From 5d2d258d5264c32e2277d9fea7e91746ac6fdf4b Mon Sep 17 00:00:00 2001
From: FunkyFr3sh <cc.red.alert.1@googlemail.com>
Date: Mon, 19 Nov 2018 08:36:18 +0100
Subject: [PATCH] save last flip tick to force redraw in case the game switches
 between blt and flip

---
 inc/surface.h |  1 +
 src/surface.c | 17 ++++++++++++++---
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/inc/surface.h b/inc/surface.h
index 149a9bd..c53b30b 100644
--- a/inc/surface.h
+++ b/inc/surface.h
@@ -50,6 +50,7 @@ typedef struct IDirectDrawSurfaceImpl
     HBITMAP bitmap;
     HDC hDC;
     DDCOLORKEY colorKey;
+    DWORD lastFlipTick;
 
 } IDirectDrawSurfaceImpl;
 
diff --git a/src/surface.c b/src/surface.c
index 2032c92..11ebea9 100644
--- a/src/surface.c
+++ b/src/surface.c
@@ -21,6 +21,9 @@
 #include "surface.h"
 #include "scale_pattern.h"
 
+// enables redraw via blt/unlock if there wasn't any flip for X ms
+#define FLIP_REDRAW_TIMEOUT 1000 / 20
+
 void dump_ddbltflags(DWORD dwFlags);
 void dump_ddscaps(DWORD dwCaps);
 void dump_ddsd(DWORD dwFlags);
@@ -425,7 +428,9 @@ HRESULT __stdcall ddraw_surface_Blt(IDirectDrawSurfaceImpl *This, LPRECT lpDestR
         }
     }
 
-    if(This->caps & DDSCAPS_PRIMARYSURFACE && !(This->flags & DDSD_BACKBUFFERCOUNT) && ddraw->render.run)
+    if(This->caps & DDSCAPS_PRIMARYSURFACE && 
+        ddraw->render.run &&
+        (!(This->flags & DDSD_BACKBUFFERCOUNT) || This->lastFlipTick + FLIP_REDRAW_TIMEOUT < timeGetTime()))
     {
         InterlockedExchange(&ddraw->render.surfaceUpdated, TRUE);
         ReleaseSemaphore(ddraw->render.sem, 1, NULL);
@@ -564,7 +569,9 @@ HRESULT __stdcall ddraw_surface_BltFast(IDirectDrawSurfaceImpl *This, DWORD dst_
         }
     }
 
-    if (This->caps & DDSCAPS_PRIMARYSURFACE && !(This->flags & DDSD_BACKBUFFERCOUNT) && ddraw->render.run)
+    if (This->caps & DDSCAPS_PRIMARYSURFACE &&
+        ddraw->render.run &&
+        (!(This->flags & DDSD_BACKBUFFERCOUNT) || This->lastFlipTick + FLIP_REDRAW_TIMEOUT < timeGetTime()))
     {
         InterlockedExchange(&ddraw->render.surfaceUpdated, TRUE);
         ReleaseSemaphore(ddraw->render.sem, 1, NULL);
@@ -639,6 +646,8 @@ HRESULT __stdcall ddraw_surface_Flip(IDirectDrawSurfaceImpl *This, LPDIRECTDRAWS
 
     if(This->caps & DDSCAPS_PRIMARYSURFACE && ddraw->render.run)
     {
+        This->lastFlipTick = timeGetTime();
+
         InterlockedExchange(&ddraw->render.surfaceUpdated, TRUE);
         
         if (ddraw->renderer == render_soft_main)
@@ -912,7 +921,9 @@ HRESULT __stdcall ddraw_surface_Unlock(IDirectDrawSurfaceImpl *This, LPVOID lpRe
     printf("DirectDrawSurface::Unlock(This=%p, lpRect=%p)\n", This, lpRect);
 #endif
     
-    if(This->caps & DDSCAPS_PRIMARYSURFACE && !(This->flags & DDSD_BACKBUFFERCOUNT) && ddraw->render.run)
+    if (This->caps & DDSCAPS_PRIMARYSURFACE &&
+        ddraw->render.run &&
+        (!(This->flags & DDSD_BACKBUFFERCOUNT) || This->lastFlipTick + FLIP_REDRAW_TIMEOUT < timeGetTime()))
     {
         InterlockedExchange(&ddraw->render.surfaceUpdated, TRUE);
         ReleaseSemaphore(ddraw->render.sem, 1, NULL);