MOHAWK: Misc Mechanical fixes. Many thanks to Patrick Monnerat for the patch.

- Adds break statements where missing in Mechanical::toggleVar() and Mechanical::setVarValue()
- Restore proper numbering of Achenar and Sirrus panel state variables, which were wrongly swapped.
- When bird is singing, play sound continuously.
- When operating the fortress elevator, keep the engine sound active while the elevator is moving.

3 files changed, 28 insertions, 6 deletions

diff --git a/engines/mohawk/myst_scripts.cpp b/engines/mohawk/myst_scripts.cpp
index 17f6de534f..307be2dd05 100644
--- a/engines/mohawk/myst_scripts.cpp
+++ b/engines/mohawk/myst_scripts.cpp
@@ -560,6 +560,7 @@ void MystScriptParser::o_playSoundBlocking(uint16 op, uint16 var, uint16 argc, u
 	debugC(kDebugScript, "Opcode %d: playSoundBlocking", op);
 	debugC(kDebugScript, "\tsoundId: %d", soundId);
 
+	_vm->_sound->stopSound();
 	_vm->_sound->playSoundBlocking(soundId);
 }
 
diff --git a/engines/mohawk/myst_stacks/mechanical.cpp b/engines/mohawk/myst_stacks/mechanical.cpp
index d6dd1b5407..12d9dc7e2f 100644
--- a/engines/mohawk/myst_stacks/mechanical.cpp
+++ b/engines/mohawk/myst_stacks/mechanical.cpp
@@ -102,6 +102,7 @@ void Mechanical::setupOpcodes() {
 
 void Mechanical::disablePersistentScripts() {
 	_fortressSimulationRunning = false;
+	_elevatorRotationLeverMoving = false;
 	_elevatorGoingMiddle = false;
 	_birdSinging = false;
 	_fortressRotationRunning = false;
@@ -126,10 +127,10 @@ void Mechanical::runPersistentScripts() {
 
 uint16 Mechanical::getVar(uint16 var) {
 	switch(var) {
-	case 0: // Sirrus's Secret Panel State
-		return _state.sirrusPanelState;
-	case 1: // Achenar's Secret Panel State
+	case 0: // Achenar's Secret Panel State
 		return _state.achenarPanelState;
+	case 1: // Sirrus's Secret Panel State
+		return _state.sirrusPanelState;
 	case 2: // Achenar's Secret Room Crate Lid Open and Blue Page Present
 		if (_state.achenarCrateOpened) {
 			if (_globals.bluePagesInBook & 4 || _globals.heldPage == 3)
@@ -195,16 +196,21 @@ uint16 Mechanical::getVar(uint16 var) {
 
 void Mechanical::toggleVar(uint16 var) {
 	switch(var) {
-	case 0: // Sirrus's Secret Panel State
-		_state.sirrusPanelState ^= 1;
-	case 1: // Achenar's Secret Panel State
+	case 0: // Achenar's Secret Panel State
 		_state.achenarPanelState ^= 1;
+		break;
+	case 1: // Sirrus's Secret Panel State
+		_state.sirrusPanelState ^= 1;
+		break;
 	case 3: // Achenar's Secret Room Crate State
 		_state.achenarCrateOpened ^= 1;
+		break;
 	case 4: // Myst Book Room Staircase State
 		_mystStaircaseState ^= 1;
+		break;
 	case 10: // Fortress Staircase State
 		_state.staircaseState ^= 1;
+		break;
 	case 16: // Code Lock Shape #1 - Left
 	case 17: // Code Lock Shape #2
 	case 18: // Code Lock Shape #3
@@ -242,6 +248,7 @@ bool Mechanical::setVarValue(uint16 var, uint16 value) {
 	switch (var) {
 	case 13:
 		_elevatorPosition = value;
+		break;
 	case 14: // Elevator going down when at top
 		_elevatorGoingDown = value;
 		break;
@@ -724,6 +731,7 @@ void Mechanical::birdSing_run() {
 	uint32 time = _vm->_system->getMillis();
 	if (_birdSingEndTime < time) {
 		_bird->pauseMovie(true);
+		_vm->_sound->stopSound();
 		_birdSinging = false;
 	}
 }
diff --git a/engines/mohawk/sound.cpp b/engines/mohawk/sound.cpp
index 6144c89e21..791b18db49 100644
--- a/engines/mohawk/sound.cpp
+++ b/engines/mohawk/sound.cpp
@@ -141,6 +141,19 @@ Audio::SoundHandle *Sound::replaceSoundMyst(uint16 id, byte volume, bool loop) {
 				&& name.equals(_vm->getResourceName(ID_MSND, convertMystID(_handles[i].id))))
 			return &_handles[i].handle;
 
+	// The original engine also forces looping for those sounds
+	switch (id) {
+	case 2205:
+	case 2207:
+	case 5378:
+	case 7220:
+	case 9119: 	// Elevator engine sound in mechanical age is looping.
+	case 9120:
+	case 9327:
+		loop = true;
+		break;
+	}
+
 	stopSound();
 	return playSound(id, volume, loop);
 }