SCI32: Centralise OSystem screen updates

7 files changed, 43 insertions, 20 deletions

diff --git a/engines/sci/engine/kevent.cpp b/engines/sci/engine/kevent.cpp
index 389277b9bc..b240c947bf 100644
--- a/engines/sci/engine/kevent.cpp
+++ b/engines/sci/engine/kevent.cpp
@@ -101,7 +101,7 @@ reg_t kGetEvent(EngineState *s, int argc, reg_t *argv) {
 		// one of these ugly loops and should be updating the screen &
 		// throttling the VM.
 		if (++s->_eventCounter > 2) {
-			g_system->updateScreen();
+			g_sci->_gfxFrameout->updateScreen();
 			s->speedThrottler(10); // 10ms is an arbitrary value
 			s->_throttleTrigger = true;
 		}
diff --git a/engines/sci/graphics/controls32.cpp b/engines/sci/graphics/controls32.cpp
index 0cd924b38d..7080c108b3 100644
--- a/engines/sci/graphics/controls32.cpp
+++ b/engines/sci/graphics/controls32.cpp
@@ -299,7 +299,6 @@ reg_t GfxControls32::kernelEditText(const reg_t controlObject) {
 		}
 
 		g_sci->_gfxFrameout->frameOut(true);
-		g_sci->getSciDebugger()->onFrame();
 		g_sci->_gfxFrameout->throttle();
 	}
 
diff --git a/engines/sci/graphics/frameout.cpp b/engines/sci/graphics/frameout.cpp
index c969f91c71..390cc81779 100644
--- a/engines/sci/graphics/frameout.cpp
+++ b/engines/sci/graphics/frameout.cpp
@@ -68,7 +68,8 @@ GfxFrameout::GfxFrameout(SegManager *segMan, GfxPalette32 *palette, GfxTransitio
 	_throttleState(0),
 	_remapOccurred(false),
 	_overdrawThreshold(0),
-	_palMorphIsOn(false) {
+	_palMorphIsOn(false),
+	_lastScreenUpdateTick(0) {
 
 	if (g_sci->getGameId() == GID_PHANTASMAGORIA) {
 		_currentBuffer = Buffer(630, 450, nullptr);
@@ -1008,7 +1009,7 @@ void GfxFrameout::mergeToShowList(const Common::Rect &drawRect, RectList &showLi
 
 void GfxFrameout::showBits() {
 	if (!_showList.size()) {
-		g_system->updateScreen();
+		updateScreen();
 		return;
 	}
 
@@ -1050,7 +1051,7 @@ void GfxFrameout::showBits() {
 	_cursor->donePainting();
 
 	_showList.clear();
-	g_system->updateScreen();
+	updateScreen();
 }
 
 void GfxFrameout::alterVmap(const Palette &palette1, const Palette &palette2, const int8 style, const int8 *const styleRanges) {
@@ -1123,6 +1124,20 @@ void GfxFrameout::alterVmap(const Palette &palette1, const Palette &palette2, co
 	}
 }
 
+void GfxFrameout::updateScreen(const int delta) {
+	// using OSystem::getMillis instead of Sci::getTickCount because these
+	// values need to be monotonically increasing for the duration of the
+	// GfxFrameout object or else the screen will stop updating
+	const uint32 now = g_system->getMillis() * 60 / 1000;
+	if (now <= _lastScreenUpdateTick + delta) {
+		return;
+	}
+
+	_lastScreenUpdateTick = now;
+	g_system->updateScreen();
+	g_sci->getSciDebugger()->onFrame();
+}
+
 void GfxFrameout::kernelFrameOut(const bool shouldShowBits) {
 	if (_transitions->hasShowStyles()) {
 		_transitions->processShowStyles();
@@ -1166,14 +1181,14 @@ void GfxFrameout::shakeScreen(int16 numShakes, const ShakeDirection direction) {
 			g_system->setShakePos(_isHiRes ? 8 : 4);
 		}
 
-		g_system->updateScreen();
+		updateScreen();
 		g_sci->getEngineState()->wait(3);
 
 		if (direction & kShakeVertical) {
 			g_system->setShakePos(0);
 		}
 
-		g_system->updateScreen();
+		updateScreen();
 		g_sci->getEngineState()->wait(3);
 	}
 }
diff --git a/engines/sci/graphics/frameout.h b/engines/sci/graphics/frameout.h
index e706f141b2..ab58f41144 100644
--- a/engines/sci/graphics/frameout.h
+++ b/engines/sci/graphics/frameout.h
@@ -155,6 +155,11 @@ public:
 #pragma mark -
 #pragma mark Rendering
 private:
+	/**
+	 * The last time the hardware screen was updated.
+	 */
+	uint32 _lastScreenUpdateTick;
+
 	GfxTransitions32 *_transitions;
 
 	/**
@@ -255,8 +260,8 @@ private:
 	void mergeToShowList(const Common::Rect &drawRect, RectList &showList, const int overdrawThreshold);
 
