A communication link is established between a first mobile device and a second mobile device using communication setup information in a machine-readable code that is displayed on a display of the second mobile device. The first mobile device captures and decodes an image of the machine-readable code to extract dynamically-generated communication setup information. A communication link is then established between the two devices using the communication setup information. The machine readable code may also be used as a fiducial marker to establish an initial relative pose between the two devices. Pose updates received from the second mobile device can then be used as user-interface inputs to the first mobile device.