NetNews Usenet Archive 1992 #27/NN_1992_27.iso/spool/alt/sys/amiga/demos/1759

Internet Message Format | 1992-11-22 | 2.7 KB

Path: sparky!uunet!vtserf!csugrad!franklin
From: [e-mail] (John Franklin)
Newsgroups: alt.sys.amiga.demos
Subject: Re: Writing a StarField. Which method is best?
Message-ID: <[e-mail]>
Date: 22 Nov 92 14:47:13 GMT
References: <[e-mail]> <[e-mail]> <[e-mail]>
Organization: Virginia Tech Computer Science Dept, Blacksburg, VA
Lines: 40

In article <[e-mail]> [e-mail] (Osma Ahvenlampi) writes:
>I said:
>>> Well, there's a easy way of getting sure 50 (or 60) fps without turning off
>>> the interrupts. Use them yourself. Make them high priority ones, and nothing
>>> can stop you from having all the time you want, while the system is running
>>> (well, would be if there's time) in background. If you don't mess with the
>>> copperlists yourself, but use Views for that, you can even switch back and
>>> forth applications... Now all this is unnecessary on a A500, as all the time
>>> is probably used anyway, but what if you have a 25MHz 68030? A lot of time
>>> is left unused, and could be used your something else, provided you don't
>>> do the blitter waiting in busy loops... There are ways around that too.
>
>In article <[e-mail]> [e-mail] (Mats Anders Knip) writes:
>>You do have a point there, but you are forgetting one thing: we are
>>talking demos here, not utilities - and demos aren't usually run
>>in the background. A demo is lika a movie - when you watch a demo
>>you watch the demo and do nothing else. You don't need multitasking in
>>a demo. Switching off all interrupts is perfectly fine in a big demo
>>(especially as a bigger demo usually loads via trackdisk from boot...)
>>as long as you reset the old pointers in the end (naturally...).
>
>The display switching just comes as a byproduct, the big thing is that,
>provided enough power, you can watch demos and download new ones at the same
>time. Even if YOU don't do anything else while watching a demo, you might wish
>that your computer does.

I'd tend to agree with you on that point, it would be nice to be dl'ing
another demo (or fonts or whatever), or doing some other meanial,
non-interactive task while watching a demo.  However, most demos are not
stable enough that I'd want to try it.  Besides, if a demo starts pulling
down time at just the point when something else (say a comm program) wants
time to prevent overflowing buffers or send an ACK, odds are the task is
going to die.  The more stuff, or rather, the more stuff*demand that you
have on a multitasking machine, the more likely it is to die.

jf
--
John Franklin
[e-mail]
[e-mail]