halcy.de v4

Revision 2012

Thu, 12 Apr 2012 16:48:00 GMT

The 2012 edition of Revision, a demoparty held annually in Saarbrücken (Germany), has come and gone. SVatG was there with record attendance (4 people!), and for once, we’d actually prepared something before the party, which is not something that usually happens - and this time, two releases!

Please enjoy:

Peridiummmm (A demo for the STM32F4 ARM-based µC)

[Pouet]- [Binary (Arm Cortex M4)]- [Source Code]

Blockparty 5 Non-Invitation

[Pouet]- [Binary (Windows)]

Meeting up with everyone (esp. Saga Musix) was great, of course, but this time, the best part was going to the party with people from my actual demo group, especially nrr, who flew over here just for the party! (Also, Mithaldu, who was spontaneously recruited at the party place).

Left to right: Mithaldu - nrr - ryx - halcy (with las^mercury sprinting in back)

Having finished up before the party, we of course didn’t party code any super dumb party prods filled with ridiculous jokes, a practice we at SVatG despise.

Finally, my favourite release from the party:

Boogietown by Ghostown & RNO

Overall, kickass party, hope to be there again next year. For me, the next party will most likely be Evoke, though I would really, really like to go to Assembly this year and see WAHa_06x36.

Stallman Box

Tue, 24 Jan 2012 21:03:00 GMT

<halcy> Oh I know what you should make
<halcy> WAHa_06x36: Make a STALLMAN BOX
<halcy> WAHa_06x36: Like a buddha box except it displays cool 
        saint ignucius effects and it plays the free software 
        song

And then I went and made it myself.

It is, of course, free software. You can find the source code on github. Users of GNU/Linux are assumed to be capable of compiling it themselves (It pretty much works out to “run make”, needs SDL and freeglut and glew). GNU/Linux graphics drivers are usually proprietary and sometimes terribly buggy, so it might or might not work.

For Microsoft Windows, there is a binary version.

Download:

(It requires a relatively new version of OpenGL to actually run, sorry about that)

Some audio and png code taken from WAHa_06x36 - thank you!

Down time

Thu, 20 Oct 2011 21:40:00 GMT

halcy.de was down due to unforseen motherboard breakage. Suprisingly, some people actually noticed this. The motherboard has been switched out, so halcy.de is back in working condition now. Welcome back. :3

Rendering images for viewing on the 3DS

Sat, 26 Mar 2011 01:59:00 GMT

So I got a 3DS, and after noticing that it uses an open format (“mpo”) for storing 3D photographs, I needed to play with that, of course.

As a result, I now have a version of my simple raytracer that can render a left and right image, which can then be combined into one stereoscopic 3D image for viewing on the 3DS with software such as this (It runs under wine).

I’ve rendered two small scenes, a 4D julia set and a trefoil knot of spheres! They look kind of neat, so if you have a 3DS, put them on your SD card in the picture folder and have a look!

(If you don’t have a 3DS, you can still look at them as if they were normal jpeg images, because they really are jpegs with some added exif data)

P.S.: My friend code is 0473-7758-5435~ feel free to add me~

"Releases" page updated!

Thu, 03 Mar 2011 00:34:00 GMT

Four new entries and live videos have been added to the “releases” page, amongst them my favourite SVatG release thus far, “It’s 1975 and this man is about to show you the future”!

Check them out!

Find ich gutt.

Sun, 27 Feb 2011 02:40:00 GMT

In the same vein as the fake twitter pages: Automatically generated pro-guttenberg facebook comments: Find ich Gutt!

(If you don’t know what this is about: Germany’s scandal-plagued defense minister must step down)

Source code, horribly inefficient.

(P.S.: The design of that page is the greatest work of art I have ever created.)

Paper: "Optical Coherence Tomography"

Sun, 27 Feb 2011 02:18:00 GMT

I wrote a paper for a proseminar at uni. Now that it is graded and got a decent grade, it is okay to publish it, I guess~

It’s an introduction to a medical imaging technique called “Optical Coherence Tomography”, OCT, for short, which enables us to create high-quality sub-surface images of tissue, we can essentially see “through” things and create 3D cutouts of samples. It’s fairly new and pretty neat. If you are interested about this sort of thing and/or the physics behind it (Low-coherence light and low-coherence interferometry / white light interferometry), it is probably a decent read~

Fake twitter pages.

Tue, 07 Dec 2010 22:05:00 GMT

So I had the idea to generate fake twitter pages from a users old tweets. I wrote a bunch of Perl scripts to do just that. It worked out well.

The process essentially consists of four steps:

Acquire a users tweets.
Train a fourth order markov model with those tweets.
Generate new tweets by having the markov model spew out new chains.
Generate a twitter page from those tweets.

Except for the last step, I’ve written scripts to do this. (Writing one for the last step wouldn’t be hard, but boring, and it’s easy enough to do by hand)

Step 1: Obtaining tweets.

Essentially, it’s a loop that gets the tweets via twitters api, page for page. Simple enough. The only real problem is twitters rate limiting, so grabbing more than one user per hour does not work.



