silphius/app/react/components/particle-worker.js

import Emitter from '@/particles/emitter.js';
import createEcs from '@/server/create/ecs.js';

import ClientEcs from './client-ecs.js';

const ecs = createEcs(ClientEcs);
ecs.$$caret = Math.pow(2, 31);

const emitter = new Emitter(ecs);

addEventListener('message', (particle) => {
  if (!ecs.get(1)) {
    ecs.createManySpecific([[1, particle.data]]);
    return;
  }
  emitter.emit(particle.data)
    .onEnd(() => {});
});

const memory = new Set();

let last = performance.now();
function tick(now) {
  const elapsed = (now - last) / 1000;
  last = now;
  requestAnimationFrame(tick);
  if (!ecs.get(1)) {
    return;
  }
  ecs.tick(elapsed);
  emitter.tick(elapsed);
  const update = {};
  const lastNearby = new Set(memory.values());
  for (const id in ecs.$$entities) {
    const entity = ecs.$$entities[id];
    lastNearby.delete(id);
    if (!memory.has(id)) {
      update[id] = entity.toJSON();
    }
    else if (ecs.diff[id]) {
      update[id] = ecs.diff[id];
    }
    memory.add(id);
  }
  for (const id of lastNearby) {
    memory.delete(id);
    update[id] = false;
  }
  if ('1' in update) {
    delete update['1'];
  }
  if (Object.keys(update).length > 0) {
    postMessage(update);
  }
  ecs.setClean();
}
requestAnimationFrame(tick);