x = x || 0;
  this.y = y || 0;
  this.z = z || 0;
  this.w = ( w !== undefined ) ? w : 1;
};

MathUtil.Quaternion.prototype = {
  constructor: MathUtil.Quaternion,

  set: function ( x, y, z, w ) {
    this.x = x;
    this.y = y;
    this.z = z;
    this.w = w;

    return this;
  },

  copy: function ( quaternion ) {
    this.x = quaternion.x;
    this.y = quaternion.y;
    this.z = quaternion.z;
    this.w = quaternion.w;

    return this;
  },

  setFromEulerXYZ: function( x, y, z ) {
    var c1 = Math.cos( x / 2 );
    var c2 = Math.cos( y / 2 );
    var c3 = Math.cos( z / 2 );
    var s1 = Math.sin( x / 2 );
    var s2 = Math.sin( y / 2 );
    var s3 = Math.sin( z / 2 );

    this.x = s1 * c2 * c3 + c1 * s2 * s3;
    this.y = c1 * s2 * c3 - s1 * c2 * s3;
    this.z = c1 * c2 * s3 + s1 * s2 * c3;
    this.w = c1 * c2 * c3 - s1 * s2 * s3;

    return this;
  },

  setFromEulerYXZ: function( x, y, z ) {
    var c1 = Math.cos( x / 2 );
    var c2 = Math.cos( y / 2 );
    var c3 = Math.cos( z / 2 );
    var s1 = Math.sin( x / 2 );
    var s2 = Math.sin( y / 2 );
    var s3 = Math.sin( z / 2 );

    this.x = s1 * c2 * c3 + c1 * s2 * s3;
    this.y = c1 * s2 * c3 - s1 * c2 * s3;
    this.z = c1 * c2 * s3 - s1 * s2 * c3;
    this.w = c1 * c2 * c3 + s1 * s2 * s3;

    return this;
  },

  setFromAxisAngle: function ( axis, angle ) {
    // http://www.euclideanspace.com/maths/geometry/rotations/conversions/angleToQuaternion/index.htm
    // assumes axis is normalized

    var halfAngle = angle / 2, s = Math.sin( halfAngle );

    this.x = axis.x * s;
    this.y = axis.y * s;
    this.z = axis.z * s;
    this.w = Math.cos( halfAngle );

    return this;
  },

  multiply: function ( q ) {
    return this.multiplyQuaternions( this, q );
  },

  multiplyQuaternions: function ( a, b ) {
    // from http://www.euclideanspace.com/maths/algebra/realNormedAlgebra/quaternions/code/index.htm

    var qax = a.x, qay = a.y, qaz = a.z, qaw = a.w;
    var qbx = b.x, qby = b.y, qbz = b.z, qbw = b.w;

    this.x = qax * qbw + qaw * qbx + qay * qbz - qaz * qby;
    this.y = qay * qbw + qaw * qby + qaz * qbx - qax * qbz;
    this.z = qaz * qbw + qaw * qbz + qax * qby - qay * qbx;
    this.w = qaw * qbw - qax * qbx - qay * qby - qaz * qbz;

    return this;
  },

  inverse: function () {
    this.x *= -1;
    this.y *= -1;
    this.z *= -1;

    this.normalize();

    return this;
  },

  normalize: function () {
    var l = Math.sqrt( this.x * this.x + this.y * this.y + this.z * this.z + this.w * this.w );

    if ( l === 0 ) {
      this.x = 0;
      this.y = 0;
      this.z = 0;
      this.w = 1;
    } else {
      l = 1 / l;

      this.x = this.x * l;
      this.y = this.y * l;
      this.z = this.z * l;
      this.w = this.w * l;
    }

    return this;
  },

  slerp: function ( qb, t ) {
    if ( t === 0 ) return this;
    if ( t === 1 ) return this.copy( qb );

    var x = this.x, y = this.y, z = this.z, w = this.w;

    // http://www.euclideanspace.com/maths/algebra/realNormedAlgebra/quaternions/slerp/

    var cosHalfTheta = w * qb.w + x * qb.x + y * qb.y + z * qb.z;

    if ( cosHalfTheta < 0 ) {
      this.w = - qb.w;
      this.x = - qb.x;
      this.y = - qb.y;
      this.z = - qb.z;

      cosHalfTheta = - cosHalfTheta;
    } else {
      this.copy( qb );
    }

    if ( cosHalfTheta >= 1.0 ) {
      this.w = w;
      this.x = x;
      this.y = y;
      this.z = z;

      return this;
    }

    var halfTheta = Math.acos( cosHalfTheta );
    var sinHalfTheta = Math.sqrt( 1.0 - cosHalfTheta * cosHalfTheta );

    if ( Math.abs( sinHalfTheta ) < 0.001 ) {
      this.w = 0.5 * ( w + this.w );
      this.x = 0.5 * ( x + this.x );
      this.y = 0.5 * ( y + this.y );
      this.z = 0.5 * ( z + this.z );

      return this;
    }

    var ratioA = Math.sin( ( 1 - t ) * halfTheta ) / sinHalfTheta,
    ratioB = Math.sin( t * halfTheta ) / sinHalfTheta;

    this.w = ( w * ratioA + this.w * ratioB );
    this.x = ( x * ratioA + this.x * ratioB );
    this.y = ( y * ratioA + this.y * ratioB );
    this.z = ( z * ratioA + this.z * ratioB );

    return this;
  },

  setFromUnitVectors: function () {
    // http://lolengine.net/blog/2014/02/24/quaternion-from-two-vectors-final
    // assumes direction vectors vFrom and vTo are normalized

    var v1, r;
    var EPS = 0.000001;

    return function ( vFrom, vTo ) {
      if ( v1 === undefined ) v1 = new MathUtil.Vector3();

      r = vFrom.dot( vTo ) + 1;

      if ( r < EPS ) {
        r = 0;

        if ( Math.abs( vFrom.x ) > Math.abs( vFrom.z ) ) {
          v1.set( - vFrom.y, vFrom.x, 0 );
        } else {
          v1.set( 0, - vFrom.z, vFrom.y );
        }
      } else {
        v1.crossVectors( vFrom, vTo );
      }

      this.x = v1.x;
      this.y = v1.y;
      this.z = v1.z;
      this.w = r;

      this.normalize();

      return this;
    }
  }(),
};

module.exports = MathUtil;

},{}],15:[function(_dereq_,module,exports){
/*
 * Copyright 2016 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var VRDisplay = _dereq_('./base.js').VRDisplay;
var MathUtil = _dereq_('./math-util.js');
var Util = _dereq_('./util.js');

// How much to rotate per key stroke.
var KEY_SPEED = 0.15;
var KEY_ANIMATION_DURATION = 80;

// How much to rotate for mouse events.
var MOUSE_SPEED_X = 0.5;
var MOUSE_SPEED_Y = 0.3;

/**
 * VRDisplay based on mouse and keyboard input. Designed for desktops/laptops
 * where orientation events aren't supported. Cannot present.
 */
function MouseKeyboardVRDisplay() {
  this.displayName = 'Mouse and Keyboard VRDisplay (webvr-polyfill)';

  this.capabilities.hasOrientation = true;

  // Attach to mouse and keyboard events.
  window.addEventListener('keydown', this.onKeyDown_.bind(this));
  window.addEventListener('mousemove', this.onMouseMove_.bind(this));
  window.addEventListener('mousedown', this.onMouseDown_.bind(this));
  window.addEventListener('mouseup', this.onMouseUp_.bind(this));

  // "Private" members.
  this.phi_ = 0;
  this.theta_ = 0;

  // Variables for keyboard-based rotation animation.
  this.targetAngle_ = null;
  this.angleAnimation_ = null;

  // State variables for calculations.
  this.orientation_ = new MathUtil.Quaternion();

  // Variables for mouse-based rotation.
  this.rotateStart_ = new MathUtil.Vector2();
  this.rotateEnd_ = new MathUtil.Vector2();
  this.rotateDelta_ = new MathUtil.Vector2();
  this.isDragging_ = false;

  this.orientationOut_ = new Float32Array(4);
}
MouseKeyboardVRDisplay.prototype = new VRDisplay();

