ASCII fluid dynamics (2013) [video] | Hacker News Reader

ASCII fluid dynamics (2013) [video]

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162 pointstambourine_man20 comments

Looks like the algorithm is based on this:

http://en.wikipedia.org/wiki/Smoothed-particle_hydrodynamics

The theory behind it is rather more complex than the equations that implement it - which is why it can be done in such a small amount of code.

It's a similar idea to those tiny raytracers and the basis of many demo effects: a relatively simple equation, iterated many times, can produce a complex and even realistic scene.

Is that "FLUID" written in ascii in the beginning of the video the source code of this fluid mechanism?

Because he starts with a "cat endoh1.c" to show it's content and it's a valid C program.

Yes.

Now, in the spirit of personal computer magazines of 1980's, you should pause the Youtube video, type in the source code from the screenshot, and run it. Good luck.

(Us wimps, we get it here: http://www.ioccc.org/2012/whowon.html )

Yes, it compiles in to the solver and then can use its own source as the initial state. The guy who writes these (this is one of his many entries to IOCCC) is a genius!

The IOCCC page: http://www.ioccc.org/2012/endoh1/hint.html

There is also a colour version. Very cool stuff.

Here are all the files in the project, including a (somewhat) de-obfuscated version of the program: http://www.ioccc.org/2012/endoh1/

Absolutely incredbile, I love the IOCCC.

Very neat. Is this using actual physics?

In some examples, I get the feeling that the conservation of volume is not correctly modeled. And in the clock example, how can the fluid escape the hourglass?

"all models are wrong but some are useful" - George E. P. Box

http://en.wikiquote.org/wiki/George_E._P._Box

I'm not certain if volume was lost or gained, but it looked possible at some points. Some of the other modeling seemed a bit 'off' but for so little code in ASCII it was pretty amazing.

Corners probably.

Well, conservation of volume for these systems with such a large discretization would be more remarkable than its abscence, I guess.

For those interested in the color version I've made it available on my server here on the web here:

https://www.minaterm.com/endoh1.html

or of course via ssh directly here:

ssh www.minaterm.com (endoh1/endoh1)

And the musical accompaniment is ... Handel's Water Music. Of course.

I would've preferred Jeux d'eau.

If someone is interested in the de-obfuscated code take a look in the source here:

http://simulationcorner.net/endoh.html

Here's the ioccc.org page for this entry:

http://www.ioccc.org/2012/endoh1/hint.html

I can't even begin to think of how I would replicate this. Truly impressive and equally beautiful!

Upload is 2013, but the code is from IOCCC 2012!

Would be even more impressive if it were a quine instead of taking the source as input :)

FWIW the guy who made this also made that huge quine from a year or two ago: https://github.com/mame/quine-relay

Run the program on its own sourcecode, Wait til the system stabilizes, take that ASCII state as output, compile THAT, and have it be the colorized version. That's how Mel would do it.

Compile? I don't think Mel would do anything past assemble.

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