i knew i wasn’t going to be able to make it out to pixelj.am 2012 but i at least wanted to contribute an entry to the demo compo.  i asked basementdigital to see if i he’d be up for doing a tune.  we’d been wanting to do a demo together for yeaaaaars so finally made it happen!  with only a few days i thought it’d be fun to try doing a browser demo with javascript and planned to do it friday before the party on the weekend.  it was like wednesday night after basementdigital sent me the track he made that i found out remote entries were actually due the following morning!! yikes!  i loved the tune he did and couldn’t let him down so stayed up to quickly put together the code and visuals for our entry.

it’s a browser demo so the code is in javascript though i actually wrote it in coffeescript which then compiles to javascript.  i had coded demos like n-0505 and the blockparty invite in python so it was great to find coffeescript and replace a lot of the wackiness of javascript with something cleaner and more familiar feeling.  the 3D is hardware accelerated with webgl (so requires a newer browser like google’s chrome to view) and uses the sweet three.js library by mr. doob.

since i only had some hours i kept things very simple and used only colored lines for the whole thing.  the letters and symbols are rendered also as lines and are glyphs from the hershey vector font.  i had fun just typing in wacky equations to get some motion then semi randomly tweaking until i’d get a nice happy accident that looked nice to me.  each of the scenes was done that way.  for sync with the audio i used the time honored technique of hitting a button on the keyboard each time i heard something interesting in the audio and gathering up all those time offsets from the debug console to toss into the code.

i like how it turned out in the end.  very short and simple but pleases my eyes and ears.  i hope you like it too!  you can watch it on vimeo or youtube or even better run it directly in your browser!  if you have a pouet.net account be sure to rate and leave a comment!

this year i’ve been working on the next version of demo studio. so in brief, version 1 (tokyo, mudballs, ccc) was your typical drop effects into a timeline and edit the parameters, version 2 (hofn, sokuseki) had more powerful sync and scripted effects, version 3 (n-0505, blockparty invite) was entirely code driven with pop-up ui only for tweaking. with version 4 i hope to get the best of both worlds between artist/designer support with ui but without sacrificing the handcrafted codery goodness that comes from not having ui.

with lots of the core of the new system done now i can get things animating and syncing to music. here’s one of the quick tests from this weekend and a peek at the ui showing how it was done. the music is from Zardonic’s remix of Nine Inch Nails Ghosts track 35.

so i gave video strokerization a try and it turned out pretty cool. here you can see the nine inch nails march of the pigs music video strokerized:

for this i told strokerizer it could only paint 64 brush strokes each frame so it didn’t get much chance to fill in fine details with the camera always moving around like crazy. it wound up making for a nice loose look.

on the code side i managed some more optimizations and am finding my way around nVidia’s CUDA visual profiler pretty well now. my laptop’s 9600M GPU gets completely pegged now which is great. on my desktop the GTX280 though is just too fast that it’s still finishing work faster than the CPU can feed it. i think i’ll have to move more parts of the algorithm over to the GPU to fix that.

so previously i blogged about my glypherizer experiment to approximate images with a small number of font glyphs. unfortunately it didn’t meet with the fantastic success i had hoped. the ideas were still a bit itchy though so i wound up working some more on it. this time around i used images instead of font glyphs so they could be brush strokes or other crazy stuff in addition to text. also i rewrote the code in CUDA so it runs on a 240 thread GPU instead of a measly 8 thread CPU. here you can see some of the strokerization tests:

you can see more of the full set on flickr if you like. thanks very much to kirill for the library of cool brush strokes!

this was my first real CUDA app and i was surprised just how quickly i was able to port everything over to GPU kernels. so getting it running on the GPU was pretty easy, but what turned out to be harder was making it fast. i had to optimize my kernels to reduce the register counts they needed quite a bit and use nvidia’s occupancy calculator spreadsheet thing to work out good block sizes and thread counts. that along with using the async stream API helped get the speed about where i expected but i still think there are some things holding it back. i can’t wait for more performance tools for tracking this stuff down.

