git.r.bdr.sh - rbdr/serpentity/blob - lib/serpentity.js

   1 export { Component } from './serpentity/component.js';
   2 export { Entity } from './serpentity/entity.js';
   3 export { Node } from './serpentity/node.js';
   4 export { System } from './serpentity/system.js';
   5
   6 import { NodeCollection } from './serpentity/node_collection.js';
   7
   8 /*
   9  * Serpentity is the main engine class
  10  */
  11 export default class Serpentity {
  12
  13   constructor(config) {
  14
  15     this.systems = [];
  16     this.entities = [];
  17     this._nodeCollections = [];
  18     this._nodeCollectionKeys = [];
  19
  20     Object.assign(this, config);
  21   }
  22
  23   /*
  24    * Adds a system to the engine, so its update method will be called
  25    * with the others. Triggers added hook.
  26    *
  27    * returns true if added succesfully, false if already added
  28    */
  29   addSystem(system, priority) {
  30
  31     if (this.systems.indexOf(system) >= 0) {
  32       return false;
  33     }
  34
  35     system.priority = priority;
  36
  37     let lastIndex = 0;
  38
  39     const found = this.systems.some((existingSystem, i) => {
  40
  41       lastIndex = i;
  42       if (existingSystem.priority >= system.priority) {
  43         return true;
  44       }
  45     });
  46
  47     if (!found) {
  48       lastIndex += 1;
  49     }
  50
  51     this.systems.splice(lastIndex, 0, system);
  52     system.added(this);
  53     return true;
  54   }
  55
  56   /*
  57    * Removes a system from the engine, so its update method will no
  58    * longer will be called. Triggers the removed hook.
  59    *
  60    * returns true if removed succesfully, false if already added
  61    */
  62   removeSystem(system) {
  63
  64     const position = this.systems.indexOf(system);
  65     if (position >= 0) {
  66       this.systems[position].removed(this);
  67       this.systems.splice(position, 1);
  68       return true;
  69     }
  70
  71     return false;
  72   }
  73
  74   /*
  75    * Adds an entity to the engine, adds to existing node collections
  76    *
  77    * returns true if added, false if already there
  78    */
  79   addEntity(entity) {
  80
  81     if (this.entities.indexOf(entity) >= 0) {
  82       return false;
  83     }
  84
  85     this.entities.push(entity);
  86
  87     for (const collection of this._nodeCollections) {
  88       collection.add(entity);
  89     }
  90
  91     return true;
  92   }
  93
  94   /*
  95    * Removes entity from system, removing from all node collections
  96    *
  97    * returns true if removed, false if not present
  98    */
  99   removeEntity(entity) {
 100
 101     const position = this.entities.indexOf(entity);
 102     if (position >= 0) {
 103       for (const collection of this._nodeCollections) {
 104         collection.remove(entity);
 105       }
 106
 107       this.entities.splice(position, 1);
 108       return true;
 109     }
 110
 111     return false;
 112   }
 113
 114   /*
 115    * Given a Node Class, retrieves a list of all the nodes for each
 116    * applicable entity.
 117    */
 118   getNodes(nodeType) {
 119
 120     const position = this._nodeCollectionKeys.indexOf(nodeType);
 121
 122     if (position >= 0) {
 123       return this._nodeCollections[position];
 124     }
 125
 126     const nodeCollection = new NodeCollection({
 127       type: nodeType
 128     });
 129
 130     this._nodeCollectionKeys.push(nodeType);
 131     this._nodeCollections.push(nodeCollection);
 132
 133     for (const entity of this.entities) {
 134       nodeCollection.add(entity);
 135     }
 136
 137     return nodeCollection;
 138   }
 139
 140   /*
 141    * Calls update for every loaded system.
 142    */
 143   update(dt) {
 144
 145     for (const system of this.systems) {
 146       system.update(dt);
 147     }
 148   }
 149 }