From da09069d7b2b0d443eafd618dd9acc65da1a17f7 Mon Sep 17 00:00:00 2001
From: FunkyFr3sh <cc.red.alert.1@googlemail.com>
Date: Wed, 22 Jan 2020 11:35:04 +0100
Subject: [PATCH] adjust fps limiter for gdi renderer

---
 inc/main.h        |  1 -
 src/main.c        |  7 -------
 src/render_soft.c | 47 ++++++++++++++++++++++++++++++++---------------
 src/surface.c     | 24 +++---------------------
 4 files changed, 35 insertions(+), 44 deletions(-)

diff --git a/inc/main.h b/inc/main.h
index d2b968e..17e11d5 100644
--- a/inc/main.h
+++ b/inc/main.h
@@ -94,7 +94,6 @@ typedef struct IDirectDrawImpl
 
         HANDLE thread;
         BOOL run;
-        HANDLE ev;
         HANDLE sem;
         DEVMODE mode;
         struct { int width; int height; int x; int y; } viewport;
diff --git a/src/main.c b/src/main.c
index 25baa8d..82c13fe 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1777,12 +1777,6 @@ ULONG __stdcall ddraw_Release(IDirectDrawImpl *This)
             ReleaseDC(This->hWnd, This->render.hDC);
             This->render.hDC = NULL;
         }
-        
-        if(This->render.ev)
-        {
-            CloseHandle(This->render.ev);
-            ddraw->render.ev = NULL;
-        }
 
         if (This->ticksLimiter.hTimer)
         {
@@ -1919,7 +1913,6 @@ HRESULT WINAPI DirectDrawCreate(GUID FAR* lpGUID, LPDIRECTDRAW FAR* lplpDD, IUnk
     }
 
     InitializeCriticalSection(&This->cs);
-    This->render.ev = CreateEvent(NULL, TRUE, FALSE, NULL);
     This->render.sem = CreateSemaphore(NULL, 0, 1, NULL);
 
     This->wine = GetProcAddress(GetModuleHandleA("ntdll.dll"), "wine_get_version") != 0;
diff --git a/src/render_soft.c b/src/render_soft.c
index f36ef4b..e09a480 100644
--- a/src/render_soft.c
+++ b/src/render_soft.c
@@ -42,7 +42,8 @@ DWORD WINAPI render_soft_main(void)
 
     Sleep(500);
 
-    DWORD lastTick = 0;
+    DWORD tickStart = 0;
+    DWORD tickEnd = 0;
     int maxFPS = ddraw->render.maxfps;
     ddraw->fpsLimiter.tickLengthNs = 0;
     ddraw->fpsLimiter.ticklength = 0;
@@ -62,23 +63,13 @@ DWORD WINAPI render_soft_main(void)
 
     while (ddraw->render.run && WaitForSingleObject(ddraw->render.sem, INFINITE) != WAIT_FAILED)
     {
-        if (ddraw->fpsLimiter.ticklength > 0)
-        {
-            DWORD curTick = timeGetTime();
-            if (lastTick + ddraw->fpsLimiter.ticklength > curTick)
-            {
-                ReleaseSemaphore(ddraw->render.sem, 1, NULL);
-                SetEvent(ddraw->render.ev);
-                SwitchToThread();
-                continue;
-            }
-            lastTick = curTick;
-        }
-
 #if _DEBUG
         DrawFrameInfoStart();
 #endif
 
+        if (ddraw->fpsLimiter.ticklength > 0)
+            tickStart = timeGetTime();
+
         EnterCriticalSection(&ddraw->cs);
 
         if (ddraw->primary && (ddraw->bpp == 16 || (ddraw->primary->palette && ddraw->primary->palette->data_rgb)))
@@ -168,7 +159,33 @@ DWORD WINAPI render_soft_main(void)
         DrawFrameInfoEnd();
 #endif
 
-        SetEvent(ddraw->render.ev);
+        if (ddraw->fpsLimiter.ticklength > 0)
+        {
+            if (ddraw->fpsLimiter.hTimer)
+            {
+                FILETIME ft = { 0 };
+                GetSystemTimeAsFileTime(&ft);
+
+                if (CompareFileTime((FILETIME*)&ddraw->fpsLimiter.dueTime, &ft) == -1)
+                {
+                    memcpy(&ddraw->fpsLimiter.dueTime, &ft, sizeof(LARGE_INTEGER));
+                }
+                else
+                {
+                    WaitForSingleObject(ddraw->fpsLimiter.hTimer, ddraw->fpsLimiter.ticklength * 2);
+                }
+
+                ddraw->fpsLimiter.dueTime.QuadPart += ddraw->fpsLimiter.tickLengthNs;
+                SetWaitableTimer(ddraw->fpsLimiter.hTimer, &ddraw->fpsLimiter.dueTime, 0, NULL, NULL, FALSE);
+            }
+            else
+            {
+                tickEnd = timeGetTime();
+
+                if (tickEnd - tickStart < ddraw->fpsLimiter.ticklength)
+                    Sleep(ddraw->fpsLimiter.ticklength - (tickEnd - tickStart));
+            }
+        }
     }
 
     return TRUE;
diff --git a/src/surface.c b/src/surface.c
index a78acc7..e9b2d19 100644
--- a/src/surface.c
+++ b/src/surface.c
@@ -466,15 +466,7 @@ HRESULT __stdcall ddraw_surface_Blt(IDirectDrawSurfaceImpl *This, LPRECT lpDestR
     {
         InterlockedExchange(&ddraw->render.surfaceUpdated, TRUE);
         ReleaseSemaphore(ddraw->render.sem, 1, NULL);
-        if (ddraw->renderer == render_soft_main)
-        {
-            WaitForSingleObject(ddraw->render.ev, INFINITE);
-            ResetEvent(ddraw->render.ev);
-        }
-        else
-        {
-            SwitchToThread();
-        }
+        SwitchToThread();
 
         if (ddraw->ticksLimiter.ticklength > 0)
         {
@@ -696,18 +688,8 @@ HRESULT __stdcall ddraw_surface_Flip(IDirectDrawSurfaceImpl *This, LPDIRECTDRAWS
         This->lastFlipTick = timeGetTime();
 
         InterlockedExchange(&ddraw->render.surfaceUpdated, TRUE);
-        
-        if (ddraw->renderer == render_soft_main)
-        {
-            ResetEvent(ddraw->render.ev);
-            ReleaseSemaphore(ddraw->render.sem, 1, NULL);
-            WaitForSingleObject(ddraw->render.ev, INFINITE);
-        }
-        else
-        {
-            ReleaseSemaphore(ddraw->render.sem, 1, NULL);
-            SwitchToThread();
-        }
+        ReleaseSemaphore(ddraw->render.sem, 1, NULL);
+        SwitchToThread();
 
         if (flags & DDFLIP_WAIT)
         {