explodorama / files / src / ui / scenes.ts
scenes.ts
33a0256b 2026-10-24 Pavel Safronov | 1 | import { generateScene, type Scene, type SceneKind } from '../sim/demo' |
| 2 | ||
| 3 | /** | |
| 4 | * Scenes for the demo and the dialogs' clips, made in a Web Worker (sim/scene-worker.ts) so the | |
| 5 | * page never waits on one (PLAN.md §13c). Where a worker can't be made, on the page instead. | |
| 6 | */ | |
| 7 | let worker: Worker | null = null | |
| 8 | try { | |
| 9 | worker = new Worker(new URL('../sim/scene-worker.ts', import.meta.url), { type: 'module' }) | |
| 10 | } catch { | |
| 11 | worker = null | |
| 12 | } | |
| 13 | ||
| 14 | let nextId = 0 | |
| 15 | const waiting = new Map<number, { kind: SceneKind; seed: number; done: (scene: Scene | null) => void }>() | |
| 16 | worker?.addEventListener('message', (e: MessageEvent<{ id: number; scene: Scene | null }>) => { | |
| 17 | waiting.get(e.data.id)?.done(e.data.scene) | |
| 18 | waiting.delete(e.data.id) | |
| 19 | }) | |
| 20 | // A worker that fails (a script that wouldn't load) answers nothing: what waits on it, and all | |
| 21 | // after, is made here. | |
| 22 | worker?.addEventListener('error', () => { | |
| 23 | worker = null | |
| 24 | for (const { kind, seed, done } of waiting.values()) done(generateScene(kind, seed)) | |
| 25 | waiting.clear() | |
| 26 | }) | |
| 27 | ||
| 28 | /** A scene of `kind` from `seed`, when it is ready; null if none was found. */ | |
| 29 | export function makeScene(kind: SceneKind, seed: number): Promise<Scene | null> { | |
| 30 | if (!worker) return Promise.resolve(generateScene(kind, seed)) | |
| 31 | const id = nextId++ | |
| 32 | return new Promise((resolve) => { | |
| 33 | waiting.set(id, { kind, seed, done: resolve }) | |
| 34 | worker!.postMessage({ id, kind, seed }) | |
| 35 | }) | |
| 36 | } |