move stats formatting to RageDisplay, so renderers can add custom stats

stepmania/src/RageDisplay.cpp

@@ -98,6 +98,15 @@ void RageDisplay::ResetStats()
 	g_LastCheckTimer.GetDeltaTime();
 }
 
+CString RageDisplay::GetStats() const
+{
+	/* If FPS == 0, we don't have stats yet. */
+	if( !GetFPS() )
+		return "-- FPS\n-- av FPS\n-- VPF";
+
+	return ssprintf( "%i FPS\n%i av FPS\n%i VPF", GetFPS(), GetCumFPS(), GetVPF() );
+}
+
 void RageDisplay::StatsAddVerts( int iNumVertsRendered ) { g_iVertsRenderedSinceLastCheck += iNumVertsRendered; }
 
 /* Draw a line as a quad.  GL_LINES with SmoothLines off can draw line

stepmania/src/RageDisplay.h

@@ -277,6 +277,7 @@ public:
 	int GetCumFPS() const; /* average FPS since last reset */
 	void ResetStats();
 	void ProcessStatsOnFlip();
+	virtual CString GetStats() const;
 	void StatsAddVerts( int iNumVertsRendered );
 
 	/* World matrix stack functions. */

stepmania/src/ScreenManager.cpp

@@ -335,15 +335,7 @@ void ScreenSystemLayer::Update( float fDeltaTime )
 	if( PREFSMAN  &&  PREFSMAN->m_bShowStats )
 	{
 		m_textStats.SetDiffuse( RageColor(1,1,1,0.7f) );
-
-		/* If FPS == 0, we don't have stats yet. */
-		if(DISPLAY->GetFPS())
-			m_textStats.SetText( ssprintf(
-				"%i FPS\n%i av FPS\n%i VPF",
-				DISPLAY->GetFPS(), DISPLAY->GetCumFPS(), 
-				DISPLAY->GetVPF()) );
-		else
-			m_textStats.SetText( "-- FPS\n-- av FPS\n-- VPF" );
+		m_textStats.SetText( DISPLAY->GetStats() );
 	} else
 		m_textStats.SetDiffuse( RageColor(1,1,1,0) ); /* hide */