MOHAWK: Myst: Update the screen only once per frame

Change all inner loops to call the same frame function.

Remove the draw delay code. Now that we have proper frame pacing it is
not necessary anymore to wait before drawing to make sure the previous
frame stayed on the screen long enough.

Fixes #9915, #9922, #9923.

13 files changed, 43 insertions, 207 deletions

diff --git a/engines/mohawk/console.cpp b/engines/mohawk/console.cpp
index cfabbd304d..374e2a51d9 100644
--- a/engines/mohawk/console.cpp
+++ b/engines/mohawk/console.cpp
@@ -194,7 +194,6 @@ bool MystConsole::Cmd_DrawImage(int argc, const char **argv) {
 		rect = Common::Rect((uint16)atoi(argv[2]), (uint16)atoi(argv[3]), (uint16)atoi(argv[4]), (uint16)atoi(argv[5]));
 
 	_vm->_gfx->copyImageToScreen((uint16)atoi(argv[1]), rect);
-	_vm->_system->updateScreen();
 	return false;
 }
 
@@ -348,9 +347,7 @@ bool MystConsole::Cmd_QuickTest(int argc, const char **argv) {
 			debug("Loading card %d", ids[j]);
 			_vm->changeToCard(ids[j], kTransitionCopy);
 
-			_vm->_video->updateMovies();
-			_vm->_scriptParser->runPersistentScripts();
-			_vm->_system->updateScreen();
+			_vm->doFrame();
 
 			int16 resIndex = _vm->_rnd->getRandomNumber(_vm->_resources.size()) - 1;
 			if (resIndex >= 0 && _vm->_resources[resIndex]->isEnabled()) {
@@ -358,9 +355,7 @@ bool MystConsole::Cmd_QuickTest(int argc, const char **argv) {
 				_vm->_resources[resIndex]->handleMouseUp();
 			}
 
-			_vm->_video->updateMovies();
-			_vm->_scriptParser->runPersistentScripts();
-			_vm->_system->updateScreen();
+			_vm->doFrame();
 
 			if (_vm->getCurStack() != i) {
 				// Clicking may have linked us to another age
diff --git a/engines/mohawk/myst.cpp b/engines/mohawk/myst.cpp
index 295abebd6d..24778fe5ae 100644
--- a/engines/mohawk/myst.cpp
+++ b/engines/mohawk/myst.cpp
@@ -251,6 +251,9 @@ void MohawkEngine_Myst::playMovieBlockingCentered(const Common::String &fileName
 }
 
 void MohawkEngine_Myst::waitUntilMovieEnds(const VideoEntryPtr &video) {
+	if (!video)
+		return;
+
 	_interactive = false;
 
 	// Sanity check
@@ -333,7 +336,11 @@ Common::Error MohawkEngine_Myst::run() {
 void MohawkEngine_Myst::doFrame() {
 	// Update any background videos
 	_video->updateMovies();
-	_scriptParser->runPersistentScripts();
+	if (!_scriptParser->isScriptRunning() && _interactive) {
+		_interactive = false;
+		_scriptParser->runPersistentScripts();
+		_interactive = true;
+	}
 
 	Common::Event event;
 	while (_system->getEventManager()->pollEvent(event)) {
@@ -422,39 +429,22 @@ void MohawkEngine_Myst::doFrame() {
 }
 
 bool MohawkEngine_Myst::wait(uint32 duration, bool skippable) {
+	_interactive = false;
 	uint32 end = getTotalPlayTime() + duration;
 
-	while (getTotalPlayTime() < end && !shouldQuit()) {
+	do {
 		doFrame();
 
 		if (_escapePressed && skippable) {
 			_escapePressed = false;
 			return true; // Return true if skipped
 		}
-	}
+	} while (getTotalPlayTime() < end && !shouldQuit());
 
+	_interactive = true;
 	return false;
 }
 
-void MohawkEngine_Myst::pollAndDiscardEvents() {
-	// Poll the events to update the mouse cursor position
-	Common::Event event;
-	while (_system->getEventManager()->pollEvent(event)) {
-		switch (event.type) {
-			case Common::EVENT_KEYDOWN:
-				switch (event.kbd.keycode) {
-					case Common::KEYCODE_SPACE:
-						pauseGame();
-						break;
-					default:
-						break;
-				}
-			default:
-				break;
-		}
-	}
-}
-
 void MohawkEngine_Myst::pauseEngineIntern(bool pause) {
 	MohawkEngine::pauseEngineIntern(pause);
 
@@ -482,8 +472,6 @@ void MohawkEngine_Myst::changeToStack(uint16 stack, uint16 card, uint16 linkSrcS
 	else
 		_gfx->clearScreenPalette();
 
-	_system->updateScreen();
-
 	_sound->stopSound();
 	_sound->stopBackgroundMyst();
 	_video->stopVideos();
@@ -680,7 +668,6 @@ void MohawkEngine_Myst::changeToCard(uint16 card, TransitionType transition) {
 			_gfx->runTransition(transition, Common::Rect(544, 333), 10, 0);
 		} else {
 			_gfx->copyBackBufferToScreen(Common::Rect(544, 333));
-			_system->updateScreen();
 		}
 	}
 
