MOHAWK: When running scripts in Myst, add delays when necessary between draws to mimic older hardware.

5 files changed, 58 insertions, 5 deletions

diff --git a/engines/mohawk/graphics.cpp b/engines/mohawk/graphics.cpp
index 9e02e70a22..b3653b1fdf 100644
--- a/engines/mohawk/graphics.cpp
+++ b/engines/mohawk/graphics.cpp
@@ -293,6 +293,9 @@ MystGraphics::MystGraphics(MohawkEngine_Myst* vm) : GraphicsManager(), _vm(vm) {
 	// Initialize our buffer
 	_backBuffer = new Graphics::Surface();
 	_backBuffer->create(_vm->_system->getWidth(), _vm->_system->getHeight(), _pixelFormat);
+
+	_nextAllowedDrawTime = _vm->_system->getMillis();
+	_enableDrawingTimeSimulation = 0;
 }
 
 MystGraphics::~MystGraphics() {
@@ -444,6 +447,8 @@ void MystGraphics::copyImageSectionToScreen(uint16 image, Common::Rect src, Comm
 	debug(3, "\twidth: %d", width);
 	debug(3, "\theight: %d", height);
 
+	simulatePreviousDrawDelay(dest);
+
 	_vm->_system->copyRectToScreen((byte *)surface->getBasePtr(src.left, top), surface->pitch, dest.left, dest.top, width, height);
 }
 
@@ -499,10 +504,18 @@ void MystGraphics::copyImageToBackBuffer(uint16 image, Common::Rect dest) {
 
 void MystGraphics::copyBackBufferToScreen(Common::Rect r) {
 	r.clip(_viewport);
+
+	simulatePreviousDrawDelay(r);
+
 	_vm->_system->copyRectToScreen((byte *)_backBuffer->getBasePtr(r.left, r.top), _backBuffer->pitch, r.left, r.top, r.width(), r.height());
 }
 
 void MystGraphics::runTransition(uint16 type, Common::Rect rect, uint16 steps, uint16 delay) {
+
+	// Do not artificially delay during transitions
+	int oldEnableDrawingTimeSimulation = _enableDrawingTimeSimulation;
+	_enableDrawingTimeSimulation = 0;
+
 	switch (type) {
 	case 0:	{
 			debugC(kDebugScript, "Left to Right");
@@ -604,6 +617,8 @@ void MystGraphics::runTransition(uint16 type, Common::Rect rect, uint16 steps, u
 		_vm->_system->updateScreen();
 		break;
 	}
+
+	_enableDrawingTimeSimulation = oldEnableDrawingTimeSimulation;
 }
 
 void MystGraphics::drawRect(Common::Rect rect, RectState state) {
@@ -629,6 +644,34 @@ void MystGraphics::drawLine(const Common::Point &p1, const Common::Point &p2, ui
 	_backBuffer->drawLine(p1.x, p1.y, p2.x, p2.y, color);
 }
 
+void MystGraphics::enableDrawingTimeSimulation(bool enable) {
+	if (enable)
+		_enableDrawingTimeSimulation++;
+	else
+		_enableDrawingTimeSimulation--;
+
+	if (_enableDrawingTimeSimulation < 0)
+		_enableDrawingTimeSimulation = 0;
+}
+
+void MystGraphics::simulatePreviousDrawDelay(const Common::Rect &dest) {
+	uint32 time = 0;
+
+	if (_enableDrawingTimeSimulation) {
+		time = _vm->_system->getMillis();
+
+		// Do not draw anything new too quickly after the previous draw call
+		// so that images stay at least a little while on screen
+		// This is enabled only for scripted draw calls
+		if (time < _nextAllowedDrawTime)
+			_vm->_system->delayMillis(_nextAllowedDrawTime - time);
+	}
+
+	// Next draw call allowed at DELAY + AERA * COEFF milliseconds from now
+	time = _vm->_system->getMillis();
+	_nextAllowedDrawTime = time + _constantDrawDelay + dest.height() * dest.width() / _proportionalDrawDelay;
+}
+
 #endif // ENABLE_MYST
 
 #ifdef ENABLE_RIVEN
diff --git a/engines/mohawk/graphics.h b/engines/mohawk/graphics.h
index e1f0b50078..d7057f48cf 100644
--- a/engines/mohawk/graphics.h
+++ b/engines/mohawk/graphics.h
@@ -128,10 +128,12 @@ public:
 	void runTransition(uint16 type, Common::Rect rect, uint16 steps, uint16 delay);
 	void drawRect(Common::Rect rect, RectState state);
 	void drawLine(const Common::Point &p1, const Common::Point &p2, uint32 color);
+	void enableDrawingTimeSimulation(bool enable);
 
 protected:
 	MohawkSurface *decodeImage(uint16 id);
 	MohawkEngine *getVM() { return (MohawkEngine *)_vm; }
+	void simulatePreviousDrawDelay(const Common::Rect &dest);
 
 private:
 	MohawkEngine_Myst *_vm;
@@ -156,6 +158,11 @@ private:
 	Graphics::Surface *_backBuffer;
 	Graphics::PixelFormat _pixelFormat;
 	Common::Rect _viewport;
+
+	int _enableDrawingTimeSimulation;
+	uint32 _nextAllowedDrawTime;
+	static const uint _constantDrawDelay = 10; // ms
+	static const uint _proportionalDrawDelay = 500; // pixels per ms
 };
 
