git.r.bdr.sh - rbdr/sumo/blob - lib/systems/physics_world_control.js

   1 import { System } from '@serpentity/serpentity';
   2 import { Engine, World } from 'matter-js';
   3
   4 import PhysicalNode from '../nodes/physical';
   5 import GrabAreaNode from '../nodes/grab_area';
   6
   7 const internals = {
   8   kNoEngine: 'No matter js physics engine found. Make sure you set the `engine` key in the config object when initializing.'
   9 };
  10
  11 /**
  12  * Adds and removes objects to the physics world and calls update
  13  *
  14  * @extends {external:Serpentity.System}
  15  * @class PhysicsWorldControlSystem
  16  * @param {object} config a configuration object to extend.
  17  */
  18 export default class PhysicsWorldControlSystem extends System {
  19
  20   constructor(config = {}) {
  21
  22     super();
  23
  24     /**
  25      * The node collection of physics entities
  26      *
  27      * @property {external:Serpentity.NodeCollection} physicalEntities
  28      * @instance
  29      * @memberof PhysicsWorldControlSystem
  30      */
  31     this.physicalEntities = null;
  32
  33     /**
  34      * The matter-js engine we will use to process physics
  35      *
  36      * @property {external:MatterJs.Engine} engine
  37      * @instance
  38      * @memberof PhysicsWorldControlSystem
  39      */
  40     this.engine = config.engine;
  41
  42     if (!this.engine) {
  43       throw new Error(internals.kNoEngine);
  44     }
  45   }
  46
  47   /**
  48    * Initializes system when added. Requests physics nodes and
  49    * attaches to event listeners to add / remove them to pixi stage
  50    *
  51    * @function added
  52    * @memberof PhysicsWorldControlSystem
  53    * @instance
  54    * @param {external:Serpentity.Engine} engine the serpentity engine to
  55    * which we are getting added
  56    */
  57   added(engine) {
  58
  59     this.physicalEntities = engine.getNodes(PhysicalNode);
  60     this.grabAreaEntities = engine.getNodes(GrabAreaNode);
  61
  62     this.physicalEntities.on('nodeAdded', (event) => {
  63
  64       World.add(this.engine.world, [event.node.body.body]);
  65     });
  66     this.physicalEntities.on('nodeRemoved', (event) => {
  67
  68       World.remove(this.engine.world, [event.node.body.body]);
  69     });
  70
  71     this.grabAreaEntities.on('nodeAdded', (event) => {
  72
  73       World.add(this.engine.world, [event.node.grabArea.area]);
  74     });
  75     this.grabAreaEntities.on('nodeRemoved', (event) => {
  76
  77       World.remove(this.engine.world, [event.node.grabArea.area]);
  78     });
  79   }
  80
  81   /**
  82    * Clears system resources when removed.
  83    *
  84    * @function removed
  85    * @instance
  86    * @memberof PhysicsWorldControlSystem
  87    */
  88   removed() {
  89
  90     this.physicalEntities.removeAllListeners('nodeAdded');
  91     this.physicalEntities.removeAllListeners('nodeRemoved');
  92     this.physicalEntities = null;
  93
  94     this.grabAreaEntities.removeAllListeners('nodeAdded');
  95     this.grabAreaEntities.removeAllListeners('nodeRemoved');
  96     this.grabAreaEntities = null;
  97   }
  98
  99   /**
 100    * Runs on every update of the loop. Updates the physics
 101    *
 102    * @function update
 103    * @instance
 104    * @param {Number} currentFrameDuration the duration of the current
 105    * frame
 106    * @memberof PhysicsWorldControlSystem
 107    */
 108   update(currentFrameDuration) {
 109
 110     Engine.update(this.engine, currentFrameDuration);
 111   }
 112 };
 113