File size: 1,866 Bytes
b797337 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 | 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 ) {
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 ( typeof performance === 'undefined' ? Date : performance ).now();
}
function handleVisibilityChange() {
if ( document.hidden === false ) this.reset();
}
export { Timer, FixedTimer };
|