I packaged up the physics simulation toy that I built for the Maker Faire. Now you can download and play with it on your Mac. It was built for use with the multi-touch table that my friend Tony built, but you can use the mouse and keyboard to control it just fine. Physix uses several open-source toolkits to do all of the hard work, specifically, Box2D, SDL, SDL_gfx and liblo. I just packaged it all up into an application and tried to make it fun to play with. You can download the application and the source code which is released under the terms of the GPL.
The application is not as polished as I would like, but it is usable and fun. You can click and drag shapes around, draw new ones and press keys to make pivots and motors. When you first launch the app, read the instructions or just press some number keys to see the demo scenes. Press ‘h’ to see the help message again.
If you happen to have your own multi-touch device that outputs TUIO flavored OSC messages then you can use this toy with it right out of the box (Physix listens on port 3333).
If you don’t have a mult-touch device, but you do have a webcam, then you can still play with multiple inputs by downloading reacTIVision, printing out the included fiducial symbols cutting them out and then holding them in front of the camera. Each symbol is tracked as a separate input. Waving a piece of paper around is no where near as intuitive or accurate as having a real multi-touch input device, but the principle is the same.
p.s. Yes I know how to spell the word physics. I called the application “Physix” because it is easier to google and the letter X is cool.