zero point nine

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How it would look if you took a webcam or camera, and captured several frames of the same scene in quick succession, and then essentially averaged them out and composited them into one image? My guess was that the resulting image would retain most of its sharpness but lose most of the ‘noise’. I made this quick mini-app with that thought in mind.

Here is an example of my results (before and after). The images were captured with a Logitech Quickcam Pro 9000 at a resolution of 1600×1200 (averaged from 128 (!) still images), and were not scaled or retouched (just cropped).

As a side benefit, if the camera — or something in the foreground of the scene — moves during the image capturing process, you can get photography-like effects that look like a long exposure…

A PNG48 encoder class…

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(A more descriptive but less catchy title would’ve been “Serializing and deserializing value objects with ByteArrays using AMFPHP, PHP, and MySQL.” But that’s ok.)

As we are now in the year 2009, for some reason you feel like there ought to be a way to take your cool shit, send it over the wire and get it back again, without having to resort to 99 searches on Google, a trip to Barnes & Noble for a stack of books with ugly green covers and stupid illustrations of birds and salamanders, and a spare weekend you’d be doing nothing better with anyway. Your cool shit’s in Flash, most likely, and it’s not just text data, presumably, so by a process of elimination we conclude that your shit — not of a lukewarm nature by any means — is most appropriately represented by a series of ones and zeros — in binary format. And that you want to get it on the database. ‘Cuz you can’t create the next viral sensation if you can’t get your cool shit to the database, now can you?

And while many prosaic and generally annoying 3-to-4-letter acronyms exist for the transmission of information across the proverbial ‘series of tubes,’ unfortunately, most of them are founded on that most old school of information encoding conventions: the alphabet. (But if it’s in UTF format, maybe we can be a little more forgiving and call it “Alphabet 2.0″). Sure, you could do something like MyCoolAssStaticUtilitiesClass.convertMyCoolShitToBase64($o:Object), but nah, fuckit, it’s the year 2009 damnit, and you’d think there’d be an easy way to take your data – made on a computer – and store it – again, on another computer, without having to first convert it into “human-readable text,” whatever the fuck that means.

Furthermore, if your shit’s actually as cool as you say it is, we must be talking about something that’s not just a single block of binary data like an bitmap, oh no, but a complex data object, full of mixed primitive types, maybe some untyped objects and an array or two, other value objects nested inside of them, and _then_ maybe an image or two. But the main thing is, it’s stuff that you want to just dump into a field in a database record, and get back, without the extra drama of converting to and from XML with a couple extra hundred lines of code…

Anyway, presented here are the important points I learned about using AMFPHP with ByteArrays and VO’s while starting on a new project/experiment thing involving user-generated character animations of 3D models, which naturally involves lots of binary data and complex data types.

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A demonstration of splitting a mesh in two along an arbitrary plane. With some faux-physics for added value. I was thinking about the ‘laser room scene’ in Resident Evil, LOL.

I’ve included the source code of a minimal example showing how to cut up the faces of a mesh along a plane:

PlaneSplitMinimalExample.as | compiled swf

This is the foundation for everything in this demo, and for the following ideas which I think would be nice to see executed in Flash–

Make sure to try resetting the scene, pausing (with spacebar), clicking through a mesh several times, and then unpausing..

Oh yeah, and the usual disclaimer/apologies about how much this demo hates your CPU, and how unoptimized it is (e.g., right now every face in the scene is tested against the plane with every click (ouch!)). Built with the most recent revision of Papervision 3D.

Also, apologies for the long hiatus.

UPDATE: John Lindquist has kindly pointed out there’s already a helper function in the Papervision framework for cutting meshes with planes! – MeshUtil.cutTriangleMesh().

Licensed under a Creative Commons Attribution 3.0 License.

Recently I’ve been thinking on ways of programmatically creating curvy and strange, organic-looking shapes in 3D. And reflecting on the fact that I can think of no particular ‘practical’ application for such an endeavor. And concluding that that’s part of what makes it interesting…

Here’s the high-level recipe:

Start with a cylinder or sphere-shaped mesh, where the vertices are evenly spaced . The vertices of the mesh can be thought of as a matrix or grid, where the left and right edges are curved 360 degrees until they meet.

Take an interesting bitmap with varying light and dark areas, whose height and width match the number of rows and columns in the mesh.