MouseKeyboardVRDisplay.prototype.getImmediatePose = function() {
  this.orientation_.setFromEulerYXZ(this.phi_, this.theta_, 0);

  this.orientationOut_[0] = this.orientation_.x;
  this.orientationOut_[1] = this.orientation_.y;
  this.orientationOut_[2] = this.orientation_.z;
  this.orientationOut_[3] = this.orientation_.w;

  return {
    position: null,
    orientation: this.orientationOut_,
    linearVelocity: null,
    linearAcceleration: null,
    angularVelocity: null,
    angularAcceleration: null
  };
};

MouseKeyboardVRDisplay.prototype.onKeyDown_ = function(e) {
  // Track WASD and arrow keys.
  if (e.keyCode == 38) { // Up key.
    this.animatePhi_(this.phi_ + KEY_SPEED);
  } else if (e.keyCode == 39) { // Right key.
    this.animateTheta_(this.theta_ - KEY_SPEED);
  } else if (e.keyCode == 40) { // Down key.
    this.animatePhi_(this.phi_ - KEY_SPEED);
  } else if (e.keyCode == 37) { // Left key.
    this.animateTheta_(this.theta_ + KEY_SPEED);
  }
};

MouseKeyboardVRDisplay.prototype.animateTheta_ = function(targetAngle) {
  this.animateKeyTransitions_('theta_', targetAngle);
};

MouseKeyboardVRDisplay.prototype.animatePhi_ = function(targetAngle) {
  // Prevent looking too far up or down.
  targetAngle = Util.clamp(targetAngle, -Math.PI/2, Math.PI/2);
  this.animateKeyTransitions_('phi_', targetAngle);
};

/**
 * Start an animation to transition an angle from one value to another.
 */
MouseKeyboardVRDisplay.prototype.animateKeyTransitions_ = function(angleName, targetAngle) {
  // If an animation is currently running, cancel it.
  if (this.angleAnimation_) {
    cancelAnimationFrame(this.angleAnimation_);
  }
  var startAngle = this[angleName];
  var startTime = new Date();
  // Set up an interval timer to perform the animation.
  this.angleAnimation_ = requestAnimationFrame(function animate() {
    // Once we're finished the animation, we're done.
    var elapsed = new Date() - startTime;
    if (elapsed >= KEY_ANIMATION_DURATION) {
      this[angleName] = targetAngle;
      cancelAnimationFrame(this.angleAnimation_);
      return;
    }
    // loop with requestAnimationFrame
    this.angleAnimation_ = requestAnimationFrame(animate.bind(this))
    // Linearly interpolate the angle some amount.
    var percent = elapsed / KEY_ANIMATION_DURATION;
    this[angleName] = startAngle + (targetAngle - startAngle) * percent;
  }.bind(this));
};

MouseKeyboardVRDisplay.prototype.onMouseDown_ = function(e) {
  this.rotateStart_.set(e.clientX, e.clientY);
  this.isDragging_ = true;
};

// Very similar to https://gist.github.com/mrflix/8351020
MouseKeyboardVRDisplay.prototype.onMouseMove_ = function(e) {
  if (!this.isDragging_ && !this.isPointerLocked_()) {
    return;
  }
  // Support pointer lock API.
  if (this.isPointerLocked_()) {
    var movementX = e.movementX || e.mozMovementX || 0;
    var movementY = e.movementY || e.mozMovementY || 0;
    this.rotateEnd_.set(this.rotateStart_.x - movementX, this.rotateStart_.y - movementY);
  } else {
    this.rotateEnd_.set(e.clientX, e.clientY);
  }
  // Calculate how much we moved in mouse space.
  this.rotateDelta_.subVectors(this.rotateEnd_, this.rotateStart_);
  this.rotateStart_.copy(this.rotateEnd_);

  // Keep track of the cumulative euler angles.
  this.phi_ += 2 * Math.PI * this.rotateDelta_.y / screen.height * MOUSE_SPEED_Y;
  this.theta_ += 2 * Math.PI * this.rotateDelta_.x / screen.width * MOUSE_SPEED_X;

  // Prevent looking too far up or down.
  this.phi_ = Util.clamp(this.phi_, -Math.PI/2, Math.PI/2);
};

MouseKeyboardVRDisplay.prototype.onMouseUp_ = function(e) {
  this.isDragging_ = false;
};

MouseKeyboardVRDisplay.prototype.isPointerLocked_ = function() {
  var el = document.pointerLockElement || document.mozPointerLockElement ||
      document.webkitPointerLockElement;
  return el !== undefined;
};

MouseKeyboardVRDisplay.prototype.resetPose = function() {
  this.phi_ = 0;
  this.theta_ = 0;
};

module.exports = MouseKeyboardVRDisplay;

},{"./base.js":3,"./math-util.js":14,"./util.js":22}],16:[function(_dereq_,module,exports){
/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var Util = _dereq_('./util.js');

function RotateInstructions() {
  this.loadIcon_();

  var overlay = document.createElement('div');
  var s = overlay.style;
  s.position = 'fixed';
  s.top = 0;
  s.right = 0;
  s.bottom = 0;
  s.left = 0;
  s.backgroundColor = 'gray';
  s.fontFamily = 'sans-serif';
  // Force this to be above the fullscreen canvas, which is at zIndex: 999999.
  s.zIndex = 1000000;

  var img = document.createElement('img');
  img.src = this.icon;
  var s = img.style;
  s.marginLeft = '25%';
  s.marginTop = '25%';
  s.width = '50%';
  overlay.appendChild(img);

  var text = document.createElement('div');
  var s = text.style;
  s.textAlign = 'center';
  s.fontSize = '16px';
  s.lineHeight = '24px';
  s.margin = '24px 25%';
  s.width = '50%';
  text.innerHTML = 'Place your phone into your Cardboard viewer.';
  overlay.appendChild(text);

  var snackbar = document.createElement('div');
  var s = snackbar.style;
  s.backgroundColor = '#CFD8DC';
  s.position = 'fixed';
  s.bottom = 0;
  s.width = '100%';
  s.height = '48px';
  s.padding = '14px 24px';
  s.boxSizing = 'border-box';
  s.color = '#656A6B';
  overlay.appendChild(snackbar);

  var snackbarText = document.createElement('div');
  snackbarText.style.float = 'left';
  snackbarText.innerHTML = 'No Cardboard viewer?';

  var snackbarButton = document.createElement('a');
  snackbarButton.href = 'https://www.google.com/get/cardboard/get-cardboard/';
  snackbarButton.innerHTML = 'get one';
  snackbarButton.target = '_blank';
  var s = snackbarButton.style;
  s.float = 'right';
  s.fontWeight = 600;
  s.textTransform = 'uppercase';
  s.borderLeft = '1px solid gray';
  s.paddingLeft = '24px';
  s.textDecoration = 'none';
  s.color = '#656A6B';

  snackbar.appendChild(snackbarText);
  snackbar.appendChild(snackbarButton);

  this.overlay = overlay;
  this.text = text;

  this.hide();
}

RotateInstructions.prototype.show = function(parent) {
  if (!parent && !this.overlay.parentElement) {
    document.body.appendChild(this.overlay);
  } else if (parent) {
    if (this.overlay.parentElement && this.overlay.parentElement != parent)
      this.overlay.parentElement.removeChild(this.overlay);

    parent.appendChild(this.overlay);
  }

  this.overlay.style.display = 'block';

  var img = this.overlay.querySelector('img');
  var s = img.style;

  if (Util.isLandscapeMode()) {
    s.width = '20%';
    s.marginLeft = '40%';
    s.marginTop = '3%';
  } else {
    s.width = '50%';
    s.marginLeft = '25%';
    s.marginTop = '25%';
  }
};

RotateInstructions.prototype.hide = function() {
  this.overlay.style.display = 'none';
};

RotateInstructions.prototype.showTemporarily = function(ms, parent) {
  this.show(parent);
  this.timer = setTimeout(this.hide.bind(this), ms);
};

RotateInstructions.prototype.disableShowTemporarily = function() {
  clearTimeout(this.timer);
};

RotateInstructions.prototype.update = function() {
  this.disableShowTemporarily();
  // In portrait VR mode, tell the user to rotate to landscape. Otherwise, hide
  // the instructions.
  if (!Util.isLandscapeMode() && Util.isMobile()) {
    this.show();
  } else {
    this.hide();
  }
};

RotateInstructions.prototype.loadIcon_ = function() {
  // Encoded asset_src/rotate-instructions.svg
  this.icon = Util.base64('image/svg+xml', ' ');
};

module.exports = RotateInstructions;

