There are multiple reasons why this is not easy. Depending on the particular setup, common reasons are:
- Closed programming environment that prevents you from working with an unknown peripheral, without going through a tedious approval process.
- Not enough processing power to service the peripheral without negatively impacting the performance of the game.
- No physical connectivity: lack of available USB ports.
- Lack of device drivers supporting the particular peripheral.
- No appetite to connecting additional wires to an otherwise portable or wireless system.
- Game (including OSVR Client) runs on phone. Peripherals (positional tracking, for example) including OSVR server runs on PC. Game receives 60 FPS updates from PC via Wifi or Bluetooth. Since PC does all the heavy lifting, the 60 FPS position updates are very short and low-bandwidth.
- Game runs on XBOX, eye tracking runs on external CPU (such as super-compact single-board computers from Gumstix or Variscite) which uses the OSVR server to provide the universal eye tracking interface. By the way, these single-board computers could run OSVR using the operating system of your choice - Linux, Android, Windows Embedded) regardless of what operating systems runs with the client.