@@ -694,8 +681,6 @@ void MohawkEngine_Myst::drawResourceRects() {
 		_resources[i]->getRect().debugPrint(0);
 		_resources[i]->drawBoundingRect();
 	}
-
-	_system->updateScreen();
 }
 
 void MohawkEngine_Myst::updateActiveResource() {
diff --git a/engines/mohawk/myst.h b/engines/mohawk/myst.h
index ae3439427e..a411b64347 100644
--- a/engines/mohawk/myst.h
+++ b/engines/mohawk/myst.h
@@ -190,7 +190,6 @@ public:
 	uint16 getMainCursor() { return _mainCursor; }
 	void checkCursorHints();
 	MystArea *forceUpdateClickedResource();
-	void pollAndDiscardEvents();
 	bool wait(uint32 duration, bool skippable = false);
 
 	/** Update the game state according to events and update the screen */
diff --git a/engines/mohawk/myst_areas.cpp b/engines/mohawk/myst_areas.cpp
index 568a95d1de..5e6b39df15 100644
--- a/engines/mohawk/myst_areas.cpp
+++ b/engines/mohawk/myst_areas.cpp
@@ -443,7 +443,6 @@ void MystAreaImageSwitch::drawConditionalDataToScreen(uint16 state, bool update)
 		// Draw to screen
 		if (update) {
 			_vm->_gfx->copyImageSectionToScreen(imageToDraw, _subImages[subImageId].rect, _rect);
-			_vm->_system->updateScreen();
 		} else {
 			_vm->_gfx->copyImageSectionToBackBuffer(imageToDraw, _subImages[subImageId].rect, _rect);
 		}
@@ -777,7 +776,6 @@ MystVideoInfo::~MystVideoInfo() {
 void MystVideoInfo::drawFrame(uint16 frame) {
 	_currentFrame = _firstFrame + frame;
 	_vm->_gfx->copyImageToScreen(_currentFrame, _frameRect);
-	_vm->_system->updateScreen();
 }
 
 bool MystVideoInfo::pullLeverV() {
@@ -808,7 +806,7 @@ void MystVideoInfo::releaseLeverV() {
 	// Release lever
 	for (int i = step; i >= 0; i--) {
 		drawFrame(i);
-		_vm->_system->delayMillis(10);
+		_vm->doFrame();
 	}
 }
 
diff --git a/engines/mohawk/myst_graphics.cpp b/engines/mohawk/myst_graphics.cpp
index 333da402fa..0aceb1de04 100644
--- a/engines/mohawk/myst_graphics.cpp
+++ b/engines/mohawk/myst_graphics.cpp
@@ -55,9 +55,6 @@ 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() {
@@ -156,8 +153,6 @@ void MystGraphics::copyImageSectionToScreen(uint16 image, Common::Rect src, Comm
 	debug(3, "\twidth: %d", width);
 	debug(3, "\theight: %d", height);
 
-	simulatePreviousDrawDelay(dest);
-
 	_vm->_system->copyRectToScreen(surface->getBasePtr(src.left, top), surface->pitch, dest.left, dest.top, width, height);
 }
 
@@ -222,16 +217,11 @@ void MystGraphics::copyImageToBackBuffer(uint16 image, Common::Rect dest) {
 void MystGraphics::copyBackBufferToScreen(Common::Rect r) {
 	r.clip(_viewport);
 
-	simulatePreviousDrawDelay(r);
-
 	_vm->_system->copyRectToScreen(_backBuffer->getBasePtr(r.left, r.top), _backBuffer->pitch, r.left, r.top, r.width(), r.height());
 }
 
 void MystGraphics::runTransition(TransitionType type, Common::Rect rect, uint16 steps, uint16 delay) {
 
-	// Transitions are barely visible without adding delays between the draw calls
-	enableDrawingTimeSimulation(true);
-
 	switch (type) {
 	case kTransitionLeftToRight:	{
 			debugC(kDebugView, "Left to Right");
@@ -242,18 +232,14 @@ void MystGraphics::runTransition(TransitionType type, Common::Rect rect, uint16
 				area.left = rect.left + step * i;
 				area.right = area.left + step;
 
-				_vm->_system->delayMillis(delay);
-				_vm->pollAndDiscardEvents();
-
 				copyBackBufferToScreen(area);
-				_vm->_system->updateScreen();
+				_vm->wait(delay);
 			}
 			if (area.right < rect.right) {
 				area.left = area.right;
 				area.right = rect.right;
 
 				copyBackBufferToScreen(area);
-				_vm->_system->updateScreen();
 			}
 		}
 		break;
@@ -266,18 +252,14 @@ void MystGraphics::runTransition(TransitionType type, Common::Rect rect, uint16
 				area.right = rect.right - step * i;
 				area.left = area.right - step;
 
