[Bug 45901] Avoid GPU synchronization due to GPU-CPU transfer (Overwatch)

https://bugs.winehq.org/show_bug.cgi?id=45901

--- Comment #3 from Henri Verbeet  ---
What kind of resources and APIs are involved here? I guess a copy from a
DEFAULT texture to a STAGING texture? What about format and CPUAccessFlags? I
think we'd prefer to avoid ReadPixels() if we can. What is the issue with
GetTexImage()? Just that it doesn't work well with PBOs? Or something else?