Bug Oculus Quest Camera Depth buffer calculations are off

Hi

I have a water shader that was driving me crazy because it works perfect in most VR systems and PC, but in the Oculus Quest 2 it looks wrong. So I was able to track it down.

Here is the simple frag code of the shader I used for testing

Code (CSharp):

1.  
2.  
3. float ori = SAMPLE_DEPTH_TEXTURE_PROJ(_CameraDepthTexture, UNITY_PROJ_COORD(i.scrPos));
4.         float d = Linear01Depth(ori);
5.         c.r=  d;
6.         c.g = d;
7.         c.b = d;
8.  
9.         surfaceEyeDepth = i.scrPos.z;
10.         sceneDepth = LinearEyeDepth(ori);
11.         viewDepth = sceneDepth - surfaceEyeDepth;
12.  
13.         edgeBlendFactor = saturate(_InvFade * viewDepth);
14.         c.rgb = lerp(1, c.rgb, edgeBlendFactor);
15.         return half4(c.rgb, 1);

This shader, what it does is to render into screen the DepthTexture in gray scale, and then the edges would render as white. Perfect because that´s exactly what I want to get, the shore lines. So here a screenshot working just perfect in the editor. You can see the mountains (depth texture) under the water plane, and the edges in white.




But, If I compile and run this on the Oculus Quest 2, something completely wrong happens.

What it seems to do is to render the mountains under (so it seems _CameraDepthTexture has the correct information), but the shore line goes up and down depending on my distance to the water. So if i fly up, the shore line moves up, and if i go down, the shore line goes to its proper position.

My guess is that LinearEyeDepth is working wrong, but I really don't know if that's the reason. Any ideas?

 

Im having similar issue. Have you found a fix?

 

nope, report it as a bug

 

do you have a project that reproduces it? if so, please submit it as a bug report. I've tried to isolate it to a small project but I can't. It seems to be a combination of things that causes this bug and I haven't been able to pinpoint it yet.

 

Instinctively I would say that it seems like the Quest is calculating Z buffer at a very low precision.
I'm having a similar problem btw, and not even need a special shader: I just have some boulders crossing at about 50 meters distance from world origin.
This is definitely a precision issue.

Oh well, and I've just found this:

https://forum.babylonjs.com/t/incor...s-quest-c-using-logarithmicdepthbuffer/7253/4

 

It seems to be that.

 

You can set it at 24 bits.

 

you can't set the default camera depth buffer precision in Unity as far as I know. There used to be a checkbox that allowed to put it at 24/32 bits and that is long gone. Unity, any help?