Updates README with revised deps and version

[rbdr/serpentity] / README.md

# Serpentity

Serpentity is a simple entity framework inspired by Ash.

Usage:

    let Serpentity = require('serpentity');

or:

    <script src="/node_modules/serpentity/dist/serpentity.js"></script>

## Instantiating an engine

    let engine = Serpentity();

Add entities or systems, systems are added with a priority (the smaller
the number, the earlier it will be called):

    engine.addEntity(entityFactory());
    engine.addSystem(new GameSystem(), priority);

Update all systems:

    engine.update(dt);

Remove entities or systems:

    engine.removeEntity(entityReference);
    engine.removeSystem(systemReference);

## Creating Entities

Entities are the basic object of Serpentity, and they do nothing.

    let entity = new Serpentity.Entity();

All the behavior is added through components

## Creating Components

Components define data that we can add to an entity. This data will
eventually be consumed by "Systems"

    let PositionComponent = class PositionComponent extends Serpentity.Component {
      constructor (config) {
        super(config);

        this.x = this.x || 0;
        this.y = this.y || 0;
      }
    };

You can add components to entities by using the add method:

    entity.addComponent(new PositionComponent());


Systems can refer to entities by requesting nodes.

## Working with Nodes

Nodes are sets of components that you define, so your system can require
entities that always follow the API defined in the node.

    let MovementNode = class MovementNode extends Serpentity.Node;
    MovementNode.position = PositionComponent;
    MovementNode.motion = MotionComponent;

You can then request an array of all the nodes representing entities
that comply with that API

    engine.getNodes(MovementNode);

## Creating Systems

Systems are called on every update, and they use components through nodes.

    let TestSystem = class TestSystem extends Serpentity.System {
      added (engine){
        this.nodeList = engine.getNodes(MovementNode);
      },
      removed (engine){
        this.nodeList = undefined;
      }
      update (dt){
        let node;
        for (node of this.nodeList) {
          console.log(`Current position is: ${node.position.x},${node.position.y}`);
        }
      }
    };

## That's it

Just run `engine.update(dt)` in your game loop :D

## TO-DO

* Minimize code (Uglify does not support ES6 yet)
* Check Performance

[ash]: http://www.ashframework.org/