WebXR, Oculus Browser, Semitransparent dark square(s) overlay?

[sylwesterdigital]

Hi, apologies if this is a duplicate question.

Q: What could be the reason for a subtle opaque dark square covering almost 80% of the frame?
See the screen grabs from Oculus Browser on Quest 2 and 3

S

[PavelBoytchev]

Does it change when you apply different values to .setFoveation(…)?

For me, the central part is higher quality, and the peripheral area is lower quality.

[sylwesterdigital]

Hi Pavel, thanks for your help, much appreciated

I did not set it initially so it uses some default values (?)

Indeed setting foveation to 0 removes the overlay completely

renderer.xr.setFoveation(0);

however when set to 1 - I can still see the square

[PavelBoytchev]

@sylwesterdigital

so it uses some default values

Yes, here is what is found in the source file:

mrdoob/three.js/blob/4527c3e8498ebdc42e7eb40fcfa90435b9c95514/src/renderers/webxr/WebXRManager.js#L27-L28

[sylwesterdigital]

I see. I do not know if this works at all - when the value is below 0.34, the square vanished, when above I see the same rather annoying square.

[PavelBoytchev]

I’m not sure what troubles you. Just use some small value. Foveation is used to save battery power, by reducing the quality of peripheral textures.

Here is an extract from https://developer.mozilla.org/en-US/docs/Web/API/XRProjectionLayer/fixedFoveation:

Fixed Foveated Rendering (FFR) renders the edges of the eye textures at a lower resolution than the center and reduces the GPU load.

It is most useful for low-contrast textures such as background images, but less for high-contrast ones such as text or detailed images. Authors can adjust the level on a per-frame basis to achieve the best tradeoff between performance and visual quality.

Value

A number between 0 and 1.

• The minimum amount of foveation is indicated by 0 (full resolution).
• The maximum amount of foveation is indicated by 1 (the edges render at lower resolution).

More info about the concept of foveated rendering.

[sylwesterdigital]

If this is set by default to 1 and “the edges render at lower resolution” and it produces visible anoying overlay - I do not think this is properly implemented.