ddraw: Separate IDirectDrawSurface4 vtable.

dlls/ddraw/ddraw.c

@@ -2050,7 +2050,7 @@ static HRESULT WINAPI ddraw4_GetGDISurface(IDirectDraw4 *iface, IDirectDrawSurfa
         return hr;
     }
     surface_impl = impl_from_IDirectDrawSurface7(surface7);
-    *surface = (IDirectDrawSurface4 *)surface_impl;
+    *surface = &surface_impl->IDirectDrawSurface4_iface;
 
     return hr;
 }
@@ -3561,7 +3561,7 @@ static HRESULT WINAPI ddraw4_CreateSurface(IDirectDraw4 *iface,
         return hr;
     }
 
-    *surface = (IDirectDrawSurface4 *)impl;
+    *surface = &impl->IDirectDrawSurface4_iface;
     ddraw_set_surface_version(impl, 4);
     IDirectDraw7_Release(&This->IDirectDraw7_iface);
     IDirectDraw4_AddRef(iface);
@@ -4257,7 +4257,7 @@ static HRESULT WINAPI ddraw4_DuplicateSurface(IDirectDraw4 *iface, IDirectDrawSu
         return hr;
     }
     dst_impl = impl_from_IDirectDrawSurface7(dst7);
-    *dst = (IDirectDrawSurface4 *)dst_impl;
+    *dst = &dst_impl->IDirectDrawSurface4_iface;
 
     return hr;
 }

dlls/ddraw/ddraw_private.h

@@ -153,6 +153,7 @@ struct IDirectDrawSurfaceImpl
 {
     /* IUnknown fields */
     IDirectDrawSurface7 IDirectDrawSurface7_iface;
+    IDirectDrawSurface4 IDirectDrawSurface4_iface;
     IDirectDrawSurface3 IDirectDrawSurface3_iface;
     const IDirectDrawGammaControlVtbl *IDirectDrawGammaControl_vtbl;
     const IDirect3DTexture2Vtbl *IDirect3DTexture2_vtbl;
@@ -225,6 +226,11 @@ static inline IDirectDrawSurfaceImpl *impl_from_IDirectDrawSurface3(IDirectDrawS
     return CONTAINING_RECORD(iface, IDirectDrawSurfaceImpl, IDirectDrawSurface3_iface);
 }
 
+static inline IDirectDrawSurfaceImpl *impl_from_IDirectDrawSurface4(IDirectDrawSurface4 *iface)
+{
+    return CONTAINING_RECORD(iface, IDirectDrawSurfaceImpl, IDirectDrawSurface4_iface);
+}
+
 static inline IDirectDrawSurfaceImpl *impl_from_IDirectDrawSurface7(IDirectDrawSurface7 *iface)
 {
     return CONTAINING_RECORD(iface, IDirectDrawSurfaceImpl, IDirectDrawSurface7_iface);

dlls/ddraw/device.c

@@ -1961,7 +1961,7 @@ static HRESULT WINAPI IDirect3DDeviceImpl_3_GetRenderTarget(IDirect3DDevice3 *if
     hr = IDirect3DDevice7_GetRenderTarget((IDirect3DDevice7 *)This, &RenderTarget7);
     if(hr != D3D_OK) return hr;
     RenderTargetImpl = impl_from_IDirectDrawSurface7(RenderTarget7);
-    *RenderTarget = (IDirectDrawSurface4 *)RenderTargetImpl;
+    *RenderTarget = &RenderTargetImpl->IDirectDrawSurface4_iface;
     return D3D_OK;
 }