[Wine] Re: Purpose of DIB Engine?

[Thunderbird]

DirectDraw was about direct framebuffer access, so similar to DGA which you just mentioned. The closest to this is opengl. It offers some interesting extensions like pixel buffer objects (PBOs) using which we have something close to direct framebuffer access. There are just things which need to be added to our DirectDraw to make it more efficient.

One of the things which we don't do in Wine but which could bring a lot of speed are 'access traps' (Windows must be using those). Most of the time when a game draws to a surface it only updates a small part but in Wine each time we reupload the whole surface (some games are nice and only 'lock' the part they need but not all). On Windows DirectDraw sets traps on the memory (the actually cause segfaults on purpose) to track which parts got updated. This is a change which could help some games a lot but it is very tricky to implement properly.