Mail Archives: djgpp/1998/12/25/22:28:57
On 25 Dec 98 at 21:04, Billy wrote:
> Hello.
> Please pardon me in advance if this question was previously
> asked, seems idiotic, or the like.
>
> I've been wondering for a while now if it's possible
> to create a graphical Allegro TSR screen saver program in DOS.
> Would anyone care to tell me of, or direct me
> to any information on the subject?
I think it could be very dodgy. Allegro doesn't try too hard
to reset the display mode after it has changed it -- IIRC it
has a quick look before it changes the mode, and if it
recognises the mode it remembers it for later, but otherwise it
just sets mode 3 (colour 80x25 I think).
Whether or not the program can safely be activated and call
Allegro functions depends upon the restrictions imposed ot
TSRs -- I don't know what these are, so I can't really help
here. What context will the Allegro functions be called in? It
may be best to initialise Allegro only after activation, and
shut it down before returning control to the foreground task.
You might be interested to look at example program 32. It
starts a MIDI file playing then spawns a command prompt. Note
that it does not work well in all circumstances; admittedly
this is a different situation though! Sound card programming
isn't something that shares too well between applications
(unless the OS intervenes, which Windows doesn't (much) here
AFAICS). Mind you, graphics programming doesn't share too
well either!
--
george DOT foot AT merton DOT oxford DOT ac DOT uk
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