SCUMM: Implement support for special sfx in MI2 Mac.

This also increases the savegame version, since it introduces a new
Instrument subclass.

5 files changed, 82 insertions, 3 deletions

diff --git a/engines/scumm/imuse/imuse_part.cpp b/engines/scumm/imuse/imuse_part.cpp
index 73e7704469..d4e4740451 100644
--- a/engines/scumm/imuse/imuse_part.cpp
+++ b/engines/scumm/imuse/imuse_part.cpp
@@ -27,6 +27,7 @@
 #include "common/util.h"
 #include "scumm/imuse/imuse_internal.h"
 #include "scumm/saveload.h"
+#include "scumm/scumm.h"
 
 namespace Scumm {
 
@@ -365,7 +366,17 @@ void Part::set_instrument(uint b) {
 	_bank = (byte)(b >> 8);
 	if (_bank)
 		error("Non-zero instrument bank selection. Please report this");
-	_instrument.program((byte)b, _player->isMT32());
+	// HACK: Horrible hack to allow tracing of program change source.
+	// The Mac version of Monkey Island 2 uses a different program "bank"
+	// when it gets program change events through the iMuse SysEx handler.
+	// We emulate this by introducing a special instrument, which sets
+	// the instrument via sysEx_customInstrument. This seems to be
+	// exclusively used for special sound effects like the "spit" sound.
+	if (g_scumm->_game.id == GID_MONKEY2 && g_scumm->_game.platform == Common::kPlatformMacintosh) {
+		_instrument.macSfx(b);
+	} else {
+		_instrument.program((byte)b, _player->isMT32());
+	}
 	if (clearToTransmit())
 		_instrument.send(_mc);
 }
diff --git a/engines/scumm/imuse/instrument.cpp b/engines/scumm/imuse/instrument.cpp
index 11bb4e7605..61c73b1e2d 100644
--- a/engines/scumm/imuse/instrument.cpp
+++ b/engines/scumm/imuse/instrument.cpp
@@ -278,6 +278,21 @@ private:
 	byte _instrument[23];
 };
 
+class Instrument_MacSfx : public InstrumentInternal {
+private:
+	byte _program;
+
+public:
+	Instrument_MacSfx(byte program);
+	Instrument_MacSfx(Serializer *s);
+	void saveOrLoad(Serializer *s);
+	void send(MidiChannel *mc);
+	void copy_to(Instrument *dest) { dest->macSfx(_program); }
+	bool is_valid() {
+		return (_program < 128);
+	}
+};
+
 ////////////////////////////////////////
 //
 // Instrument class members
@@ -326,6 +341,14 @@ void Instrument::pcspk(const byte *instrument) {
 	_instrument = new Instrument_PcSpk(instrument);
 }
 
+void Instrument::macSfx(byte prog) {
+	clear();
+	if (prog > 127)
+		return;
+	_type = itMacSfx;
+	_instrument = new Instrument_MacSfx(prog);
+}
+
 void Instrument::saveOrLoad(Serializer *s) {
 	if (s->isSaving()) {
 		s->saveByte(_type);
@@ -349,6 +372,9 @@ void Instrument::saveOrLoad(Serializer *s) {
 		case itPcSpk:
 			_instrument = new Instrument_PcSpk(s);
 			break;
+		case itMacSfx:
+			_instrument = new Instrument_MacSfx(s);
+			break;
 		default:
 			warning("No known instrument classification #%d", (int)_type);
 			_type = itNone;
@@ -528,4 +554,38 @@ void Instrument_PcSpk::send(MidiChannel *mc) {
 	mc->sysEx_customInstrument('SPK ', (byte *)&_instrument);
 }
 
+////////////////////////////////////////
+//
+// Instrument_MacSfx class members
+//
+////////////////////////////////////////
+
+Instrument_MacSfx::Instrument_MacSfx(byte program) :
+	_program(program) {
+	if (program > 127) {
+		_program = 255;
+	}
+}
+
+Instrument_MacSfx::Instrument_MacSfx(Serializer *s) {
+	_program = 255;
+	if (!s->isSaving()) {
+		saveOrLoad(s);
+	}
+}
+
+void Instrument_MacSfx::saveOrLoad(Serializer *s) {
+	if (s->isSaving()) {
+		s->saveByte(_program);
+	} else {
+		_program = s->loadByte();
+	}
+}
+
+void Instrument_MacSfx::send(MidiChannel *mc) {
+	if (_program > 127) {
+		return;
+	}
+	mc->sysEx_customInstrument('MAC ', &_program);
+}
 } // End of namespace Scumm
diff --git a/engines/scumm/imuse/instrument.h b/engines/scumm/imuse/instrument.h
index a855c64155..7e09e86fa5 100644
--- a/engines/scumm/imuse/instrument.h
+++ b/engines/scumm/imuse/instrument.h
@@ -52,7 +52,8 @@ public:
 		itProgram = 1,
 		itAdLib = 2,
 		itRoland = 3,
-		itPcSpk = 4
+		itPcSpk = 4,
+		itMacSfx = 5
 	};
 
 	Instrument() : _type(0), _instrument(0) { }
@@ -72,6 +73,7 @@ public:
 	void adlib(const byte *instrument);
 	void roland(const byte *instrument);
 	void pcspk(const byte *instrument);
+	void macSfx(byte program);
 
 	byte getType() { return _type; }
 	bool isValid() { return (_instrument ? _instrument->is_valid() : false); }
diff --git a/engines/scumm/imuse/mac_m68k.cpp b/engines/scumm/imuse/mac_m68k.cpp
index 9d6bdd0544..4d7a6a64c0 100644
--- a/engines/scumm/imuse/mac_m68k.cpp
+++ b/engines/scumm/imuse/mac_m68k.cpp
@@ -111,6 +111,7 @@ void MacM68kDriver::send(uint32 d) {
 }
 
 void MacM68kDriver::sysEx_customInstrument(byte channel, uint32 type, const byte *instr) {
+	assert(false);
 }
 
 MidiChannel *MacM68kDriver::allocateChannel() {
@@ -416,6 +417,10 @@ void MacM68kDriver::MidiChannel_MacM68k::priority(byte value) {
 }
 
 void MacM68kDriver::MidiChannel_MacM68k::sysEx_customInstrument(uint32 type, const byte *instr) {
+	assert(instr);
+	if (type == 'MAC ') {
+		_instrument = _owner->getInstrument(*instr + kSysExBase);
+	}
 }
 
 void MacM68kDriver::MidiChannel_MacM68k::init(MacM68kDriver *owner, byte channel) {
diff --git a/engines/scumm/imuse/mac_m68k.h b/engines/scumm/imuse/mac_m68k.h
index a8686e776f..59e2f68b9b 100644
--- a/engines/scumm/imuse/mac_m68k.h
+++ b/engines/scumm/imuse/mac_m68k.h
@@ -74,7 +74,8 @@ private:
 
 	enum {
 		kDefaultInstrument = 0x3E7,
-		kProgramChangeBase = 0x3E8
+		kProgramChangeBase = 0x3E8,
+		kSysExBase         = 0x7D0
 	};
 
 	Instrument getInstrument(int idx) const;