add GenericTweenOn()

stepmania/src/ScreenWithMenuElements.cpp

@@ -140,7 +140,10 @@ void ScreenWithMenuElements::BeginScreen()
 	m_Out.Reset();
 	m_Cancel.Reset();
 
-	TweenOnScreen();
+	if( GenericTweenOn() )
+		this->PlayCommand( "On" );
+	else
+		TweenOnScreen(); // deprecated
 	m_In.StartTransitioning( SM_DoneFadingIn );
 
 	Screen::BeginScreen();

stepmania/src/ScreenWithMenuElements.h

@@ -41,6 +41,11 @@ protected:
 	virtual void StartPlayingMusic();
 	virtual void LoadHelpText();
 
+	/* If true, BeginScreen() will run OnCommand on the whole screen, and
+	 * TweenOnScreen will not be called.  (Eventually, all screens should
+	 * use this, and this will be removed.) */
+	virtual bool GenericTweenOn() const { return false; }
+
 	AutoActor			m_sprUnderlay;
 	AutoActor			m_autoHeader;
 	Sprite				m_sprStyleIcon;