If a sound is started, plays for a while, then stopped, repositioned and

started quickly, queued position data from the previous play will still
be flushed.  We clear already-flushed data in StopMixing (pos_map.clear())
so we don't have stale data, but some is being re-flushed afterwards because
we have the same ID.  Change sound IDs when stopping a sound.

(The symptom was the first frame in Play mode in the editor would process
using an old position; the position was usually later in the song, which
sometimes marked hold notes as dead.)

stepmania/src/RageSound.cpp

@@ -72,7 +72,9 @@ RageSound::RageSound():
 	databuf.reserve(internal_buffer_size);
 
 	/* Register ourself. */
-	ID = SOUNDMAN->RegisterSound( this );
+	SOUNDMAN->RegisterSound( this );
+
+	ID = SOUNDMAN->GetUniqueID();
 }
 
 RageSound::~RageSound()
@@ -98,8 +100,11 @@ RageSound::RageSound(const RageSound &cpy):
 
 	*this = cpy;
 
-	/* Register ourself.  We have a different ID than our parent. */
-	ID = SOUNDMAN->RegisterSound( this );
+	/* Register ourself. */
+	SOUNDMAN->RegisterSound( this );
+
+	/* We have a different ID than our parent. */
+	ID = SOUNDMAN->GetUniqueID();
 }
 
 RageSound &RageSound::operator=( const RageSound &cpy )
@@ -605,6 +610,12 @@ void RageSound::StopPlaying()
 	
 	max_driver_frame = 0;
 	pos_map.Clear();
+
+	/* We may still have positions queued up in RageSoundManager.  We need to make sure
+	 * that we don't accept those; otherwise, if we start playing again quickly, they'll
+	 * confuse GetPositionSeconds().  Do this by changing our ID. */
+	ID = SOUNDMAN->GetUniqueID();
+
 //	LOG->Trace("StopPlaying %p finished (%s)", this, this->GetLoadedFilePath().c_str());
 
 	m_Mutex.Unlock();

stepmania/src/RageSoundManager.cpp

@@ -122,14 +122,11 @@ void RageSoundManager::Update(float delta)
 }
 
 /* Register the given sound, and return a unique ID. */
-int RageSoundManager::RegisterSound( RageSound *p )
+void RageSoundManager::RegisterSound( RageSound *p )
 {
-	LockMut(g_SoundManMutex); /* lock for access to all_sounds and iID */
-
+	g_SoundManMutex.Lock(); /* lock for access to all_sounds */
 	all_sounds.insert( p );
-
-	static int iID = 0;
-	return ++iID;
+	g_SoundManMutex.Unlock(); /* finished with all_sounds */
 }
 
 void RageSoundManager::UnregisterSound( RageSound *p )
@@ -139,6 +136,14 @@ void RageSoundManager::UnregisterSound( RageSound *p )
 	g_SoundManMutex.Unlock(); /* finished with all_sounds */
 }
 
+/* Return a unique ID. */
+int RageSoundManager::GetUniqueID()
+{
+	LockMut(g_SoundManMutex); /* serialize iID */
+	static int iID = 0;
+	return ++iID;
+}
+
 void RageSoundManager::RegisterPlayingSound( RageSound *p )
 {
 	g_SoundManMutex.Lock(); /* lock for access to playing_sounds */

stepmania/src/RageSoundManager.h

@@ -44,8 +44,9 @@ public:
 	void StartMixing( RageSoundBase *snd );	/* used by RageSound */
 	void StopMixing( RageSoundBase *snd );	/* used by RageSound */
 	int64_t GetPosition( const RageSoundBase *snd ) const;	/* used by RageSound */
-	int RegisterSound( RageSound *p );		/* used by RageSound */
+	void RegisterSound( RageSound *p );		/* used by RageSound */
 	void UnregisterSound( RageSound *p );	/* used by RageSound */
+	int GetUniqueID();						/* used by RageSound */
 	void RegisterPlayingSound( RageSound *p );	/* used by RageSound */
 	void UnregisterPlayingSound( RageSound *p );	/* used by RageSound */
 	void CommitPlayingPosition( int ID, int64_t frameno, int pos, int got_bytes );	/* used by drivers */