Hi Jaakko, thanks for looking into dcomp. The problem with dcomp is that while adding stubs is enough to make some games happy, it's not good enough for upstream. After you add the stubs, other applications will start calling those stub functions, and more methods will be needed. Eventually, we will need a complete solution. Not having those stubs forces some games to fall back to other code paths that don't require dcomp. A proper solution would be to implement a compositor, utilizing Rémi's recent shared resource work, which allows sharing images across different processes. To do that, we need to support shared resources for wined3d first, then implement a compositor(dwm.exe?), then implement dcomp to control the compositor. It wouldn't be trivial. For what it's worth, I have a slightly better version of dcomp at https://gitlab.winehq.org/zhiyi/wine/-/commits/bug-23698-react-native. It's still not a proper implementation, but it helps some applications. -- https://gitlab.winehq.org/wine/wine/-/merge_requests/9839#note_126236