phaser/src/polyfills/requestAnimationFrame.js
2018-01-09 21:43:56 +00:00

66 lines
2 KiB
JavaScript

// References:
// http://paulirish.com/2011/requestanimationframe-for-smart-animating/
// https://gist.github.com/1579671
// http://updates.html5rocks.com/2012/05/requestAnimationFrame-API-now-with-sub-millisecond-precision
// https://gist.github.com/timhall/4078614
// https://github.com/Financial-Times/polyfill-service/tree/master/polyfills/requestAnimationFrame
// Expected to be used with Browserfiy
// Browserify automatically detects the use of `global` and passes the
// correct reference of `global`, `self`, and finally `window`
// Date.now
if (!(Date.now && Date.prototype.getTime)) {
Date.now = function now() {
return new Date().getTime();
};
}
// performance.now
if (!(global.performance && global.performance.now)) {
var startTime = Date.now();
if (!global.performance) {
global.performance = {};
}
global.performance.now = function () {
return Date.now() - startTime;
};
}
// requestAnimationFrame
var lastTime = Date.now();
var vendors = ['ms', 'moz', 'webkit', 'o'];
for(var x = 0; x < vendors.length && !global.requestAnimationFrame; ++x) {
global.requestAnimationFrame = global[vendors[x] + 'RequestAnimationFrame'];
global.cancelAnimationFrame = global[vendors[x] + 'CancelAnimationFrame'] ||
global[vendors[x] + 'CancelRequestAnimationFrame'];
}
if (!global.requestAnimationFrame) {
global.requestAnimationFrame = function (callback) {
if (typeof callback !== 'function') {
throw new TypeError(callback + 'is not a function');
}
var currentTime = Date.now(),
delay = 16 + lastTime - currentTime;
if (delay < 0) {
delay = 0;
}
lastTime = currentTime;
return setTimeout(function () {
lastTime = Date.now();
callback(performance.now());
}, delay);
};
}
if (!global.cancelAnimationFrame) {
global.cancelAnimationFrame = function(id) {
clearTimeout(id);
};
}