Multiplayer example for melonJS with PubNub

mp.js

var Multiplayer = Object.extend({
    init : function (new_player) {
        this.pubnub = PUBNUB.init({
            publish_key   : 'demo',
            subscribe_key : 'demo'
        });

        this.new_player = new_player;

        // Record my UUID, so I don't process my own messages
        this.UUID = this.pubnub.uuid();

        // Listen for incoming messages
        this.pubnub.subscribe({
            channel : "my_game",
            message : this.handleMessage.bind(this)
        });
    },

    handleMessage : function (msg) {
        // Did I send this message?
        if (msg.UUID === this.UUID)
            return;

        // Get a reference to the object for the player that sent this message
        var obj = me.game.getEntityByName(msg.UUID);
        if (obj.length) {
            obj = obj[0];
        }
        else if (typeof(this.new_player) === "function") {
            // Create a new object with the given UUID
            var x = obj.pos && obj.pos.x || 50;
            var y = obj.pos && obj.pos.y || 50;
            if (!(obj = this.new_player(x, y)))
                return;

            obj.name = msg.UUID;
        }

        // Route message
        switch (msg.action) {
        case "update":
            // Position update
            obj.pos.setV(msg.pos);
            obj.vel.setV(msg.vel);
            break;

        case "key":
            if (msg.key == "jump")
                obj.doJump();

            break;
        }
    },

    sendMessage : function (msg) {
        msg.UUID = this.UUID;

        this.pubnub.publish({
            channel : "my_game", 
            message : msg
        });
    }
});


/* EXAMPLE */

// Create a new Multiplayer object
var mp = new Multiplayer(function (x, y) {
    var obj = new me.ObjectEntity(x, y, {
        name : mp.UUID,
        image : "my_sprite",
        sprite_width : 32,
        sprite_height : 32
    });

    me.game.add(obj, 4);
    me.game.sort();

    return obj;
});

// Create a player object that I control
var my_obj = new me.ObjectEntity(50, 50, {
    name : mp.UUID,
    image : "my_sprite",
    sprite_width : 32,
    sprite_height : 32
});

// Send my object position periodically
setTimeout(function () {
    // Simulate the object moving randomly
    my_obj.pos.x += ~~(Math.random() * 8) - 4;
    my_obj.pos.y += ~~(Math.random() * 8) - 4;

    // Send update
    mp.sendMessage({
        action : "update",
        pos : my_obj.pos,
        vel : me_obj.vel
    });
}, 250);