Several experiments with flash pixel bender kernels and neuroscience math.
First is the 2D grid of coupled neural oscillators ( the neuroscientific equivalent of usual coupled oscillators descripted by some differential equations. Nice example is a double pendulum on youtube ).
So every pixel behaves like an oscillator and gives its energy to neighboring pixels. I’ve decided to store the energy in alpha component of 32 pixel.
On every render action, I’m stripping this alpha component and showing only 24 bit pixels:
mainBmp.bitmapData.applyFilter( mainBmp.bitmapData , mainBmp.bitmapData.rect , pt , shader );
bufBmp.bitmapData.copyPixels( mainBmp.bitmapData , mainBmp.bitmapData.rect , pt , null , null , false );
The last argument of copyPixels function tells flash to skip the alpha component. “shader” ( last argument of mainBmp’s applyFilter ) is the pixel bender filter.
This is the .as source: sine_pixel.as
And this is the kernel source: neur.pbk
Compiled kernel: neur.pbj
CLICK to see online simulation. Pretty cpu demanding, but it’s 256×256 oscillators grid. Click and drag on the stage like you were drawing, to start oscillation ( in the beginning the grid is synchronized ).
This is how it behaves in pure actionscript( flash player 10 needed, because I’ve optimized it using the Vector class ): sine_waves.swf … it has lower resolution though, 100×100. ( source )
The big resolution version ( 512×512 ): sine-hi.swf. CPU burning shader. I didn’t optimize it too much, maybe something can be changed to speed it up even more.
Ok, so that was the oscillation. There’s one more thing – grid of Sodium-Potassium neurons from previous post. I wanted to check if it’s going to be faster with pixel bender. And indeed – it is.
This is the source . I’m simulating current and the neuron response:
mainBmp.bitmapData.applyFilter( mainBmp.bitmapData , mainBmp.bitmapData.rect , pt , shader );
vBmp.bitmapData.copyChannel( mainBmp.bitmapData , mainBmp.bitmapData.rect , pt , BitmapDataChannel.RED, BitmapDataChannel.RED );
nBmp.bitmapData.copyChannel( mainBmp.bitmapData , mainBmp.bitmapData.rect , pt , BitmapDataChannel.BLUE, BitmapDataChannel.BLUE );
On every frame, I’m applying the shader on bitmap. Red component of pixel is the neuron response, green is the input current and blue is the gating variable. This time, I’m leaving alpha component alone. Because of this approach, I must copy RED channel from shaded bitmap to output bitmap, to see the graphical illustration of neuron response. The same thing happens with BLUE channel, which I copy to another bitmap. This is the kernel source: model.pbk. And this is the compiled kernel: model.pbj
I don’t want to bore you with neuron model theory, if you are here, you probably know what’s this. And if you don’t, you probably don’t want to know : )
I’ve made 3 experiments. All of them are based on real-life sodium – potassium Hodgkin-Huxley model.
First one is a 2d plot of current flow. The blue line is the input current, red and green ones are the neuron’s answer to the input current. Green is gating variable, red – neuron’s voltage.
It shows, how the current propagate in neurons connected into some kind of chain.
The third experiment pictures Hodgkin-Huxley’s model bifurcations from sample vector field. It’s shown as particles propagating thourgh the vector field. Click and hold the left mouse button to shoot the particles.
That’s the little AS3 Class I’ve written. Nowadays there’s some strange trend in ripping off OSX GUI, so I’ve decided to make your life a little easier.
I’ve been googlin for this effect, but I haven’t seen anything event close, to what you can see on OSX.
So here comes this little class – GenieFX:
Click grey button-like object to see the animation.
This is the fragment pulled from demo’s source:
addChild( gfx = new GenieFx(
( new demoBmp() ).bitmapData , /* object to animate - DisplayObject or BitmapData */
150 , /* x position of genie's "tail" */
0 /* start from hidden image */
) );
You can pass a vector shape or whatever else to animate. The “x position of genie’s tail” is randomly generated after every button click,that’s why the image comes to and from different places.
Source for this demo is available for download here: http://exp.teleranek.org/proj/genie/demo.zip
The demo uses almost all functions of this effect, so you will figure out how to use it : ) It’s ultra-simple.
The class uses a bit buggy ( but free to use on commercial projects : P ) tweening lib called “Twease”, feel free to change it to TweenLite or whatever else.
You can download your decimated model and do whatever the hell you want with it.
I’ve also created a model viewer. I had to make custom pv3d camera control, because papervision3d’s Camera class has million bugs ( with rotations for example ). There are some bugs in environment mapping too, but I didn’t have time to fix them …
I wrote today a little class which converts font outlines to TriangleMesh3D objects:
Click on the image, you will se a demo. I wasn’t tweaking my code too much, so there are several bugs in this 3D fonts class. Major bug is, that glyphs like “i” or “%” aren’t rendered properly. And it doesn’t work with all typefaces, hence this demo is based on only one typeface ( helvetica bold italic ).
And don’t exaggerate with typing your own phrases in the input textbox – I wasn’t optimizing my code, so CPU usage can be high.
