1. A method comprising: receiving information corresponding to a physical space from one or more cameras; mapping a position of a user in the physical space to a position in a virtual space based at least in part on the received information; determining an activation level of the user based on a position of a hand of the user with respect to a position of another portion of the user; and generating an image comprising: a virtual object; and a visually perceptible indicator that changes in appearance in response to a magnitude of a difference between the activation level and an activation threshold.