simplify. Don't separate "next" and "cancel" as much: to cancel, set the next screen to PREV_SCREEN, and use SM_GoToNextScreen.

stepmania/src/Screen.cpp

@@ -72,7 +72,6 @@ void Screen::BeginScreen()
 	/* Screens set these when they determine their next screen dynamically.  Reset them
 	 * here, so a reused screen doesn't inherit these from the last time it was used. */
 	m_sNextScreen = RString();
-	m_sPrevScreen = RString();
 	
 	this->RunCommands( THEME->GetMetricA(m_sName, "ScreenOnCommand") );
 }
@@ -213,20 +212,13 @@ void Screen::HandleScreenMessage( const ScreenMessage SM )
 		FOREACH_HumanPlayer(p)
 			MenuStart( p );
 	}
-	else if( SM == SM_GoToNextScreen )
+	else if( SM == SM_GoToNextScreen || SM == SM_GoToPrevScreen )
 	{
 		if( SCREENMAN->IsStackedScreen(this) )
 			SCREENMAN->PopTopScreen( m_smSendOnPop );
 		else
 			SCREENMAN->SetNewScreen( GetNextScreen() );
 	}
-	else if( SM == SM_GoToPrevScreen )
-	{
-		if( SCREENMAN->IsStackedScreen(this) )
-			SCREENMAN->PopTopScreen( m_smSendOnPop );
-		else
-			SCREENMAN->SetNewScreen( GetPrevScreen() );
-	}
 }
 
 RString Screen::GetNextScreen() const
@@ -238,8 +230,6 @@ RString Screen::GetNextScreen() const
 
 RString Screen::GetPrevScreen() const
 {
-	if( !m_sPrevScreen.empty() )
-		return m_sPrevScreen;
 	return PREV_SCREEN;
 }
 

stepmania/src/Screen.h

@@ -81,8 +81,8 @@ protected:
 	RString GetNextScreen() const;
 	RString GetPrevScreen() const;
 
-	// If these are left blank, the NextScreen and PrevScreen metrics will be used.
-	RString m_sNextScreen, m_sPrevScreen;
+	// If left blank, the NextScreen metric will be used.
+	RString m_sNextScreen;
 	ScreenMessage m_smSendOnPop;
 
 public:

stepmania/src/ScreenGameplay.cpp

@@ -2500,6 +2500,8 @@ void ScreenGameplay::HandleScreenMessage( const ScreenMessage SM )
 
 		GAMESTATE->CancelStage();
 
+		m_sNextScreen = GetPrevScreen();
+
 		if( AdjustSync::IsSyncDataChanged() )
 			ScreenSaveSync::PromptSaveSync( SM_GoToPrevScreen );
 		else

stepmania/src/ScreenStage.cpp

@@ -107,6 +107,7 @@ void ScreenStage::MenuBack( PlayerNumber pn )
 		return;
 	
 	this->ClearMessageQueue();
+	m_sNextScreen = GetPrevScreen();
 	m_Cancel.StartTransitioning( SM_GoToPrevScreen );
 
 	/* If a Back is buffered while we're prepping the screen (very common), we'll

stepmania/src/ScreenWithMenuElements.cpp

@@ -285,6 +285,8 @@ void ScreenWithMenuElements::TweenOffScreen()
 
 void ScreenWithMenuElements::Cancel( ScreenMessage smSendWhenDone )
 {
+	m_sNextScreen = GetPrevScreen();
+
 	if( CANCEL_TRANSITIONS_OUT )
 	{
 		SCREENMAN->PlayCancelSound();