For Qt GUI, changed onFrameFinished callback to only update video buffer. Don't do any input processing as this will mess up when running turbo mode. Added a draw timer to SDL video renderer to better align is scheduling with the next vsync.

src/drivers/Qt/ConsoleViewerSDL.cpp

@@ -82,6 +82,11 @@ ConsoleViewSDL_t::ConsoleViewSDL_t(QWidget *parent)
 
 	vsyncEnabled = false;
 	mouseButtonMask = 0;
+	drawTimer = new QTimer(this);
+	drawTimer->setInterval(14);
+	drawTimer->setSingleShot(true);
+	drawTimer->setTimerType(Qt::PreciseTimer);
+	connect(drawTimer, &QTimer::timeout, this, &ConsoleViewSDL_t::onDrawSignal);
 
 	localBufSize = (4 * GL_NES_WIDTH) * (4 * GL_NES_HEIGHT) * sizeof(uint32_t);
 
@@ -123,6 +128,8 @@ ConsoleViewSDL_t::ConsoleViewSDL_t(QWidget *parent)
 ConsoleViewSDL_t::~ConsoleViewSDL_t(void)
 {
 	//printf("Destroying SDL Viewport\n");
+	drawTimer->stop();
+	delete drawTimer;
 
 	if ( localBuf )
 	{
@@ -585,6 +592,19 @@ void  ConsoleViewSDL_t::getNormalizedCursorPos( double &x, double &y )
 	//printf("Normalized Cursor (%f,%f) \n", x, y );
 }
 
+void ConsoleViewSDL_t::queueRedraw(void)
+{
+	if (!drawTimer->isActive())
+	{
+		render();
+	}
+}
+
+void ConsoleViewSDL_t::onDrawSignal(void)
+{
+	render();
+}
+
 void ConsoleViewSDL_t::render(void)
 {
 	int nesWidth  = GL_NES_WIDTH;
@@ -707,5 +727,8 @@ void ConsoleViewSDL_t::render(void)
 
 	videoBufferSwapMark();
 
+	// Schedule draw timing inline with vsync
+	drawTimer->start();
+
 	nes_shm->render_count++;
 }

src/drivers/Qt/ConsoleViewerSDL.h

@@ -24,7 +24,7 @@ class ConsoleViewSDL_t : public QWidget, public ConsoleViewerBase
 		void reset(void);
 		void cleanup(void);
 		void render(void);
-		void queueRedraw(void){ render(); };
+		void queueRedraw(void);
 		int  driver(void){ return VIDEO_DRIVER_SDL; };
 
 		void transfer2LocalBuffer(void);
@@ -83,6 +83,7 @@ class ConsoleViewSDL_t : public QWidget, public ConsoleViewerBase
 	bool forceAspect;
 	bool autoScaleEna;
 	QColor *bgColor;
+	QTimer  *drawTimer;
 
 	uint32_t  *localBuf;
 	uint32_t   localBufSize;
@@ -95,5 +96,6 @@ class ConsoleViewSDL_t : public QWidget, public ConsoleViewerBase
 	//SDL_Rect      sdlViewport;
 
 	private slots:
+		void onDrawSignal();
 };
 

src/drivers/Qt/ConsoleWindow.cpp

@@ -154,6 +154,7 @@ consoleWin_t::consoleWin_t(QWidget *parent)
 	mainMenuEmuWasPaused   = false;
 	mainMenuPauseWhenActv  = false;
 	autoHideMenuFullscreen = false;
+	redrawVideoRequest     = false;
 
 	createMainMenu();
 
@@ -412,7 +413,7 @@ void consoleWin_t::winScreenChanged(QScreen *scr)
 		return;
 	}
 	refreshRate = scr->refreshRate();
-	//printf("Screen Refresh Rate: %f\n", scr->refreshRate() );
+	printf("Screen Refresh Rate: %f\n", scr->refreshRate() );
 
 	//printf("Screen Changed: %p\n", scr );
 	if ( viewport_GL != NULL )
@@ -4555,9 +4556,8 @@ int consoleWin_t::getPeriodicInterval(void)
 	return gameTimer->interval();
 }
 
-void consoleWin_t::transferVideoBuffer(void)
+void consoleWin_t::transferVideoBuffer(bool allowRedraw)
 {
-	bool redraw = false;
 	FCEU_PROFILE_FUNC(prof, "VideoXfer");
 
 	{
@@ -4569,21 +4569,22 @@ void consoleWin_t::transferVideoBuffer(void)
 			if (viewport_Interface != nullptr)
 			{
 				viewport_Interface->transfer2LocalBuffer();
-				redraw = true;
+				redrawVideoRequest = true;
 			}
 		}
 	}
 
 	// Don't queue redraw in mutex lock scope
-	if (redraw && (viewport_Interface != nullptr))
+	if (allowRedraw && redrawVideoRequest && (viewport_Interface != nullptr))
 	{
 		viewport_Interface->queueRedraw();
+		redrawVideoRequest = false;
 	}
 }
 
 void consoleWin_t::emuFrameFinish(void)
 {
-	static bool eventProcessingInProg = false;
+	//static bool eventProcessingInProg = false;
 
 	guiSignalRecvMark();
 
@@ -4592,16 +4593,16 @@ void consoleWin_t::emuFrameFinish(void)
 	//	return;
 	//}
 	// Prevent recursion as processEvents function can double back on us
-	if ( !eventProcessingInProg )
-	{
-		eventProcessingInProg = true;
-		// Process all events before attempting to render viewport
-		QCoreApplication::processEvents();
-		eventProcessingInProg = false;
-	}
+	//if ( !eventProcessingInProg )
+	//{
+	//	eventProcessingInProg = true;
+	//	// Process all events before attempting to render viewport
+	//	QCoreApplication::processEvents();
+	//	eventProcessingInProg = false;
+	//}
 
 	// Update Input Devices
-	FCEUD_UpdateInput();
+	//FCEUD_UpdateInput();
 	
 	//printf("EMU Frame Finish\n");
 
@@ -4609,7 +4610,7 @@ void consoleWin_t::emuFrameFinish(void)
 //	QtScriptManager::getInstance()->frameFinishedUpdate();
 //#endif
 
-	transferVideoBuffer();
+	transferVideoBuffer(false);
 }
 
 void consoleWin_t::updatePeriodic(void)
@@ -4634,7 +4635,7 @@ void consoleWin_t::updatePeriodic(void)
 	FCEUD_UpdateInput();
 	
 	// RePaint Game Viewport
-	transferVideoBuffer();
+	transferVideoBuffer(true);
 
 	// Low Rate Updates
 	if ( (updateCounter % 30) == 0 )

src/drivers/Qt/ConsoleWindow.h

@@ -278,6 +278,7 @@ class  consoleWin_t : public QMainWindow
 		bool        contextMenuEnable;
 		bool        soundUseGlobalFocus;
 		bool        autoHideMenuFullscreen;
+		bool        redrawVideoRequest;
 
 		std::list <std::string*> romList;
 		std::vector <autoFireMenuAction*> afActList;
@@ -313,7 +314,7 @@ class  consoleWin_t : public QMainWindow
 		void changeState(int slot);
 		void saveState(int slot);
 		void loadState(int slot);
-		void transferVideoBuffer(void);
+		void transferVideoBuffer(bool allowRedraw);
 		void syncAutoFirePatternMenu(void);
 
 		std::string findHelpFile(void);