yumechi-no-kuni/packages/frontend/src/scripts/idle-render.ts

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const requestIdleCallback: typeof globalThis.requestIdleCallback = globalThis.requestIdleCallback ?? (callback) => {
const start = performance.now();
const timeoutId = setTimeout(() => {
callback({
didTimeout: false, // polyfill でタイムアウト発火することはない
timeRemaining() {
const diff = performance.now() - start;
return Math.max(0, 50 - diff); // <https://www.w3.org/TR/requestidlecallback/#idle-periods>
},
});
});
return timeoutId;
};
const cancelIdleCallback: typeof globalThis.cancelIdleCallback = globalThis.cancelIdleCallback ?? (timeoutId) => {
clearTimeout(timeoutId);
};
class IdlingRenderScheduler {
#renderers: Set<FrameRequestCallback>;
#rafId: number;
#ricId: number;
constructor() {
this.#renderers = new Set();
this.#rafId = 0;
this.#ricId = requestIdleCallback((deadline) => this.#schedule(deadline));
}
#schedule(deadline: IdleDeadline): void {
if (deadline.timeRemaining()) {
this.#rafId = requestAnimationFrame((time) => {
for (const renderer of this.#renderers) {
renderer(time);
}
});
}
this.#ricId = requestIdleCallback((arg) => this.#schedule(arg));
}
add(renderer: FrameRequestCallback): void {
this.#renderers.add(renderer);
}
delete(renderer: FrameRequestCallback): void {
this.#renderers.delete(renderer);
}
dispose(): void {
this.#renderers.clear();
cancelAnimationFrame(this.#rafId);
cancelIdleCallback(this.#ricId);
}
}
export const defaultIdlingRenderScheduler = new IdlingRenderScheduler();