From 399aa7e4189e4bf8e040dcec00050590cd93cace Mon Sep 17 00:00:00 2001
From: Alex <dudesuchamazing@gmail.com>
Date: Thu, 17 Nov 2022 21:29:11 +0500
Subject: [PATCH] Implement SetSwapInterval on Windows.

---
 include/gal/opengl/kiglew.h |  8 +++++++-
 include/gl_utils.h          | 19 +++++++++++++------
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/include/gal/opengl/kiglew.h b/include/gal/opengl/kiglew.h
index 40ff93e2e6..a846731605 100644
--- a/include/gal/opengl/kiglew.h
+++ b/include/gal/opengl/kiglew.h
@@ -1,7 +1,7 @@
 /*
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
- * Copyright (C) 2020 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 2020-2022 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -65,4 +65,10 @@
 
 #endif  // __WXGTK__
 
+#ifdef _WIN32
+
+    #include <GL/wglew.h>
+
+#endif  // _WIN32
+
 #endif  // KIGLEW_H_
diff --git a/include/gl_utils.h b/include/gl_utils.h
index 0a80f31991..f2c3d24ec6 100644
--- a/include/gl_utils.h
+++ b/include/gl_utils.h
@@ -1,7 +1,7 @@
 /*
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
- * Copyright (C) 2020 Kicad Developers, see AUTHORS.txt for contributors
+ * Copyright (C) 2020-2022 Kicad Developers, see AUTHORS.txt for contributors
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -41,8 +41,6 @@ public:
      */
     static int SetSwapInterval( int aVal )
     {
-        /// This routine is written for Linux using X11 only.  The equivalent functions under
-        /// Windows would include <wglext.h> and call wglSwapIntervalEXT
 #if defined( __linux__ ) && !defined( KICAD_USE_EGL )
 
         if( Display* dpy = glXGetCurrentDisplay() )
@@ -104,10 +102,19 @@ public:
             }
         }
 
-        return std::numeric_limits<int>::max();
-#else
-        return 0;
+#elif defined( _WIN32 )
+
+        if( wglSwapIntervalEXT && wxGLCanvas::IsExtensionSupported( "WGL_EXT_swap_control" ) )
+        {
+            if( aVal == -1 && !wxGLCanvas::IsExtensionSupported( "WGL_EXT_swap_control_tear" ) )
+                aVal = 1;
+
+            if( wglSwapIntervalEXT( aVal ) )
+                return aVal;
+        }
+
 #endif
+        return 0;
     }
 };