1. A method of rendering computer-generated content on a handheld device held by a user, the method comprising: tracking the user, thereby creating user-tracking data; determining a position of the device, thereby creating device-position data; calculating rendering data using the user-tracking data and the device-position data; and displaying the computer-generated content on the handheld device according to the rendering data, wherein rendering of the computer-generated content is spatially correct, presenting a realistic visual experience when viewing the computer-generated content on the handheld device.