},{"./util.js":22}],17:[function(_dereq_,module,exports){
/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var SensorSample = _dereq_('./sensor-sample.js');
var MathUtil = _dereq_('../math-util.js');
var Util = _dereq_('../util.js');

/**
 * An implementation of a simple complementary filter, which fuses gyroscope and
 * accelerometer data from the 'devicemotion' event.
 *
 * Accelerometer data is very noisy, but stable over the long term.
 * Gyroscope data is smooth, but tends to drift over the long term.
 *
 * This fusion is relatively simple:
 * 1. Get orientation estimates from accelerometer by applying a low-pass filter
 *    on that data.
 * 2. Get orientation estimates from gyroscope by integrating over time.
 * 3. Combine the two estimates, weighing (1) in the long term, but (2) for the
 *    short term.
 */
function ComplementaryFilter(kFilter) {
  this.kFilter = kFilter;

  // Raw sensor measurements.
  this.currentAccelMeasurement = new SensorSample();
  this.currentGyroMeasurement = new SensorSample();
  this.previousGyroMeasurement = new SensorSample();

  // Set default look direction to be in the correct direction.
  if (Util.isIOS()) {
    this.filterQ = new MathUtil.Quaternion(-1, 0, 0, 1);
  } else {
    this.filterQ = new MathUtil.Quaternion(1, 0, 0, 1);
  }
  this.previousFilterQ = new MathUtil.Quaternion();
  this.previousFilterQ.copy(this.filterQ);

  // Orientation based on the accelerometer.
  this.accelQ = new MathUtil.Quaternion();
  // Whether or not the orientation has been initialized.
  this.isOrientationInitialized = false;
  // Running estimate of gravity based on the current orientation.
  this.estimatedGravity = new MathUtil.Vector3();
  // Measured gravity based on accelerometer.
  this.measuredGravity = new MathUtil.Vector3();

  // Debug only quaternion of gyro-based orientation.
  this.gyroIntegralQ = new MathUtil.Quaternion();
}

ComplementaryFilter.prototype.addAccelMeasurement = function(vector, timestampS) {
  this.currentAccelMeasurement.set(vector, timestampS);
};

ComplementaryFilter.prototype.addGyroMeasurement = function(vector, timestampS) {
  this.currentGyroMeasurement.set(vector, timestampS);

  var deltaT = timestampS - this.previousGyroMeasurement.timestampS;
  if (Util.isTimestampDeltaValid(deltaT)) {
    this.run_();
  }

  this.previousGyroMeasurement.copy(this.currentGyroMeasurement);
};

ComplementaryFilter.prototype.run_ = function() {

  if (!this.isOrientationInitialized) {
    this.accelQ = this.accelToQuaternion_(this.currentAccelMeasurement.sample);
    this.previousFilterQ.copy(this.accelQ);
    this.isOrientationInitialized = true;
    return;
  }

  var deltaT = this.currentGyroMeasurement.timestampS -
      this.previousGyroMeasurement.timestampS;

  // Convert gyro rotation vector to a quaternion delta.
  var gyroDeltaQ = this.gyroToQuaternionDelta_(this.currentGyroMeasurement.sample, deltaT);
  this.gyroIntegralQ.multiply(gyroDeltaQ);

  // filter_1 = K * (filter_0 + gyro * dT) + (1 - K) * accel.
  this.filterQ.copy(this.previousFilterQ);
  this.filterQ.multiply(gyroDeltaQ);

  // Calculate the delta between the current estimated gravity and the real
  // gravity vector from accelerometer.
  var invFilterQ = new MathUtil.Quaternion();
  invFilterQ.copy(this.filterQ);
  invFilterQ.inverse();

  this.estimatedGravity.set(0, 0, -1);
  this.estimatedGravity.applyQuaternion(invFilterQ);
  this.estimatedGravity.normalize();

  this.measuredGravity.copy(this.currentAccelMeasurement.sample);
  this.measuredGravity.normalize();

  // Compare estimated gravity with measured gravity, get the delta quaternion
  // between the two.
  var deltaQ = new MathUtil.Quaternion();
  deltaQ.setFromUnitVectors(this.estimatedGravity, this.measuredGravity);
  deltaQ.inverse();

  if (Util.isDebug()) {
    console.log('Delta: %d deg, G_est: (%s, %s, %s), G_meas: (%s, %s, %s)',
                MathUtil.radToDeg * Util.getQuaternionAngle(deltaQ),
                (this.estimatedGravity.x).toFixed(1),
                (this.estimatedGravity.y).toFixed(1),
                (this.estimatedGravity.z).toFixed(1),
                (this.measuredGravity.x).toFixed(1),
                (this.measuredGravity.y).toFixed(1),
                (this.measuredGravity.z).toFixed(1));
  }

  // Calculate the SLERP target: current orientation plus the measured-estimated
  // quaternion delta.
  var targetQ = new MathUtil.Quaternion();
  targetQ.copy(this.filterQ);
  targetQ.multiply(deltaQ);

  // SLERP factor: 0 is pure gyro, 1 is pure accel.
  this.filterQ.slerp(targetQ, 1 - this.kFilter);

  this.previousFilterQ.copy(this.filterQ);
};

ComplementaryFilter.prototype.getOrientation = function() {
  return this.filterQ;
};

ComplementaryFilter.prototype.accelToQuaternion_ = function(accel) {
  var normAccel = new MathUtil.Vector3();
  normAccel.copy(accel);
  normAccel.normalize();
  var quat = new MathUtil.Quaternion();
  quat.setFromUnitVectors(new MathUtil.Vector3(0, 0, -1), normAccel);
  quat.inverse();
  return quat;
};

ComplementaryFilter.prototype.gyroToQuaternionDelta_ = function(gyro, dt) {
  // Extract axis and angle from the gyroscope data.
  var quat = new MathUtil.Quaternion();
  var axis = new MathUtil.Vector3();
  axis.copy(gyro);
  axis.normalize();
  quat.setFromAxisAngle(axis, gyro.length() * dt);
  return quat;
};


module.exports = ComplementaryFilter;

},{"../math-util.js":14,"../util.js":22,"./sensor-sample.js":20}],18:[function(_dereq_,module,exports){
/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
var ComplementaryFilter = _dereq_('./complementary-filter.js');
var PosePredictor = _dereq_('./pose-predictor.js');
var TouchPanner = _dereq_('../touch-panner.js');
var MathUtil = _dereq_('../math-util.js');
var Util = _dereq_('../util.js');

/**
 * The pose sensor, implemented using DeviceMotion APIs.
 */
function FusionPoseSensor() {
  this.deviceId = 'webvr-polyfill:fused';
  this.deviceName = 'VR Position Device (webvr-polyfill:fused)';

  this.accelerometer = new MathUtil.Vector3();
  this.gyroscope = new MathUtil.Vector3();

  this.start();

  this.filter = new ComplementaryFilter(WebVRConfig.K_FILTER);
  this.posePredictor = new PosePredictor(WebVRConfig.PREDICTION_TIME_S);
  this.touchPanner = new TouchPanner();

  this.filterToWorldQ = new MathUtil.Quaternion();

  // Set the filter to world transform, depending on OS.
  if (Util.isIOS()) {
    this.filterToWorldQ.setFromAxisAngle(new MathUtil.Vector3(1, 0, 0), Math.PI / 2);
  } else {
    this.filterToWorldQ.setFromAxisAngle(new MathUtil.Vector3(1, 0, 0), -Math.PI / 2);
  }

  this.inverseWorldToScreenQ = new MathUtil.Quaternion();
  this.worldToScreenQ = new MathUtil.Quaternion();
  this.originalPoseAdjustQ = new MathUtil.Quaternion();
  this.originalPoseAdjustQ.setFromAxisAngle(new MathUtil.Vector3(0, 0, 1),
                                           -window.orientation * Math.PI / 180);

  this.setScreenTransform_();
  // Adjust this filter for being in landscape mode.
  if (Util.isLandscapeMode()) {
    this.filterToWorldQ.multiply(this.inverseWorldToScreenQ);
  }

  // Keep track of a reset transform for resetSensor.
  this.resetQ = new MathUtil.Quaternion();

  this.isFirefoxAndroid = Util.isFirefoxAndroid();
  this.isIOS = Util.isIOS();

  this.orientationOut_ = new Float32Array(4);
}

FusionPoseSensor.prototype.getPosition = function() {
  // This PoseSensor doesn't support position
  return null;
};

