MOHAWK: Rework Myst GFX updates

- Initial card state is drawn to the back buffer
- Script driven updates are drawn to the front buffer
Allows opcode 28 (copy back buffer to screen) and opcodes 29/33 (copy image to screen / back buffer) to work properly.
Fixes among others the generator room lights, and the matchbox.

svn-id: r54907

5 files changed, 23 insertions, 18 deletions

diff --git a/engines/mohawk/myst_stacks/credits.cpp b/engines/mohawk/myst_stacks/credits.cpp
index 152740139a..7bd652079b 100644
--- a/engines/mohawk/myst_stacks/credits.cpp
+++ b/engines/mohawk/myst_stacks/credits.cpp
@@ -75,7 +75,7 @@ void MystScriptParser_Credits::runPersistentScripts() {
 
 		// Note: The modulus by 6 is because the 6th image is the one at imageBaseId
 		_vm->_gfx->copyImageToScreen(_baseImageId + curImageIndex % 6, Common::Rect(0, 0, 544, 333));
-		_vm->_gfx->updateScreen();
+		_vm->_system->updateScreen();
 
 		_vm->_varStore->setVar(_creditsVar, curImageIndex + 1);
 		_lastCardTime = _vm->_system->getMillis();
diff --git a/engines/mohawk/myst_stacks/intro.cpp b/engines/mohawk/myst_stacks/intro.cpp
index 0741c22e1f..b2f5d927cb 100644
--- a/engines/mohawk/myst_stacks/intro.cpp
+++ b/engines/mohawk/myst_stacks/intro.cpp
@@ -173,13 +173,16 @@ void MystScriptParser_Intro::o_playIntroMovies(uint16 op, uint16 var, uint16 arg
 void MystScriptParser_Intro::opcode_201(uint16 op, uint16 var, uint16 argc, uint16 *argv) {
 	varUnusedCheck(op, var);
 
-	_vm->_gfx->updateScreen();
+	_vm->_gfx->copyBackBufferToScreen(Common::Rect(544, 333));
+	_vm->_system->updateScreen();
 	_vm->_system->delayMillis(4 * 1000);
-	_vm->_gfx->copyImageToScreen(4, Common::Rect(0, 0, 544, 333));
+	_vm->_gfx->copyImageToBackBuffer(4, Common::Rect(544, 333));
+	_vm->_gfx->copyBackBufferToScreen(Common::Rect(544, 333));
+	_vm->_system->updateScreen();
 
 	MystResourceType6 *resource = static_cast<MystResourceType6 *>(_invokingResource);
 	resource->playMovie();
-	// TODO: Complete
+	// TODO: Complete / Fix
 }
 
 void MystScriptParser_Intro::opcode_300(uint16 op, uint16 var, uint16 argc, uint16 *argv) {
diff --git a/engines/mohawk/myst_stacks/myst.cpp b/engines/mohawk/myst_stacks/myst.cpp
index 89793c7bdf..2fc763ade9 100644
--- a/engines/mohawk/myst_stacks/myst.cpp
+++ b/engines/mohawk/myst_stacks/myst.cpp
@@ -579,7 +579,7 @@ void MystScriptParser_Myst::o_libraryBookPageTurnLeft(uint16 op, uint16 var, uin
 		else
 			_vm->_sound->playSound(_libraryBookSound2);
 
-		_vm->_gfx->updateScreen();
+		_vm->_system->updateScreen();
 	}
 }
 
@@ -597,7 +597,7 @@ void MystScriptParser_Myst::o_libraryBookPageTurnRight(uint16 op, uint16 var, ui
 		else
 			_vm->_sound->playSound(_libraryBookSound2);
 
-		_vm->_gfx->updateScreen();
+		_vm->_system->updateScreen();
 	}
 }
 
@@ -615,7 +615,7 @@ void MystScriptParser_Myst::o_fireplaceToggleButton(uint16 op, uint16 var, uint1
 		// Unset button
 		for (uint i = 4795; i >= 4779; i--) {
 			_vm->_gfx->copyImageToScreen(i, _invokingResource->getRect());
-			_vm->_gfx->updateScreen();
+			_vm->_system->updateScreen();
 			_vm->_system->delayMillis(1);
 		}
 		_fireplaceLines[var - 17] &= ~bitmask;
@@ -623,7 +623,7 @@ void MystScriptParser_Myst::o_fireplaceToggleButton(uint16 op, uint16 var, uint1
 		// Set button
 		for (uint i = 4779; i <= 4795; i++) {
 			_vm->_gfx->copyImageToScreen(i, _invokingResource->getRect());
-			_vm->_gfx->updateScreen();
+			_vm->_system->updateScreen();
 			_vm->_system->delayMillis(1);
 		}
 		_fireplaceLines[var - 17] |= bitmask;
@@ -1698,7 +1698,7 @@ void MystScriptParser_Myst::libraryCombinationBookTurnLeft() {
 		else
 			_vm->_sound->playSound(_libraryBookSound2);
 