-				_vm->_system->delayMillis(delay);
-				_vm->pollAndDiscardEvents();
-
 				copyBackBufferToScreen(area);
-				_vm->_system->updateScreen();
+				_vm->wait(delay);
 			}
 			if (area.left > rect.left) {
 				area.right = area.left;
 				area.left = rect.left;
 
 				copyBackBufferToScreen(area);
-				_vm->_system->updateScreen();
 			}
 		}
 		break;
@@ -293,11 +275,8 @@ void MystGraphics::runTransition(TransitionType type, Common::Rect rect, uint16
 			debugC(kDebugView, "Dissolve");
 
 			for (int16 step = 0; step < 8; step++) {
-				// Only one eighth of the rect pixels are updated by a draw step,
-				// delay by one eighth of the regular time
-				simulatePreviousDrawDelay(Common::Rect(rect.width() / 8, rect.height()));
-
 				transitionDissolve(rect, step);
+				_vm->doFrame();
 			}
 		}
 		break;
@@ -310,18 +289,14 @@ void MystGraphics::runTransition(TransitionType type, Common::Rect rect, uint16
 				area.top = rect.top + step * i;
 				area.bottom = area.top + step;
 
-				_vm->_system->delayMillis(delay);
-				_vm->pollAndDiscardEvents();
-
 				copyBackBufferToScreen(area);
-				_vm->_system->updateScreen();
+				_vm->wait(delay);
 			}
 			if (area.bottom < rect.bottom) {
 				area.top = area.bottom;
 				area.bottom = rect.bottom;
 
 				copyBackBufferToScreen(area);
-				_vm->_system->updateScreen();
 			}
 		}
 		break;
@@ -334,18 +309,14 @@ void MystGraphics::runTransition(TransitionType type, Common::Rect rect, uint16
 				area.bottom = rect.bottom - step * i;
 				area.top = area.bottom - step;
 
-				_vm->_system->delayMillis(delay);
-				_vm->pollAndDiscardEvents();
-
 				copyBackBufferToScreen(area);
-				_vm->_system->updateScreen();
+				_vm->wait(delay);
 			}
 			if (area.top > rect.top) {
 				area.bottom = area.top;
 				area.top = rect.top;
 
 				copyBackBufferToScreen(area);
-				_vm->_system->updateScreen();
 			}
 		}
 		break;
@@ -371,13 +342,10 @@ void MystGraphics::runTransition(TransitionType type, Common::Rect rect, uint16
 		break;
 	case kTransitionCopy:
 		copyBackBufferToScreen(rect);
-		_vm->_system->updateScreen();
 		break;
 	default:
 		error("Unknown transition %d", type);
 	}
-
-	enableDrawingTimeSimulation(false);
 }
 
 void MystGraphics::transitionDissolve(Common::Rect rect, uint step) {
@@ -460,8 +428,6 @@ void MystGraphics::transitionDissolve(Common::Rect rect, uint step) {
 	}
 
 	_vm->_system->unlockScreen();
-	_vm->pollAndDiscardEvents();
-	_vm->_system->updateScreen();
 }
 
 void MystGraphics::transitionSlideToLeft(Common::Rect rect, uint16 steps, uint16 delay) {
@@ -475,18 +441,13 @@ void MystGraphics::transitionSlideToLeft(Common::Rect rect, uint16 steps, uint16
 		dstRect.right = dstRect.left + step * stepWidth;
 		srcRect.left = srcRect.right - step * stepWidth;
 
-		_vm->_system->delayMillis(delay);
-
-		simulatePreviousDrawDelay(dstRect);
 		_vm->_system->copyRectToScreen(_backBuffer->getBasePtr(dstRect.left, dstRect.top),
 				_backBuffer->pitch, srcRect.left, srcRect.top, srcRect.width(), srcRect.height());
-		_vm->pollAndDiscardEvents();
-		_vm->_system->updateScreen();
+		_vm->wait(delay);
 	}
 
 	if (dstRect.right != rect.right) {
 		copyBackBufferToScreen(rect);
-		_vm->_system->updateScreen();
 	}
 }
 
@@ -501,18 +462,13 @@ void MystGraphics::transitionSlideToRight(Common::Rect rect, uint16 steps, uint1
 		dstRect.left = dstRect.right - step * stepWidth;
 		srcRect.right = srcRect.left + step * stepWidth;
 
-		_vm->_system->delayMillis(delay);
-
-		simulatePreviousDrawDelay(dstRect);
 		_vm->_system->copyRectToScreen(_backBuffer->getBasePtr(dstRect.left, dstRect.top),
 				_backBuffer->pitch, srcRect.left, srcRect.top, srcRect.width(), srcRect.height());
-		_vm->pollAndDiscardEvents();
-		_vm->_system->updateScreen();
+		_vm->wait(delay);
 	}
 
 	if (dstRect.left != rect.left) {
 		copyBackBufferToScreen(rect);
-		_vm->_system->updateScreen();
 	}
 }
 
