
Break down of a C64 demo effect - nurpax
http://nurpax.github.io/posts/2018-06-07-c64-filled-sinewave.html
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burnte
David Murray, the 8 Bit Guy on Youtube, he doesn't have the best delivery but
he's a fascinating watch with a lot of his videos. His favorite is the C64 and
has done some amazing videos about the hardware and history, etc, and has
talked about how various tricks like this work. It was an amazingly capable
machine, and the folks who exploited every little aspect were/are clever as
hell.

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jacquesm
> It was an amazingly capable machine, and the folks who exploited every
> little aspect were/are clever as hell.

If you had been alive and busy with computer programming back in the day you
too would have been clever as hell. It was the only way you'd get anything
done and if there is one thing that will bring out the hacker in people it is
a bunch of unreasonable constraints and a job that needs to be done anyway.

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userbinator
A lot of demo effects are almost like magic tricks --- before you understand
how they're done, they seem like impossible magic; but once you do, you think
"that's so simple, why didn't I think of that?"

Animation by essentially "panning" inside a larger pre-rendered image is one
of those tricks:

[http://norecess.cpcscene.net/the-elders-
scrollers.html](http://norecess.cpcscene.net/the-elders-scrollers.html)

~~~
bostik
Old-school demos have another common trait with magic. Like the best stage
magic, you _know_ you are being fooled - but even after seeing how the trick
is done, you remain amazed by it.

The best one I have seen: Cubase-64 [0]

0:
[https://www.youtube.com/watch?v=artEQkifGG0](https://www.youtube.com/watch?v=artEQkifGG0)

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EvanAnderson
VGA has redefinable character sets. I tried doing some animation with them
back in the day, but I ran into some kind of limitation that I don't recall. I
was trying to accomplish an animation effect by altering the character
definitions in realtime, which I recall being very slow. It never occurred to
me to do something like this. Now it'll be everything I can do to stop myself
from trying this on an old PC! Goodbye weekend productivity!

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bitwize
Redefining the character set was how some text-mode programs like the old
Norton suite got "graphical" mouse cursors and the like.

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dwd
As someone who spend half their teenage years drawing on graph paper creating
custom character sets for use with graphics and large sprites, this is a
pretty cool and novel way to do an animation.

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floatingatoll
I loved this writeup, original author of it, whenever you see these comments.
Thanks for writing this up.

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nurpax
Thanks!

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asciimo
Clever stuff. I like that the author used modern techniques (python) to
generate the custom C64 character set.

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bnastic
That was usually the case “back in the day”, people would use their Amigas and
Ataris to prep work - I’d use my Atari ST and GFA Basic to generate all sorts
of lookup tables which was too tedious to do on the C-64 (esp. if all you had
was a “datasette”)

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babbit999
Old schooler here, mainly Amiga 500. If you want to drown in old and new c64
stuff, visit:

[http://www.cascade64.de](http://www.cascade64.de)

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scottlu2
Nice demo. Reminds me of a well done Galaxians clone for Atari 400/800 that
used programmable character set animation for the aliens. It was impressive.

~~~
bitwize
Fun fact: The Commodore VIC-20 lacked hardware sprites, so programming the
character set was how you did any animation on it. There were still some
pretty amazing games given that limitation.

