When adjusting the song position for duplicate positions being returned from the sound driver, multiply the time delta since last update by the rate. Whoa, stutter on rates is gone for DirectSound-sw!

Author: xwidghet

src/GameState.cpp

@@ -1250,9 +1250,15 @@ void GameState::UpdateSongPosition( float fPositionSeconds, const TimingData &ti
 	/* It's not uncommon to get a lot of duplicated positions from the sound
 	 * driver, like so: 13.120953,13.130975,13.130975,13.130975,13.140998,...
 	 * This causes visual stuttering of the arrows. To compensate, keep a
-	 * RageTimer since the last change. */
-	if(fPositionSeconds == m_LastPositionSeconds && !m_paused)
-		fPositionSeconds += m_LastPositionTimer.Ago();
+	 * RageTimer since the last change and multiply the delta by the current
+	 * rate when applied. */
+	if (fPositionSeconds == m_LastPositionSeconds && !m_paused)
+	{
+		//LOG->Info("Time unchanged, adding: %+f",
+		//	m_LastPositionTimer.Ago()*m_SongOptions.GetSong().m_fMusicRate
+		//);
+		fPositionSeconds += m_LastPositionTimer.Ago()*m_SongOptions.GetSong().m_fMusicRate;
+	}
 	else
 	{
 		//LOG->Info("Time difference: %+f",