public SpaceInvadersGame()
        {
            graphics = new GraphicsDeviceManager(this);
            Services.AddService(typeof(GraphicsDeviceManager), graphics);
            Content.RootDirectory = "Content";
            this.IsMouseVisible = true;

            InputManager inputManager = new InputManager(this, 1);
            GameLevelDataManager gameLevelDataManager = new GameLevelDataManager(this);

            PauseScreen pauseScreen = new PauseScreen(this);
            ScreensMananger screensMananger = new ScreensMananger(this);
            BackgroundScreen backgroundScreen = new BackgroundScreen(this, 100);
            screensMananger.Push(backgroundScreen);

            MainMenuScreen mainMenu = new MainMenuScreen(this);
            mainMenu.IsModal = true;
            screensMananger.Push(mainMenu);

            WelcomeScreen welcomeScreen = new WelcomeScreen(this);
            screensMananger.SetCurrentScreen(welcomeScreen);
            backgroundScreen.State = eScreenState.Active;

            m_SoundManager = new SoundManager(this);
        }
        /// <summary>
        /// Initialize the screen by setting it's sound manager
        /// </summary>
        public override void Initialize()
        {
            base.Initialize();

            m_SoundManager = Game.Services.GetService(typeof(SoundManager)) as SoundManager;
        }