Re: The point of EGLConfig?
It's partly a legacy issue and partly that there are still restrictions of displayable windows to a subset of the formats the graphics card can support - you may be able to have RGBA32F or RGBA4444 renderbuffer attachments for offscreen rendering, but that doesn't mean you can necessarily have an X11 (GDI, etc.) window in that format when the framebuffer is configured as RGB888, for example.
Originally Posted by cheery
As window systems based on composition become the norm, this restriction starts to look sillier, since there's always a copy operation involved in SwapBuffers in such systems. We are thinking about different approaches going forward but it will be some time until that might appear as formal specifications.