some time back i was experimenting with some procedural animation and simulation as part of researching how i could animate a creature for a future demo. i didn’t really achieve what i was wanting but i had a lot of fun playing around with it and giving some life to a bowl full of worms. here’s a video capture of them in action:

anyway, when kirill saw the worms he got excited and suggested that he could cut out the top of the fire skull so we could use it as the bowl for the worms. after that we decided we also needed to cut out the eye sockets so the worms could wiggle and drip out of the eyes! this was, as you may be able to imagine, entirely too much fun! i hooked up a hot key so we could drop worms into the skull and another to rotate the skull back and forth and we had ourselves a great little toy. here you can see it in action:

finally for fun we did some offline renders of it:

i’m not sure what the future holds for the skull worms. maybe a halloweentro is in order.

i was trying to make some cool stuff out of text glyphs and kinda failed. i thought: wouldn’t it be neat if i could reproduce an image using a small number of glyphs from wingdings or even a regular font? i’d only need to store the quantized position, rotation, scale, the glyph itself and some color.

so i wrote a nicely threaded program to churn through the possibilities and find me some nice glyph placements. it uses the simulated annealing meta-heuristic so i could be lazy and just tell it how close it is to the target image and let it figure out for itself a good path to the minimum error.

unfortunately the results are not the coolness i was hoping for. i think packing of glyphs without overlap is much cooler in the end. with all the overlap it looks like a jumbled mess! okay here you can see what i’m talking about:

my first iphone app has made it’s way to the app store! just search for “plasma effect” to find it in the store (or click here to open in itunes directly) and download it for free! the app is a modern implementation of the old school demoscene plasma effect. while running you can touch the screen to interact with the plasma and shake the iphone to switch color palettes and plasma shapes.

i used x-code to develop it and did the implementation almost entirely in C. i dipped into the objective-C code only to plumb through the touch and accelerometer values. while i’m sure objective-C is quite nice once you get used to it i just really had no desire to teach my brain to parse it’s wacky notation. here’s the simple api between the obj-c code and the plasma effect:
void EffectCreate ();
void EffectDestroy ();
void EffectRender (float time, float accelX, float accelY, float accelZ);
void EffectShake ();
void EffectTouchBegin (float x, float y);
void EffectTouch (float x, float y);
void EffectTouchEnd ();

the effect itself works by adding three layers of waves (recomputed only when you launch or shake) and looking the wrapped result up in a 256 entry color table. the top layer has perturbed radial waves that come out around where you touch with your finger. to smooth out some of the artifacts from the low precision waves i blend a bit with the previous frame. the plasma is all done on the iphone’s cpu then rendered on a single quad to the screen using open gl es.

making it was quite fun and interesting since i haven’t hobby coded for an apple platform in 19 years! and wow have they come a long way since the apple IIgs! if you have an iphone or ipod touch give it a try! i’m hoping to see more fun demoscene content on this cool platform.

gloom, kirill, and i have released our invitation demo to blockparty 2009! you can visit pouet.net to comment on the demo or watch it online at vimeo or capped.tv. hope you enjoy it!

blockparty 2009 invite from blackpawn on Vimeo.

not long ago i was tackling again the problem of getting nice sync between visuals and audio and tried a bunch of different things. i made this tool to make manually syncing pretty efficient. it shows you the waveform or amplitude or other visualizations and you draw a curve on top of it with some nice controls for duplicating points and stuff. that still took much too long so then i tried some stuff with rendering out fft and other data to images and using graphics stuff i was more familiar with to process them. here’s a pretty bad example of that.

anyhow what i wound up finding and using for the demo n-0505 is an awesome web service called echonest. it’s crazy. you upload your mp3 with the music and it analyzes it for a bit then you can download xml data with tons of info you can sync to. the most useful by far is some data that tells you essentially how many beats per minute and the time of the first beat. that’s covered like 99% of syncing for me as i set absolutely everything to start on beat indices or pulse with waves centered at the beats and things like that. suuuper simple!

i’ve been gathering up spare life seconds to experiment with some new procedural geometry
and fancy rendering. here are some highlights if you’re interested: