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

   1 import { System } from '@serpentity/serpentity';
   2
   3 import RenderableNode from '../nodes/renderable';
   4
   5 const internals = {
   6   kNoPixiError: 'No pixi application passed to render system. Make sure you set the `application` key in the config object when initializing.'
   7 };
   8
   9 /**
  10  * Renders renderable objects using pixi
  11  *
  12  * @extends {external:Serpentity.System}
  13  * @class RenderSystem
  14  * @param {object} config a configuration object to extend.
  15  */
  16 export default class RenderSystem extends System {
  17
  18   constructor(config = {}) {
  19
  20     super();
  21
  22     /**
  23      * The node collection of renderable entities
  24      *
  25      * @property {external:Serpentity.NodeCollection} renderables
  26      * @instance
  27      * @memberof RenderSystem
  28      */
  29     this.renderables = null;
  30
  31     /**
  32      * The pixi engine we will use to render
  33      *
  34      * @property {external:PixiJs.Application} application
  35      * @instance
  36      * @memberof RenderSystem
  37      */
  38     this.application = config.application;
  39
  40     if (!this.application) {
  41       throw new Error(internals.kNoPixiError);
  42     }
  43   }
  44
  45   /**
  46    * Initializes system when added. Requests renderable nodes and
  47    * attaches to event listeners to add / remove them to pixi stage
  48    *
  49    * @function added
  50    * @memberof RenderSystem
  51    * @instance
  52    * @param {external:Serpentity.Engine} engine the serpentity engine to
  53    * which we are getting added
  54    */
  55   added(engine) {
  56
  57     this.renderables = engine.getNodes(RenderableNode);
  58     this.renderables.on('nodeAdded', (event) => {
  59
  60       this.application.stage.addChild(event.node.container.container);
  61     });
  62     this.renderables.on('nodeRemoved', (event) => {
  63
  64       this.application.stage.removeChild(event.node.container.container);
  65     });
  66   }
  67
  68   /**
  69    * Clears system resources when removed.
  70    *
  71    * @function removed
  72    * @instance
  73    * @memberof RenderSystem
  74    */
  75   removed() {
  76
  77     this.renderables.removeAllListeners('nodeAdded');
  78     this.renderables.removeAllListeners('nodeRemoved');
  79     this.renderables = null;
  80   }
  81
  82   /**
  83    * Runs on every update of the loop. Does nothing.
  84    *
  85    * @function update
  86    * @instance
  87    * @param {Number} currentFrameDuration the duration of the current
  88    * frame
  89    * @memberof RenderSystem
  90    */
  91   update(currentFrameDuration) {}
  92 };