void MidiPlayer::run()
{
// Workaround to fix errors with the Microsoft GS Wavetable Synth on
// Windows 10 - see http://stackoverflow.com/a/32553208/586978
#ifdef _WIN32
CoInitializeEx(nullptr, COINIT_MULTITHREADED);
BOOST_SCOPE_EXIT(this_) {
CoUninitialize();
} BOOST_SCOPE_EXIT_END
#endif
boost::signals2::scoped_connection connection(
mySettingsManager.subscribeToChanges([&]() {
auto settings = mySettingsManager.getReadHandle();
myMetronomeEnabled = settings->get(Settings::MetronomeEnabled);
}));
setIsPlaying(true);
MidiFile::LoadOptions options;
options.myEnableMetronome = true;
options.myRecordPositionChanges = true;
// Load MIDI settings.
int api;
int port;
{
auto settings = mySettingsManager.getReadHandle();
myMetronomeEnabled = settings->get(Settings::MetronomeEnabled);
api = settings->get(Settings::MidiApi);
port = settings->get(Settings::MidiPort);
options.myMetronomePreset = settings->get(Settings::MetronomePreset) +
Midi::MIDI_PERCUSSION_PRESET_OFFSET;
options.myStrongAccentVel =
settings->get(Settings::MetronomeStrongAccent);
options.myWeakAccentVel = settings->get(Settings::MetronomeWeakAccent);
options.myVibratoStrength = settings->get(Settings::MidiVibratoLevel);
options.myWideVibratoStrength =
settings->get(Settings::MidiWideVibratoLevel);
}
MidiFile file;
file.load(myScore, options);
const int ticks_per_beat = file.getTicksPerBeat();
// Merge the MIDI evvents for each track.
MidiEventList events;
for (MidiEventList &track : file.getTracks())
{
track.convertToAbsoluteTicks();
events.concat(track);
}
// TODO - since each track is already sorted, an n-way merge should be faster.
std::stable_sort(events.begin(), events.end());
events.convertToDeltaTicks();
// Initialize RtMidi and set the port.
MidiOutputDevice device;
if (!device.initialize(api, port))
{
emit error(tr("Error initializing MIDI output device."));
return;
}
bool started = false;
int beat_duration = Midi::BEAT_DURATION_120_BPM;
const SystemLocation start_location(myStartLocation.getSystemIndex(),
myStartLocation.getPositionIndex());
SystemLocation current_location = start_location;
for (auto event = events.begin(); event != events.end(); ++event)
{
if (!isPlaying())
break;
if (event->isTempoChange())
beat_duration = event->getTempo();
// Skip events before the start location, except for events such as
// instrument changes. Tempo changes are tracked above.
if (!started)
{
if (event->getLocation() < start_location)
{
if (event->isProgramChange())
device.sendMessage(event->getData());
continue;
}
else
{
performCountIn(device, event->getLocation(), beat_duration);
started = true;
}
}
const int delta = event->getTicks();
assert(delta >= 0);
const int duration_us = boost::rational_cast<int>(
boost::rational<int>(delta, ticks_per_beat) * beat_duration);
usleep(duration_us * (100.0 / myPlaybackSpeed));
// Don't play metronome events if the metronome is disabled.
if (event->isNoteOnOff() && event->getChannel() == METRONOME_CHANNEL &&
!myMetronomeEnabled)
{
continue;
}
device.sendMessage(event->getData());
// Notify listeners of the current playback position.
if (event->getLocation() != current_location)
{
const SystemLocation &new_location = event->getLocation();
// Don't move backwards unless a repeat occurred.
if (new_location < current_location && !event->isPositionChange())
continue;
if (new_location.getSystem() != current_location.getSystem())
emit playbackSystemChanged(new_location.getSystem());
emit playbackPositionChanged(new_location.getPosition());
current_location = new_location;
}
}
}
