tobspr_shapez.io/src/js/webworkers/background_animation_frame_emittter.worker.js

// We clamp high deltas so 30 fps is fairly ok
const bgFps = 30;
const desiredMsDelay = 1000 / bgFps;

let lastTick = performance.now();

function tick() {
    const now = performance.now();
    const delta = now - lastTick;
    lastTick = now;

    // @ts-ignore
    self.postMessage({ delta });
}

setInterval(tick, desiredMsDelay);