add UpdateSongPosition

stepmania/src/GameState.cpp

@@ -105,6 +105,14 @@ void GameState::ResetMusicStatistics()
 	m_bPastHereWeGo = false;
 }
 
+void GameState::UpdateSongPosition(float fPositionSeconds)
+{
+	ASSERT(m_pCurSong);
+
+	m_fMusicSeconds = fPositionSeconds;
+	m_pCurSong->GetBeatAndBPSFromElapsedTime( m_fMusicSeconds, m_fSongBeat, m_fCurBPS, m_bFreeze );
+}
+
 int GameState::GetStageIndex()
 {
 	return m_iCurrentStageIndex;

stepmania/src/GameState.h

@@ -96,7 +96,8 @@ public:
 	bool		m_bPastHereWeGo;
 
 	void ResetMusicStatistics();		// Call this when it's time to play a new song.  Clears the values above.
-	
+	void UpdateSongPosition(float fPositionSeconds);
+
 	//
 	// Stage Statistics: 
 	// Arcade:	for the current stage (one song).