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     import Serpentity from '@serpentity/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     import { Entity } from '@serpentity/serpentity';
  33     const entity = new Entity();
  34
  35 All the behavior is added through components
  36
  37 ## Creating Components
  38
  39 Components define data that we can add to an entity. This data will
  40 eventually be consumed by "Systems"
  41
  42     import { Component } from '@serpentity/serpentity';
  43     const PositionComponent = class PositionComponent extends Component {
  44       constructor(config) {
  45
  46         this.x = 0;
  47         this.y = 0;
  48
  49         super(config);
  50       }
  51     };
  52
  53 You can add components to entities by using the add method:
  54
  55     entity.addComponent(new PositionComponent());
  56
  57
  58 Systems can refer to entities by requesting nodes.
  59
  60 ## Working with Nodes
  61
  62 Nodes are sets of components that you define, so your system can require
  63 entities that always follow the API defined in the node.
  64
  65     import { Node } from '@serpentity/serpentity';
  66     const MovementNode = class MovementNode extends Node;
  67     MovementNode.position = PositionComponent;
  68     MovementNode.motion = MotionComponent;
  69
  70 You can then request an array of all the nodes representing entities
  71 that comply with that API
  72
  73     engine.getNodes(MovementNode);
  74
  75 ## Creating Systems
  76
  77 Systems are called on every update, and they use components through nodes.
  78
  79     import { System } from '@serpentity/serpentity';
  80     const TestSystem = class TestSystem extends System {
  81       added(engine){
  82
  83         this.nodeList = engine.getNodes(MovementNode);
  84       }
  85
  86       removed(engine){
  87
  88         this.nodeList = undefined;
  89       }
  90
  91       update(dt){
  92
  93         for (const node of this.nodeList) {
  94           console.log(`Current position is: ${node.position.x},${node.position.y}`);
  95         }
  96       }
  97     };
  98
  99 ## That's it
 100
 101 Just run `engine.update(dt)` in your game loop :D
 102
 103 [ash]: http://www.ashframework.org/