RetroArch/diff.diff

diff --git a/gfx/drivers_context/wgl_ctx.cpp b/gfx/drivers_context/wgl_ctx.cpp
index fc6132d..6c81bcb 100644
--- a/gfx/drivers_context/wgl_ctx.cpp
+++ b/gfx/drivers_context/wgl_ctx.cpp
@@ -81,6 +81,20 @@
 #endif
 
 #if defined(HAVE_OPENGL)
+typedef BOOL  (WINAPI * PFNWGLGETSYNCVALUESOMLPROC)(HDC hdc, INT64 *ust, INT64 *msc, INT64 *sbc);
+typedef BOOL  (WINAPI * PFNWGLGETMSCRATEOMLPROC)(HDC hdc, INT32 *numerator, INT32 *denominator);
+typedef INT64 (WINAPI * PFNWGLSWAPBUFFERSMSCOMLPROC)(HDC hdc, INT64 target_msc, INT64 divisor, INT64 remainder);
+typedef BOOL  (WINAPI * PFNWGLWAITFORMSCOMLPROC)(HDC hdc, INT64 target_msc, INT64 divisor, INT64 remainder, INT64 *ust, INT64 *msc, INT64 *sbc);
+typedef BOOL  (WINAPI * PFNWGLWAITFORSBCOMLPROC)(HDC hdc, INT64 traget_sbc, INT64 *ust, INT64 *msc, INT64 *sbc);
+typedef const char * (WINAPI * PFNWGLGETEXTENSIONSSTRINGARBPROC)(HDC hdc);
+
+static PFNWGLGETEXTENSIONSSTRINGARBPROC wglGetExtensionsStringARB;
+static PFNWGLGETSYNCVALUESOMLPROC  wglGetSyncValuesOML;
+static PFNWGLGETMSCRATEOMLPROC     wglGetMscRateOML;
+static PFNWGLSWAPBUFFERSMSCOMLPROC wglSwapBuffersMscOML;
+static PFNWGLWAITFORMSCOMLPROC     wglWaitForMscOML;
+static PFNWGLWAITFORSBCOMLPROC     wglWaitForSbcOML;
+
 typedef HGLRC (APIENTRY *wglCreateContextAttribsProc)(HDC, HGLRC, const int*);
 static wglCreateContextAttribsProc pcreate_context;
 #endif
@@ -91,6 +105,13 @@ static HGLRC win32_hw_hrc;
 static HDC   win32_hdc;
 static bool  win32_use_hw_ctx             = false;
 static bool  win32_core_hw_context_enable = false;
+static unsigned g_wgl_swap_mode           = 0;
+
+static int     g_wgl_divisor              = 0;
+static int     g_wgl_remainder            = 0;
+static int64_t g_wgl_ust                  = 0;
+static int64_t g_wgl_msc                  = 0;
+static int64_t g_wgl_sbc                  = 0;
 
 #ifdef HAVE_VULKAN
 static gfx_ctx_vulkan_data_t win32_vk;
@@ -103,6 +124,44 @@ static enum gfx_ctx_api win32_api         = GFX_CTX_NONE;
 
 static dylib_t          dll_handle        = NULL; /* Handle to OpenGL32.dll */
 
+static unsigned strclen(const unsigned char *s, unsigned char c)
+{
+	unsigned i = 0;
+	while (s + i != NULL && s[i] != '\0' && s[i] != c)
+		i++;
+	return i;
+}
+
+static bool strsame(const unsigned char *a, const unsigned char *b, unsigned n)
+{
+	unsigned i = 0;
+	while (i < n && a + i != NULL && b + i != NULL && a[i] == b[i])
+		i++;
+	return i == n;
+}
+
+static bool  wgl_has_extension(HDC hdc, const char *ext)
+{
+	char *end;
+	int len = strlen(ext);
+	char *p = (char*)wglGetExtensionsStringARB(hdc);
+
+	if (p == 0)
+		return false;
+
+	end = p + strlen(p);
+
+	while (p < end)
+	{
+		int n = strclen((const unsigned char*)p, ' ');
+		if (len == n && strsame((const unsigned char*)ext, (const unsigned char*)p, n))
+			return true;
+		p += n+1;
+	}
+
+	return false;
+}
+
 static void setup_pixel_format(HDC hdc)
 {
    PIXELFORMATDESCRIPTOR pfd = {0};
@@ -282,9 +341,7 @@ static void gfx_ctx_wgl_swap_interval(void *data, unsigned interval)
       case GFX_CTX_OPENGL_API:
 #ifdef HAVE_OPENGL
          win32_interval = interval;
-         if (!win32_hrc)
-            return;
-         if (!p_swap_interval)
+         if (!win32_hrc || !p_swap_interval)
             return;
 
