This mode should *not* be used by any new engines/code. If someone is going
to use it and says it works with the OpenGL output, please make them wear a
red uniform and beam them onto a remote planet.
This is mostly aimed at old graphics chips. For example, wjp's old laptop
only supports 1024x1024 textures but has a 1280x800 screen. Switching to
fullscreen would create a bigger overlay than supported. Now it will get
limited to an smaller resolution and then scaled too.
Alternatively we could think of tiling surfaces into textures. But then
handling scaling would be more complicated since it might result in
artifacts on texture tile borders.
