I just had a neat idea. As I understand it, SDL, in the fbcon driver,
uses “image stacking” to accomplish double buffering with fbcon.
Essentially there is one double-height frame buffer, and the viewing
area is panned up or down each frame flip.
Video games very often run at 640x480, and X11 servers often are
configured to support 1280x1024 or higher. I am aware that, in X, the
resolution is fixed (although you can “zoom in” very often to an area of
the screen using the XV extension).
What I’m wondering is if when:
XV is available and
the X11 “desktop” is more than twice as high or twice as wide as the
desired resolution and
we are in full screen mode (and zoomed in using the XV extension)
can we pan the screen up and down (or back and forth) fast enough to
emulate double-buffering in full screen X11?