          RARCH_LOG("[WGL]: wglSwapInterval(%u)\n", win32_interval);
@@ -339,7 +396,19 @@ static void gfx_ctx_wgl_swap_buffers(void *data, video_frame_info_t video_info)
    {
       case GFX_CTX_OPENGL_API:
 #ifdef HAVE_OPENGL
-         SwapBuffers(win32_hdc);
+		  if (g_wgl_swap_mode)
+		  {
+			  if (win32_interval)
+			  {
+				  wglWaitForMscOML(win32_hdc, g_wgl_msc + win32_interval,
+					  0, 0, &g_wgl_ust, &g_wgl_msc, &g_wgl_sbc);
+				  wglSwapBuffersMscOML(win32_hdc, 0, 0, 0);
+			  }
+			  else
+				  wglSwapBuffersMscOML(win32_hdc, 0, g_wgl_divisor, g_wgl_remainder);
+		  }
+		  else
+		     SwapBuffers(win32_hdc);
 #endif
          break;
 
@@ -439,11 +508,35 @@ static void *gfx_ctx_wgl_init(video_frame_info_t video_info, void *video_driver)
    win32_monitor_init();
 
    wndclass.lpfnWndProc   = WndProcGL;
+   g_wgl_swap_mode        = 0;
    if (!win32_window_init(&wndclass, true, NULL))
            return NULL;
 
    switch (win32_api)
    {
+      case GFX_CTX_OPENGL_API:
+		  RARCH_LOG("Testing if extension WGL_OML_sync_control is available...\n");
+		  wglGetExtensionsStringARB = (PFNWGLGETEXTENSIONSSTRINGARBPROC)wglGetProcAddress("wglGetExtensionsStringARB");
+
+		  if (wgl_has_extension(win32_hdc, "WGL_OML_sync_control"))
+		  {
+            RARCH_LOG("WGL_OML_sync_control supported, using better swap control method...\n");
+
+			g_wgl_swap_mode      = 1;
+			wglGetSyncValuesOML  = (PFNWGLGETSYNCVALUESOMLPROC)
+			  wglGetProcAddress("wglGetSyncValuesOML");
+			wglGetMscRateOML     = (PFNWGLGETMSCRATEOMLPROC)
+			  wglGetProcAddress("wglGetMscRateOML");
+			wglSwapBuffersMscOML = (PFNWGLSWAPBUFFERSMSCOMLPROC)
+			  wglGetProcAddress("wglSwapBuffersMscOML");
+			wglWaitForMscOML = (PFNWGLWAITFORMSCOMLPROC)
+			  wglGetProcAddress("wglWaitForMscOML");
+			wglWaitForSbcOML = (PFNWGLWAITFORSBCOMLPROC)
+			  wglGetProcAddress("wglWaitForSbcOML");
+
+			wglGetSyncValuesOML(win32_hdc, &g_wgl_ust, &g_wgl_msc, &g_wgl_sbc);
+		  }
+	     break;
       case GFX_CTX_VULKAN_API:
 #ifdef HAVE_VULKAN
          if (!vulkan_context_init(&win32_vk, VULKAN_WSI_WIN32))
@@ -522,6 +615,13 @@ static void gfx_ctx_wgl_destroy(void *data)
    win32_major                  = 0;
    win32_minor                  = 0;
    p_swap_interval              = NULL;
+
+   g_wgl_swap_mode              = 0;
+   g_wgl_divisor                = 0;
+   g_wgl_remainder              = 0;
+   g_wgl_ust                    = 0;
+   g_wgl_msc                    = 0;
+   g_wgl_sbc                    = 0;
 }
 
 static bool gfx_ctx_wgl_set_video_mode(void *data,