Jeff Thomas <a2forever@usa.net> wrote:

> Is it possible to write an Applesoft Basic program in DOS 3.3 or ProDOS
> to access "Super Hi-Res" pictures on Apple IIGS, similar to loading the
> standard Apple II graphic modes with "Bload Pic.1, A$2000"?

It is certainly possible, but nowhere near as easy as using Hi-res
graphics, due to the requirements of setting the memory mapping mode
correctly and the buffer only exists in auxiliary memory (actually in
bank $E1, but it can be shadowed from bank $01).

The best solution is probably to get hold of one of the various machine
code packages which gives you a series of commands for accessing the SHR
screen via the '&' command.  Nibble magazine did at least two of these,
and I'm pretty sure there was at least one commercial package.

Even the relatively simple task of loading an image onto the Super
Hi-Res screen is somewhat difficult, because it requires loading 32K of
data into auxiliary memory.  You would have to load the image in pieces
and move them into auxiliary memory using some machine code support
routines.

The Super Hi-res graphics buffer is located at $2000-$9FFF, but you need
to know enough about controlling shadowing and the NEWVIDEO register
before you can use it effectively.

-- 
David Empson
dempson@actrix.gen.nz