API here : [http://dvergar.github.io/osis/](http://dvergar.github.io/osis/)

Entity Component System architecture with networking support (for haxe).

• Simple API
• Simple source
• Networking is optional, none of the network API is polluating the ECS
• API support for shared code betwen client & server
• Automatic & fine-grained serialization of components via PODStream
• Avoids magic !

(Iteration from old ECS-Networking-Haxe)

Check out the sample for a quick overview of the architecture. The library assumes you are in a client/server architecture where the server is authoritative.

ECS ?

Entity is an aggregation of data-only components
Logics are in systems
Systems act on components

Networking

• Components updates are always done from server to clients (not the opposite) and only at your demand.
• Messages are the only types of network events that can go both ways.
• In a game w/ this framework, communications should sum up to the client sending a list of pressed keys and/or events and the server dispatching everything else.

Notes

• Based on my network library Anette which is actually broken on the server websocket/JS target at the moment, OSIS is inheriting the same issue
• 64 components max, 64 entity sets max
• It's TCP, I really want UDP support so stay tuned for that

Usage

Setup

var em:EntityManager = new EntityManager();

If you're going networked you can get the network entity manager via.

var net = em.listen("127.0.0.1", 32000);

on the server and

var net = em.connect("127.0.0.1", 32000);

on the client.

EntitySet

An entity set will allow to manipulate entities having the specified components; here CPosition and CMonster.

var entitySet = em.getEntitySet([CPosition, CMonster]);

You will then be able to iterate through entitySet.adds, entitySet.changes, entitySet.removes and entitySet.entities. entitySet.applyChanges() will update the entity set to the last changes.

System

A system is a really simple structure that will give you a loop where you can iterate over your entity sets and an init where you will initialize your entity sets.

Example :

class MovementSystem extends System
{
    var entitySet:EntitySet;

    public override function init()
        entitySet = em.getEntitySet([CPosition, CMonster]);

    public override function loop()
    {
        entitySet.applyChanges();

        for(entity in entitySet.entities)
        {
            var pos = entity.get(CPosition);
            pos.x += 0.1;
            net.markChanged(entity, pos, entitySet);
        }
    }
}

net.markChanged here will notify the change to all the clients.

Network event

The content of an event is called a Message and will be shared to client & server, here is an example :

class MessageHello implements Message
{
    @String public var txt:String;

    public function new() {}
}

The receiver registers to the event

net.addEvent(MessageHello, function(msg:MessageHello, connection:Connection) {
    trace(msg.txt);
});

And the sender sends the message

var msg = new MessageHello();
msg.txt = "coucou";
net.sendEvent(msg);

Templates

A template is a set of components defining a specific entity

public function player()
{
  var entity = em.createEntity();
  var pos = em.addComponent(entity, new CPosition());

  return entity;
}

Adds a template like this em.addTemplate("player", player); and call the template like that em.createEntity("player");

Plugging everything together

class Server
{
    var em:EntityManager = new EntityManager();
    var net:NetEntityManager;

    public function new()
    {
        net = em.listen("127.0.0.1", 32000);
        net.onConnection = onConnection;
        net.onDisconnection = onDisconnection;
        net.addEvent(MessageHello, onMessage);

        em.addSystem(new MovementSystem());

        while(true)
        {
            em.fixedUpdate(function()
            {
                em.processAllSystems();
            });
        }
    }

    function onMessage(msg:MessageHello, connection:Connection)
    {
        trace("Message: " + msg.txt);
    }
    
    function onConnection(connection:Connection)
    {
        var player = net.createEntity("player");
        net.bindEntity(connection, player);
        net.sendWorldStateTo(connection);

        var msg = new MessageHello();
        msg.txt = "youhou";
        net.sendEvent(msg);

        net.addComponent(player, new CHealer());
    }

    function onDisconnection(conn:Connection)
    {
        var boundEntity = net.getBoundEntity(conn);
        net.destroyEntity(boundEntity);
    }

    static function main() {new Server();}
}