herd / files / src / game / GameLoop.ts

GameLoop.ts

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`1001e9ef` 2026-05-17 Pavel Safronov	1	const FIXED_STEP_MS = 16 // ~60 Hz physics
	2
	3	export class GameLoop {
	4	private rafId = 0
	5	private lastTime = 0
	6	private accumulator = 0
	7	private running = false
	8	private onUpdate: (dt: number) => void
	9	private onRender: (alpha: number) => void
	10
	11	constructor(onUpdate: (dt: number) => void, onRender: (alpha: number) => void) {
	12	this.onUpdate = onUpdate
	13	this.onRender = onRender
	14	}
	15
	16	start() {
	17	if (this.running) return
	18	this.running = true
	19	this.lastTime = performance.now()
	20	this.rafId = requestAnimationFrame(this.tick)
	21	}
	22
	23	stop() {
	24	this.running = false
	25	cancelAnimationFrame(this.rafId)
	26	}
	27
	28	private tick = (now: number) => {
	29	if (!this.running) return
	30	this.rafId = requestAnimationFrame(this.tick)
	31
	32	const elapsed = Math.min(now - this.lastTime, 200) // cap at 200ms to avoid spiral of death
	33	this.lastTime = now
	34	this.accumulator += elapsed
	35
	36	while (this.accumulator >= FIXED_STEP_MS) {
	37	this.onUpdate(FIXED_STEP_MS / 1000) // pass seconds
	38	this.accumulator -= FIXED_STEP_MS
	39	}
	40
	41	this.onRender(this.accumulator / FIXED_STEP_MS)
	42	}
	43	}