@@ -527,19 +483,14 @@ void MystGraphics::transitionSlideToTop(Common::Rect rect, uint16 steps, uint16
 		dstRect.bottom = dstRect.top + step * stepWidth;
 		srcRect.top = srcRect.bottom - step * stepWidth;
 
-		_vm->_system->delayMillis(delay);
-
-		simulatePreviousDrawDelay(dstRect);
 		_vm->_system->copyRectToScreen(_backBuffer->getBasePtr(dstRect.left, dstRect.top),
 				_backBuffer->pitch, srcRect.left, srcRect.top, srcRect.width(), srcRect.height());
-		_vm->pollAndDiscardEvents();
-		_vm->_system->updateScreen();
+		_vm->wait(delay);
 	}
 
 
 	if (dstRect.bottom < rect.bottom) {
 		copyBackBufferToScreen(rect);
-		_vm->_system->updateScreen();
 	}
 }
 
@@ -554,19 +505,14 @@ void MystGraphics::transitionSlideToBottom(Common::Rect rect, uint16 steps, uint
 		dstRect.top = dstRect.bottom - step * stepWidth;
 		srcRect.bottom = srcRect.top + step * stepWidth;
 
-		_vm->_system->delayMillis(delay);
-
-		simulatePreviousDrawDelay(dstRect);
 		_vm->_system->copyRectToScreen(_backBuffer->getBasePtr(dstRect.left, dstRect.top),
 				_backBuffer->pitch, srcRect.left, srcRect.top, srcRect.width(), srcRect.height());
-		_vm->pollAndDiscardEvents();
-		_vm->_system->updateScreen();
+		_vm->wait(delay);
 	}
 
 
 	if (dstRect.top > rect.top) {
 		copyBackBufferToScreen(rect);
-		_vm->_system->updateScreen();
 	}
 }
 
@@ -581,15 +527,12 @@ void MystGraphics::transitionPartialToRight(Common::Rect rect, uint32 width, uin
 		dstRect.right = dstRect.left + step * stepWidth;
 		srcRect.left = srcRect.right - step * stepWidth;
 
-		simulatePreviousDrawDelay(dstRect);
 		_vm->_system->copyRectToScreen(_backBuffer->getBasePtr(dstRect.left, dstRect.top),
 				_backBuffer->pitch, srcRect.left, srcRect.top, srcRect.width(), srcRect.height());
-		_vm->pollAndDiscardEvents();
-		_vm->_system->updateScreen();
+		_vm->doFrame();
 	}
 
 	copyBackBufferToScreen(rect);
-	_vm->_system->updateScreen();
 }
 
 void MystGraphics::transitionPartialToLeft(Common::Rect rect, uint32 width, uint32 steps) {
@@ -603,15 +546,12 @@ void MystGraphics::transitionPartialToLeft(Common::Rect rect, uint32 width, uint
 		dstRect.left = dstRect.right - step * stepWidth;
 		srcRect.right = srcRect.left + step * stepWidth;
 
-		simulatePreviousDrawDelay(dstRect);
 		_vm->_system->copyRectToScreen(_backBuffer->getBasePtr(dstRect.left, dstRect.top),
 				_backBuffer->pitch, srcRect.left, srcRect.top, srcRect.width(), srcRect.height());
-		_vm->pollAndDiscardEvents();
-		_vm->_system->updateScreen();
+		_vm->doFrame();
 	}
 
 	copyBackBufferToScreen(rect);
-	_vm->_system->updateScreen();
 }
 
 void MystGraphics::drawRect(Common::Rect rect, RectState state) {
@@ -637,36 +577,6 @@ 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) {
-			debugC(kDebugView, "Delaying draw call by %d ms", _nextAllowedDrawTime - time);
-			_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;
-}
-
 void MystGraphics::fadeToBlack() {
 	// This is only for the demo
 	assert(!(_vm->getFeatures() & GF_ME));
@@ -681,7 +591,7 @@ void MystGraphics::fadeToBlack() {
 			*dst++ = *src++ * i / 64;
 
 		_vm->_system->getPaletteManager()->setPalette(palette, 0, 256);
-		_vm->_system->updateScreen();
+		_vm->doFrame();
 	}
 }
 
@@ -701,12 +611,11 @@ void MystGraphics::fadeFromBlack() {
 			*dst++ = *src++ * i / 64;
 
 		_vm->_system->getPaletteManager()->setPalette(palette, 0, 256);
-		_vm->_system->updateScreen();
+		_vm->doFrame();
 	}
 
 	// Set the full palette
 	_vm->_system->getPaletteManager()->setPalette(_palette, 0, 256);
-	_vm->_system->updateScreen();
 }
 
 void MystGraphics::clearScreenPalette() {
diff --git a/engines/mohawk/myst_graphics.h b/engines/mohawk/myst_graphics.h
index cd09a53a3a..173e02357d 100644
--- a/engines/mohawk/myst_graphics.h
+++ b/engines/mohawk/myst_graphics.h
@@ -72,12 +72,6 @@ private:
 	Common::Rect _viewport;
 	byte _palette[256 * 3];
 
