TrackIR: Optical Tracker

NaturalPoint's product list contains various motion capture cameras/systems to measure position and orientation of tracked objects.

Supported devices:

- Linux:
  - NaturalPoint's TrackIR is tested. Other devices supported by linux-track (SmartNav, Wiimote, and some webcams) may work https://code.google.com/p/linux-track/wiki/InputDevices
- Windows:
  - NaturalPoint's TrackIR is tested. All OptiTrack and SmartNav models are expected to work.

Dependencies:

- Linux: Requires linuxtrack https://code.google.com/p/linux-track/
  - Change file 51-TIR.rules to (replace the "simquest" with your group name): SUBSYSTEM=="usb", ATTRS{idVendor}=="131d", GROUP="simquest", MODE="0666"
    - Then move it to /lib/udev/rules.d/ and restart the udev service.
  - Run ltr_gui (requires Wine).
  - (Probably optional) An environment variable named NP_CAMERASDK may be set to the directory containing `(include/)linuxtrack.h`
- Windows: Requires NaturalPoint's Camera SDK https://www.naturalpoint.com/optitrack/downloads/developer-tools.html
  - An environment variable named NP_CAMERASDK must be set to the directory containing `(include\)cameralibrary.h`