Serpentity

Serpentity is a simple entity framework inspired by Ash.

Usage:

require('serpentity');

Instantiating an engine

var 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.

var 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"

Class("PositionComponent").inherits(Serpentity.Component)({
    prototype : {
        x : 0,
        y : 0
    }
});

You can add components to entities by using the addComponent 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.

Class("MovementNode").inherits(Serpentity.Node)({
    types : {
        position : PositionComponent,
        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.

Class("TestSystem").inherits(Serpentity.System)({
    prototype : {
        added : function added(engine){
            this.nodeList = engine.getNodes(MovementNode);
        },
        removed : function removed(engine){
            this.nodeList = undefined;
        }
        update : function update(dt){
            this.nodeList.forEach(function (node) {
                console.log("Current position is: " + node.position.x + "," + node.position.y);
            });
        }
    }
});

That's it

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

Checking it in the frontend (dev).

You can link the bower package to test it out locally. Spawn a python server (python -m SimpleHTTPServer) to see the test page in http://localhost:8000/browser_test/

TO-DO

• Removing components
• Implement the ashteroids demo (Serpentoids)
• Actually check performance