Real-time MIDI playback using RtMidi

Before this, MIDI playback was done by generating an SMF data stream,
which was then played using platform-specific methods (MCI on Windows,
MediaPlayer on Android, SDL_Mixer on other platforms). However, this
approach had an issue where the Y18 command (which reads loop counts and
markers) did not work correctly.

With this change, the MAKOMidi class now uses the RtMidi library to
control MIDI devices in real-time. This approach was used in the
original "System3 for win32", but has now been made cross-platform.

The dependency on RtMidi is optional. If RtMidi is not available at
build time or a MIDI device is unavailable at runtime, FM synthesis will
be used.

src/win/mako.cpp

@@ -41,11 +41,6 @@ enum MakoThreadMessage {
 	MAKO_EXIT
 };
 
-enum MakoOpenFlags {
-	OPEN_CD = 0,
-	OPEN_MIDI = 1,
-};
-
 const char* mci_geterror(DWORD err)
 {
 	static char buf[128];
@@ -82,8 +77,7 @@ private:
 			switch (msg.message) {
 			case MAKO_OPEN:
 				close();
-				open(reinterpret_cast<std::string*>(msg.wParam),
-					 static_cast<MakoOpenFlags>(msg.lParam));
+				open(reinterpret_cast<std::string*>(msg.wParam));
 				break;
 
 			case MAKO_PLAY:
@@ -101,18 +95,13 @@ private:
 		}
 	}
 
-	void open(std::string* file, MakoOpenFlags open_flags)
+	void open(std::string* file)
 	{
 		file_playing = file;
-		is_midi = open_flags & OPEN_MIDI;
 
 		MCI_OPEN_PARMS open;
 		open.lpstrElementName = file_playing->c_str();
 		DWORD flags = MCI_OPEN_ELEMENT | MCI_WAIT;
-		if (is_midi) {
-			flags |= MCI_OPEN_TYPE | MCI_OPEN_TYPE_ID;
-			open.lpstrDeviceType = (LPCSTR)MCI_DEVTYPE_SEQUENCER;
-		}
 		MCIERROR err = mciSendCommand(0, MCI_OPEN, flags, (DWORD_PTR)&open);
 		if (err) {
 			WARNING("MCI_OPEN failed: %s: %s",
@@ -139,8 +128,6 @@ private:
 			devid = 0;
 		}
 		if (file_playing) {
-			if (is_midi)
-				DeleteFile(file_playing->c_str());  // remove temporary file
 			delete file_playing;
 			file_playing = nullptr;
 		}
@@ -149,7 +136,6 @@ private:
 	HWND hwnd_notify;
 	unsigned thread_id;
 	std::string* file_playing = nullptr;
-	bool is_midi;
 	MCIDEVICEID devid = 0;
 };
 
@@ -159,38 +145,7 @@ class Music {
 public:
 	Music(const char* fname, int loop) : loops(loop) {
 		std::string* fname_str = new std::string(fname);
-		mci_thread->post_message(MAKO_OPEN, (WPARAM)fname_str, OPEN_CD);
-		mci_thread->post_message(MAKO_PLAY, 0, 0);
-		playing = true;
-	}
-
-	Music(std::unique_ptr<MAKOMidi> midi, int loop) : loops(loop ? 1 : 0) {
-		std::vector<uint8> smf = midi->generate_smf(loop);
-		char path[MAX_PATH + 1];
-		if (!GetTempPath(sizeof(path), path)) {
-			WARNING("GetTempPath failed: 0x%x", GetLastError());
-			return;
-		}
-		char fname[MAX_PATH + 1];
-		if (!GetTempFileName(path, "mid", 0, fname)) {
-			WARNING("GetTempFileName failed: 0x%x", GetLastError());
-			return;
-		}
-		FILE* fp = fopen(fname, "wb");
-		if (!fp) {
-			WARNING("Cannot open %s: %s", fname, strerror(errno));
-			return;
-		}
-		if (fwrite(smf.data(), smf.size(), 1, fp) != 1) {
-			WARNING("Cannot write to %s: %s", fname, strerror(errno));
-			fclose(fp);
-			DeleteFile(fname);
-			return;
-		}
-		fclose(fp);
-
-		std::string* fname_str = new std::string(fname);
-		mci_thread->post_message(MAKO_OPEN, (WPARAM)fname_str, OPEN_MIDI);
+		mci_thread->post_message(MAKO_OPEN, (WPARAM)fname_str, 0);
 		mci_thread->post_message(MAKO_PLAY, 0, 0);
 		playing = true;
 	}
@@ -235,6 +190,7 @@ Music* music;
 uint8* wav_buffer;
 SDL_mutex* fm_mutex;
 std::unique_ptr<MakoYmfm> fm;
+std::unique_ptr<MAKOMidi> midi;
 
