From 23a0e1251e276c28680fdfd364113f325ccda7d1 Mon Sep 17 00:00:00 2001
From: Brandon Wright <bearoso@gmail.com>
Date: Tue, 5 Mar 2019 14:25:50 -0600
Subject: [PATCH] win32:opengl: Use DWM sync in windowed, Vsync in fullscreen
 exclusive.

---
 win32/COpenGL.cpp       |  6 ++++++
 win32/COpenGL.h         |  3 ++-
 win32/win32_display.cpp | 19 ++++++++++++++-----
 3 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/win32/COpenGL.cpp b/win32/COpenGL.cpp
index b06b67a8..a9cb58a2 100644
--- a/win32/COpenGL.cpp
+++ b/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) {
diff --git a/win32/COpenGL.h b/win32/COpenGL.h
index b01a5df2..20cf2971 100644
--- a/win32/COpenGL.h
+++ b/win32/COpenGL.h
@@ -81,7 +81,8 @@ public:
 	bool ApplyDisplayChanges(void);
 	bool SetFullscreen(bool fullscreen);
 	void SetSnes9xColorFormat(void);
-	void EnumModes(std::vector<dMode> *modeVector);	
+	void EnumModes(std::vector<dMode> *modeVector);
+    void SetSwapInterval(int frames);
 	GLSLShader *GetActiveShader()
 	{
 		return glslShader;
diff --git a/win32/win32_display.cpp b/win32/win32_display.cpp
index 10d487d7..5e413743 100644
--- a/win32/win32_display.cpp
+++ b/win32/win32_display.cpp
@@ -286,17 +286,26 @@ bool8 S9xDeinitUpdate (int Width, int Height)
         LastWidth = Width;
         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);
 }