129 lines
1.9 KiB
JavaScript
129 lines
1.9 KiB
JavaScript
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 ( typeof performance === 'undefined' ? Date : performance ).now();
|
|
|
|
}
|
|
|
|
function handleVisibilityChange() {
|
|
|
|
if ( document.hidden === false ) this.reset();
|
|
|
|
}
|
|
|
|
export { Timer, FixedTimer };
|