FusionPoseSensor.prototype.getOrientation = function() {
  // Convert from filter space to the the same system used by the
  // deviceorientation event.
  var orientation = this.filter.getOrientation();

  // Predict orientation.
  this.predictedQ = this.posePredictor.getPrediction(orientation, this.gyroscope, this.previousTimestampS);

  // Convert to THREE coordinate system: -Z forward, Y up, X right.
  var out = new MathUtil.Quaternion();
  out.copy(this.filterToWorldQ);
  out.multiply(this.resetQ);
  if (!WebVRConfig.TOUCH_PANNER_DISABLED) {
    out.multiply(this.touchPanner.getOrientation());
  }
  out.multiply(this.predictedQ);
  out.multiply(this.worldToScreenQ);

  // Handle the yaw-only case.
  if (WebVRConfig.YAW_ONLY) {
    // Make a quaternion that only turns around the Y-axis.
    out.x = 0;
    out.z = 0;
    out.normalize();
  }

  this.orientationOut_[0] = out.x;
  this.orientationOut_[1] = out.y;
  this.orientationOut_[2] = out.z;
  this.orientationOut_[3] = out.w;
  return this.orientationOut_;
};

FusionPoseSensor.prototype.resetPose = function() {
  // Reduce to inverted yaw-only.
  this.resetQ.copy(this.filter.getOrientation());
  this.resetQ.x = 0;
  this.resetQ.y = 0;
  this.resetQ.z *= -1;
  this.resetQ.normalize();

  // Take into account extra transformations in landscape mode.
  if (Util.isLandscapeMode()) {
    this.resetQ.multiply(this.inverseWorldToScreenQ);
  }

  // Take into account original pose.
  this.resetQ.multiply(this.originalPoseAdjustQ);

  if (!WebVRConfig.TOUCH_PANNER_DISABLED) {
    this.touchPanner.resetSensor();
  }
};

FusionPoseSensor.prototype.onDeviceMotion_ = function(deviceMotion) {
  this.updateDeviceMotion_(deviceMotion);
};

FusionPoseSensor.prototype.updateDeviceMotion_ = function(deviceMotion) {
  var accGravity = deviceMotion.accelerationIncludingGravity;
  var rotRate = deviceMotion.rotationRate;
  var timestampS = deviceMotion.timeStamp / 1000;

  // Firefox Android timeStamp returns one thousandth of a millisecond.
  if (this.isFirefoxAndroid) {
    timestampS /= 1000;
  }

  var deltaS = timestampS - this.previousTimestampS;
  if (deltaS <= Util.MIN_TIMESTEP || deltaS > Util.MAX_TIMESTEP) {
    console.warn('Invalid timestamps detected. Time step between successive ' +
                 'gyroscope sensor samples is very small or not monotonic');
    this.previousTimestampS = timestampS;
    return;
  }
  this.accelerometer.set(-accGravity.x, -accGravity.y, -accGravity.z);
  this.gyroscope.set(rotRate.alpha, rotRate.beta, rotRate.gamma);

  // With iOS and Firefox Android, rotationRate is reported in degrees,
  // so we first convert to radians.
  if (this.isIOS || this.isFirefoxAndroid) {
    this.gyroscope.multiplyScalar(Math.PI / 180);
  }

  this.filter.addAccelMeasurement(this.accelerometer, timestampS);
  this.filter.addGyroMeasurement(this.gyroscope, timestampS);

  this.previousTimestampS = timestampS;
};

FusionPoseSensor.prototype.onOrientationChange_ = function(screenOrientation) {
  this.setScreenTransform_();
};

/**
 * This is only needed if we are in an cross origin iframe on iOS to work around
 * this issue: https://bugs.webkit.org/show_bug.cgi?id=152299.
 */
FusionPoseSensor.prototype.onMessage_ = function(event) {
  var message = event.data;

  // If there's no message type, ignore it.
  if (!message || !message.type) {
    return;
  }

  // Ignore all messages that aren't devicemotion.
  var type = message.type.toLowerCase();
  if (type !== 'devicemotion') {
    return;
  }

  // Update device motion.
  this.updateDeviceMotion_(message.deviceMotionEvent);
};

FusionPoseSensor.prototype.setScreenTransform_ = function() {
  this.worldToScreenQ.set(0, 0, 0, 1);
  switch (window.orientation) {
    case 0:
      break;
    case 90:
      this.worldToScreenQ.setFromAxisAngle(new MathUtil.Vector3(0, 0, 1), -Math.PI / 2);
      break;
    case -90:
      this.worldToScreenQ.setFromAxisAngle(new MathUtil.Vector3(0, 0, 1), Math.PI / 2);
      break;
    case 180:
      // TODO.
      break;
  }
  this.inverseWorldToScreenQ.copy(this.worldToScreenQ);
  this.inverseWorldToScreenQ.inverse();
};

FusionPoseSensor.prototype.start = function() {
  this.onDeviceMotionCallback_ = this.onDeviceMotion_.bind(this);
  this.onOrientationChangeCallback_ = this.onOrientationChange_.bind(this);
  this.onMessageCallback_ = this.onMessage_.bind(this);

  // Only listen for postMessages if we're in an iOS and embedded inside a cross
  // domain IFrame. In this case, the polyfill can still work if the containing
  // page sends synthetic devicemotion events. For an example of this, see
  // iframe-message-sender.js in VR View: https://goo.gl/XDtvFZ
  if (Util.isIOS() && Util.isInsideCrossDomainIFrame()) {
    window.addEventListener('message', this.onMessageCallback_);
  }
  window.addEventListener('orientationchange', this.onOrientationChangeCallback_);
  window.addEventListener('devicemotion', this.onDeviceMotionCallback_);
};

FusionPoseSensor.prototype.stop = function() {
  window.removeEventListener('devicemotion', this.onDeviceMotionCallback_);
  window.removeEventListener('orientationchange', this.onOrientationChangeCallback_);
  window.removeEventListener('message', this.onMessageCallback_);
};

module.exports = FusionPoseSensor;

},{"../math-util.js":14,"../touch-panner.js":21,"../util.js":22,"./complementary-filter.js":17,"./pose-predictor.js":19}],19:[function(_dereq_,module,exports){
/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
var MathUtil = _dereq_('../math-util');
var Util = _dereq_('../util');

/**
 * Given an orientation and the gyroscope data, predicts the future orientation
 * of the head. This makes rendering appear faster.
 *
 * Also see: http://msl.cs.uiuc.edu/~lavalle/papers/LavYerKatAnt14.pdf
 *
 * @param {Number} predictionTimeS time from head movement to the appearance of
 * the corresponding image.
 */
function PosePredictor(predictionTimeS) {
  this.predictionTimeS = predictionTimeS;

  // The quaternion corresponding to the previous state.
  this.previousQ = new MathUtil.Quaternion();
  // Previous time a prediction occurred.
  this.previousTimestampS = null;

  // The delta quaternion that adjusts the current pose.
  this.deltaQ = new MathUtil.Quaternion();
  // The output quaternion.
  this.outQ = new MathUtil.Quaternion();
}

PosePredictor.prototype.getPrediction = function(currentQ, gyro, timestampS) {
  if (!this.previousTimestampS) {
    this.previousQ.copy(currentQ);
    this.previousTimestampS = timestampS;
    return currentQ;
  }

  // Calculate axis and angle based on gyroscope rotation rate data.
  var axis = new MathUtil.Vector3();
  axis.copy(gyro);
  axis.normalize();

  var angularSpeed = gyro.length();

  // If we're rotating slowly, don't do prediction.
  if (angularSpeed < MathUtil.degToRad * 20) {
    if (Util.isDebug()) {
      console.log('Moving slowly, at %s deg/s: no prediction',
                  (MathUtil.radToDeg * angularSpeed).toFixed(1));
    }
    this.outQ.copy(currentQ);
    this.previousQ.copy(currentQ);
    return this.outQ;
  }

  // Get the predicted angle based on the time delta and latency.
  var deltaT = timestampS - this.previousTimestampS;
  var predictAngle = angularSpeed * this.predictionTimeS;

  this.deltaQ.setFromAxisAngle(axis, predictAngle);
  this.outQ.copy(this.previousQ);
  this.outQ.multiply(this.deltaQ);

  this.previousQ.copy(currentQ);
  this.previousTimestampS = timestampS;

  return this.outQ;
};


module.exports = PosePredictor;

