Accueil / npm / three@0.171.0 / examples / jsm / misc / Timer.js
Timer.js
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 };