@Override
	public void beginContact(Contact contact) {
		Fixture fixA = contact.getFixtureA();
		Fixture fixB = contact.getFixtureB();
		Body bodyA = fixA.getBody();
		Body bodyB = fixB.getBody();
		Entity entityA = null;
		Entity entityB = null;
		//checks if the userdata is a class that extends Entity. Is not really needed, is just for lazy programmers :)
		if (bodyA.getUserData() != null && Entity.class.isAssignableFrom(bodyA.getUserData().getClass()) && bodyB.getUserData() != null && Entity.class.isAssignableFrom(bodyB.getUserData().getClass())) { 
			entityA = (Entity) bodyA.getUserData();
			entityB = (Entity) bodyB.getUserData();
			CoupleOfEntities entities = CoupleOfEntitiesFactory.getInstance().createCoupleOfEntities(entityA, entityB,this.currentRound);
			if(entities!=null){
				entities.collisionHappened();
			}
		}

	}