},{"../math-util":14,"../util":22}],20:[function(_dereq_,module,exports){
function SensorSample(sample, timestampS) {
  this.set(sample, timestampS);
};

SensorSample.prototype.set = function(sample, timestampS) {
  this.sample = sample;
  this.timestampS = timestampS;
};

SensorSample.prototype.copy = function(sensorSample) {
  this.set(sensorSample.sample, sensorSample.timestampS);
};

module.exports = SensorSample;

},{}],21:[function(_dereq_,module,exports){
/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
var MathUtil = _dereq_('./math-util.js');
var Util = _dereq_('./util.js');

var ROTATE_SPEED = 0.5;
/**
 * Provides a quaternion responsible for pre-panning the scene before further
 * transformations due to device sensors.
 */
function TouchPanner() {
  window.addEventListener('touchstart', this.onTouchStart_.bind(this));
  window.addEventListener('touchmove', this.onTouchMove_.bind(this));
  window.addEventListener('touchend', this.onTouchEnd_.bind(this));

  this.isTouching = false;
  this.rotateStart = new MathUtil.Vector2();
  this.rotateEnd = new MathUtil.Vector2();
  this.rotateDelta = new MathUtil.Vector2();

  this.theta = 0;
  this.orientation = new MathUtil.Quaternion();
}

TouchPanner.prototype.getOrientation = function() {
  this.orientation.setFromEulerXYZ(0, 0, this.theta);
  return this.orientation;
};

TouchPanner.prototype.resetSensor = function() {
  this.theta = 0;
};

TouchPanner.prototype.onTouchStart_ = function(e) {
  // Only respond if there is exactly one touch.
  if (e.touches.length != 1) {
    return;
  }
  this.rotateStart.set(e.touches[0].pageX, e.touches[0].pageY);
  this.isTouching = true;
};

TouchPanner.prototype.onTouchMove_ = function(e) {
  if (!this.isTouching) {
    return;
  }
  this.rotateEnd.set(e.touches[0].pageX, e.touches[0].pageY);
  this.rotateDelta.subVectors(this.rotateEnd, this.rotateStart);
  this.rotateStart.copy(this.rotateEnd);

  // On iOS, direction is inverted.
  if (Util.isIOS()) {
    this.rotateDelta.x *= -1;
  }

  var element = document.body;
  this.theta += 2 * Math.PI * this.rotateDelta.x / element.clientWidth * ROTATE_SPEED;
};

TouchPanner.prototype.onTouchEnd_ = function(e) {
  this.isTouching = false;
};

module.exports = TouchPanner;

},{"./math-util.js":14,"./util.js":22}],22:[function(_dereq_,module,exports){
/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var objectAssign = _dereq_('object-assign');

var Util = window.Util || {};

Util.MIN_TIMESTEP = 0.001;
Util.MAX_TIMESTEP = 1;

Util.base64 = function(mimeType, base64) {
  return 'data:' + mimeType + ';base64,' + base64;
};

Util.clamp = function(value, min, max) {
  return Math.min(Math.max(min, value), max);
};

Util.lerp = function(a, b, t) {
  return a + ((b - a) * t);
};

Util.isIOS = (function() {
  var isIOS = /iPad|iPhone|iPod/.test(navigator.platform);
  return function() {
    return isIOS;
  };
})();

Util.isSafari = (function() {
  var isSafari = /^((?!chrome|android).)*safari/i.test(navigator.userAgent);
  return function() {
    return isSafari;
  };
})();

Util.isFirefoxAndroid = (function() {
  var isFirefoxAndroid = navigator.userAgent.indexOf('Firefox') !== -1 &&
      navigator.userAgent.indexOf('Android') !== -1;
  return function() {
    return isFirefoxAndroid;
  };
})();

Util.isLandscapeMode = function() {
  return (window.orientation == 90 || window.orientation == -90);
};

// Helper method to validate the time steps of sensor timestamps.
Util.isTimestampDeltaValid = function(timestampDeltaS) {
  if (isNaN(timestampDeltaS)) {
    return false;
  }
  if (timestampDeltaS <= Util.MIN_TIMESTEP) {
    return false;
  }
  if (timestampDeltaS > Util.MAX_TIMESTEP) {
    return false;
  }
  return true;
};

Util.getScreenWidth = function() {
  return Math.max(window.screen.width, window.screen.height) *
      window.devicePixelRatio;
};

Util.getScreenHeight = function() {
  return Math.min(window.screen.width, window.screen.height) *
      window.devicePixelRatio;
};

Util.requestFullscreen = function(element) {
  if (element.requestFullscreen) {
    element.requestFullscreen();
  } else if (element.webkitRequestFullscreen) {
    element.webkitRequestFullscreen();
  } else if (element.mozRequestFullScreen) {
    element.mozRequestFullScreen();
  } else if (element.msRequestFullscreen) {
    element.msRequestFullscreen();
  } else {
    return false;
  }

  return true;
};

Util.exitFullscreen = function() {
  if (document.exitFullscreen) {
    document.exitFullscreen();
  } else if (document.webkitExitFullscreen) {
    document.webkitExitFullscreen();
  } else if (document.mozCancelFullScreen) {
    document.mozCancelFullScreen();
  } else if (document.msExitFullscreen) {
    document.msExitFullscreen();
  } else {
    return false;
  }

  return true;
};

Util.getFullscreenElement = function() {
  return document.fullscreenElement ||
      document.webkitFullscreenElement ||
      document.mozFullScreenElement ||
      document.msFullscreenElement;
};

Util.linkProgram = function(gl, vertexSource, fragmentSource, attribLocationMap) {
  // No error checking for brevity.
  var vertexShader = gl.createShader(gl.VERTEX_SHADER);
  gl.shaderSource(vertexShader, vertexSource);
  gl.compileShader(vertexShader);

  var fragmentShader = gl.createShader(gl.FRAGMENT_SHADER);
  gl.shaderSource(fragmentShader, fragmentSource);
  gl.compileShader(fragmentShader);

  var program = gl.createProgram();
  gl.attachShader(program, vertexShader);
  gl.attachShader(program, fragmentShader);

  for (var attribName in attribLocationMap)
    gl.bindAttribLocation(program, attribLocationMap[attribName], attribName);

  gl.linkProgram(program);

  gl.deleteShader(vertexShader);
  gl.deleteShader(fragmentShader);

  return program;
};

Util.getProgramUniforms = function(gl, program) {
  var uniforms = {};
  var uniformCount = gl.getProgramParameter(program, gl.ACTIVE_UNIFORMS);
  var uniformName = '';
  for (var i = 0; i < uniformCount; i++) {
    var uniformInfo = gl.getActiveUniform(program, i);
    uniformName = uniformInfo.name.replace('[0]', '');
    uniforms[uniformName] = gl.getUniformLocation(program, uniformName);
  }
  return uniforms;
};

Util.orthoMatrix = function (out, left, right, bottom, top, near, far) {
  var lr = 1 / (left - right),
      bt = 1 / (bottom - top),
      nf = 1 / (near - far);
  out[0] = -2 * lr;
  out[1] = 0;
  out[2] = 0;
  out[3] = 0;
  out[4] = 0;
  out[5] = -2 * bt;
  out[6] = 0;
  out[7] = 0;
  out[8] = 0;
  out[9] = 0;
  out[10] = 2 * nf;
  out[11] = 0;
  out[12] = (left + right) * lr;
  out[13] = (top + bottom) * bt;
  out[14] = (far + near) * nf;
  out[15] = 1;
  return out;
};

Util.isMobile = function() {
  var check = false;
  (function(a){if(/(android|bb\d+|meego).+mobile|avantgo|bada\/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|mobile.+firefox|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|series(4|6)0|symbian|treo|up\.(browser|link)|vodafone|wap|windows ce|xda|xiino/i.test(a)||/1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\-(n|u)|c55\/|capi|ccwa|cdm\-|cell|chtm|cldc|cmd\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\-s|devi|dica|dmob|do(c|p)o|ds(12|\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\-|_)|g1 u|g560|gene|gf\-5|g\-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd\-(m|p|t)|hei\-|hi(pt|ta)|hp( i|ip)|hs\-c|ht(c(\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\-(20|go|ma)|i230|iac( |\-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc\-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|\-[a-w])|libw|lynx|m1\-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m\-cr|me(rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\-2|po(ck|rt|se)|prox|psio|pt\-g|qa\-a|qc(07|12|21|32|60|\-[2-7]|i\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\-|oo|p\-)|sdk\/|se(c(\-|0|1)|47|mc|nd|ri)|sgh\-|shar|sie(\-|m)|sk\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\-|v\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\-|tdg\-|tel(i|m)|tim\-|t\-mo|to(pl|sh)|ts(70|m\-|m3|m5)|tx\-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|yas\-|your|zeto|zte\-/i.test(a.substr(0,4)))check = true})(navigator.userAgent||navigator.vendor||window.opera);
  return check;
};

