function gameLoop() {
  const [gp] = navigator.getGamepads();

  let a = 0;
  let b = 0;
  if (gp.axes[0] !== 0) {
    b -= gp.axes[0];
  } else if (gp.axes[1] !== 0) {
    a += gp.axes[1];
  } else if (gp.axes[2] !== 0) {
    b += gp.axes[2];
  } else if (gp.axes[3] !== 0) {
    a -= gp.axes[3];
  }

  ball.style.left = `${a * 2}px`;
  ball.style.top = `${b * 2}px`;

  const start = requestAnimationFrame(gameLoop);
}