I'm starting to consider wrapping more vulkan objects in win32u, I think it'll be useful to implement compositing (and incidentally shared resources with interop with the D3DKMT/NtGdi API), starting with nulldrv/offscreen swapchains. Alternatively we could export more functions from win32u and keep all the wrappers in winevulkan, but having access to win32u internals with a generic vulkan object wrapping mechanism seems to be more interesting.
Right now this is not very convenient because the vulkan object hierarchy is only available in winevulkan. This introduces shared structures and API between win32u and winevulkan so they can manipulate the wrapped objects from both side. The interface would only expose what is necessary, ie: the object hierarchy and wrapped handles, the instance and device functions, and the objects rbtree for debugging, so win32u can insert its wrapper there as well.
After moving the surface and swapchain wrappers to win32u, the interface would look like this: https://gitlab.winehq.org/rbernon/wine/-/blob/65ca1280d46a2dff792e298c222426... (I pushed a complete WIP branch to https://gitlab.winehq.org/rbernon/wine/-/commits/wip/vulkan-win32u-driver?re...). We can also consider moving all the winevulkan wrappers to win32u but it's not clear whether it's necessary or desirable, and we can also do that later using this interface.
-- v6: winevulkan: Introduce a new vulkan_physical_device base structure. winevulkan: Introduce a new vulkan_instance base structure. winevulkan: Hoist physical device array and client instance handle. winevulkan: Name wine_instance parameters and variables more consistently. winevulkan: Move vulkan_client_object header to wine/vulkan_driver.h. winevulkan: Generate ALL_VK_(DEVICE|INSTANCE)_FUNCS in wine/vulkan.h. winevulkan: Get rid of the instance/device funcs structs. win32u: Use PFN_* typedefs for vulkan function pointers. winevulkan: Add missing wine_vkGetPhysicalDeviceSurfaceFormatsKHR manual wrapper.