From a6af34fbff448f2b0ba5622fee198e9c57a2b550 Mon Sep 17 00:00:00 2001
From: FunkyFr3sh <cc.red.alert.1@googlemail.com>
Date: Mon, 22 Feb 2021 09:09:21 +0100
Subject: [PATCH] optional wait_for_vblank on flip

---
 inc/fps_limiter.h |  2 +-
 src/dd.c          |  2 +-
 src/fps_limiter.c | 29 ++++++++++++++++-------------
 3 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/inc/fps_limiter.h b/inc/fps_limiter.h
index 21cf1de..7a44cb3 100644
--- a/inc/fps_limiter.h
+++ b/inc/fps_limiter.h
@@ -53,7 +53,7 @@ typedef struct fps_limiter
 extern fps_limiter g_fpsl;
 
 void fpsl_init();
-BOOL fpsl_wait_for_vblank();
+BOOL fpsl_wait_for_vblank(BOOL open_adapter);
 BOOL fpsl_dwm_flush();
 BOOL fpsl_dwm_is_enabled();
 void fpsl_frame_start();
diff --git a/src/dd.c b/src/dd.c
index fd61a1c..f6d5fde 100644
--- a/src/dd.c
+++ b/src/dd.c
@@ -706,7 +706,7 @@ HRESULT dd_WaitForVerticalBlank(DWORD dwFlags, HANDLE h)
 {
     if (g_ddraw->maxgameticks == -2)
     {
-        if (fpsl_dwm_flush())
+        if (fpsl_dwm_flush() || fpsl_wait_for_vblank(FALSE))
             return DD_OK;
     }
 
diff --git a/src/fps_limiter.c b/src/fps_limiter.c
index fa28e8d..083f0d3 100644
--- a/src/fps_limiter.c
+++ b/src/fps_limiter.c
@@ -76,22 +76,25 @@ void fpsl_init()
     g_fpsl.initialized = TRUE;
 }
 
-BOOL fpsl_wait_for_vblank()
+BOOL fpsl_wait_for_vblank(BOOL open_adapter)
 {
-    if (g_fpsl.initialized && g_fpsl.D3DKMTOpenAdapterFromHdc && !g_fpsl.got_adapter)
+    if (g_fpsl.initialized)
     {
-        g_fpsl.adapter.hDc = g_ddraw->render.hdc;
-
-        if (g_fpsl.D3DKMTOpenAdapterFromHdc(&g_fpsl.adapter) == 0)
+        if (open_adapter && g_fpsl.D3DKMTOpenAdapterFromHdc && !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.got_adapter && g_fpsl.D3DKMTWaitForVerticalBlankEvent)
-    {
-        return g_fpsl.D3DKMTWaitForVerticalBlankEvent(&g_fpsl.vblank_event) == 0;
+            if (g_fpsl.D3DKMTOpenAdapterFromHdc(&g_fpsl.adapter) == 0)
+            {
+                g_fpsl.vblank_event.hAdapter = g_fpsl.adapter.hAdapter;
+                g_fpsl.got_adapter = TRUE;
+            }
+        }
+
+        if (g_fpsl.got_adapter && g_fpsl.D3DKMTWaitForVerticalBlankEvent)
+        {
+            return g_fpsl.D3DKMTWaitForVerticalBlankEvent(&g_fpsl.vblank_event) == 0;
+        }
     }
 
     return FALSE;
@@ -122,7 +125,7 @@ void fpsl_frame_end()
 {
     if (g_ddraw->render.maxfps < 0 || g_ddraw->vsync)
     {
-        if (fpsl_dwm_flush() || fpsl_wait_for_vblank())
+        if (fpsl_dwm_flush() || fpsl_wait_for_vblank(TRUE))
             return;
     }