bferrer@Bonnie.ICS.UCI.EDU (02/07/91)
Can somebody please show me or send email to me on how to write a terminate and stay resident program for the ST or/and STe. I am currently working (on my spare time) on a RayTracer and I want to render in the background while doing some other things in the foreground. Any Help will be appreciated, Bill Ferrer
rosenkra@convex.com (William Rosencranz) (02/08/91)
[ question about doing computationally intensive things in background with
a TSR... ]
first, do u really mean TSR? a TSR is a program, ususally started at boot
time, which remains resident in memory, and runs under special circumstances,
generally when another "forground" program tries to access the OS. these
programs are generally used for things like ramdisks, and to modify how
TOS works.
i think you really want more a multitasking capability. here you have several
choices. perhaps the easiest is to look into MiNT, a multitasking extension
to TOS. it does not multitask GEM programs, only TOS programs (.ttp, .tos)
as far as i know. what you can consider, however, is to build sort of a
raytracing server which runs purely as a TOS program. it can be a TSR,
but you will also need some form of interprocess communication between your
main application and this server, probably. consider pipes or shared
memory. at a minumum, you will need to tell the server to start/stop, and
give it an image to render as well as whatever parameters are needed
(light source, etc).
another solution is to write the raytracer as a DA, and send it messages
from your application after some prescribed time (evnt_timer) like an
alarm clock. it will only run, however, when u tell it to, so u will have
to tell it often.
another solution, which i have used, is to multitask within an application
itself. you can install things to be done in the background which take
place at each vertical blank interrupt (VBL). this works well for things
like disk formatters, and (in my case) doing lots of numerical calculations
while you go off and do something else. i had written a program to generate
and edit digital audio samples, and i used each VBL to do the sample
generation. the tradeoff involves how much work to do during the VBL
before things like mouse and keyboard start getting too sluggish. in your
case, consider 1 ray/VBL as a start (or 1 pixel/VBL ?). the VBL technique
works with GEM programs, too, but you are only multitasking within the
application, so when u quit, the renderer goes away, too. you should be
especially careful to clean up properly (de-install the VBL routine) when
the application quits. i can't remember whether u can call XBIOS/BIOS/GEMDOS
during a VBLANK. maybe someone can answer this (for me, too)?
you will be rendering to memory and not to the screen, of course.
you can find MiNT at atari.archive.umich.edu (terminator) as well as the
library to roll your own VBL stuff. look for vbi*.arc or vbl*.arc for the
latter. i think the VBL stuff is there, if not i can mail it. i think it
was also posted some time ago.
sounds like an interesting little project. i hope this helps...
-bill
rosenkra@convex.com
--
Bill Rosenkranz |UUCP: {uunet,texsun}!convex!c1yankee!rosenkra
Convex Computer Corp. |ARPA: rosenkra%c1yankee@convex.com