@megavr/ecsy-babylon/src/systems/InputSystem.ts

babylon.js ecsy binding and helpers

import * as BABYLON from "@babylonjs/core";
import { Entity, System } from "ecsy";
import { Input } from "../components/index";
import { getScene, getScenes, getSystem } from "../utils/gameUtils";
import { GameSystem } from "./GameSystem";

/** System for Input component */
export class InputSystem extends System {
  /** @hidden */
  static queries = {
    input: { components: [Input], listen: { added: true, removed: true } },
  };
  /** @hidden */
  queries: any;

  private _inputs: Map<String, Input> = new Map<String, Input>();
  private _input: Input;

  init() {
    getSystem(this, GameSystem).onSceneSwitched.add(scene => this._updateOnKey(scene));
    this._onKey = this._onKey.bind(this);
  }

  /** @hidden */
  execute() {
    this.queries.input.added.forEach((entity: Entity) => {
      let input = entity.getComponent(Input);
      let scene = getScene(this, input.scene);
      switch (input.type) {
        default:
          if (!this._inputs.has(scene.uid)) {
            this._inputs.set(scene.uid, input);
            this._updateOnKey(scene);
          }
          break;
      }
    });

    this.queries.input.removed.forEach((entity: Entity) => {
      let input = entity.getComponent(Input);
      let scene = getScene(this, input.scene);
      switch (input.type) {
        default:
          if (this._inputs.has(scene.uid)) {
            this._inputs.delete(scene.uid);
            this._removeOnKey(scene);
          }
          break;
      }
    });
  }

  private _updateOnKey(targetScene: BABYLON.Scene) {
    if (targetScene.uid === getScene(this).uid) {
      getScenes(this).forEach(scene => this._removeOnKey(scene));
      this._input = this._inputs.get(targetScene.uid)!;
      this._input.onKey && targetScene.onKeyboardObservable.add(this._onKey);
    }
  }

  private _removeOnKey(scene: BABYLON.Scene) {
    scene.onKeyboardObservable.removeCallback(this._onKey);
  }

  private _onKey(keyInfo: BABYLON.KeyboardInfo): void {
    // BABYLON.KeyboardEventTypes.KEYDOWN = 1, BABYLON.KeyboardEventTypes.KEYUP = 2
    (this._input.onKey as any).call(this._input, keyInfo.event.key, keyInfo.type === 1, keyInfo.type === 2);
  }
}