One sentence summary: This app generates a simple physics simulation, then processes it into a black and white dithered movie. Cool part: retro-looking physics. Uncool part: low frame rate.

As I was going through the ofxaddons, I saw an addon that takes an image file and returns a dithered version of it. The addon includes a few different dithering algorithms. I was intrigued by the aesthetic quality of the dithered images, and I wanted to see what the addon would do with motion content.

I originally connected the addon to the video camera on my computer, and I toyed with connecting the dithering to some kind of openCV processing, but ofxOpenCV is an included addon. I found an addon that wrapped Box2d with openFrameworks. So I thought I’d create a basic physics simulation, then dither it.

Setting up box2d was simple using the openFrameworks project generator. The dithering didn’t work with the generator so I played with the files and finally got the two projects running in the same app. The final piece was figuring out how to get the dithering to apply to the physics simulation. I used openFrameworks buffers to store an image of the simulation, then processed the buffer and drew the dithered image.

Click on the image below to see a full-resolution screenshot:

Github Link: https://github.com/SciutoAlex/iacd-ofxaddons

I chose two ofxAddons: ofxAudioUnit and ofxParticleEmitter, because it’s always a great idea for me to make audio interaction applications.

The reason to choose particle emitter, is that I have seen many great works simulating the motions of particles and I thought it might be good to try this. And as many of you may have known, ofxAudioUnit is a widely used addon which makes Audio Units easy to work on OS X and iOS. It is a wise choice for me to use ofxAudioUnit — it has many examples, really detailed comments, and less bugs.

I made an attempt to use these two addons, created ParameterChanger combining the examples from these two addons. As the mouse moves, the parameters of music will change, more specifically, the x axis will affect the playback rate, and the y axis will affect the cutoff frequency. Furthermore, position of particle will also be affected by mouse position.

Here is the video:

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After the initial attempt, I try to use environment sound to interact with particle emitter.

The amplitude can randomly change the position of the particle.

Here are the github repos: ParameterChanger and AmplitudeTrigger.