Use brightness (or some other color-derived property) from the pixels of the bitmap as a multiplier value to dictate the distance of the corresponding vertices from the z-axis (center) of the shape.

That’s basically it. In Flash, the built-in BitmapData.perlinNoise method is perfect for generating interesting gradients. The kicker is that the last parameter of the method allows you to change the x & y offset for each ‘octave’ (think semi-transparent layer), allowing for gradual, random-looking changes over time.

So on each update, change the offset of each octave of the perlin noise image and recalculate the vertices accordingly. The behavior and properties of Perlin noise does the rest.

Licensed under a Creative Commons Attribution 3.0 License.

I’ve been getting comfortable with Processing over the last few days by experimenting with what else but … particles. The three-dimensional patterns that emerge by moving the sliders to change the internal parameters can be quite complex and unexpected, and sometimes strange attractor-like.

The algorithm governing the particle motion is very straightforward. New particles are created with a starting orientation which rotates linearly on 2 axes over time. On each frame, a given amount of x, y, and z rotation is added to each particle and then the particle is translated according to its orientation by a steadily increasing distance.

Click on the buttons in the bottom right corner to change the order that the x, y, and z rotations are applied (which creates very different results from each other). The 3 sliders on top-left control the amount of rotation added per frame; the two sliders in the middle control the rate of ‘spin’ for the initial orientation of new particles; and the slider on the right controls the ‘speed’ that particles move away from the point of origin.

Licensed under a Creative Commons Attribution 3.0 License.

I drew up this example a few weeks ago to learn about the new features in Papervision 2.0 alpha. If you’re thinking of looking into the new version, then hopefully you’ll find the supplied source code below of some use. I used the code from this screencast on unitzeroone.com as a starting point.

The source code has example usage of the following things…

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A basic example of collision detection in 3D, where moving particles bounce off a static terrain.

A couple things on it which could be of use …

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A matrix of vectors acting upon a field of particles. Reminiscent of falling water or snow, slightly. Click and drag to ‘draw’ vectors on the field to influence the movement of particles.

For me, the idea comes from Charles Forman’s blog post in Setpixel from 2004, “Snow is fun.” Which is incredibly great. And done in Processing.

Source code:

- Actionscript 3 class

- Full project (Flash 9/AS3)

Licensed under a Creative Commons Attribution 3.0 License.

An Actionscript 3 class for use with Adobe AIR to create uncompressed Macromedia Flash Video (FLV) files to the local filesystem. It will add proper onMetaData info as well. It’s very simple to use.

Example usage:

var myWriter:SimpleFlvWriter = SimpleFlvWriter.getInstance();
myWriter.createFile(myFile, 320,240, 30, 120);
myWriter.saveFrame( myBitmapData1 );
myWriter.saveFrame( myBitmapData2 );
myWriter.saveFrame( myBitmapData3 ); // ... etc.
myWriter.closeFile();

See the comment blocks in the source for more info. It doesn’t support audio.

This comes out of the app I made a little while ago, Webcam DVR. I’m posting the class file now because the app is fresh in my mind, as I just updated it to make it compatible with the current AIR runtime to enter it into the Adobe AIR Developer Derby.

Download Webcam DVR for AIR, updated for the beta AIR runtime (See the previous Webcam DVR post for usage notes).

Licensed under a Creative Commons Attribution 3.0 License.

Seam carving — the recently unveiled technique by Shai Avidan and Ariel Shamir to intelligently resize images (YouTube; white paper) — really captured my imagination when I came across it last night, as it has for many others.

Like Hector Yee (whose writeup was very useful), I decided to try my hand at an implementation of it just for the hell of it, but in Actionscript 3.

The attached demo only resizes images vertically, not horizontally. I wish I could have, but didn’t bother including a dynamic image loader. It’s also, well, very pokey, but the code is readable and the output seems accurate. If you can stand the wait, press [M] a few times to load up the seam calculation queue.

But the most valuable thing about this demo is its publicly available source code under a Creative Commons license:

So if you’re so inclined, please improve, extend, optimize, and/or port this code. I’m not planning on doing any further work on it. Just let me know if you find the code useful, and share your work.

If you’re interested in a more fully-realized online demo of seam carving, here’s one that’s been done in Java.

Update: Additionally, as it turns out, Patrick Swieskowski has already put up an online seam carving Flash demo here.

Version: 0.8

Licensed under a Creative Commons Attribution 3.0 License.