This project was so cool. It was about loading a track and the obstacles from a real drawing and then playing a car race in that track in the computer!
To capture the shapes from the paper, I used a webcam and the OpenCV library. These shapes were then transformed into Box2d bodies and added to the physics world in the app.
The cars and the rest of the logic was all C++ and OpenFrameworks. All the captured shapes were static bodies that the cars could collide with. There was a marker also to define the start/end point.
Later on, I also started to play with the idea of using characters rather than cars and platforms rather than a track. The idea was that the user would draw the platforms and the characters in the paper and the app would load all this information into the app…