@animech-public/playcanvas/build/playcanvas.dbg/src/framework/components/component.js

PlayCanvas WebGL game engine

import { EventHandler } from '../../core/event-handler.js';

/**
 * Components are used to attach functionality on a {@link Entity}. Components can receive update
 * events each frame, and expose properties to the PlayCanvas Editor.
 */
class Component extends EventHandler {
  /**
   * Base constructor for a Component.
   *
   * @param {import('./system.js').ComponentSystem} system - The ComponentSystem used to create
   * this Component.
   * @param {import('../entity.js').Entity} entity - The Entity that this Component is attached
   * to.
   */
  constructor(system, entity) {
    super();
    /**
     * The ComponentSystem used to create this Component.
     *
     * @type {import('./system.js').ComponentSystem}
     */
    this.system = void 0;
    /**
     * The Entity that this Component is attached to.
     *
     * @type {import('../entity.js').Entity}
     */
    this.entity = void 0;
    this.system = system;
    this.entity = entity;
    if (this.system.schema && !this._accessorsBuilt) {
      this.buildAccessors(this.system.schema);
    }
    this.on('set', function (name, oldValue, newValue) {
      this.fire(`set_${name}`, name, oldValue, newValue);
    });
    this.on('set_enabled', this.onSetEnabled, this);
  }

  /** @ignore */
  static _buildAccessors(obj, schema) {
    // Create getter/setter pairs for each property defined in the schema
    schema.forEach(descriptor => {
      // If the property descriptor is an object, it should have a `name`
      // member. If not, it should just be the plain property name.
      const name = typeof descriptor === 'object' ? descriptor.name : descriptor;
      Object.defineProperty(obj, name, {
        get: function () {
          return this.data[name];
        },
        set: function (value) {
          const data = this.data;
          const oldValue = data[name];
          data[name] = value;
          this.fire('set', name, oldValue, value);
        },
        configurable: true
      });
    });
    obj._accessorsBuilt = true;
  }

  /** @ignore */
  buildAccessors(schema) {
    Component._buildAccessors(this, schema);
  }

  /** @ignore */
  onSetEnabled(name, oldValue, newValue) {
    if (oldValue !== newValue) {
      if (this.entity.enabled) {
        if (newValue) {
          this.onEnable();
        } else {
          this.onDisable();
        }
      }
    }
  }

  /** @ignore */
  onEnable() {}

  /** @ignore */
  onDisable() {}

  /** @ignore */
  onPostStateChange() {}

  /**
   * Access the component data directly. Usually you should access the data properties via the
   * individual properties as modifying this data directly will not fire 'set' events.
   *
   * @type {*}
   * @ignore
   */
  get data() {
    const record = this.system.store[this.entity.getGuid()];
    return record ? record.data : null;
  }

  /**
   * Sets the enabled state of the component.
   *
   * @type {boolean}
   */
  set enabled(arg) {}

  /**
   * Gets the enabled state of the component.
   *
   * @type {boolean}
   */
  get enabled() {
    return true;
  }
}

export { Component };