win32:opengl: Use DWM sync in windowed, Vsync in fullscreen exclusive.

win32/COpenGL.cpp

@@ -384,6 +384,12 @@ bool COpenGL::ChangeRenderSize(unsigned int newWidth, unsigned int newHeight)
 	return true;
 }
 
+void COpenGL::SetSwapInterval(int frames)
+{
+    if (wglSwapIntervalEXT)
+        wglSwapIntervalEXT(frames);
+}
+
 bool COpenGL::ApplyDisplayChanges(void)
 {
 	if(wglSwapIntervalEXT) {

win32/COpenGL.h

@@ -82,6 +82,7 @@ public:
 	bool SetFullscreen(bool fullscreen);
 	void SetSnes9xColorFormat(void);
 	void EnumModes(std::vector<dMode> *modeVector);
+    void SetSwapInterval(int frames);
 	GLSLShader *GetActiveShader()
 	{
 		return glslShader;

win32/win32_display.cpp

@@ -287,16 +287,25 @@ bool8 S9xDeinitUpdate (int Width, int Height)
         LastHeight = Height;
     }
 
-	WinRefreshDisplay();
-
-    if (GUI.DWMSync)
+    if (GUI.DWMSync && GUI.outputMethod == OPENGL)
     {
         BOOL DWMEnabled = false;
-
         DwmIsCompositionEnabledProc(&DWMEnabled);
-        if (DWMEnabled)
+
+        if (GUI.FullScreen || !DWMEnabled)
+            ((COpenGL *)S9xDisplayOutput)->SetSwapInterval(GUI.Vsync ? 1 : 0);
+        else
+            ((COpenGL *)S9xDisplayOutput)->SetSwapInterval(0);
+
+        WinRefreshDisplay();
+
+        if (DWMEnabled && !GUI.FullScreen)
             DwmFlushProc();
     }
+    else
+    {
+        WinRefreshDisplay();
+    }
 
     return (true);
 }