 	/**
-	 * Writes the internal frame buffer out to hardware and
-	 * clears the show list.
+	 * Sends all dirty rects from the internal frame buffer to the backend,
+	 * then updates the hardware screen.
 	 */
 	void showBits();
 
@@ -285,6 +290,18 @@ private:
 	}
 
 public:
+	/**
+	 * Updates the hardware screen, no more than once per tick.
+	 *
+	 * @param delta An additional number of ticks that should elapse
+	 * since the last time the screen was updated before it gets updated now.
+	 * This is used for updating the screen within run_vm, where we normally
+	 * expect that a call to kFrameOut will occur later during the current
+	 * frame, but if it does not, then update the screen on the second frame
+	 * anyway since the game is doing something bad.
+	 */
+	void updateScreen(const int delta = 0);
+
 	void setPixelFormat(const Graphics::PixelFormat &format) const {
 		initGraphics(_currentBuffer.screenWidth, _currentBuffer.screenHeight, _isHiRes, &format);
 	}
diff --git a/engines/sci/graphics/transitions32.cpp b/engines/sci/graphics/transitions32.cpp
index 6da1772c48..b5e498528d 100644
--- a/engines/sci/graphics/transitions32.cpp
+++ b/engines/sci/graphics/transitions32.cpp
@@ -83,7 +83,6 @@ void GfxTransitions32::addShowRect(const Common::Rect &rect) {
 
 void GfxTransitions32::sendShowRects() {
 	g_sci->_gfxFrameout->showBits();
-	g_sci->getSciDebugger()->onFrame();
 	clearShowRects();
 	throttle();
 }
@@ -126,7 +125,6 @@ void GfxTransitions32::processShowStyles() {
 
 		if (doFrameOut) {
 			g_sci->_gfxFrameout->frameOut(true);
-			g_sci->getSciDebugger()->onFrame();
 			throttle();
 		}
 	} while(continueProcessing && doFrameOut);
diff --git a/engines/sci/graphics/video32.cpp b/engines/sci/graphics/video32.cpp
index 8b804cfa40..f4b15517fe 100644
--- a/engines/sci/graphics/video32.cpp
+++ b/engines/sci/graphics/video32.cpp
@@ -145,7 +145,6 @@ void SEQPlayer::renderFrame(SciBitmap &bitmap) const {
 
 	g_sci->_gfxFrameout->updateScreenItem(*_screenItem);
 	g_sci->_gfxFrameout->frameOut(true);
-	g_sci->getSciDebugger()->onFrame();
 }
 
 #pragma mark -
@@ -419,7 +418,6 @@ void AVIPlayer::renderFrame() const {
 
 		g_sci->_gfxFrameout->updateScreenItem(*_screenItem);
 		g_sci->_gfxFrameout->frameOut(true);
-		g_sci->getSciDebugger()->onFrame();
 	} else {
 		assert(surface->format.bytesPerPixel == 4);
 
@@ -455,8 +453,7 @@ void AVIPlayer::renderFrame() const {
 			g_system->copyRectToScreen(surface->getPixels(), surface->pitch, drawRect.left, drawRect.top, surface->w, surface->h);
 		}
 
-		g_system->updateScreen();
-		g_sci->getSciDebugger()->onFrame();
+		g_sci->_gfxFrameout->updateScreen();
 	}
 }
 
@@ -885,7 +882,6 @@ void VMDPlayer::renderFrame() const {
 		g_sci->_gfxPalette32->submit(palette);
 		g_sci->_gfxFrameout->updateScreenItem(*_screenItem);
 		g_sci->_gfxFrameout->frameOut(true);
-		g_sci->getSciDebugger()->onFrame();
 
 #if SCI_VMD_BLACK_PALETTE
 		if (_blackPalette) {
@@ -898,7 +894,6 @@ void VMDPlayer::renderFrame() const {
 	} else {
 		g_sci->_gfxFrameout->updateScreenItem(*_screenItem);
 		g_sci->_gfxFrameout->frameOut(true);
-		g_sci->getSciDebugger()->onFrame();
 	}
 }
 
@@ -1164,8 +1159,7 @@ void DuckPlayer::renderFrame() const {
 		g_system->copyRectToScreen(surface->getPixels(), surface->pitch, _drawRect.left, _drawRect.top, surface->w, surface->h);
 	}
 
-	g_system->updateScreen();
-	g_sci->getSciDebugger()->onFrame();
+	g_sci->_gfxFrameout->updateScreen();
 }
 
 } // End of namespace Sci
diff --git a/engines/sci/sci.cpp b/engines/sci/sci.cpp
index a84f50ea2b..634652cd3f 100644
--- a/engines/sci/sci.cpp
+++ b/engines/sci/sci.cpp
@@ -849,7 +849,7 @@ void SciEngine::sleep(uint32 msecs) {
 		// movement is still occurring and the screen needs to be updated to
 		// reflect it
 		if (getSciVersion() >= SCI_VERSION_2) {
-			g_system->updateScreen();
+			g_sci->_gfxFrameout->updateScreen();
 		}
 #endif
 		time = g_system->getMillis();