flame HudButtonComponent 的功能

final flipButton = HudButtonComponent(
  button: SpriteComponent(
    sprite: sheet.getSpriteById(2),
    size: buttonSize,
  ),
  buttonDown: SpriteComponent(
    sprite: sheet.getSpriteById(4),
    size: buttonSize,
  ),
  margin: const EdgeInsets.only(
    right: 80,
    bottom: 60,
  ),
  onPressed: player.flipHorizontally,
);

可以设置两种状态的button button 正常展示内容 buttonDown 按下展示内容。