 void audio_callback(void*, Uint8* stream, int len) {
 	SDL_LockMutex(fm_mutex);
@@ -279,6 +235,10 @@ MAKO::MAKO(NACT* parent, const Config& config) :
 	if (!SDL_GetWindowWMInfo(g_window, &info))
 		parent->fatal("SDL_GetWindowWMInfo failed: %s", SDL_GetError());
 	mci_thread = new MCIThread(parent, info.info.win.window);
+
+	midi = std::make_unique<MAKOMidi>();
+	if (!midi->is_available())
+		use_fm = true;
 }
 
 MAKO::~MAKO()
@@ -287,6 +247,7 @@ MAKO::~MAKO()
 	stop_pcm();
 	mci_thread->post_message(MAKO_EXIT, 0, 0);
 	mci_thread = nullptr;  // MCIThread self-destructs on the worker thread.
+	midi.reset();
 
 	SDL_LockMutex(fm_mutex);
 	SDL_CloseAudio();
@@ -337,12 +298,9 @@ void MAKO::play_music(int page)
 		fm = std::make_unique<MakoYmfm>(SAMPLE_RATE, data, true);
 		SDL_UnlockMutex(fm_mutex);
 		SDL_PauseAudio(0);
-	} else {
-		auto midi = std::make_unique<MAKOMidi>(nact, amus);
-		if (!midi->load_mml(page))
+	} else if (midi->is_available()) {
+		if (!midi->play(nact, amus, page, next_loop))
 			return;
-		midi->load_mda(page);
-		music = new Music(std::move(midi), next_loop);
 	}
 	current_music = page;
 }
@@ -359,6 +317,9 @@ void MAKO::stop_music()
 		fm = nullptr;
 		SDL_UnlockMutex(fm_mutex);
 	}
+	if (midi->is_available()) {
+		midi->stop();
+	}
 	current_music = 0;
 }
 
@@ -371,7 +332,11 @@ bool MAKO::check_music()
 		SDL_UnlockMutex(fm_mutex);
 		return !loop;
 	}
-	return music && music->is_playing();
+	else if (music) {
+		return music->is_playing();
+	} else {
+		return midi->is_playing();
+	}
 }
 
 void MAKO::select_sound(BGMDevice dev)
@@ -386,7 +351,10 @@ void MAKO::select_sound(BGMDevice dev)
 	case BGM_MIDI:
 		for (int i = 1; i <= 99; i++)
 			cd_track[i] = 0;
-		use_fm = dev == BGM_FM;
+		if (midi->is_available())
+			use_fm = dev == BGM_FM;
+		else
+			dev = BGM_FM;
 		break;
 
 	case BGM_CD:
@@ -435,11 +403,11 @@ void MAKO::get_mark(int* mark, int* loop)
 	SDL_LockMutex(fm_mutex);
 	if (fm) {
 		fm->get_mark(mark, loop);
-	} else {
-		*mark = 0;
-		*loop = 0;
+		SDL_UnlockMutex(fm_mutex);
+		return;
 	}
 	SDL_UnlockMutex(fm_mutex);
+	midi->get_mark(mark, loop);
 }
 
 void MAKO::play_pcm(int page, bool loop)