Examples are disclosed that relate to displaying a hologram via an HMD. One disclosed example provides a method comprising obtaining depth data from a direct-measurement depth sensor included in the case for the HMD, the depth data comprising a depth map of a real-world environment. The method further comprises determining a distance from the HMD to an object in the real-world environment using the depth map, obtaining holographic imagery for display based at least upon the distance, and outputting the holographic imagery for display on the HMD.