-	int _enableDrawingTimeSimulation;
-	uint32 _nextAllowedDrawTime;
-	static const uint _constantDrawDelay = 10; // ms
-	static const uint _proportionalDrawDelay = 500; // pixels per ms
-
-	void simulatePreviousDrawDelay(const Common::Rect &dest);
 	void transitionDissolve(Common::Rect rect, uint step);
 	void transitionSlideToLeft(Common::Rect rect, uint16 steps, uint16 delay);
 	void transitionSlideToRight(Common::Rect rect, uint16 steps, uint16 delay);
diff --git a/engines/mohawk/myst_scripts.cpp b/engines/mohawk/myst_scripts.cpp
index 59d736296e..f3e44bc154 100644
--- a/engines/mohawk/myst_scripts.cpp
+++ b/engines/mohawk/myst_scripts.cpp
@@ -158,9 +158,6 @@ void MystScriptParser::setupCommonOpcodes() {
 void MystScriptParser::runScript(MystScript script, MystArea *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);
 	_scriptNestingLevel++;
 
 	for (uint16 i = 0; i < script->size(); i++) {
@@ -176,7 +173,6 @@ void MystScriptParser::runScript(MystScript script, MystArea *invokingResource)
 	}
 
 	_scriptNestingLevel--;
-	_vm->_gfx->enableDrawingTimeSimulation(false);
 }
 
 void MystScriptParser::runOpcode(uint16 op, uint16 var, uint16 argc, uint16 *argv) {
@@ -412,7 +408,6 @@ void MystScriptParser::o_redrawCard(uint16 op, uint16 var, uint16 argc, uint16 *
 	_vm->drawCardBackground();
 	_vm->drawResourceImages();
 	_vm->_gfx->copyBackBufferToScreen(Common::Rect(544, 333));
-	_vm->_system->updateScreen();
 }
 
 void MystScriptParser::o_goToDest(uint16 op, uint16 var, uint16 argc, uint16 *argv) {
@@ -671,7 +666,6 @@ void MystScriptParser::o_copyBackBufferToScreen(uint16 op, uint16 var, uint16 ar
 	debugC(kDebugScript, "\trect.bottom: %d", rect.bottom);
 
 	_vm->_gfx->copyBackBufferToScreen(rect);
-	_vm->_system->updateScreen();
 }
 
 void MystScriptParser::o_copyImageToBackBuffer(uint16 op, uint16 var, uint16 argc, uint16 *argv) {
@@ -772,7 +766,6 @@ void MystScriptParser::o_copyImageToScreen(uint16 op, uint16 var, uint16 argc, u
 	debugC(kDebugScript, "\tdstRect.bottom: %d", dstRect.bottom);
 
 	_vm->_gfx->copyImageSectionToScreen(imageId, srcRect, dstRect);
-	_vm->_system->updateScreen();
 }
 
 void MystScriptParser::o_changeCard(uint16 op, uint16 var, uint16 argc, uint16 *argv) {
@@ -797,7 +790,7 @@ void MystScriptParser::o_drawImageChangeCard(uint16 op, uint16 var, uint16 argc,
 		debugC(kDebugScript, "\tcardId: %d", cardId);
 
 		_vm->_gfx->copyImageToScreen(imageId, Common::Rect(0, 0, 544, 333));
-		_vm->_system->updateScreen();
+		_vm->wait(200);
 
 		_vm->changeToCard(cardId, transition);
 }
@@ -915,7 +908,7 @@ void MystScriptParser::o_soundWaitStop(uint16 op, uint16 var, uint16 argc, uint1
 	debugC(kDebugScript, "Opcode %d: Wait for foreground sound to finish", op);
 
 	while (_vm->_sound->isPlaying())
-		_vm->_system->delayMillis(10);
+		_vm->doFrame();
 }
 
 void MystScriptParser::o_quit(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 7e91dbb2c1..b8cdb599be 100644
--- a/engines/mohawk/myst_stacks/channelwood.cpp
+++ b/engines/mohawk/myst_stacks/channelwood.cpp
@@ -350,7 +350,7 @@ void Channelwood::o_drawImageChangeCardAndVolume(uint16 op, uint16 var, uint16 a
 	debugC(kDebugScript, "\tcardId: %d", cardId);
 
 	_vm->_gfx->copyImageToScreen(imageId, Common::Rect(0, 0, 544, 333));
-	_vm->_system->updateScreen();
+	_vm->wait(200);
 
 	_vm->changeToCard(cardId, kTransitionPartToLeft);
 
