Physics Engine (#4)

[rbdr/sumo] / lib / systems / physics_to_attributes.js

import { System } from '@serpentity/serpentity';

import PhysicalWithAttributesNode from '../nodes/physical_with_attributes';

/**
 * Distribuets physics data to the related components
 *
 * @extends {external:Serpentity.System}
 * @class PhysicsToAttributesSystem
 * @param {object} config a configuration object to extend.
 */
export default class PhysicsToAttributesSystem extends System {

  constructor(config = {}) {

    super();

    /**
     * The node collection of physics entities
     *
     * @property {external:Serpentity.NodeCollection} physicalEntities
     * @instance
     * @memberof PhysicsToAttributesSystem
     */
    this.physicalEntities = null;
  }

  /**
   * Initializes system when added. Requests physics nodes
   *
   * @function added
   * @memberof PhysicsToAttributesSystem
   * @instance
   * @param {external:Serpentity.Engine} engine the serpentity engine to
   * which we are getting added
   */
  added(engine) {

    this.physicalEntities = engine.getNodes(PhysicalWithAttributesNode);
  }

  /**
   * Clears system resources when removed.
   *
   * @function removed
   * @instance
   * @memberof PhysicsToAttributesSystem
   */
  removed() {

    this.physicalEntities = null;
  }

  /**
   * Runs on every update of the loop. Updates the other components
   * based on physics
   *
   * @function update
   * @instance
   * @param {Number} currentFrameDuration the duration of the current
   * frame
   * @memberof PhysicsToAttributesSystem
   */
  update(currentFrameDuration) {

    for (const physicalEntity of this.physicalEntities) {
      physicalEntity.position.x = physicalEntity.body.body.position.x;
      physicalEntity.position.y = physicalEntity.body.body.position.y;
      physicalEntity.angle.angle = physicalEntity.body.body.angle;
    }
  }
};