I started development of a TUIO Patch for Quartz Composer. TUIO is the protocol used by the reactable project which is a “state-of-the-art multi-user electro-acoustic music instrument with a tabletop tangible user interface”. The visual engine behind reactable is reacTIVision. When an so called “fiducial” is recognized by the engine it’s X, Y and Angle are send over the TUIO protocol to any listening client. The TUIOClient for Quartz Composer is such a client.
The code status is not much more then a proof-of-concept, but you can drop Tuio patches on your compositions which have an X, Y and angle as output parameters. The scaling is wrong (only middle part of compositions works). The code is Cocoa with the Java TUIO client. Maybe I will port the client to Objective-C. Help would be appreciated.
Download the QC plugin, the XCode source and a very basic sample here.