@@ -368,8 +368,7 @@ void Channelwood::o_waterTankValveOpen(uint16 op, uint16 var, uint16 argc, uint1
 	for (uint i = 0; i < 2; i++)
 		for (uint16 imageId = 3601; imageId >= 3595; imageId--) {
 			_vm->_gfx->copyImageToScreen(imageId, rect);
-			_vm->pollAndDiscardEvents();
-			_vm->_system->updateScreen();
+			_vm->doFrame();
 		}
 
 	pipeChangeValve(true, 0x80);
@@ -448,14 +447,14 @@ void Channelwood::o_leverEndMoveWithSound(uint16 op, uint16 var, uint16 argc, ui
 
 void Channelwood::o_leverElev3StartMove(uint16 op, uint16 var, uint16 argc, uint16 *argv) {
 	_vm->_gfx->copyImageToScreen(3970, Common::Rect(544, 333));
-	_vm->_system->updateScreen();
+	_vm->doFrame();
 	o_leverStartMove(op, var, argc, argv);
 }
 
 void Channelwood::o_leverElev3EndMove(uint16 op, uint16 var, uint16 argc, uint16 *argv) {
 	o_leverEndMove(op, var, argc, argv);
 	_vm->_gfx->copyImageToScreen(3265, Common::Rect(544, 333));
-	_vm->_system->updateScreen();
+	_vm->doFrame();
 	_vm->_sound->replaceSoundMyst(5265);
 }
 
@@ -700,8 +699,7 @@ void Channelwood::o_waterTankValveClose(uint16 op, uint16 var, uint16 argc, uint
 	for (uint i = 0; i < 2; i++)
 		for (uint16 imageId = 3595; imageId <= 3601; imageId++) {
 			_vm->_gfx->copyImageToScreen(imageId, rect);
-			_vm->pollAndDiscardEvents();
-			_vm->_system->updateScreen();
+			_vm->doFrame();
 		}
 
 	pipeChangeValve(false, 0x80);
diff --git a/engines/mohawk/myst_stacks/credits.cpp b/engines/mohawk/myst_stacks/credits.cpp
index c382263f7c..b295255dfb 100644
--- a/engines/mohawk/myst_stacks/credits.cpp
+++ b/engines/mohawk/myst_stacks/credits.cpp
@@ -74,7 +74,6 @@ void Credits::runPersistentScripts() {
 		// Draw next image
 		_vm->drawCardBackground();
 		_vm->_gfx->copyBackBufferToScreen(Common::Rect(544, 333));
-		_vm->_system->updateScreen();
 
 		_startTime = _vm->_system->getMillis();
 	}
diff --git a/engines/mohawk/myst_stacks/mechanical.cpp b/engines/mohawk/myst_stacks/mechanical.cpp
index 3bbf749c1f..5f49e694d1 100644
--- a/engines/mohawk/myst_stacks/mechanical.cpp
+++ b/engines/mohawk/myst_stacks/mechanical.cpp
@@ -381,7 +381,7 @@ void Mechanical::o_elevatorRotationStop(uint16 op, uint16 var, uint16 argc, uint
 	// Release lever
 	for (int i = step; i >= 0; i--) {
 		lever->drawFrame(i);
-		_vm->_system->delayMillis(10);
+		_vm->doFrame();
 	}
 
 	// Stop persistent script
@@ -449,7 +449,7 @@ void Mechanical::o_fortressRotationSpeedStop(uint16 op, uint16 var, uint16 argc,
 	// Release lever
 	for (int i = _fortressRotationSpeed; i >= 0; i--) {
 		lever->drawFrame(i);
-		_vm->_system->delayMillis(10);
+		_vm->doFrame();
 	}
 
 	_fortressRotationSpeed = 0;
@@ -528,7 +528,7 @@ void Mechanical::o_fortressSimulationSpeedStop(uint16 op, uint16 var, uint16 arg
 	// Release lever
 	for (int i = _fortressSimulationSpeed; i >= 0; i--) {
 		lever->drawFrame(i);
-		_vm->_system->delayMillis(10);
+		_vm->doFrame();
 	}
 
 	_fortressSimulationSpeed = 0;
@@ -607,7 +607,6 @@ void Mechanical::elevatorGoMiddle_run() {
 			// Draw button pressed
 			if (_elevatorInCabin) {
 				_vm->_gfx->copyImageSectionToScreen(6332, Common::Rect(0, 35, 51, 63), Common::Rect(10, 137, 61, 165));
-				_vm->_system->updateScreen();
 			}
 
 			// Blip
@@ -616,7 +615,6 @@ void Mechanical::elevatorGoMiddle_run() {
 			// Restore button
 			if (_elevatorInCabin) {
 				_vm->_gfx->copyBackBufferToScreen(Common::Rect(10, 137, 61, 165));
-				_vm->_system->updateScreen();
 			 }
 		} else {
 			_elevatorTooLate = true;
@@ -690,7 +688,7 @@ void Mechanical::o_elevatorWaitTimeout(uint16 op, uint16 var, uint16 argc, uint1
 	// Wait while the elevator times out
 	while (_elevatorGoingMiddle) {
 		runPersistentScripts();
-		_vm->_system->delayMillis(10);
+		_vm->doFrame();
 	}
 }
 
