Hi, found a small quirk.
Scenario: I want to launch a Sketchfab Viewer API iframe straight into VR mode as seemlessly as possible.
I have the Sketchfab Viewer API app initialising with "cardboard: 1" parameter. This starts and splits the browser view into the stereo pair and starts HMD camera pose tracking as expected. BUT, the HMD screen doesn't show the Sketchfab scene it stays in SteamVR arena.
If I click on the iframe VR goggle icon twice (once to come out of VR and again to go back to VR) the viewport splits, tracking starts AND the HMD screen activates.
Probably this is a vr browser safety thing to ensure there is user-interaction before taking over the HMD.
ChromeVR 56.0.2902, HTC Vive, Windows 10/64
Andrew | Western Sydney University