sdf-2d/src/graphics/rendering/fps-autoscaler.ts
2020-10-13 22:37:23 +02:00

110 lines
2.8 KiB
TypeScript

import { clamp } from '../../helper/clamp';
import { exponentialDecay } from '../../helper/exponential-decay';
import { mix } from '../../helper/mix';
import { Insights } from './insights';
/** @internal */
const settings = {
targetDeltaTimeInMilliseconds: 20,
deltaTimeErrorInMilliseconds: 3,
deltaTimeResponsiveness: 1 / 32,
adjusmentRateInMilliseconds: 1000,
targets: [
{
distanceRenderScale: 0.1,
finalRenderScale: 0.2,
},
{
distanceRenderScale: 0.1,
finalRenderScale: 0.6,
},
{
distanceRenderScale: 0.5,
finalRenderScale: 1.0,
},
{
distanceRenderScale: 0.5,
finalRenderScale: 1.0,
},
],
qualityStepIncrease: 0.01,
qualityStepDecrese: 0.2,
};
/** @internal */
export class FpsAutoscaler {
private timeSinceLastAdjusment = 0;
private exponentialDecayedDeltaTime = settings.targetDeltaTimeInMilliseconds;
// can have fractions
private index = 3;
constructor(private setters: { [key: string]: (value: number | boolean) => void }) {
this.applyScaling();
}
public increase() {
this.index += settings.qualityStepIncrease;
this.applyScaling();
}
public decrease() {
this.index -= settings.qualityStepDecrese;
this.applyScaling();
}
private applyScaling() {
this.index = clamp(this.index, 0, settings.targets.length - 1);
const floor = Math.floor(this.index);
const fract = this.index - floor;
const previousTarget: any = settings.targets[floor];
const nextTarget =
floor + 1 == settings.targets.length ? previousTarget : settings.targets[floor + 1];
const result: any = {};
for (const key in this.setters) {
const previous = previousTarget[key];
const next = nextTarget[key];
let current: number | boolean;
if (typeof previous == 'number') {
current = mix(previous, next as number, fract);
} else {
current = next;
}
result[key] = current;
this.setters[key](current);
}
Insights.setValue('quality', result);
}
public autoscale(lastDeltaTime: DOMHighResTimeStamp) {
this.exponentialDecayedDeltaTime = exponentialDecay(
this.exponentialDecayedDeltaTime,
lastDeltaTime,
settings.deltaTimeResponsiveness
);
Insights.setValue('FPS', 1000 / this.exponentialDecayedDeltaTime);
if (
(this.timeSinceLastAdjusment += lastDeltaTime) >=
settings.adjusmentRateInMilliseconds
) {
this.timeSinceLastAdjusment = 0;
if (
this.exponentialDecayedDeltaTime + settings.deltaTimeErrorInMilliseconds <=
settings.targetDeltaTimeInMilliseconds
) {
this.increase();
} else if (
this.exponentialDecayedDeltaTime > settings.targetDeltaTimeInMilliseconds
) {
this.decrease();
}
}
}
}