For Qt GUI add code that forces video alpha bits to 255 for all pixels. Some video drivers aren't ignoring the alpha bits as they should so make sure they as always set to be safe.

src/CMakeLists.txt

@@ -550,6 +550,7 @@ set(SRC_DRIVERS_SDL
   ${CMAKE_CURRENT_SOURCE_DIR}/drivers/Qt/ConsoleViewerGL.cpp  
   ${CMAKE_CURRENT_SOURCE_DIR}/drivers/Qt/ConsoleViewerSDL.cpp  
   ${CMAKE_CURRENT_SOURCE_DIR}/drivers/Qt/ConsoleViewerQWidget.cpp  
+  ${CMAKE_CURRENT_SOURCE_DIR}/drivers/Qt/ConsoleViewerInterface.cpp  
   ${CMAKE_CURRENT_SOURCE_DIR}/drivers/Qt/InputConf.cpp  
   ${CMAKE_CURRENT_SOURCE_DIR}/drivers/Qt/GamePadConf.cpp  
   ${CMAKE_CURRENT_SOURCE_DIR}/drivers/Qt/FamilyKeyboard.cpp  

src/drivers/Qt/ConsoleViewerGL.cpp

@@ -92,7 +92,7 @@ ConsoleViewGL_t::ConsoleViewGL_t(QWidget *parent)
 
 	if ( localBuf )
 	{
-		memset( localBuf, 0, localBufSize );
+		memset32( localBuf, alphaMask, localBufSize );
 	}
 
 	vsyncEnabled = true;
@@ -502,7 +502,7 @@ void ConsoleViewGL_t::transfer2LocalBuffer(void)
 	}
 	else
 	{
-		memcpy( localBuf, src, cpSize );
+		copyPixels32( dest, src, cpSize, alphaMask);
 	}
 }
 

src/drivers/Qt/ConsoleViewerInterface.cpp

@@ -0,0 +1,28 @@
+// ConsoleViewerInterface.cpp
+//
+#include "Qt/ConsoleViewerInterface.h"
+
+//----------------------------------------------------------
+void ConsoleViewerBase::memset32( void *buf, uint32_t val, size_t size)
+{
+	uint32_t *p = static_cast<uint32_t*>(buf);
+	size_t n = size / sizeof(uint32_t);
+
+	for (size_t i=0; i<n; i++)
+	{
+		*p = val; p++;
+	}
+}
+//----------------------------------------------------------
+void ConsoleViewerBase::copyPixels32( void *dest, void *src, size_t size, uint32_t alphaMask)
+{
+	uint32_t *d = static_cast<uint32_t*>(dest);
+	uint32_t *s = static_cast<uint32_t*>(src);
+	size_t n = size / sizeof(uint32_t);
+
+	for (size_t i=0; i<n; i++)
+	{
+		*d = *s | alphaMask; d++; s++;
+	}
+}
+//----------------------------------------------------------

src/drivers/Qt/ConsoleViewerInterface.h

@@ -1,6 +1,7 @@
 // ConsoleViewerInterface.h
 //
 #pragma once
+#include <stdint.h>
 
 #include <QColor>
 #include <QCursor>
@@ -47,5 +48,9 @@ class ConsoleViewerBase
 		virtual void    setMinimumSize(const QSize &) = 0;
 		virtual void    setMaximumSize(const QSize &) = 0;
 
+		static  void    memset32( void *buf, uint32_t val, size_t size);
+		static  void    copyPixels32( void *dest, void *src, size_t size, uint32_t alphaMask);
+
+		static constexpr uint32_t alphaMask = 0xff000000;
 	protected:
 };

src/drivers/Qt/ConsoleViewerQWidget.cpp

@@ -25,6 +25,7 @@
 #include <math.h>
 //#include <unistd.h>
 
+#include "../../profiler.h"
 #include "Qt/nes_shm.h"
 #include "Qt/throttle.h"
 #include "Qt/fceuWrapper.h"
@@ -86,7 +87,7 @@ ConsoleViewQWidget_t::ConsoleViewQWidget_t(QWidget *parent)
 
 	if ( localBuf )
 	{
-		memset( localBuf, 0, localBufSize );
+		memset32( localBuf, alphaMask, localBufSize );
 	}
 
 	forceAspect  = true;
@@ -227,7 +228,8 @@ void ConsoleViewQWidget_t::transfer2LocalBuffer(void)
 	}
 	else
 	{
-		memcpy( localBuf, src, cpSize );
+		//memcpy( localBuf, src, cpSize );
+		copyPixels32( dest, src, cpSize, alphaMask);
 	}
 }
 
@@ -488,7 +490,7 @@ void ConsoleViewQWidget_t::paintEvent(QPaintEvent *event)
 
 	int rowPitch = nesWidth * sizeof(uint32_t);
 
-	QImage tmpImage( (const uchar*)localBuf, nesWidth, nesHeight, rowPitch, QImage::Format_RGB32);
+	QImage tmpImage( (const uchar*)localBuf, nesWidth, nesHeight, rowPitch, QImage::Format_ARGB32);
 
 	//SDL_Rect source = {0, 0, nesWidth, nesHeight };
 	QRect dest( sx, sy, rw, rh );

src/drivers/Qt/ConsoleViewerSDL.cpp

@@ -89,7 +89,7 @@ ConsoleViewSDL_t::ConsoleViewSDL_t(QWidget *parent)
 
 	if ( localBuf )
 	{
-		memset( localBuf, 0, localBufSize );
+		memset32( localBuf, alphaMask, localBufSize );
 	}
 
 	forceAspect  = true;
@@ -240,7 +240,7 @@ void ConsoleViewSDL_t::transfer2LocalBuffer(void)
 	}
 	else
 	{
-		memcpy( localBuf, src, cpSize );
+		copyPixels32( dest, src, cpSize, alphaMask);
 	}
 }