// 单例的使用
 private ControllerCenter()
 {
     renderSystem     = new RendererSystem();
     playerSystem     = new PlayerSystem();
     ActionSystem     = new ActionSystem();
     gameobjectSystem = new GameObjectSystem();
     itemSystem       = new ItemSystem();
     skillitemSystem  = new SkillItemSystem();
 }
        protected override void Handle(KeyPressed keyPressed)
        {
            if (keyPressed.Key != Keys.LeftControl)
            {
                return;
            }

            EnabledSystem = EnabledSystem == RendererSystem.Polygonal
                ? RendererSystem.Sprite
                : RendererSystem.Polygonal;

            RefreshRenderers();
        }