Change: Invalidate music volume when restarting music playback on Windows. (#11836)

src/music/dmusic.cpp

@@ -651,6 +651,9 @@ static void MidiThreadProc()
 				TransmitNotesOff(_buffer, block_time, cur_time);
 
 				MemSetT<byte>(channel_volumes, 127, lengthof(channel_volumes));
+				/* Invalidate current volume. */
+				current_volume = UINT8_MAX;
+				last_volume_time = 0;
 
 				/* Take the current time plus the preload time as the music start time. */
 				clock->GetTime(&playback_start_time);

src/music/win32_m.cpp

@@ -110,6 +110,8 @@ static void TransmitStandardSysex(MidiSysexMessage msg)
  */
 void CALLBACK TimerCallback(UINT uTimerID, UINT, DWORD_PTR, DWORD_PTR, DWORD_PTR)
 {
+	static int volume_throttle = 0;
+
 	/* Ensure only one timer callback is running at once, and prevent races on status flags */
 	std::unique_lock<std::mutex> mutex_lock(_midi.lock, std::defer_lock);
 	if (!mutex_lock.try_lock()) return;
@@ -163,6 +165,9 @@ void CALLBACK TimerCallback(UINT uTimerID, UINT, DWORD_PTR, DWORD_PTR, DWORD_PTR
 			_midi.current_block = 0;
 
 			MemSetT<byte>(_midi.channel_volumes, 127, lengthof(_midi.channel_volumes));
+			/* Invalidate current volume. */
+			_midi.current_volume = UINT8_MAX;
+			volume_throttle = 0;
 		}
 	} else if (!_midi.playing) {
 		/* not playing, stop the timer */
@@ -173,7 +178,6 @@ void CALLBACK TimerCallback(UINT uTimerID, UINT, DWORD_PTR, DWORD_PTR, DWORD_PTR
 	}
 
 	/* check for volume change */
-	static int volume_throttle = 0;
 	if (_midi.current_volume != _midi.new_volume) {
 		if (volume_throttle == 0) {
 			Debug(driver, 2, "Win32-MIDI: timer: volume change");