Util.extend = objectAssign;

Util.safariCssSizeWorkaround = function(canvas) {
  // TODO(smus): Remove this workaround when Safari for iOS is fixed.
  // iOS only workaround (for https://bugs.webkit.org/show_bug.cgi?id=152556).
  //
  // "To the last I grapple with thee;
  //  from hell's heart I stab at thee;
  //  for hate's sake I spit my last breath at thee."
  // -- Moby Dick, by Herman Melville
  if (Util.isIOS()) {
    var width = canvas.style.width;
    var height = canvas.style.height;
    canvas.style.width = (parseInt(width) + 1) + 'px';
    canvas.style.height = (parseInt(height)) + 'px';
    setTimeout(function() {
      canvas.style.width = width;
      canvas.style.height = height;
    }, 100);
  }

  // Debug only.
  window.Util = Util;
  window.canvas = canvas;
};

Util.isDebug = function() {
  return Util.getQueryParameter('debug');
};

Util.getQueryParameter = function(name) {
  var name = name.replace(/[\[]/, "\\[").replace(/[\]]/, "\\]");
  var regex = new RegExp("[\\?&]" + name + "=([^&#]*)"),
      results = regex.exec(location.search);
  return results === null ? "" : decodeURIComponent(results[1].replace(/\+/g, " "));
};

Util.frameDataFromPose = (function() {
  var piOver180 = Math.PI / 180.0;
  var rad45 = Math.PI * 0.25;

  // Borrowed from glMatrix.
  function mat4_perspectiveFromFieldOfView(out, fov, near, far) {
    var upTan = Math.tan(fov ? (fov.upDegrees * piOver180) : rad45),
    downTan = Math.tan(fov ? (fov.downDegrees * piOver180) : rad45),
    leftTan = Math.tan(fov ? (fov.leftDegrees * piOver180) : rad45),
    rightTan = Math.tan(fov ? (fov.rightDegrees * piOver180) : rad45),
    xScale = 2.0 / (leftTan + rightTan),
    yScale = 2.0 / (upTan + downTan);

    out[0] = xScale;
    out[1] = 0.0;
    out[2] = 0.0;
    out[3] = 0.0;
    out[4] = 0.0;
    out[5] = yScale;
    out[6] = 0.0;
    out[7] = 0.0;
    out[8] = -((leftTan - rightTan) * xScale * 0.5);
    out[9] = ((upTan - downTan) * yScale * 0.5);
    out[10] = far / (near - far);
    out[11] = -1.0;
    out[12] = 0.0;
    out[13] = 0.0;
    out[14] = (far * near) / (near - far);
    out[15] = 0.0;
    return out;
  }

  function mat4_fromRotationTranslation(out, q, v) {
    // Quaternion math
    var x = q[0], y = q[1], z = q[2], w = q[3],
        x2 = x + x,
        y2 = y + y,
        z2 = z + z,

        xx = x * x2,
        xy = x * y2,
        xz = x * z2,
        yy = y * y2,
        yz = y * z2,
        zz = z * z2,
        wx = w * x2,
        wy = w * y2,
        wz = w * z2;

    out[0] = 1 - (yy + zz);
    out[1] = xy + wz;
    out[2] = xz - wy;
    out[3] = 0;
    out[4] = xy - wz;
    out[5] = 1 - (xx + zz);
    out[6] = yz + wx;
    out[7] = 0;
    out[8] = xz + wy;
    out[9] = yz - wx;
    out[10] = 1 - (xx + yy);
    out[11] = 0;
    out[12] = v[0];
    out[13] = v[1];
    out[14] = v[2];
    out[15] = 1;

    return out;
  };

  function mat4_translate(out, a, v) {
    var x = v[0], y = v[1], z = v[2],
        a00, a01, a02, a03,
        a10, a11, a12, a13,
        a20, a21, a22, a23;

    if (a === out) {
      out[12] = a[0] * x + a[4] * y + a[8] * z + a[12];
      out[13] = a[1] * x + a[5] * y + a[9] * z + a[13];
      out[14] = a[2] * x + a[6] * y + a[10] * z + a[14];
      out[15] = a[3] * x + a[7] * y + a[11] * z + a[15];
    } else {
      a00 = a[0]; a01 = a[1]; a02 = a[2]; a03 = a[3];
      a10 = a[4]; a11 = a[5]; a12 = a[6]; a13 = a[7];
      a20 = a[8]; a21 = a[9]; a22 = a[10]; a23 = a[11];

      out[0] = a00; out[1] = a01; out[2] = a02; out[3] = a03;
      out[4] = a10; out[5] = a11; out[6] = a12; out[7] = a13;
      out[8] = a20; out[9] = a21; out[10] = a22; out[11] = a23;

      out[12] = a00 * x + a10 * y + a20 * z + a[12];
      out[13] = a01 * x + a11 * y + a21 * z + a[13];
      out[14] = a02 * x + a12 * y + a22 * z + a[14];
      out[15] = a03 * x + a13 * y + a23 * z + a[15];
    }

    return out;
  };

  function mat4_invert(out, a) {
    var a00 = a[0], a01 = a[1], a02 = a[2], a03 = a[3],
        a10 = a[4], a11 = a[5], a12 = a[6], a13 = a[7],
        a20 = a[8], a21 = a[9], a22 = a[10], a23 = a[11],
        a30 = a[12], a31 = a[13], a32 = a[14], a33 = a[15],

        b00 = a00 * a11 - a01 * a10,
        b01 = a00 * a12 - a02 * a10,
        b02 = a00 * a13 - a03 * a10,
        b03 = a01 * a12 - a02 * a11,
        b04 = a01 * a13 - a03 * a11,
        b05 = a02 * a13 - a03 * a12,
        b06 = a20 * a31 - a21 * a30,
        b07 = a20 * a32 - a22 * a30,
        b08 = a20 * a33 - a23 * a30,
        b09 = a21 * a32 - a22 * a31,
        b10 = a21 * a33 - a23 * a31,
        b11 = a22 * a33 - a23 * a32,

        // Calculate the determinant
        det = b00 * b11 - b01 * b10 + b02 * b09 + b03 * b08 - b04 * b07 + b05 * b06;

    if (!det) {
      return null;
    }
    det = 1.0 / det;

    out[0] = (a11 * b11 - a12 * b10 + a13 * b09) * det;
    out[1] = (a02 * b10 - a01 * b11 - a03 * b09) * det;
    out[2] = (a31 * b05 - a32 * b04 + a33 * b03) * det;
    out[3] = (a22 * b04 - a21 * b05 - a23 * b03) * det;
    out[4] = (a12 * b08 - a10 * b11 - a13 * b07) * det;
    out[5] = (a00 * b11 - a02 * b08 + a03 * b07) * det;
    out[6] = (a32 * b02 - a30 * b05 - a33 * b01) * det;
    out[7] = (a20 * b05 - a22 * b02 + a23 * b01) * det;
    out[8] = (a10 * b10 - a11 * b08 + a13 * b06) * det;
    out[9] = (a01 * b08 - a00 * b10 - a03 * b06) * det;
    out[10] = (a30 * b04 - a31 * b02 + a33 * b00) * det;
    out[11] = (a21 * b02 - a20 * b04 - a23 * b00) * det;
    out[12] = (a11 * b07 - a10 * b09 - a12 * b06) * det;
    out[13] = (a00 * b09 - a01 * b07 + a02 * b06) * det;
    out[14] = (a31 * b01 - a30 * b03 - a32 * b00) * det;
    out[15] = (a20 * b03 - a21 * b01 + a22 * b00) * det;

    return out;
  };

  var defaultOrientation = new Float32Array([0, 0, 0, 1]);
  var defaultPosition = new Float32Array([0, 0, 0]);

  function updateEyeMatrices(projection, view, pose, parameters, vrDisplay) {
    mat4_perspectiveFromFieldOfView(projection, parameters ? parameters.fieldOfView : null, vrDisplay.depthNear, vrDisplay.depthFar);

    var orientation = pose.orientation || defaultOrientation;
    var position = pose.position || defaultPosition;

    mat4_fromRotationTranslation(view, orientation, position);
    if (parameters)
      mat4_translate(view, view, parameters.offset);
    mat4_invert(view, view);
  }

  return function(frameData, pose, vrDisplay) {
    if (!frameData || !pose)
      return false;

    frameData.pose = pose;
    frameData.timestamp = pose.timestamp;

    updateEyeMatrices(
        frameData.leftProjectionMatrix, frameData.leftViewMatrix,
        pose, vrDisplay.getEyeParameters("left"), vrDisplay);
    updateEyeMatrices(
        frameData.rightProjectionMatrix, frameData.rightViewMatrix,
        pose, vrDisplay.getEyeParameters("right"), vrDisplay);

    return true;
  };
})();

