'use strict';
exports.__esModule = true;
var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();
var _settings = require('../settings');
var _settings2 = _interopRequireDefault(_settings);
var _eventemitter = require('eventemitter3');
var _eventemitter2 = _interopRequireDefault(_eventemitter);
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
// Internal event used by composed emitter
var TICK = 'tick';
var TARGET_FPMS = _settings2.default.TARGET_FPMS;
/**
* A Ticker class that runs an update loop that other objects listen to.
* This class is composed around an EventEmitter object to add listeners
* meant for execution on the next requested animation frame.
* Animation frames are requested only when necessary,
* e.g. When the ticker is started and the emitter has listeners.
*
* @class
* @memberof PIXI.ticker
*/
var Ticker = function () {
/**
*
*/
function Ticker() {
var _this = this;
_classCallCheck(this, Ticker);
/**
* Internal emitter used to fire 'tick' event
* @private
*/
this._emitter = new _eventemitter2.default();
/**
* Internal current frame request ID
* @private
*/
this._requestId = null;
/**
* Internal value managed by minFPS property setter and getter.
* This is the maximum allowed milliseconds between updates.
* @private
*/
this._maxElapsedMS = 100;
/**
* Whether or not this ticker should invoke the method
* {@link PIXI.ticker.Ticker#start} automatically
* when a listener is added.
*
* @member {boolean}
* @default false
*/
this.autoStart = false;
/**
* Scalar time value from last frame to this frame.
* This value is capped by setting {@link PIXI.ticker.Ticker#minFPS}
* and is scaled with {@link PIXI.ticker.Ticker#speed}.
* **Note:** The cap may be exceeded by scaling.
*
* @member {number}
* @default 1
*/
this.deltaTime = 1;
/**
* Time elapsed in milliseconds from last frame to this frame.
* Opposed to what the scalar {@link PIXI.ticker.Ticker#deltaTime}
* is based, this value is neither capped nor scaled.
* If the platform supports DOMHighResTimeStamp,
* this value will have a precision of 1 µs.
*
* @member {number}
* @default 1 / TARGET_FPMS
*/
this.elapsedMS = 1 / TARGET_FPMS; // default to target frame time
/**
* The last time {@link PIXI.ticker.Ticker#update} was invoked.
* This value is also reset internally outside of invoking
* update, but only when a new animation frame is requested.
* If the platform supports DOMHighResTimeStamp,
* this value will have a precision of 1 µs.
*
* @member {number}
* @default 0
*/
this.lastTime = 0;
/**
* Factor of current {@link PIXI.ticker.Ticker#deltaTime}.
* @example
* // Scales ticker.deltaTime to what would be
* // the equivalent of approximately 120 FPS
* ticker.speed = 2;
*
* @member {number}
* @default 1
*/
this.speed = 1;
/**
* Whether or not this ticker has been started.
* `true` if {@link PIXI.ticker.Ticker#start} has been called.
* `false` if {@link PIXI.ticker.Ticker#stop} has been called.
* While `false`, this value may change to `true` in the
* event of {@link PIXI.ticker.Ticker#autoStart} being `true`
* and a listener is added.
*
* @member {boolean}
* @default false
*/
this.started = false;
/**
* Internal tick method bound to ticker instance.
* This is because in early 2015, Function.bind
* is still 60% slower in high performance scenarios.
* Also separating frame requests from update method
* so listeners may be called at any time and with
* any animation API, just invoke ticker.update(time).
*
* @private
* @param {number} time - Time since last tick.
*/
this._tick = function (time) {
_this._requestId = null;
if (_this.started) {
// Invoke listeners now
_this.update(time);
// Listener side effects may have modified ticker state.
if (_this.started && _this._requestId === null && _this._emitter.listeners(TICK, true)) {
_this._requestId = requestAnimationFrame(_this._tick);
}
}
};
}
/**
* Conditionally requests a new animation frame.
* If a frame has not already been requested, and if the internal
* emitter has listeners, a new frame is requested.
*
* @private
*/
Ticker.prototype._requestIfNeeded = function _requestIfNeeded() {
if (this._requestId === null && this._emitter.listeners(TICK, true)) {
// ensure callbacks get correct delta
this.lastTime = performance.now();
this._requestId = requestAnimationFrame(this._tick);
}
};
/**
* Conditionally cancels a pending animation frame.
*
* @private
*/
Ticker.prototype._cancelIfNeeded = function _cancelIfNeeded() {
if (this._requestId !== null) {
cancelAnimationFrame(this._requestId);
this._requestId = null;
}
};
/**
* Conditionally requests a new animation frame.
* If the ticker has been started it checks if a frame has not already
* been requested, and if the internal emitter has listeners. If these
* conditions are met, a new frame is requested. If the ticker has not
* been started, but autoStart is `true`, then the ticker starts now,
* and continues with the previous conditions to request a new frame.
*
* @private
*/
Ticker.prototype._startIfPossible = function _startIfPossible() {
if (this.started) {
this._requestIfNeeded();
} else if (this.autoStart) {
this.start();
}
};
/**
* Calls {@link module:eventemitter3.EventEmitter#on} internally for the
* internal 'tick' event. It checks if the emitter has listeners,
* and if so it requests a new animation frame at this point.
