SCI: Omit SysEx delays when sending to MT-32 emulator

Real MIDI devices, and MT-32 in particular, need delays between
SysEx messages to ensure sufficient time to receive and process
the incoming data buffer. Sending too much data too quickly to
these devices can cause them to crash with a buffer overflow.

The MT-32 emulator, on the other hand, has no problem receiving
SysEx data instantly, so skipping the delays means that games that
send lots of data to the MT-32 will start up much faster.

1 files changed, 33 insertions, 18 deletions

diff --git a/engines/sci/sound/drivers/midi.cpp b/engines/sci/sound/drivers/midi.cpp
index 6821b2219f..3f6149daf9 100644
--- a/engines/sci/sound/drivers/midi.cpp
+++ b/engines/sci/sound/drivers/midi.cpp
@@ -134,6 +134,12 @@ public:
 		kMaxSysExSize = 264
 	};
 
+	enum Mt32Type {
+		kMt32TypeNone,
+		kMt32TypeReal,
+		kMt32TypeEmulated
+	};
+
 	MidiPlayer_Midi(SciVersion version);
 	virtual ~MidiPlayer_Midi();
 
@@ -191,7 +197,7 @@ private:
 			keyShift(0), volAdjust(0), pan(0x40), hold(0), volume(0x7f) { }
 	};
 
-	bool _isMt32;
+	Mt32Type _mt32Type;
 	bool _useMT32Track;
 	bool _hasReverb;
 	bool _playSwitch;
@@ -214,12 +220,17 @@ private:
 	byte _sysExBuf[kMaxSysExSize];
 };
 
-MidiPlayer_Midi::MidiPlayer_Midi(SciVersion version) : MidiPlayer(version), _playSwitch(true), _masterVolume(15), _isMt32(false), _hasReverb(false), _useMT32Track(true) {
+MidiPlayer_Midi::MidiPlayer_Midi(SciVersion version) : MidiPlayer(version), _playSwitch(true), _masterVolume(15), _mt32Type(kMt32TypeNone), _hasReverb(false), _useMT32Track(true) {
 	MidiDriver::DeviceHandle dev = MidiDriver::detectDevice(MDT_MIDI);
 	_driver = MidiDriver::createMidi(dev);
 
-	if (MidiDriver::getMusicType(dev) == MT_MT32 || ConfMan.getBool("native_mt32"))
-		_isMt32 = true;
+	if (MidiDriver::getMusicType(dev) == MT_MT32 || ConfMan.getBool("native_mt32")) {
+		if (MidiDriver::getDeviceString(dev, MidiDriver::kDriverId) == "mt32") {
+			_mt32Type = kMt32TypeEmulated;
+		} else {
+			_mt32Type = kMt32TypeReal;
+		}
+	}
 
 	_sysExBuf[0] = 0x41;
 	_sysExBuf[1] = 0x10;
@@ -439,13 +450,13 @@ void MidiPlayer_Midi::send(uint32 b) {
 // We return 1 for mt32, because if we remap channels to 0 for mt32, those won't get played at all
 // NOTE: SSCI uses channels 1 through 8 for General MIDI as well, in the drivers I checked
 int MidiPlayer_Midi::getFirstChannel() const {
-	if (_isMt32)
+	if (_mt32Type != kMt32TypeNone)
 		return 1;
 	return 0;
 }
 
 int MidiPlayer_Midi::getLastChannel() const {
-	if (_isMt32)
+	if (_mt32Type != kMt32TypeNone)
 		return 8;
 	return 15;
 }
@@ -998,8 +1009,10 @@ void MidiPlayer_Midi::resetMt32() {
 	Common::MemoryReadStream s((const byte *)"\x01\x00", 2);
 	sendMt32SysEx(0x7f0000, s, 2, true);
 
-	// This seems to require a longer delay than usual
-	g_system->delayMillis(150);
+	if (_mt32Type != kMt32TypeEmulated) {
+		// This seems to require a longer delay than usual
+		g_sci->sleep(150);
+	}
 }
 
 int MidiPlayer_Midi::open(ResourceManager *resMan) {
@@ -1038,7 +1051,7 @@ int MidiPlayer_Midi::open(ResourceManager *resMan) {
 		}
 	}
 
-	if (_isMt32) {
+	if (_mt32Type != kMt32TypeNone) {
 		// MT-32
 		resetMt32();
 
@@ -1145,7 +1158,7 @@ int MidiPlayer_Midi::open(ResourceManager *resMan) {
 }
 
 void MidiPlayer_Midi::close() {
-	if (_isMt32) {
+	if (_mt32Type != kMt32TypeNone) {
 		// Send goodbye message
 		sendMt32SysEx(0x200000, SciSpan<const byte>(_goodbyeMsg, 20), true);
 	}
@@ -1156,15 +1169,17 @@ void MidiPlayer_Midi::close() {
 void MidiPlayer_Midi::sysEx(const byte *msg, uint16 length) {
 	_driver->sysEx(msg, length);
 
-	// Wait the time it takes to send the SysEx data
-	uint32 delay = (length + 2) * 1000 / 3125;
+	if (_mt32Type != kMt32TypeEmulated) {
+		// Wait the time it takes to send the SysEx data
+		uint32 delay = (length + 2) * 1000 / 3125;
 
-	// Plus an additional delay for the MT-32 rev00
-	if (_isMt32)
-		delay += 40;
+		// Plus an additional delay for the MT-32 rev00
+		if (_mt32Type == kMt32TypeReal)
+			delay += 40;
 
-	g_system->updateScreen();
-	g_sci->sleep(delay);
+		g_system->updateScreen();
+		g_sci->sleep(delay);
+	}
 }
 
 byte MidiPlayer_Midi::getPlayId() const {
@@ -1173,7 +1188,7 @@ byte MidiPlayer_Midi::getPlayId() const {
 	case SCI_VERSION_0_LATE:
 		return 0x01;
 	default:
-		if (_isMt32)
+		if (_mt32Type != kMt32TypeNone)
 			return 0x0c;
 		else
 			return _useMT32Track ? 0x0c : 0x07;