double frametime = 1000000.f/60, delta = 0;
void Game::gameLoop(sf::RenderWindow &window)
{
    t = clock.getElapsedTime().asMicroseconds();
    if (t + delta >= frametime)
    {
        clock.restart();
        delta = t + delta - frametime;
        update();
    }
    render(window);
}