sdf-2d-demo/src/helper/delta-time-calculator.ts
schmelczerandras 36f01c6716 Copy files
2020-09-16 16:03:01 +02:00

23 lines
596 B
TypeScript

export class DeltaTimeCalculator {
private previousTime: DOMHighResTimeStamp | null = null;
constructor() {
document.addEventListener('visibilitychange', this.handleVisibilityChange.bind(this));
}
public getNextDeltaTime(currentTime: DOMHighResTimeStamp): DOMHighResTimeStamp {
if (this.previousTime === null) {
this.previousTime = currentTime;
}
const delta = currentTime - this.previousTime;
this.previousTime = currentTime;
return delta;
}
private handleVisibilityChange() {
if (!document.hidden) {
this.previousTime = null;
}
}
}