ddrawex: Implement a GetDC special behavior Internet Explorer depends on.
Tests show that in ddrawex.dll it is legal to create a surface with
both DDSCAPS_VIDEOMEMORY and DDSCAPS_SYSTEMMEMORY flag set. A surface
created that way shows different behavior in IDirectDrawSurface::GetDC.
diff --git a/dlls/ddrawex/ddraw.c b/dlls/ddrawex/ddraw.c
index 9645a3d..9e8066a 100644
--- a/dlls/ddrawex/ddraw.c
+++ b/dlls/ddrawex/ddraw.c
@@ -387,6 +387,8 @@
{
IDirectDrawImpl *This = impl_from_dd4(iface);
HRESULT hr;
+ const DWORD perm_dc_flags = DDSCAPS_VIDEOMEMORY | DDSCAPS_SYSTEMMEMORY;
+ BOOL permanent_dc;
TRACE("(%p)(%p, %p, %p)\n", This, DDSD, Surf, UnkOuter);
if(UnkOuter != NULL)
@@ -395,8 +397,25 @@
FIXME("Implement aggregation for ddrawex surfaces\n");
}
+ /* plain ddraw.dll refuses to create a surface that has both VIDMEM and SYSMEM flags
+ * set. In ddrawex this succeeds, and the GetDC() call changes the behavior. The DC
+ * is permanently valid, and the surface can be locked between GetDC() and ReleaseDC()
+ * calls. GetDC() can be called more than once too
+ */
+ if((DDSD->ddsCaps.dwCaps & perm_dc_flags) == perm_dc_flags)
+ {
+ permanent_dc = TRUE;
+ DDSD->ddsCaps.dwCaps &= ~DDSCAPS_VIDEOMEMORY;
+ DDSD->ddsCaps.dwCaps |= DDSCAPS_OWNDC;
+ }
+ else
+ {
+ permanent_dc = FALSE;
+ }
+
hr = IDirectDraw4_CreateSurface(This->parent, DDSD, Surf, UnkOuter);
*Surf = dds_get_outer(*Surf);
+ if(permanent_dc) prepare_permanent_dc(*Surf);
return hr;
}
