git.r.bdr.sh - rbdr/serpentity/blob - README.md

   1 # Serpentity
   2
   3 Serpentity is a simple entity framework inspired by [Ash][ash].
   4
   5 Usage:
   6
   7     const Serpentity = require('serpentity');
   8
   9 ## Instantiating an engine
  10
  11     const engine = new Serpentity();
  12
  13 Add entities or systems, systems are added with a priority (the smaller
  14 the number, the earlier it will be called):
  15
  16     engine.addEntity(entityFactory());
  17     engine.addSystem(new GameSystem(), priority);
  18
  19 Update all systems:
  20
  21     engine.update(dt);
  22
  23 Remove entities or systems:
  24
  25     engine.removeEntity(entityReference);
  26     engine.removeSystem(systemReference);
  27
  28 ## Creating Entities
  29
  30 Entities are the basic object of Serpentity, and they do nothing.
  31
  32     const entity = new Serpentity.Entity();
  33
  34 All the behavior is added through components
  35
  36 ## Creating Components
  37
  38 Components define data that we can add to an entity. This data will
  39 eventually be consumed by "Systems"
  40
  41     const PositionComponent = class PositionComponent extends Serpentity.Component {
  42       constructor(config) {
  43
  44         this.x = 0;
  45         this.y = 0;
  46
  47         super(config);
  48       }
  49     };
  50
  51 You can add components to entities by using the add method:
  52
  53     entity.addComponent(new PositionComponent());
  54
  55
  56 Systems can refer to entities by requesting nodes.
  57
  58 ## Working with Nodes
  59
  60 Nodes are sets of components that you define, so your system can require
  61 entities that always follow the API defined in the node.
  62
  63     const MovementNode = class MovementNode extends Serpentity.Node;
  64     MovementNode.position = PositionComponent;
  65     MovementNode.motion = MotionComponent;
  66
  67 You can then request an array of all the nodes representing entities
  68 that comply with that API
  69
  70     engine.getNodes(MovementNode);
  71
  72 ## Creating Systems
  73
  74 Systems are called on every update, and they use components through nodes.
  75
  76     const TestSystem = class TestSystem extends Serpentity.System {
  77       added(engine){
  78
  79         this.nodeList = engine.getNodes(MovementNode);
  80       }
  81
  82       removed(engine){
  83
  84         this.nodeList = undefined;
  85       }
  86
  87       update(dt){
  88
  89         for (const node of this.nodeList) {
  90           console.log(`Current position is: ${node.position.x},${node.position.y}`);
  91         }
  92       }
  93     };
  94
  95 ## That's it
  96
  97 Just run `engine.update(dt)` in your game loop :D
  98
  99 ![Travis CI Build Status][travis-ci-badge]
 100
 101 [ash]: http://www.ashframework.org/
 102 [travis-ci-badge]: https://travis-ci.org/serpentity/serpentity.svg?branch=master