@@ -914,16 +912,9 @@ void Mechanical::fortressSimulation_run() {
 		// Init sequence
 		_vm->_sound->replaceBackgroundMyst(_fortressSimulationStartSound1, 65535);
 		_vm->wait(5000, true);
-		_vm->_sound->replaceSoundMyst(_fortressSimulationStartSound2);
 
-		// Update movie while the sound is playing
 		VideoEntryPtr startup = _fortressSimulationStartup->playMovie();
-		while (_vm->_sound->isPlaying(_fortressSimulationStartSound2)) {
-			if (_vm->_video->updateMovies())
-				_vm->_system->updateScreen();
-
-			_vm->_system->delayMillis(10);
-		}
+		_vm->playSoundBlocking(_fortressSimulationStartSound2);
 		_vm->_sound->replaceBackgroundMyst(_fortressSimulationStartSound1, 65535);
 		_vm->waitUntilMovieEnds(startup);
 		_vm->_sound->stopBackgroundMyst();
@@ -934,7 +925,6 @@ void Mechanical::fortressSimulation_run() {
 		Common::Rect dst = Common::Rect(187, 3, 363, 179);
 		_vm->_gfx->copyImageSectionToBackBuffer(6046, src, dst);
 		_vm->_gfx->copyBackBufferToScreen(dst);
-		_vm->_system->updateScreen();
 
 		_fortressSimulationStartup->pauseMovie(true);
 		VideoEntryPtr holo = _fortressSimulationHolo->playMovie();
diff --git a/engines/mohawk/myst_stacks/myst.cpp b/engines/mohawk/myst_stacks/myst.cpp
index 8e130c8c62..d5e3fe25c2 100644
--- a/engines/mohawk/myst_stacks/myst.cpp
+++ b/engines/mohawk/myst_stacks/myst.cpp
@@ -828,8 +828,6 @@ void Myst::o_libraryBookPageTurnLeft(uint16 op, uint16 var, uint16 argc, uint16
 			_vm->_sound->replaceSoundMyst(_libraryBookSound1);
 		else
 			_vm->_sound->replaceSoundMyst(_libraryBookSound2);
-
-		_vm->_system->updateScreen();
 	}
 }
 
@@ -846,8 +844,6 @@ void Myst::o_libraryBookPageTurnRight(uint16 op, uint16 var, uint16 argc, uint16
 			_vm->_sound->replaceSoundMyst(_libraryBookSound1);
 		else
 			_vm->_sound->replaceSoundMyst(_libraryBookSound2);
-
-		_vm->_system->updateScreen();
 	}
 }
 
@@ -865,16 +861,14 @@ void Myst::o_fireplaceToggleButton(uint16 op, uint16 var, uint16 argc, uint16 *a
 		// Unset button
 		for (uint i = 4795; i >= 4779; i--) {
 			_vm->_gfx->copyImageToScreen(i, getInvokingResource<MystArea>()->getRect());
-			_vm->pollAndDiscardEvents();
-			_vm->_system->updateScreen();
+			_vm->doFrame();
 		}
 		_fireplaceLines[var - 17] &= ~bitmask;
 	} else {
 		// Set button
 		for (uint i = 4779; i <= 4795; i++) {
 			_vm->_gfx->copyImageToScreen(i, getInvokingResource<MystArea>()->getRect());
-			_vm->pollAndDiscardEvents();
-			_vm->_system->updateScreen();
+			_vm->doFrame();
 		}
 		_fireplaceLines[var - 17] |= bitmask;
 	}
@@ -1178,12 +1172,11 @@ void Myst::o_imagerPlayButton(uint16 op, uint16 var, uint16 argc, uint16 *argv)
 	Common::Rect src = Common::Rect(0, 0, 32, 75);
 	Common::Rect dest = Common::Rect(261, 257, 293, 332);
 	_vm->_gfx->copyImageSectionToScreen(4699, src, dest);
-	_vm->_system->updateScreen();
 
 	_vm->wait(200);
 
 	_vm->_gfx->copyBackBufferToScreen(dest);
-	_vm->_system->updateScreen();
+	_vm->doFrame();
 
 	_vm->_cursor->hideCursor();
 
@@ -2316,7 +2309,6 @@ void Myst::o_rocketPianoStart(uint16 op, uint16 var, uint16 argc, uint16 *argv)
 
 	// Draw pressed piano key
 	_vm->_gfx->copyImageSectionToScreen(key->getSubImage(1).wdib, src, dest);
-	_vm->_system->updateScreen();
 
 	// Play note
 	_rocketPianoSound = 0;
@@ -2386,7 +2378,6 @@ void Myst::o_rocketPianoStop(uint16 op, uint16 var, uint16 argc, uint16 *argv) {
 
 	// Draw unpressed piano key
 	_vm->_gfx->copyImageSectionToScreen(key->getSubImage(0).wdib, src, dest);
-	_vm->_system->updateScreen();
 
