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Break down of a C64 demo effect

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Re: Break down of a C64 demo effect

#21

Post by pjmlp »

panic wrote: post #9
jacquesm wrote: post #5

Earlier quoted context omitted.

> 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.

The great thing about the C64 is that it never changes. It's the same hardware as it was last year, and it'll be the same hardware next year. Modern systems have plenty of unreasonable constraints, but the foundations are always shifting. How many cool web hacks from 5 or 10 years ago will run unmodified on a modern web browser?

You just described why game developers prefer to target consoles.

Re: Break down of a C64 demo effect

#22

Post by bostik »

userbinator wrote: post #14
jacquesm wrote: post #5

Earlier quoted context omitted.

> 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.

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

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

Re: Break down of a C64 demo effect

#23

Post by bnastic »

asciimo wrote: post #4

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

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”)

Re: Break down of a C64 demo effect

#24

Post by bnastic »

jacquesm wrote: post #5
burnte wrote: post #2

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.

> 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.

> If you had been alive and busy with computer programming back in the day you too would have been clever as hell.

Don’t underestimate the power of internet today and the ease of obtaining information - that certainly was not the case in the ‘80s. Unless you were close to demo groups you were left with two choices: a) reverse engineer the code (good old “Monitor 49152”), or b) give up

Re: Break down of a C64 demo effect

#25

Post by keyle »

bnastic wrote: post #24
jacquesm wrote: post #5

Earlier quoted context omitted.

> 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.

> If you had been alive and busy with computer programming back in the day you too would have been clever as hell. Don’t underestimate the power of internet today and the ease of obtaining information - that certainly was not the case in the ‘80s. Unless you were close to demo groups you were left with two choices: a) reverse engineer the code (good old “Monitor 49152”), or b) give up

That's true. With no internet and only a crappy book, my use of the ZX 80 was pretty poor compared to what I would have mentally capable of doing, if I had access to further knowledge.

Re: Break down of a C64 demo effect

#26

Post by digi_owl »

userbinator wrote: post #14
jacquesm wrote: post #5

Earlier quoted context omitted.

> 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.

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

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

Hand animated cartoons would often used that trick as well.

The anime Bubblegum Crisis used a massive cityscape painting for their panning shots.

Re: Break down of a C64 demo effect

#27

Post by eb0la »

EvanAnderson wrote: post #15

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…

If I remember well to overcome flicker with custom Character you has to wait for vsync.

I don't remember what esd the port for that, somethin un the 4p sets... except if you wait for VSYNC like if you were usibg a double framebuffer.

Re: Break down of a C64 demo effect

#28

Post by StavrosK »

userbinator wrote: post #14
jacquesm wrote: post #5

Earlier quoted context omitted.

> 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.

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

I'm not so sure how simple the example you mentioned is. I've seen it many times and I'm still not sure how I would generate the source image.

Re: Break down of a C64 demo effect

#29

Post by vardump »

digi_owl wrote: post #11
cromwellian wrote: post #10

Earlier quoted context omitted.

Yup, constraint = hack/freedom is one of the paradoxes as long as there are hidden degrees of freedom that can break the constraints. Here’s some old c64 intros I did, including a trick of bank switching to fake z ordering of fonts and sprite scs rasters, as well as using FLD to stabilize rasters in the presence of moving sprites in both PAL/NTSC modes. https://youtu.be/aViXXbUg_yU

I think it may be less "constraint" and more "fixed platform". Meaning that every C64 was like very other C64, so you knew what you had to work with on the hardware side. You could see this with consoles as well, as the games steadily improved as developers learned how to push that fixed hardware around (though the cartridge ones often allowed in-cart chips to assist). I guess we have gotten so incredibly used to eit…

> Meaning that every C64 was like very other C64, so you knew what you had to work with on the hardware side.

Well, other than:

1) PAL vs NTSC systems. True compatibility breaker.

2) Two different versions of SID sound chips (and every SID being more or less unique)

3) Different VIC-II versions (or at least some chips where VSP (variable screen positioning, a fast method for horizontal scrolling) works and some where it doesn't)).

Re: Break down of a C64 demo effect

#30

Post by wiz21c »

keyle wrote: post #25
bnastic wrote: post #24

Earlier quoted context omitted.

> If you had been alive and busy with computer programming back in the day you too would have been clever as hell. Don’t underestimate the power of internet today and the ease of obtaining information - that certainly was not the case in the ‘80s. Unless you were close to demo groups you were left with two choices: a) reverse engineer the code (good old “Monitor 49152”), or b) give up

That's true. With no internet and only a crappy book, my use of the ZX 80 was pretty poor compared to what I would have mentally capable of doing, if I had access to further knowledge.

Cleverness could express itself in the way you actually gathered documentation... Back in those days, it was really tough to get any. For example, I was out of the scene. So I decided to create a disk magazine to talk bout the scene, hopefully getting in contact with it. That's exactly what happened and a s a result of that, I got access to one marvelous piece of software I couldn't write by himself : a MOD player (included with SoundBlaster DMA access which was very hard to code)...
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