private void input() {
   if (Keyboard.isKeyDown(Keyboard.KEY_UP)) {
     bat.setDY(-.2);
   } else if (Keyboard.isKeyDown(Keyboard.KEY_DOWN)) {
     bat.setDY(.2);
   } else {
     bat.setDY(0);
   }
 }
 private void logic(int delta) {
   ball.update(delta);
   bat.update(delta);
   if (ball.getX() <= bat.getX() + bat.getWidth()
       && ball.getX() >= bat.getX()
       && ball.getY() >= bat.getY()
       && ball.getY() <= bat.getY() + bat.getHeight()) {
     ball.setDX(0.3);
   }
 }
 private void render() {
   glClear(GL_COLOR_BUFFER_BIT);
   ball.draw();
   bat.draw();
 }