 #endif // ENABLE_MYST
diff --git a/engines/mohawk/myst_scripts.cpp b/engines/mohawk/myst_scripts.cpp
index 6148c48c60..a6351449b0 100644
--- a/engines/mohawk/myst_scripts.cpp
+++ b/engines/mohawk/myst_scripts.cpp
@@ -154,6 +154,11 @@ void MystScriptParser::setupCommonOpcodes() {
 
 void MystScriptParser::runScript(MystScript script, MystResource *invokingResource) {
 	debugC(kDebugScript, "Script Size: %d", script->size());
+
+	// Scripted drawing takes more time to simulate older hardware
+	// This way opcodes can't overwrite what the previous ones drew too quickly
+	_vm->_gfx->enableDrawingTimeSimulation(true);
+
 	for (uint16 i = 0; i < script->size(); i++) {
 		MystScriptEntry &entry = script->operator[](i);
 		debugC(kDebugScript, "\tOpcode %d: %d", i, entry.opcode);
@@ -165,6 +170,8 @@ void MystScriptParser::runScript(MystScript script, MystResource *invokingResour
 
 		runOpcode(entry.opcode, entry.var, entry.argc, entry.argv);
 	}
+
+	_vm->_gfx->enableDrawingTimeSimulation(false);
 }
 
 void MystScriptParser::runOpcode(uint16 op, uint16 var, uint16 argc, uint16 *argv) {
diff --git a/engines/mohawk/myst_stacks/channelwood.cpp b/engines/mohawk/myst_stacks/channelwood.cpp
index 2ed651fb9c..0dd69a673a 100644
--- a/engines/mohawk/myst_stacks/channelwood.cpp
+++ b/engines/mohawk/myst_stacks/channelwood.cpp
@@ -330,7 +330,7 @@ void Channelwood::o_drawImageChangeCardAndVolume(uint16 op, uint16 var, uint16 a
 
 	_vm->_gfx->copyImageToScreen(imageId, Common::Rect(0, 0, 544, 333));
 	_vm->_system->updateScreen();
-	_vm->_system->delayMillis(10);
+
 	_vm->changeToCard(cardId, true);
 
 	if (argc == 3) {
@@ -348,7 +348,6 @@ void Channelwood::o_waterTankValveOpen(uint16 op, uint16 var, uint16 argc, uint1
 		for (uint16 imageId = 3601; imageId >= 3595; imageId--) {
 			_vm->_gfx->copyImageToScreen(imageId, rect);
 			_vm->_system->updateScreen();
-			_vm->_system->delayMillis(5);
 		}
 
 	pipeChangeValve(true, 0x80);
@@ -663,7 +662,6 @@ void Channelwood::o_waterTankValveClose(uint16 op, uint16 var, uint16 argc, uint
 		for (uint16 imageId = 3595; imageId <= 3601; imageId++) {
 			_vm->_gfx->copyImageToScreen(imageId, rect);
 			_vm->_system->updateScreen();
-			_vm->_system->delayMillis(5);
 		}
 
 	pipeChangeValve(false, 0x80);
diff --git a/engines/mohawk/myst_stacks/myst.cpp b/engines/mohawk/myst_stacks/myst.cpp
index 43cbdc85e4..f77ae753d9 100644
--- a/engines/mohawk/myst_stacks/myst.cpp
+++ b/engines/mohawk/myst_stacks/myst.cpp
@@ -859,7 +859,6 @@ void Myst::o_fireplaceToggleButton(uint16 op, uint16 var, uint16 argc, uint16 *a
 		for (uint i = 4795; i >= 4779; i--) {
 			_vm->_gfx->copyImageToScreen(i, _invokingResource->getRect());
 			_vm->_system->updateScreen();
-			_vm->_system->delayMillis(1);
 		}
 		_fireplaceLines[var - 17] &= ~bitmask;
 	} else {
@@ -867,7 +866,6 @@ void Myst::o_fireplaceToggleButton(uint16 op, uint16 var, uint16 argc, uint16 *a
 		for (uint i = 4779; i <= 4795; i++) {
 			_vm->_gfx->copyImageToScreen(i, _invokingResource->getRect());
 			_vm->_system->updateScreen();
-			_vm->_system->delayMillis(1);
 		}
 		_fireplaceLines[var - 17] |= bitmask;
 	}