remember the time of the current beat data

stepmania/src/GameState.cpp

@@ -389,6 +389,8 @@ void GameState::UpdateSongPosition( float fPositionSeconds, const TimingData &ti
 {
 	m_fMusicSeconds = fPositionSeconds;
 	timing.GetBeatAndBPSFromElapsedTime( m_fMusicSeconds, m_fSongBeat, m_fCurBPS, m_bFreeze );
+	m_LastBeatUpdate.Touch();
+
 //	LOG->Trace( "m_fMusicSeconds = %f, m_fSongBeat = %f, m_fCurBPS = %f, m_bFreeze = %f", m_fMusicSeconds, m_fSongBeat, m_fCurBPS, m_bFreeze );
 }
 

stepmania/src/GameState.h

@@ -18,6 +18,7 @@
 #include "Style.h"
 #include "Grade.h"
 #include "Attack.h"
+#include "RageTimer.h"
 
 #include <map>
 
@@ -144,6 +145,7 @@ public:
 	float		m_fSongBeat;
 	float		m_fCurBPS;
 	bool		m_bFreeze;	// in the middle of a freeze
+	RageTimer	m_LastBeatUpdate; // time of last m_fSongBeat, etc. update
 	bool		m_bPastHereWeGo;
 	float		m_fLastDrawnBeat[NUM_PLAYERS]; // set by NoteField