-		_vm->_gfx->updateScreen();
+		_vm->_system->updateScreen();
 	}
 }
 
@@ -1724,7 +1724,7 @@ void MystScriptParser_Myst::libraryCombinationBookTurnRight() {
 		else
 			_vm->_sound->playSound(_libraryBookSound2);
 
-		_vm->_gfx->updateScreen();
+		_vm->_system->updateScreen();
 	}
 }
 
@@ -1879,7 +1879,8 @@ void MystScriptParser_Myst::towerRotationMap_run() {
 		towerRotationDrawBuildings();
 
 		// Draw to screen
-		_vm->_gfx->updateScreen();
+		_vm->_gfx->copyBackBufferToScreen(Common::Rect(106, 42, 459, 273));
+		_vm->_system->updateScreen();
 	}
 
 	uint32 time = _vm->_system->getMillis();
@@ -1998,7 +1999,7 @@ void MystScriptParser_Myst::towerRotationMapDrawLine(const Common::Point &center
 	src.bottom = 333 - rect.top;
 
 	// Redraw background
-	_vm->_gfx->copyImageSectionToScreen(_vm->getCardBackgroundId(), src, rect);
+	_vm->_gfx->copyImageSectionToBackBuffer(_vm->getCardBackgroundId(), src, rect);
 
 	// Draw buildings
 	towerRotationDrawBuildings();
@@ -2011,7 +2012,8 @@ void MystScriptParser_Myst::towerRotationMapDrawLine(const Common::Point &center
 
 	// Draw line
 	_vm->_gfx->drawLine(center, end, color);
-	_vm->_gfx->updateScreen();
+	_vm->_gfx->copyBackBufferToScreen(rect);
+	_vm->_system->updateScreen();
 }
 
 void MystScriptParser_Myst::towerRotationMapRotate() {
diff --git a/engines/mohawk/myst_stacks/preview.cpp b/engines/mohawk/myst_stacks/preview.cpp
index 169411cc00..64d0898000 100644
--- a/engines/mohawk/myst_stacks/preview.cpp
+++ b/engines/mohawk/myst_stacks/preview.cpp
@@ -115,12 +115,12 @@ void MystScriptParser_Preview::opcode_298(uint16 op, uint16 var, uint16 argc, ui
 	// TODO: Flash Library Red
 	// TODO: Move to run process based delay to prevent
 	//       blocking...
-	_vm->_gfx->updateScreen();
+	_vm->_system->updateScreen();
 	_vm->_system->delayMillis(20 * 1000);
 
 	for (uint16 imageId = 3001; imageId <= 3012; imageId++) {
 		_vm->_gfx->copyImageToScreen(imageId, Common::Rect(0, 0, 544, 333));
-		_vm->_gfx->updateScreen();
+		_vm->_system->updateScreen();
 		_vm->_system->delayMillis(5 * 1000);
 	}
 }
diff --git a/engines/mohawk/myst_stacks/selenitic.cpp b/engines/mohawk/myst_stacks/selenitic.cpp
index 183c92745d..161c90b6f5 100644
--- a/engines/mohawk/myst_stacks/selenitic.cpp
+++ b/engines/mohawk/myst_stacks/selenitic.cpp
@@ -872,12 +872,12 @@ void MystScriptParser_Selenitic::o_soundLockEndMove(uint16 op, uint16 var, uint1
 	*value = stepped;
 
 	slider->setStep(stepped);
-	slider->drawDataToScreen();
-	_vm->_gfx->updateScreen();
+	slider->restoreBackground();
+	slider->drawConditionalDataToScreen(1);
 
 	uint16 soundId = slider->getList3(0);
 	if (soundId)
-		_vm->_sound->playSoundBlocking(soundId);
+		_vm->_sound->playSound(soundId);
 
 	_vm->_sound->stopSound();
 	_vm->_sound->resumeBackground();