MYST3: Partial implementation of opcode 127 - drag lever

Also contains a build fix for older GCC versions

engines/myst3/movie.cpp

@@ -212,7 +212,7 @@ void ScriptedMovie::update() {
 		if (_nextFrameReadVar) {
 			int32 nextFrame = _vm->_state->getVar(_nextFrameReadVar);
 			if (nextFrame > 0) {
-				if (_bink.getCurFrame() != nextFrame) {
+				if (_bink.getCurFrame() != nextFrame - 1) {
 					_bink.seekToFrame(nextFrame - 1);
 					drawNextFrameToTexture();
 				}

engines/myst3/script.cpp

@@ -160,6 +160,7 @@ Script::Script(Myst3Engine *vm):
 	OP_2(124, ifPitchInRange,				kValue,		kValue											);
 	OP_4(125, ifHeadingPitchInRect,			kValue,		kValue,		kValue,		kValue					);
 	OP_4(126, ifMouseIsInRect,				kValue,		kValue,		kValue,		kValue					);
+	OP_5(127, leverDrag,					kValue,		kValue,		kValue,		kValue, 	kVar		); // Six args
 	OP_5(134, runScriptWhileDragging,		kVar, 		kVar,		kValue,		kValue, 	kVar		); // Eight args
 	OP_3(135, chooseNextNode,				kCondition, kValue,		kValue								);
 	OP_2(136, goToNodeTransition,			kValue,		kValue											);
@@ -1197,7 +1198,7 @@ void Script::varRatioToPercents(Context &c, const Opcode &cmd) {
 	int32 value = _vm->_state->getVar(cmd.args[0]);
 
 	value = 100 * (cmd.args[2] - abs(value - cmd.args[1])) / cmd.args[2];
-	value = MAX(0, value);
+	value = MAX<int32>(0, value);
 
 	_vm->_state->setVar(cmd.args[0], value);
 }
@@ -1496,6 +1497,80 @@ void Script::ifMouseIsInRect(Context &c, const Opcode &cmd) {
 	goToElse(c);
 }
 
+void Script::leverDrag(Context &c, const Opcode &cmd) {
+	debugC(kDebugScript, "Opcode %d: Drag lever for var %d wit script %d", cmd.op, cmd.args[4], cmd.args[6]);
+
+	int16 minPosX = cmd.args[0];
+	int16 minPosY = cmd.args[1];
+	int16 maxPosX = cmd.args[2];
+	int16 maxPosY = cmd.args[3];
+	int16 var = cmd.args[4];
+	int16 numPositions = cmd.args[5];
+	int16 script = cmd.args[6];
+	int16 topOffset = _vm->_state->getViewType() != kMenu ? 30 : 0;
+
+	if (_vm->_state->getViewType() == kCube) {
+		warning("Opcode 127 is not implemented for the cube view.");
+		return;
+	}
+
+	if (script > 0) {
+		warning("Opcode 127 is not implemented for positive script cases.");
+		return;
+	}
+
+	_vm->_cursor->changeCursor(2);
+
+	bool mousePressed = true;
+	 while (true) {
+		Common::Point mouse = _vm->_cursor->getPosition();
+		int16 amplitude;
+		int16 pixelPosition;
+
+		if (minPosX == maxPosX) {
+			// Vertical slider
+			amplitude = maxPosY - minPosY;
+			pixelPosition = mouse.y - minPosY - topOffset;
+		} else {
+			// Horizontal slider
+			amplitude = maxPosX - minPosX;
+			pixelPosition = mouse.x - minPosX;
+		}
+
+		float ratioPosition = pixelPosition / (float) amplitude;
+
+		int16 position = ratioPosition * (numPositions + 1);
+		position = CLIP<int16>(position, 1, numPositions);
+
+		if (_vm->_state->getDragLeverLimited()) {
+			int16 minPosition = _vm->_state->getDragLeverLimitMin();
+			int16 maxPosition = _vm->_state->getDragLeverLimitMax();
+			position = CLIP(position, minPosition, maxPosition);
+		}
+
+		// Set new lever position
+		_vm->_state->setVar(var, position);
+
+		// Draw a frame
+		_vm->processInput(true);
+		_vm->drawFrame();
+
+		mousePressed = _vm->getEventManager()->getButtonState() & Common::EventManager::LBUTTON;
+		_vm->_state->setDragEnded(!mousePressed);
+
+		if (script) {
+			_vm->_state->setVar(var, position);
+			_vm->runScriptsFromNode(abs(script));
+		}
+
+		if (!mousePressed)
+			break;
+	}
+
+	_vm->_state->setDragLeverLimited(0);
+	_vm->_state->setDragLeverSpeed(0);
+}
+
 void Script::runScriptWhileDragging(Context &c, const Opcode &cmd) {
 	debugC(kDebugScript, "Opcode %d: While dragging lever, run script %d", cmd.op, cmd.args[7]);
 
@@ -1786,7 +1861,7 @@ void Script::runScriptForVarDrawFramesHelper(uint16 var, int32 startValue, int32
 
 		while (1) {
 			if ((positiveDirection && (currentValue >= endValue))
-					|| (!positiveDirection && (currentValue <= startValue)))
+					|| (!positiveDirection && (currentValue <= endValue)))
 				break;
 
 			_vm->_state->setVar(var, currentValue);

engines/myst3/script.h

@@ -211,6 +211,7 @@ private:
 	DECLARE_OPCODE(ifPitchInRange);
 	DECLARE_OPCODE(ifHeadingPitchInRect);
 	DECLARE_OPCODE(ifMouseIsInRect);
+	DECLARE_OPCODE(leverDrag);
 	DECLARE_OPCODE(runScriptWhileDragging);
 	DECLARE_OPCODE(chooseNextNode);
 	DECLARE_OPCODE(goToNodeTransition);

engines/myst3/state.cpp

@@ -32,6 +32,7 @@ GameState::GameState(Myst3Engine *vm):
 #define VAR(var, x, unk) _descriptions.setVal(var, Description(var, #x, unk));
 
 	VAR(57, DragEnded, true)
+	VAR(58, DragLeverSpeed, false)
 	VAR(59, DragPositionFound, true)
 	VAR(60, DragLeverPositionChanged, true)
 
@@ -115,6 +116,10 @@ GameState::GameState(Myst3Engine *vm):
 	VAR(1352, MenuSaveLoadSelectedItem, false)
 	VAR(1353, MenuSaveLoadCurrentPage, false)
 
+	VAR(1399, DragLeverLimited, true)
+	VAR(1400, DragLeverLimitMin, true)
+	VAR(1401, DragLeverLimitMax, true)
+
 #undef VAR
 
 	newGame();

engines/myst3/state.h

@@ -60,6 +60,7 @@ public:
 	const Common::String describeCondition(int16 condition);
 
 	DECLARE_VAR(57, DragEnded)
+	DECLARE_VAR(58, DragLeverSpeed)
 	DECLARE_VAR(59, DragPositionFound)
 	DECLARE_VAR(60, DragLeverPositionChanged)
 
@@ -127,6 +128,10 @@ public:
 	DECLARE_VAR(1352, MenuSaveLoadSelectedItem)
 	DECLARE_VAR(1353, MenuSaveLoadCurrentPage)
 
+	DECLARE_VAR(1399, DragLeverLimited)
+	DECLARE_VAR(1400, DragLeverLimitMin)
+	DECLARE_VAR(1401, DragLeverLimitMax)
+
 	uint getFrameCount() { return _data.currentFrame; }
 	void incFrameCount() { _data.currentFrame++; }