1. A method implemented by a computing device, the method comprising: rendering a frame of an augmented-reality display based at least in part on an optical basis based on optical data obtained from an optical sensor that describes a current orientation or position of at least a part of the computing device; generating, during the rendering of the frame, a sensor basis based on sensor data obtained from an inertial measurement unit of the computing device that describes the current orientation or position of at least the part of the computing device; determining, during the rendering of the frame, that the optical basis is not consistent with the sensor basis to describe a likely orientation or position of the part of the computing device; extrapolating, during the rendering of the frame and responsive to said determining that the optical basis is not consistent with the sensor basis, based on a previous basis and the sensor basis to generate an updated optical basis that describes the likely orientation or position of the part of the computing device, said extrapolating effective to account for a lag time duration between said rendering the frame to displaying the frame of the augmented-reality display; and updating the rendered frame of the augmented-reality display during the lag time duration and before the rendered frame is displayed, said updating based at least in part on the updated optical basis that describes the likely orientation or position of the part of the computing device.