Util.isInsideCrossDomainIFrame = function() {
  var isFramed = (window.self !== window.top);
  var refDomain = Util.getDomainFromUrl(document.referrer);
  var thisDomain = Util.getDomainFromUrl(window.location.href);

  return isFramed && (refDomain !== thisDomain);
};

// From http://stackoverflow.com/a/23945027.
Util.getDomainFromUrl = function(url) {
  var domain;
  // Find & remove protocol (http, ftp, etc.) and get domain.
  if (url.indexOf("://") > -1) {
    domain = url.split('/')[2];
  }
  else {
    domain = url.split('/')[0];
  }

  //find & remove port number
  domain = domain.split(':')[0];

  return domain;
}

module.exports = Util;

},{"object-assign":2}],23:[function(_dereq_,module,exports){
/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var DeviceInfo = _dereq_('./device-info.js');
var EventEmitter3 = _dereq_('eventemitter3');
var Util = _dereq_('./util.js');

var DEFAULT_VIEWER = 'CardboardV1';
var VIEWER_KEY = 'WEBVR_CARDBOARD_VIEWER';
var CLASS_NAME = 'webvr-polyfill-viewer-selector';

/**
 * Creates a viewer selector with the options specified. Supports being shown
 * and hidden. Generates events when viewer parameters change. Also supports
 * saving the currently selected index in localStorage.
 */
function ViewerSelector() {
  // Try to load the selected key from local storage. If none exists, use the
  // default key.
  try {
    this.selectedKey = localStorage.getItem(VIEWER_KEY) || DEFAULT_VIEWER;
  } catch (error) {
    console.error('Failed to load viewer profile: %s', error);
  }
  this.dialog = this.createDialog_(DeviceInfo.Viewers);
  this.root = null;
}
ViewerSelector.prototype = new EventEmitter3();

ViewerSelector.prototype.show = function(root) {
  this.root = root;

  root.appendChild(this.dialog);

  // Ensure the currently selected item is checked.
  var selected = this.dialog.querySelector('#' + this.selectedKey);
  selected.checked = true;

  // Show the UI.
  this.dialog.style.display = 'block';
};

ViewerSelector.prototype.hide = function() {
  if (this.root && this.root.contains(this.dialog)) {
    this.root.removeChild(this.dialog);
  }
  this.dialog.style.display = 'none';
};

ViewerSelector.prototype.getCurrentViewer = function() {
  return DeviceInfo.Viewers[this.selectedKey];
};

ViewerSelector.prototype.getSelectedKey_ = function() {
  var input = this.dialog.querySelector('input[name=field]:checked');
  if (input) {
    return input.id;
  }
  return null;
};

ViewerSelector.prototype.onSave_ = function() {
  this.selectedKey = this.getSelectedKey_();
  if (!this.selectedKey || !DeviceInfo.Viewers[this.selectedKey]) {
    console.error('ViewerSelector.onSave_: this should never happen!');
    return;
  }

  this.emit('change', DeviceInfo.Viewers[this.selectedKey]);

  // Attempt to save the viewer profile, but fails in private mode.
  try {
    localStorage.setItem(VIEWER_KEY, this.selectedKey);
  } catch(error) {
    console.error('Failed to save viewer profile: %s', error);
  }
  this.hide();
};

/**
 * Creates the dialog.
 */
ViewerSelector.prototype.createDialog_ = function(options) {
  var container = document.createElement('div');
  container.classList.add(CLASS_NAME);
  container.style.display = 'none';
  // Create an overlay that dims the background, and which goes away when you
  // tap it.
  var overlay = document.createElement('div');
  var s = overlay.style;
  s.position = 'fixed';
  s.left = 0;
  s.top = 0;
  s.width = '100%';
  s.height = '100%';
  s.background = 'rgba(0, 0, 0, 0.3)';
  overlay.addEventListener('click', this.hide.bind(this));

  var width = 280;
  var dialog = document.createElement('div');
  var s = dialog.style;
  s.boxSizing = 'border-box';
  s.position = 'fixed';
  s.top = '24px';
  s.left = '50%';
  s.marginLeft = (-width/2) + 'px';
  s.width = width + 'px';
  s.padding = '24px';
  s.overflow = 'hidden';
  s.background = '#fafafa';
  s.fontFamily = "'Roboto', sans-serif";
  s.boxShadow = '0px 5px 20px #666';

  dialog.appendChild(this.createH1_('Select your viewer'));
  for (var id in options) {
    dialog.appendChild(this.createChoice_(id, options[id].label));
  }
  dialog.appendChild(this.createButton_('Save', this.onSave_.bind(this)));

  container.appendChild(overlay);
  container.appendChild(dialog);

  return container;
};

ViewerSelector.prototype.createH1_ = function(name) {
  var h1 = document.createElement('h1');
  var s = h1.style;
  s.color = 'black';
  s.fontSize = '20px';
  s.fontWeight = 'bold';
  s.marginTop = 0;
  s.marginBottom = '24px';
  h1.innerHTML = name;
  return h1;
};

ViewerSelector.prototype.createChoice_ = function(id, name) {
  /*
  <div class="choice">
  <input id="v1" type="radio" name="field" value="v1">
  <label for="v1">Cardboard V1</label>
  </div>
  */
  var div = document.createElement('div');
  div.style.marginTop = '8px';
  div.style.color = 'black';

  var input = document.createElement('input');
  input.style.fontSize = '30px';
  input.setAttribute('id', id);
  input.setAttribute('type', 'radio');
  input.setAttribute('value', id);
  input.setAttribute('name', 'field');

  var label = document.createElement('label');
  label.style.marginLeft = '4px';
  label.setAttribute('for', id);
  label.innerHTML = name;

  div.appendChild(input);
  div.appendChild(label);

  return div;
};

ViewerSelector.prototype.createButton_ = function(label, onclick) {
  var button = document.createElement('button');
  button.innerHTML = label;
  var s = button.style;
  s.float = 'right';
  s.textTransform = 'uppercase';
  s.color = '#1094f7';
  s.fontSize = '14px';
  s.letterSpacing = 0;
  s.border = 0;
  s.background = 'none';
  s.marginTop = '16px';

  button.addEventListener('click', onclick);

  return button;
};

module.exports = ViewerSelector;

},{"./device-info.js":8,"./util.js":22,"eventemitter3":1}],24:[function(_dereq_,module,exports){
/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var Util = _dereq_('./util.js');

