From 5b3a7b4994188df4ef6cec9e0028ddbe4b6998b6 Mon Sep 17 00:00:00 2001
From: FunkyFr3sh <cc.red.alert.1@googlemail.com>
Date: Sun, 25 Feb 2024 23:46:32 +0100
Subject: [PATCH] add debug code for possible DwmFlush failure

---
 inc/fps_limiter.h |  4 +++-
 src/dd.c          |  6 +-----
 src/fps_limiter.c | 41 +++++++++++++++++++++++++++++++++--------
 3 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/inc/fps_limiter.h b/inc/fps_limiter.h
index 5c8049f..ec0f7bc 100644
--- a/inc/fps_limiter.h
+++ b/inc/fps_limiter.h
@@ -48,12 +48,14 @@ typedef struct FPSLIMITER
     D3DKMTCLOSEADAPTERPROC D3DKMTCloseAdapter;
     BOOL got_adapter;
     BOOL initialized;
+    CRITICAL_SECTION cs;
+    BOOL cs_initialized;
 } FPSLIMITER;
 
 extern FPSLIMITER g_fpsl;
 
 void fpsl_init();
-BOOL fpsl_wait_for_vblank(BOOL open_adapter);
+BOOL fpsl_wait_for_vblank();
 BOOL fpsl_dwm_flush();
 BOOL fpsl_dwm_is_enabled();
 void fpsl_frame_start();
diff --git a/src/dd.c b/src/dd.c
index 750e69b..06abd7d 100644
--- a/src/dd.c
+++ b/src/dd.c
@@ -1224,11 +1224,7 @@ HRESULT dd_WaitForVerticalBlank(DWORD dwFlags, HANDLE hEvent)
 {
     if (g_config.maxgameticks == -2)
     {
-        BOOL open = 
-            !(g_config.maxfps < 0 || 
-                (g_config.vsync && (!g_config.maxfps || g_config.maxfps >= g_ddraw->mode.dmDisplayFrequency)));
-
-        if (fpsl_dwm_flush() || fpsl_wait_for_vblank(open))
+        if (fpsl_dwm_flush() || fpsl_wait_for_vblank())
             return DD_OK;
     }
 
diff --git a/src/fps_limiter.c b/src/fps_limiter.c
index 97c0ec1..90c8076 100644
--- a/src/fps_limiter.c
+++ b/src/fps_limiter.c
@@ -35,6 +35,12 @@ void fpsl_init()
         g_fpsl.D3DKMTCloseAdapter(&g_fpsl.close_adapter);
     }
 
+    if (!g_fpsl.cs_initialized)
+    {
+        g_fpsl.cs_initialized = TRUE;
+        InitializeCriticalSection(&g_fpsl.cs);
+    }
+
     if (!g_fpsl.gdi32_dll)
     {
         g_fpsl.gdi32_dll = real_LoadLibraryA("gdi32.dll");
@@ -78,19 +84,26 @@ void fpsl_init()
     g_fpsl.initialized = TRUE;
 }
 
-BOOL fpsl_wait_for_vblank(BOOL open_adapter)
+BOOL fpsl_wait_for_vblank()
 {
     if (g_fpsl.initialized)
     {
-        if (open_adapter && g_fpsl.D3DKMTOpenAdapterFromHdc && !g_fpsl.got_adapter)
+        if (!g_fpsl.got_adapter && g_fpsl.D3DKMTOpenAdapterFromHdc && g_ddraw->render.hdc)
         {
-            g_fpsl.adapter.hDc = g_ddraw->render.hdc;
+            EnterCriticalSection(&g_fpsl.cs);
 
-            if (g_fpsl.D3DKMTOpenAdapterFromHdc(&g_fpsl.adapter) == 0)
+            if (!g_fpsl.got_adapter)
             {
-                g_fpsl.vblank_event.hAdapter = g_fpsl.adapter.hAdapter;
-                g_fpsl.got_adapter = TRUE;
+                g_fpsl.adapter.hDc = g_ddraw->render.hdc;
+
+                if (g_fpsl.D3DKMTOpenAdapterFromHdc(&g_fpsl.adapter) == 0)
+                {
+                    g_fpsl.vblank_event.hAdapter = g_fpsl.adapter.hAdapter;
+                    g_fpsl.got_adapter = TRUE;
+                }
             }
+
+            LeaveCriticalSection(&g_fpsl.cs);
         }
 
         if (g_fpsl.got_adapter && g_fpsl.D3DKMTWaitForVerticalBlankEvent)
@@ -104,7 +117,19 @@ BOOL fpsl_wait_for_vblank(BOOL open_adapter)
 
 BOOL fpsl_dwm_flush()
 {
-    return g_fpsl.initialized && fpsl_dwm_is_enabled() && g_fpsl.DwmFlush && SUCCEEDED(g_fpsl.DwmFlush());
+    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()
@@ -128,7 +153,7 @@ void fpsl_frame_end()
     if (g_config.maxfps < 0 || 
         (g_config.vsync && (!g_config.maxfps || g_config.maxfps >= g_ddraw->mode.dmDisplayFrequency)))
     {
-        if (fpsl_dwm_flush() || fpsl_wait_for_vblank(TRUE))
+        if (fpsl_dwm_flush() || fpsl_wait_for_vblank())
             return;
     }