#!/usr/bin/perl

my $max_page = 200;
my $start_page = 0;
my $user = "username";

for( my $page = $start_page; $page < $max_page; $page++ ) {
        my $cmd = "wget http://twitter.com/statuses/user_timeline/$user.json?page=$page -O - >> tweets.json";
        `$cmd`;
}

Step 2 and 3: Training and generating.

This script takes json as output by the script in step 1 as the input, and outputs generated, fake tweets, one per line.

Since I was too lazy to implement a markov chain myself, I used a library off CPAN to do the heavy lifting.



#!/usr/bin/perl

use JSON;
use Encode;
use Algorithm::MarkovChain;

# Parse JSON
my @tweetsJsonA = <>;
my $tweetsJson =decode_utf8( join( "", @tweetsJsonA ) );
$tweetsJson =~ s/\]\[/,/gi;
my $tweets = decode_json( $tweetsJson );

# Train
my $user = Algorithm::MarkovChain::->new();
foreach my $tweet (@{$tweets}) {
    my @symbs = ("START", split( " ", $tweet->{text}), "END" );
    $user->seed(
        symbols => \@symbs,
        longest => 4
    );
}

# Generate 20 tweets
binmode STDOUT, ":utf8";
for( my $i = 0; $i < 20; $i++ ) {
    my @generated = ("START");
    my $l = 1;
    while( $generated[-1] ne "END" ) {
        @generated = $user->spew(
            length => $l,
            complete => \@generated
        );
        $l++;
    }
    @generated = @generated[1..(@generated-2)];
    print join( " ", @generated ) . "\n";
}

Step 4: Generating a fake twitter page.

This consists of two parts, making the tweets into twittery html, and adding what comes before and after the tweets in a twitter HTML page. For the former, I wrote a small script, again, which mostly just concatenates text a lot, I put it here if you want it (Save as “mktwpage.pl”).

The second part, I’ve done by hand, thus far, assisted by my browsers “Save page” feature. Too lazy to automate.

And, there you have it: Autogenerated fake twitter pages. Halfway convincing, too. Go generate your own!

Modern OpenGL

Mon, 06 Dec 2010 01:00:00 GMT

Something I sort of completely forgot about.

At the GulaschProgrammierNacht 10 - the entropia ev/CCC Karlsruhes annual hacker event - I held a talk about modern OpenGL. While the talk itself wasn’t held very well (I rushed through everything aaaaaaaaah oh god), the base material is, actually, a pretty okay introduction to modern OpenGL - without fixed function pipeline, as it should be.

You can download the english version of the slides here, and - probably more interestingly, can grab a copy of the demo program I made, which is very well-commented and does nothing but simply render a rotating cube, as seen below.

If you’re the type that learns best from examples, have a look.

Also, if you need more writing and explanation, have a look at Joes blog, where a longer explanation of basically the same thing is provided. :)

(Additional links to a video recording of the talk [german] and german version of the slides after the image)

Has multiculturalism failed in germany?

Sat, 23 Oct 2010 00:14:00 GMT

(Warning: What follows is a somewhat long political rant.)

So, since I am german, I get asked what I think about multiculturalism in germany a lot, recently, because of some ridiculous remarks made by our chanellor earlier this month.

As you might have guessed from that itroductory paragraph already, I do not believe that what Merkel said holds and water at all, and I find such claims detestable and damaging to not only germanys reputation in the world.

Merkel and her right-wing social-convervative party buddies are framing an issue that is primarily one of social inequality in education - rich parents, good education, poor parents, not so much - as a “culture” issue. This is quite obviously bullshit, as you can see by looking at your average poor neighbourhood - there’ll be just as many kids with german parents as not, all similiarily bad in school.

The reason for this is, as I (And as most students and teachers) see it, our highly selective school system where kids are seperated into three schools based on pretty much one teachers opinion at age 8 to 10. Since that age is far, far too young to be able to actually tell anyones ability at anything much, this ends up basically selectiong by social status. I’ve seen this happen live and in colour with a friend of mine getting sent to a more vocational school while I got to go to the more academic one - with us both having the same grades. On the other hand, in the school I later went to, there were people whose parents had immigrated, but had managed to make some money - some of them dumb as fuck, some really smart.

There’s also notoric underfunding of the more vocational schools and of schools in “bad” neighbourhoods, and the fact that in some states you now have to pay a lot of money to go to uni, which - as studies have shown - further discourages someone who is poor from going to uni. All in all, our educational system is set up so that the result is that for the most part, people who are poor, stay poor.

Those are all issues students have been protesting about for years. These are all issues Merkel and the CDU have been ignoring or, in some cases, been making worse.

These are very much issues that happen to affect first-gen immigrants kids - being a first-gen immigrant happens to coincide with being poor as fuck a lot, since rich people do not generally emmigrate from their home county to germany to do shit jobs for little money - they are, however, not issues of “culture” - and framing them as such only serves to isolate, which is horrible.

All these things coming up close to elections (BW state elections, in polls for which the CDU is doing very badly right now) makes me doubt Merkels honesty here - I simply cannot see this as anything else but a grab for votes from the people who are still afraid of brown people and the kind of persons that are enraged by a mosque with a minarett higher than the local churches church tower. It’s a subtle playing of the racism card in a way that makes it hard to call anyone out on it, but that really is what it is.

It’s detestable and stupid, and it makes me feel ashamed of living here that it seems to be working.