 	_vm->_sound->stopSound();
 	_vm->_sound->resumeBackgroundMyst();
@@ -2469,7 +2460,6 @@ void Myst::o_treePressureReleaseStart(uint16 op, uint16 var, uint16 argc, uint16
 	Common::Rect src = Common::Rect(0, 0, 49, 86);
 	Common::Rect dest = Common::Rect(78, 46, 127, 132);
 	_vm->_gfx->copyImageSectionToScreen(4631, src, dest);
-	_vm->_system->updateScreen();
 
 	_tempVar = _state.cabinValvePosition;
 
@@ -2485,7 +2475,6 @@ void Myst::o_treePressureReleaseStop(uint16 op, uint16 var, uint16 argc, uint16
 
 	Common::Rect rect = Common::Rect(78, 46, 127, 132);
 	_vm->_gfx->copyBackBufferToScreen(rect);
-	_vm->_system->updateScreen();
 
 	_state.cabinValvePosition = _tempVar;
 	_treeMinPosition = 0;
@@ -2789,8 +2778,6 @@ void Myst::libraryCombinationBookTurnLeft() {
 			_vm->_sound->replaceSoundMyst(_libraryBookSound1);
 		else
 			_vm->_sound->replaceSoundMyst(_libraryBookSound2);
-
-		_vm->_system->updateScreen();
 	}
 }
 
@@ -2815,8 +2802,6 @@ void Myst::libraryCombinationBookTurnRight() {
 			_vm->_sound->replaceSoundMyst(_libraryBookSound1);
 		else
 			_vm->_sound->replaceSoundMyst(_libraryBookSound2);
-
-		_vm->_system->updateScreen();
 	}
 }
 
@@ -3166,7 +3151,6 @@ void Myst::towerRotationMap_run() {
 
 		// Draw to screen
 		_vm->_gfx->copyBackBufferToScreen(Common::Rect(106, 42, 459, 273));
-		_vm->_system->updateScreen();
 	}
 
 	uint32 time = _vm->_system->getMillis();
@@ -3305,7 +3289,6 @@ void Myst::towerRotationMapDrawLine(const Common::Point &center, const Common::P
 	// Draw line
 	_vm->_gfx->drawLine(center, end, color);
 	_vm->_gfx->copyBackBufferToScreen(rect);
-	_vm->_system->updateScreen();
 }
 
 void Myst::towerRotationMapRotate() {
diff --git a/engines/mohawk/myst_stacks/stoneship.cpp b/engines/mohawk/myst_stacks/stoneship.cpp
index 5fbb664d7b..26c38f2a4f 100644
--- a/engines/mohawk/myst_stacks/stoneship.cpp
+++ b/engines/mohawk/myst_stacks/stoneship.cpp
@@ -481,7 +481,6 @@ void Stoneship::o_telescopeMove(uint16 op, uint16 var, uint16 argc, uint16 *argv
 
     // Draw lighthouse
     telescopeLighthouseDraw();
-    _vm->_system->updateScreen();
 }
 
 void Stoneship::o_telescopeStop(uint16 op, uint16 var, uint16 argc, uint16 *argv) {
@@ -890,7 +889,6 @@ void Stoneship::batteryGauge_run() {
 		_vm->drawCardBackground();
 		_vm->drawResourceImages();
 		_vm->_gfx->copyBackBufferToScreen(Common::Rect(544, 333));
-		_vm->_system->updateScreen();
 	}
 }
 
@@ -920,7 +918,6 @@ void Stoneship::tunnel_run() {
 			// Draw tunnel black
 			if (_tunnelImagesCount) {
 				_vm->_gfx->copyImageToScreen(_tunnelImages[1], Common::Rect(544, 333));
-				_vm->_system->updateScreen();
 			}
 
 			_vm->_sound->replaceSoundMyst(_tunnelAlarmSound);
@@ -928,7 +925,6 @@ void Stoneship::tunnel_run() {
 			// Draw tunnel dark
 			if (_tunnelImagesCount) {
 				_vm->_gfx->copyImageToScreen(_tunnelImages[0], Common::Rect(544, 333));
-				_vm->_system->updateScreen();
 			}
 		}
 	}
@@ -969,7 +965,6 @@ void Stoneship::telescope_run() {
 		_telescopeLighthouseState = !_telescopeLighthouseState;
 
 		telescopeLighthouseDraw();
-		_vm->_system->updateScreen();
 	}
 }
 
diff --git a/engines/mohawk/riven.cpp b/engines/mohawk/riven.cpp
index 495f399de7..d3f9e61d9f 100644
--- a/engines/mohawk/riven.cpp
+++ b/engines/mohawk/riven.cpp
@@ -164,7 +164,6 @@ Common::Error MohawkEngine_Riven::run() {
 	// Start at main cursor
 	_cursor->setCursor(kRivenMainCursor);
 	_cursor->showCursor();
-	_system->updateScreen();
 
 	// Let's begin, shall we?
 	if (getFeatures() & GF_DEMO) {
@@ -283,7 +282,6 @@ void MohawkEngine_Riven::pauseEngineIntern(bool pause) {
 		_video->pauseVideos();
 	} else {
 		_video->resumeVideos();
-		_system->updateScreen();
 	}
 }