freeblox/packages/engine/src/components/level.ts

import { Renderer } from '../core/renderer';
import { EngineComponent } from '../types/engine-component';
import {
  ChangeEvent,
  EngineEvents,
  InstanceEvent,
  RemoveEvent,
  ReparentEvent,
} from '../types/events';
import { EventEmitter } from '../utils/events';
import { Environment } from '../gameobjects/environment.object';
import { assetManager } from '../assets/manager';
import { WorldFile } from '../types/world-file';
import { World } from '../gameobjects/world.object';
import { instancableGameObjects } from '../gameobjects';
import { Object3D } from 'three';
import { GameObject } from '../types/game-object';

/**
 * Game level management component
 * @listens change Applies changes to objects
 * @listens remove Removes objects from scene
 * @listens reparent Reparents object
 */
export class LevelComponent extends EngineComponent {
  private world!: World;
  private environment!: Environment;
  private cleanUpEvents?: Function;

  constructor(
    protected renderer: Renderer,
    protected events: EventEmitter<EngineEvents>
  ) {
    super(renderer, events);
  }

  initialize(): void {
    this.world = this.renderer.scene.getObjectByName('World') as World;
    this.environment = this.renderer.scene.getObjectByName(
      'Environment'
    ) as Environment;
    this.cleanUpEvents = this.bindEvents();
  }

  update(delta: number): void {}

  cleanUp(): void {
    this.cleanUpEvents?.call(this);
  }

  public getSceneTree() {
    return {
      world: this.world,
      environment: this.environment,
    };
  }

  public createObject(object: string, setParent?: Object3D) {
    const parent = setParent || this.world;
    const ObjectType = instancableGameObjects[object];
    if (!ObjectType) return;
    const newObject = new ObjectType();
    parent.add(newObject);
    this.events.emit('sceneJoin', newObject);
  }

  public serializeLevelSave(name: string): WorldFile {
    const world = this.world.serialize();
    const environment = this.environment.serialize();
    const assets = assetManager.serialize();
    return {
      name,
      world,
      environment,
      assets,
    };
  }

  private bindEvents() {
    const changeEvent = (event: ChangeEvent) => {
      if (event.applied || !event.object) return;
      const prop = (event.object as any)[event.property];
      if (prop?.copy) prop.copy(event.value);
      else (event.object as any)[event.property] = event.value;
    };

    const removeEvent = (event: RemoveEvent) => {
      if (event.applied || !event.object) return;
      if ((event.object as GameObject).virtual) return;
      if (Array.isArray(event.object)) {
        event.object.forEach((object) => object.removeFromParent());
        return;
      }

      event.object.removeFromParent();
      this.events.emit('sceneLeave', event.object);
    };

    const reparentEvent = (event: ReparentEvent) => {
      if (event.applied || !event.object || !event.parent) return;
      if (Array.isArray(event.object)) {
        event.object.forEach((object) => {
          object.removeFromParent();
          event.parent.add(object);
        });
        return;
      }

      event.object.removeFromParent();
      event.parent.add(event.object);
    };

    const instanceEvent = (event: InstanceEvent) =>
      this.createObject(event.type, event.parent);

    this.events.addListener('change', changeEvent);
    this.events.addListener('remove', removeEvent);
    this.events.addListener('reparent', reparentEvent);
    this.events.addListener('instance', instanceEvent);

    return () => {
      this.events.removeEventListener('change', changeEvent);
      this.events.removeEventListener('remove', removeEvent);
      this.events.removeEventListener('reparent', reparentEvent);
      this.events.removeEventListener('instance', instanceEvent);
    };
  }
}