In March, b67c2d72d6 moved some MIDI
initialization from the main thread to the MIDI thread. This caused
MidiPlayer_Midi::sysEx() to run on the MIDI thread for the first time.
This is a problem because it calls SciEngine:sleep(), which polls
events, and that causes MacOS to throw an exception for calling
SDL_PollEvent() on a non-main thread.
While investigating, it also turns out that MidiPlayer_Midi::sysEx()
and MidiPlayer_Fb01::sysEx() were calling OSystem::updateScreen(),
and that also shouldn't be happening on a non-main thread.
Now SciEngine::sleep() is only called on the main thread, and
OSystem::delayMillis() is called on the MIDI timer thread.
Continuing to call sleep() on the main thread keeps the UI responsive
when loading patches, which can take several seconds.
The OSystem::updateScreen() calls had no effect and have been removed.
Fixes bug #12947
- The mutex was added to avoid the triggering of the assert in backends/midi/windows.cpp, line 95. Meanwhile, this issue has been addressed differently.
- SCI does not per se require a mutex for the sound drivers. The engine is mostly thread-safe by avoiding driver calls through the main thread.
Fix SCI0 (LATE/EARLY) variants of the driver which were broken (didn't play at all). This might be of my own doing, since I introduced the initTrack() method into the driver class and the fb01 driver didn't have one so far.
SCI1 didn't seem to require much fixing. I modified some things according to my findings in the driver disasms. QFG2 and JONES seem to be fine. I am not too happy with KQ5. It has volume issues, but they might be present in the original, too.
I also added an isOpen() check and a mutex to avoid threading issues. When aborting SCI (either quitting ScummVM or returning ot the launcher) while using the fb01 driver I frequently (more often than not) got the assert from backends/midi/windows.cpp, line 95. This fixes that.
I've done plenty of checks and experiments with the sound bank initialization. But I found no bugs or possible improvements there. Hard to tell whether the sound is right. That device seems to have a mind of its own...
Fix up SCI0_LATE variant of the driver so that it actually plays anything (and even correctly). SCI1 hasn't seen any testing from me so far. I don't know whether that version works. Same for SCI0_EARLY...
Many engines follow the advice in audio/midiparser.h and create a
"pseudo-MidiDriver" subclass. But MidiParser really only needs a tiny
subset of the MidiDriver capabilities, namely those found in
MidiDriver_BASE. So we try to subclass from that whenever possible; this
allows us to remove many stub methods, and enables further future
simplifications.