A handheld controller for controlling a computer video game that receives streaming video data defining images of regions of a virtual game environment that the computer transmits; projects the images defined by the video data along a projection axis to form the images on a surface that the projection axis intersects so that a user may view and interact with the images; transmits position and/or orientation (P/O) data that defines positions and/or orientations of the projection axis to control for which regions of the virtual environment the computer streams video; and comprises an actuator operable to disengage the P/O data so that video data received from the computer does not change responsive to changes in position and/or orientation of the controller.