pouët.net

baah: ive regrouped them a bit more. im not sure if i have the time to explain every effect at this time. however if i begin the work, i will post here sooner or later.

thanks for all the positive feedback.

latest update: http://www.home.no/rudibs/dox/demoeffects%20list.txt

Well it's really a hard work to try to classify demo effects! I think it would be easier to stick to only one category of effect where one has a clear idea of what is going on (eg scrollers, sprites, 3d...) and try then to explain/show different techniques...

Anyway thanks doing/improving such a list.

picture morphing (e.g. credits part in iguana-heartquake). also the pseudo-3d wobble-morph in that demo is quite nice (how is that done anyway pixel-by-pixel?)

baah: you're right. first its better to just write down all the effects. i tried categorizing them while doing just that, but as the list gets longer i guess some of it will be changed in time.

maali: noted down.

i need someone who can explain to me what category to put these effects:
laser effect, hypnoglow, strobo, fluffy, wolfram

Maali: if you mean that rubber vectors, those are not pixel by pixel but probably just texturemapped and the corners are some kind of string-physics, i would guess that.

glitch art effects.. such as in dessert dream when the blade cuts into the screen.

Now you said Iguana, I remember "rubber vectors/physics" (Heartquake)
Also, cloth simulation (maybe not oldschool, appeared in Robotnik/Rage)

Where snowflake, fractal-tree, fern fractal, serpinsky?

?Wolfram? is a Mathematician, author of Mathematica and also of the www.wolframalpha.com "search" engine. The only way i think his name can be associated with demos is through 1D cellular automaton which he studied quite extensively, and claimed to have found one which is a Turing machine...

@BiTL: Fern fractal is IFS (Iterated Function System) and the other can be classified this way too, though for Sierpinsky and Von Koch's there exist many way to produce way (eor, grammar...)

... to produce THEM (...

heres another effect
idk the name of it (maybe someone can give it to me? :)

What is the name of these kind of polar effects?
I used to call them polar plasmas but maybe they are called whirlwinds or something?
How about the one with a texture (bill gates rotated head)
Are these effects already in the list under another name I don't know?

And the effect from Cobalhext.
I have seen it in few demos.
The formations look similar to fluid dynamics, but they are a different algorithm, I am sure because I have seen them in older demos and because the patterns are more regular.
And how is it done?

well i forget the exact name, but the bottom one i think is a water effect

they're also just called plane deformations
heres an example of the second one (fewer flares)
http://www.chromeexperiments.com/detail/plane-deformations/

Not sure about the following, but:

@Optim(o)us(e): it's probably only a kind of tweaked mapping/conversion from polar to cartesian coords. I think ruderudy categorised them under Freedir.

@Cobalthex: And your snapshot looks the same but repeated over a grid.

There's also a kind of "fractal zoom" which used, afaik, only translations of tiny blocks. First time i saw it was in a 40k by Virtual Dream. Another example by MentASM:
http://pouet.net/prod.php?which=18270

opti: the one in the middle i think was called flower effect. but all of those are sin/cos lookup-table effects with or without polar coordinates.

baah: No. The CobaltHex thing is like a map storing the movement direction and velocity per pixel and then moves pixels per frame according to that, so the image appears to flow and twirl on the screen.
Forgot what it's called though, too...

baah: looks like it may be brownian zoom. those irregularities looks a bit random. ill add it to the list.

Maybe the original for chaoszoom/fractalzoom/brownianzoom whatever it's called, by Virtual Dreams. 1993 is the date, so not that oldschool! (Ok, i'm growing old... :)
http://pouet.net/prod.php?which=51862


@ruderudy: afaik you're right. Garry copper told me the very important thing was the way the translation table was created, and that there was a small randomness included in it.

@RareWtFailWhale: thanks, but probably it's better to tell, for each pixel of the destination screen, where to get the source pixel instead of the other way? Anyway it can probably be put in a plane transformation category?

here's another one in a mobile demo called Crime minister of europe by katastro.fi:

From 1963
http://www.youtube.com/watch?v=BKM3CmRqK2o
At 6:21 - Hidden lines with polygon overlap-cut
At 4:22 - Raypicking / reverseprojection

Respect!