/**
 * Android and iOS compatible wakelock implementation.
 *
 * Refactored thanks to dkovalev@.
 */
function AndroidWakeLock() {
  var video = document.createElement('video');

  video.addEventListener('ended', function() {
    video.play();
  });

  this.request = function() {
    if (video.paused) {
      // Base64 version of videos_src/no-sleep-120s.mp4.
      video.src = Util.base64('video/mp4', ' ');
      video.play();
    }
  };

  this.release = function() {
    video.pause();
    video.src = '';
  };
}

function iOSWakeLock() {
  var timer = null;

  this.request = function() {
    if (!timer) {
      timer = setInterval(function() {
        window.location = window.location;
        setTimeout(window.stop, 0);
      }, 30000);
    }
  }

  this.release = function() {
    if (timer) {
      clearInterval(timer);
      timer = null;
    }
  }
}


function getWakeLock() {
  var userAgent = navigator.userAgent || navigator.vendor || window.opera;
  if (userAgent.match(/iPhone/i) || userAgent.match(/iPod/i)) {
    return iOSWakeLock;
  } else {
    return AndroidWakeLock;
  }
}

module.exports = getWakeLock();
},{"./util.js":22}],25:[function(_dereq_,module,exports){
/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var Util = _dereq_('./util.js');
var CardboardVRDisplay = _dereq_('./cardboard-vr-display.js');
var MouseKeyboardVRDisplay = _dereq_('./mouse-keyboard-vr-display.js');
// Uncomment to add positional tracking via webcam.
//var WebcamPositionSensorVRDevice = require('./webcam-position-sensor-vr-device.js');
var VRDisplay = _dereq_('./base.js').VRDisplay;
var VRFrameData = _dereq_('./base.js').VRFrameData;
var HMDVRDevice = _dereq_('./base.js').HMDVRDevice;
var PositionSensorVRDevice = _dereq_('./base.js').PositionSensorVRDevice;
var VRDisplayHMDDevice = _dereq_('./display-wrappers.js').VRDisplayHMDDevice;
var VRDisplayPositionSensorDevice = _dereq_('./display-wrappers.js').VRDisplayPositionSensorDevice;

function WebVRPolyfill() {
  this.displays = [];
  this.devices = []; // For deprecated objects
  this.devicesPopulated = false;
  this.nativeWebVRAvailable = this.isWebVRAvailable();
  this.nativeLegacyWebVRAvailable = this.isDeprecatedWebVRAvailable();
  this.nativeGetVRDisplaysFunc = this.nativeWebVRAvailable ?
                                 navigator.getVRDisplays :
                                 null;

  if (!this.nativeLegacyWebVRAvailable) {
    this.enablePolyfill();
    if (WebVRConfig.ENABLE_DEPRECATED_API) {
      this.enableDeprecatedPolyfill();
    }
  }

  // Put a shim in place to update the API to 1.1 if needed.
  InstallWebVRSpecShim();
}

WebVRPolyfill.prototype.isWebVRAvailable = function() {
  return ('getVRDisplays' in navigator);
};

WebVRPolyfill.prototype.isDeprecatedWebVRAvailable = function() {
  return ('getVRDevices' in navigator) || ('mozGetVRDevices' in navigator);
};

WebVRPolyfill.prototype.populateDevices = function() {
  if (this.devicesPopulated) {
    return;
  }

  // Initialize our virtual VR devices.
  var vrDisplay = null;

  // Add a Cardboard VRDisplay on compatible mobile devices
  if (this.isCardboardCompatible()) {
    vrDisplay = new CardboardVRDisplay();
    this.displays.push(vrDisplay);

    // For backwards compatibility
    if (WebVRConfig.ENABLE_DEPRECATED_API) {
      this.devices.push(new VRDisplayHMDDevice(vrDisplay));
      this.devices.push(new VRDisplayPositionSensorDevice(vrDisplay));
    }
  }

  // Add a Mouse and Keyboard driven VRDisplay for desktops/laptops
  if (!this.isMobile() && !WebVRConfig.MOUSE_KEYBOARD_CONTROLS_DISABLED) {
    vrDisplay = new MouseKeyboardVRDisplay();
    this.displays.push(vrDisplay);

    // For backwards compatibility
    if (WebVRConfig.ENABLE_DEPRECATED_API) {
      this.devices.push(new VRDisplayHMDDevice(vrDisplay));
      this.devices.push(new VRDisplayPositionSensorDevice(vrDisplay));
    }
  }

  // Uncomment to add positional tracking via webcam.
  //if (!this.isMobile() && WebVRConfig.ENABLE_DEPRECATED_API) {
  //  positionDevice = new WebcamPositionSensorVRDevice();
  //  this.devices.push(positionDevice);
  //}

  this.devicesPopulated = true;
};

WebVRPolyfill.prototype.enablePolyfill = function() {
  // Provide navigator.getVRDisplays.
  navigator.getVRDisplays = this.getVRDisplays.bind(this);

  // Provide the VRDisplay object.
  window.VRDisplay = VRDisplay;

  // Provide navigator.vrEnabled.
  var self = this;
  Object.defineProperty(navigator, 'vrEnabled', {
    get: function () {
      return self.isCardboardCompatible() &&
          (self.isFullScreenAvailable() || Util.isIOS());
    }
  });

  if (!'VRFrameData' in window) {
    // Provide the VRFrameData object.
    window.VRFrameData = VRFrameData;
  }
};

WebVRPolyfill.prototype.enableDeprecatedPolyfill = function() {
  // Provide navigator.getVRDevices.
  navigator.getVRDevices = this.getVRDevices.bind(this);

  // Provide the CardboardHMDVRDevice and PositionSensorVRDevice objects.
  window.HMDVRDevice = HMDVRDevice;
  window.PositionSensorVRDevice = PositionSensorVRDevice;
};

WebVRPolyfill.prototype.getVRDisplays = function() {
  this.populateDevices();
  var polyfillDisplays = this.displays;

  if (this.nativeWebVRAvailable) {
    return this.nativeGetVRDisplaysFunc.call(navigator).then(function(nativeDisplays) {
      if (WebVRConfig.ALWAYS_APPEND_POLYFILL_DISPLAY) {
        return nativeDisplays.concat(polyfillDisplays);
      } else {
        return nativeDisplays.length > 0 ? nativeDisplays : polyfillDisplays;
      }
    });
  } else {
    return new Promise(function(resolve, reject) {
      try {
        resolve(polyfillDisplays);
      } catch (e) {
        reject(e);
      }
    });
  }
};

WebVRPolyfill.prototype.getVRDevices = function() {
  console.warn('getVRDevices is deprecated. Please update your code to use getVRDisplays instead.');
  var self = this;
  return new Promise(function(resolve, reject) {
    try {
      if (!self.devicesPopulated) {
        if (self.nativeWebVRAvailable) {
          return navigator.getVRDisplays(function(displays) {
            for (var i = 0; i < displays.length; ++i) {
              self.devices.push(new VRDisplayHMDDevice(displays[i]));
              self.devices.push(new VRDisplayPositionSensorDevice(displays[i]));
            }
            self.devicesPopulated = true;
            resolve(self.devices);
          }, reject);
        }

        if (self.nativeLegacyWebVRAvailable) {
          return (navigator.getVRDDevices || navigator.mozGetVRDevices)(function(devices) {
            for (var i = 0; i < devices.length; ++i) {
              if (devices[i] instanceof HMDVRDevice) {
                self.devices.push(devices[i]);
              }
              if (devices[i] instanceof PositionSensorVRDevice) {
                self.devices.push(devices[i]);
              }
            }
            self.devicesPopulated = true;
            resolve(self.devices);
          }, reject);
        }
      }

      self.populateDevices();
      resolve(self.devices);
    } catch (e) {
      reject(e);
    }
  });
};

/**
 * Determine if a device is mobile.
 */
WebVRPolyfill.prototype.isMobile = function() {
  return /Android/i.test(navigator.userAgent) ||
      /iPhone|iPad|iPod/i.test(navigator.userAgent);
};

WebVRPolyfill.prototype.isCardboardCompatible = function() {
  // For now, support all iOS and Android devices.
  // Also enable the WebVRConfig.FORCE_VR flag for debugging.
  return this.isMobile() || WebVRConfig.FORCE_ENABLE_VR;
};

WebVRPolyfill.prototype.isFullScreenAvailable = function() {
  return (document.fullscreenEnabled ||
          document.mozFullScreenEnabled ||
          document.webkitFullscreenEnabled ||
          false);
};

// Installs a shim that updates a WebVR 1.0 spec implementation to WebVR 1.1
function InstallWebVRSpecShim() {
  if ('VRDisplay' in window && !('VRFrameData' in window)) {
    // Provide the VRFrameData object.
    window.VRFrameData = VRFrameData;

    // A lot of Chrome builds don't have depthNear and depthFar, even
    // though they're in the WebVR 1.0 spec. Patch them in if they're not present.
    if(!('depthNear' in window.VRDisplay.prototype)) {
      window.VRDisplay.prototype.depthNear = 0.01;
    }

    if(!('depthFar' in window.VRDisplay.prototype)) {
      window.VRDisplay.prototype.depthFar = 10000.0;
    }

    window.VRDisplay.prototype.getFrameData = function(frameData) {
      return Util.frameDataFromPose(frameData, this.getPose(), this);
    }
  }
};

module.exports.WebVRPolyfill = WebVRPolyfill;

},{"./base.js":3,"./cardboard-vr-display.js":6,"./display-wrappers.js":9,"./mouse-keyboard-vr-display.js":15,"./util.js":22}]},{},[13])(13)
});