Hubs loads into a black screen

Hardware

Oculus Go

Steps to Reproduce

1. go to hubs.mozilla.com
2. create a room with the “atrium” space
3. hit “enter in VR” on the landing page

Current Behavior

black screen (may not be 100% of the time)

Expected Behavior

you should enter the scene in 3d

Possible Solution

this may be related to shaders we are using in the scene. the “wide open space” scene may work for comparison

[MortimerGoro]

I found that the black screen happens when the canvas is not composited before entering VR. I also was able to reproduce the problem with the “wide open space” that @gfodor thought that worked ok.

The canvas is not composited in this 2 situations:

• I created a local test project. If we don’t add a canvas to the DOM and use it in VR, FxR always renders a black screen. I tried the same on Oculus Go and it works ok.
• In Hubs (or WebVR link traversal) there is a race condition in which the canvas is not composited. When we enter VR we pause the FxR compositor. As Hubs (or link traversal) doesn’t show the final canvas in a WebGL 2D scene before entering VR, the change of this issue happening is higher

I’m going to try to find a solution in Gecko for the problem. In the worst case we can delay the compositor pause a bit to fix the problem in Hubs or Link traversal. But the good solution is that a canvas that is never added to the DOM should also work.

[MortimerGoro]

Gecko PR already merged