Revert "Don't use DwmFlush"

This reverts commit 27dbd0792582f060616f1c74e55678f9ed863484.

inc/fps_limiter.h

@@ -22,6 +22,8 @@ typedef struct _D3DKMT_CLOSEADAPTER {
     UINT hAdapter;
 } D3DKMT_CLOSEADAPTER;
 
+typedef HRESULT(WINAPI* DWMFLUSHPROC)(VOID);
+typedef HRESULT(WINAPI* DWMISCOMPOSITIONENABLEDPROC)(BOOL*);
 typedef NTSTATUS(WINAPI* D3DKMTWAITFORVERTICALBLANKEVENTPROC)(const D3DKMT_WAITFORVERTICALBLANKEVENT* Arg1);
 typedef NTSTATUS(WINAPI* D3DKMTOPENADAPTERFROMHDCPROC)(D3DKMT_OPENADAPTERFROMHDC* Arg1);
 typedef NTSTATUS(WINAPI* D3DKMTCLOSEADAPTERPROC)(D3DKMT_CLOSEADAPTER* Arg1);
@@ -38,6 +40,9 @@ typedef struct FPSLIMITER
     D3DKMT_OPENADAPTERFROMHDC adapter;
     D3DKMT_CLOSEADAPTER close_adapter;
     HMODULE gdi32_dll;
+    HMODULE dwmapi_dll;
+    DWMFLUSHPROC DwmFlush;
+    DWMISCOMPOSITIONENABLEDPROC DwmIsCompositionEnabled;
     D3DKMTWAITFORVERTICALBLANKEVENTPROC D3DKMTWaitForVerticalBlankEvent;
     D3DKMTOPENADAPTERFROMHDCPROC D3DKMTOpenAdapterFromHdc;
     D3DKMTCLOSEADAPTERPROC D3DKMTCloseAdapter;
@@ -51,6 +56,8 @@ extern FPSLIMITER g_fpsl;
 
 void fpsl_init();
 BOOL fpsl_wait_for_vblank();
+BOOL fpsl_dwm_flush();
+BOOL fpsl_dwm_is_enabled();
 void fpsl_frame_start();
 void fpsl_frame_end();
 

src/dd.c

@@ -1568,8 +1568,17 @@ HRESULT dd_WaitForVerticalBlank(DWORD dwFlags, HANDLE hEvent)
 {
     if (g_config.maxgameticks == -2 || g_ddraw.wait_for_real_vblank)
     {
-        if (fpsl_wait_for_vblank())
+        /* Workaround for DwmFlush() freeze (e.g. slow alt+tab) issue on windows 7 SP1 */
-            return DD_OK;
+        if (g_ddraw.renderer == ogl_render_main && !IsWine() && !IsWindows8OrGreater())
+        {
+            if (fpsl_wait_for_vblank())
+                return DD_OK;
+        }
+        else
+        {
+            if (fpsl_dwm_flush() || fpsl_wait_for_vblank())
+                return DD_OK;
+        }
     }
 
     if (!g_ddraw.flip_limiter.tick_length)

src/fps_limiter.c

@@ -49,6 +49,23 @@ void fpsl_init()
         g_fpsl.gdi32_dll = real_LoadLibraryA("gdi32.dll");
     }
 
+    if (!g_fpsl.dwmapi_dll)
+    {
+        g_fpsl.dwmapi_dll = real_LoadLibraryA("dwmapi.dll");
+    }
+
+    if (!g_fpsl.DwmFlush)
+    {
+        g_fpsl.DwmFlush =
+            (DWMFLUSHPROC)real_GetProcAddress(g_fpsl.dwmapi_dll, "DwmFlush");
+    }
+
+    if (!g_fpsl.DwmIsCompositionEnabled)
+    {
+        g_fpsl.DwmIsCompositionEnabled =
+            (DWMISCOMPOSITIONENABLEDPROC)real_GetProcAddress(g_fpsl.dwmapi_dll, "DwmIsCompositionEnabled");
+    }
+
     if (!g_fpsl.D3DKMTWaitForVerticalBlankEvent)
     {
         g_fpsl.D3DKMTWaitForVerticalBlankEvent =
@@ -101,6 +118,33 @@ BOOL fpsl_wait_for_vblank()
     return FALSE;
 }
 
+BOOL fpsl_dwm_flush()
+{
+    if (g_fpsl.initialized && fpsl_dwm_is_enabled() && g_fpsl.DwmFlush)
+    {
+        HRESULT x = g_fpsl.DwmFlush();
+
+        if (!SUCCEEDED(x))
+        {
+            //TRACE(" ERROR %s(result=%08X)\n", __FUNCTION__, x);
+        }
+
+        return SUCCEEDED(x);
+    }
+
+    return FALSE;
+}
+
+BOOL fpsl_dwm_is_enabled()
+{
+    BOOL dwm_enabled = FALSE;
+
+    if (g_fpsl.DwmIsCompositionEnabled)
+        g_fpsl.DwmIsCompositionEnabled(&dwm_enabled);
+
+    return dwm_enabled;
+}
+
 void fpsl_frame_start()
 {
     if (g_fpsl.tick_length > 0)
@@ -112,8 +156,17 @@ void fpsl_frame_end()
     if (g_config.maxfps < 0 || 
         (g_config.vsync && (!g_config.maxfps || g_config.maxfps >= g_ddraw.mode.dmDisplayFrequency)))
     {
-        if (fpsl_wait_for_vblank())
+        /* Workaround for DwmFlush() freeze (e.g. slow alt+tab) issue on windows 7 SP1 */
-            return;
+        if (g_ddraw.renderer == ogl_render_main && !IsWine() && !IsWindows8OrGreater())
+        {
+            if (fpsl_wait_for_vblank())
+                return;
+        }
+        else
+        {
+            if (fpsl_dwm_flush() || fpsl_wait_for_vblank())
+                return;
+        }
     }
 
     if (g_fpsl.tick_length > 0)