*
* @param {Function} fn - The listener function to be added for updates
* @param {Function} [context] - The listener context
* @returns {PIXI.ticker.Ticker} This instance of a ticker
*/
Ticker.prototype.add = function add(fn, context) {
this._emitter.on(TICK, fn, context);
this._startIfPossible();
return this;
};
/**
* Calls {@link module:eventemitter3.EventEmitter#once} internally for the
* internal 'tick' event. It checks if the emitter has listeners,
* and if so it requests a new animation frame at this point.
*
* @param {Function} fn - The listener function to be added for one update
* @param {Function} [context] - The listener context
* @returns {PIXI.ticker.Ticker} This instance of a ticker
*/
Ticker.prototype.addOnce = function addOnce(fn, context) {
this._emitter.once(TICK, fn, context);
this._startIfPossible();
return this;
};
/**
* Calls {@link module:eventemitter3.EventEmitter#off} internally for 'tick' event.
* It checks if the emitter has listeners for 'tick' event.
* If it does, then it cancels the animation frame.
*
* @param {Function} [fn] - The listener function to be removed
* @param {Function} [context] - The listener context to be removed
* @returns {PIXI.ticker.Ticker} This instance of a ticker
*/
Ticker.prototype.remove = function remove(fn, context) {
this._emitter.off(TICK, fn, context);
if (!this._emitter.listeners(TICK, true)) {
this._cancelIfNeeded();
}
return this;
};
/**
* Starts the ticker. If the ticker has listeners
* a new animation frame is requested at this point.
*/
Ticker.prototype.start = function start() {
if (!this.started) {
this.started = true;
this._requestIfNeeded();
}
};
/**
* Stops the ticker. If the ticker has requested
* an animation frame it is canceled at this point.
*/
Ticker.prototype.stop = function stop() {
if (this.started) {
this.started = false;
this._cancelIfNeeded();
}
};
/**
* Triggers an update. An update entails setting the
* current {@link PIXI.ticker.Ticker#elapsedMS},
* the current {@link PIXI.ticker.Ticker#deltaTime},
* invoking all listeners with current deltaTime,
* and then finally setting {@link PIXI.ticker.Ticker#lastTime}
* with the value of currentTime that was provided.
* This method will be called automatically by animation
* frame callbacks if the ticker instance has been started
* and listeners are added.
*
* @param {number} [currentTime=performance.now()] - the current time of execution
*/
Ticker.prototype.update = function update() {
var currentTime = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : performance.now();
var elapsedMS = void 0;
// If the difference in time is zero or negative, we ignore most of the work done here.
// If there is no valid difference, then should be no reason to let anyone know about it.
// A zero delta, is exactly that, nothing should update.
//
// The difference in time can be negative, and no this does not mean time traveling.
// This can be the result of a race condition between when an animation frame is requested
// on the current JavaScript engine event loop, and when the ticker's start method is invoked
// (which invokes the internal _requestIfNeeded method). If a frame is requested before
// _requestIfNeeded is invoked, then the callback for the animation frame the ticker requests,
// can receive a time argument that can be less than the lastTime value that was set within
// _requestIfNeeded. This difference is in microseconds, but this is enough to cause problems.
//
// This check covers this browser engine timing issue, as well as if consumers pass an invalid
// currentTime value. This may happen if consumers opt-out of the autoStart, and update themselves.
if (currentTime > this.lastTime) {
// Save uncapped elapsedMS for measurement
elapsedMS = this.elapsedMS = currentTime - this.lastTime;
// cap the milliseconds elapsed used for deltaTime
if (elapsedMS > this._maxElapsedMS) {
elapsedMS = this._maxElapsedMS;
}
this.deltaTime = elapsedMS * TARGET_FPMS * this.speed;
// Invoke listeners added to internal emitter
this._emitter.emit(TICK, this.deltaTime);
} else {
this.deltaTime = this.elapsedMS = 0;
}
this.lastTime = currentTime;
};
/**
* The frames per second at which this ticker is running.
* The default is approximately 60 in most modern browsers.
* **Note:** This does not factor in the value of
* {@link PIXI.ticker.Ticker#speed}, which is specific
* to scaling {@link PIXI.ticker.Ticker#deltaTime}.
*
* @memberof PIXI.ticker.Ticker#
* @readonly
*/
_createClass(Ticker, [{
key: 'FPS',
get: function get() {
return 1000 / this.elapsedMS;
}
/**
* Manages the maximum amount of milliseconds allowed to
* elapse between invoking {@link PIXI.ticker.Ticker#update}.
* This value is used to cap {@link PIXI.ticker.Ticker#deltaTime},
* but does not effect the measured value of {@link PIXI.ticker.Ticker#FPS}.
* When setting this property it is clamped to a value between
* `0` and `PIXI.settings.TARGET_FPMS * 1000`.
*
* @memberof PIXI.ticker.Ticker#
* @default 10
*/
}, {
key: 'minFPS',
get: function get() {
return 1000 / this._maxElapsedMS;
}
/**
* Sets the min fps.
*
* @param {number} fps - value to set.
*/
,
set: function set(fps) {
// Clamp: 0 to TARGET_FPMS
var minFPMS = Math.min(Math.max(0, fps) / 1000, TARGET_FPMS);
this._maxElapsedMS = 1 / minFPMS;
}
}]);
return Ticker;
}();
exports.default = Ticker;
//# sourceMappingURL=Ticker.js.map
