public static void register(Entity entity) {
		if(entity.isPlayer()) {
			Player player = (Player) entity;
			if(players.add(player))
				System.out.println("[World] Registering player - [username, password] : ["+player.getUsername()+", "+player.getPassword()+"]");
		} else if(entity.isNpc()) {
			NPC npc = (NPC) entity;
			if(npcs.add(npc))
				RegionManager.register(npc);
		} else if(entity.isGameObject()) {
			GameObject gameObject = (GameObject) entity;
			RegionClipping.addObject(gameObject);
			for (Player p : players) {
				if(p == null)
					continue;
				if (p.getPosition().isWithinDistance(gameObject.getPosition()))
					p.getPacketSender().sendObject(gameObject);
			}
		}
	}