Fixed crash in demo if no songs.

stepmania/src/RageDisplay.cpp

@@ -77,6 +77,13 @@ RageDisplay::RageDisplay( bool windowed, int width, int height, int bpp, int rat
 
 	SetupOpenGL();
 
+	// Log driver details
+	LOG->Trace("OpenGL driver:");
+	LOG->Trace("  Vendor: %s", glGetString(GL_VENDOR));
+	LOG->Trace("  Renderer: %s", glGetString(GL_RENDERER));
+	LOG->Trace("  Version: %s", glGetString(GL_VERSION));
+
+
 	/* Log this, so if people complain that the radar looks bad on their
 	 * system we can compare them: */
 	glGetFloatv(GL_LINE_WIDTH_RANGE, m_oglspecs->line_range);

stepmania/src/ScreenDemonstration.cpp

@@ -54,11 +54,7 @@ bool SetUpSongOptions()		// always return true.
 	{
 		Song* pSong = SONGMAN->GetRandomSong();
 		if( pSong == NULL )	// returns NULL there are no songs
-		{
-			// we didn't find a song.  Abort demonstration.
-			SCREENMAN->SendMessageToTopScreen( SM_GoToNextScreen, 0 );
-			return true;
-		}
+			return true;	// we need to detect this and abort demonstration later
 
 		if( pSong->m_apNotes.empty() )
 			continue;	// skip
@@ -141,6 +137,12 @@ ScreenDemonstration::ScreenDemonstration() : ScreenGameplay(SetUpSongOptions())
 	LOG->Trace( "ScreenDemonstration::ScreenDemonstration()" );
 	GAMESTATE->m_bDemonstration = true;
 
+	if( GAMESTATE->m_pCurSong == NULL )	// we didn't find a song.
+	{
+		this->SendScreenMessage( SM_GoToNextScreen, 0 );	// Abort demonstration.
+		return;
+	}
+
 
 	m_sprDemonstrationOverlay.Load( THEME->GetPathTo("Graphics","demonstration overlay") );
 	m_sprDemonstrationOverlay.SetXY( CENTER_X, CENTER_Y );

stepmania/src/ScreenGameplay.cpp

@@ -100,6 +100,9 @@ ScreenGameplay::ScreenGameplay( bool bDemonstration )
 {
 	LOG->Trace( "ScreenGameplay::ScreenGameplay()" );
 
+	if( GAMESTATE->m_pCurSong == NULL )
+		return;	// ScreenDemonstration will move us to the next scren.  We just need to survive for one update without crashing.
+
 	int p;
 
 	for( p=0; p<NUM_PLAYERS; p++ )

stepmania/src/StepMania.cpp

@@ -199,10 +199,16 @@ static void BoostAppPri()
 		return;
 	}
 
+#ifndef ABOVE_NORMAL_PRIORITY_CLASS
+#define ABOVE_NORMAL_PRIORITY_CLASS 0x00008000
+#endif
+
 	DWORD pri = HIGH_PRIORITY_CLASS;
 	if(version.dwMajorVersion >= 5)
 		pri = ABOVE_NORMAL_PRIORITY_CLASS;
 
+#include <winbase.h>
+
 	/* Be sure to boost the app, not the thread, to make sure the
 	 * sound thread stays higher priority than the main thread. */
 	SetPriorityClass(GetCurrentProcess(), pri);