Glenn wrote:

> So you blit the whole background each time - doesn't that slow things down?

Works like a charm. I'm getting good frame rates. Most games actually 
redraw the whole screen multiple times per second.

You could slow things up by doing exactly that (my version redraws 
*everything* the whole time even if it's not in the ViewPort) or by 
using a system to detect what region of the Screen has actually changed 
-- but I'd think that the overhead added by that would actually exceed 
any performance gained.