Spaces:
Running
Running
| class Timer { | |
| constructor() { | |
| this._previousTime = 0; | |
| this._currentTime = 0; | |
| this._startTime = now(); | |
| this._delta = 0; | |
| this._elapsed = 0; | |
| this._timescale = 1; | |
| // use Page Visibility API to avoid large time delta values | |
| this._usePageVisibilityAPI = ( typeof document !== 'undefined' && document.hidden !== undefined ); | |
| if ( this._usePageVisibilityAPI === true ) { | |
| this._pageVisibilityHandler = handleVisibilityChange.bind( this ); | |
| document.addEventListener( 'visibilitychange', this._pageVisibilityHandler, false ); | |
| } | |
| } | |
| getDelta() { | |
| return this._delta / 1000; | |
| } | |
| getElapsed() { | |
| return this._elapsed / 1000; | |
| } | |
| getTimescale() { | |
| return this._timescale; | |
| } | |
| setTimescale( timescale ) { | |
| this._timescale = timescale; | |
| return this; | |
| } | |
| reset() { | |
| this._currentTime = now() - this._startTime; | |
| return this; | |
| } | |
| dispose() { | |
| if ( this._usePageVisibilityAPI === true ) { | |
| document.removeEventListener( 'visibilitychange', this._pageVisibilityHandler ); | |
| } | |
| return this; | |
| } | |
| update( timestamp ) { | |
| if ( this._usePageVisibilityAPI === true && document.hidden === true ) { | |
| this._delta = 0; | |
| } else { | |
| this._previousTime = this._currentTime; | |
| this._currentTime = ( timestamp !== undefined ? timestamp : now() ) - this._startTime; | |
| this._delta = ( this._currentTime - this._previousTime ) * this._timescale; | |
| this._elapsed += this._delta; // _elapsed is the accumulation of all previous deltas | |
| } | |
| return this; | |
| } | |
| } | |
| class FixedTimer extends Timer { | |
| constructor( fps = 60 ) { | |
| super(); | |
| this._delta = ( 1 / fps ) * 1000; | |
| } | |
| update() { | |
| this._elapsed += ( this._delta * this._timescale ); // _elapsed is the accumulation of all previous deltas | |
| return this; | |
| } | |
| } | |
| function now() { | |
| return performance.now(); | |
| } | |
| function handleVisibilityChange() { | |
| if ( document.hidden === false ) this.reset(); | |
| } | |
| export { Timer, FixedTimer }; | |