'META_ENVIRONMENT_DEPTH_TEXEL_SIZE' does not exist

[noahlessard]

I tried downloading the sample scene for interacting with the meta scene api, in particular the occlusion functionality, but I get a compiler error for the shader that comes with the scene. The shader appears to be repeated here: https://godotvr.github.io/godot_openxr_vendors/manual/meta/environment_depth.html, but the issue is that META_ENVIRONMENT_DEPTH_TEXEL_SIZE doesn't exist in the project settings in either the sample project, or a new project started with Godot 4.5.

I did find a different version of the shader here: #347, and while this one compiles it doesn't fix any issues with the depth map being offset from it's actual position, which I think the shader method is supposed to help with.

What's the best way to set up this shader correctly? The doc's set up instructions are a bit out of date here I believe. If I was able to get this working, I'd be happy to try and contribute to them to help other people new to the occlusion api. I'm on Godot 4.5 and I am using openxr_vendors version 4.1.1. Please let me know if you need any other info

[noahlessard]

I've confirmed that adding META_ENVIRONMENT_DEPTH_TEXEL_SIZE as a vec2 to the shader uniforms in the project settings does resolve the compiler issue, but boxes with this shader applied to their meshes just show up as invisible if they have OCCLUSION_MODE set to anything other than 0 (which is the only mode that doesn't use texel size).

[dsnopek]

Sorry for the confusion!

The META_ENVIRONMENT_DEPTH_TEXEL_SIZE variable was added in #354 which isn't in godot_openxr_vendors 4.1.1 - only on the master branch

We're planning to release version 4.2.0 pretty soon, though!

it doesn't fix any issues with the depth map being offset from it's actual position, which I think the shader method is supposed to help with.

Can you describe this problem some more? The depth map won't ever be 100% accurate, because it's just not very high resolution, so it's a question of if it's off by an expected amount or more than that?

The changes from #354 do make the occlusion look a lot nicer, although, it won't really be any more accurate

[noahlessard]

Thanks for the response! I'll try building from the master branch and see if that fixes this and the offset issue. As for the the offset one, I am experiencing a very similar issue as this forum user described: https://forum.godotengine.org/t/meta-quest-3-xr-environment-depth-occlusion-not-behaving-as-expected/124445. Basically the occlusion works only when I face one direction (which seems to change at random, and is not set when doing an hmd_center call or holding down the view reset button on quest).

[dsnopek]

Ah, thanks for sharing! I hadn't seen that thread on the forum, and that's not a bug I've ever personally experienced.

Can you share an MRP that demonstrates this behavior?

I just tried to reproduce with the sample and was unable to. Certainly, small changes in position can lead to bigger changes in the occlusion due to the low resolution of the depth map, but I still see occlusion working regardless of the direction I'm facing.

doing an hmd_center call

This isn't something you should do in an MR application. That function messes with how Godot maps its positions to OpenXR's positions, but those need to remain one-to-one for MR to work correctly.

[noahlessard]

Disabling all of the hmd_center calls appears to fix this issue! However, if I have an application that has a mode where I want to enable MR after being in a VR scene, what's the best way to call start_environment_depth()? Is there a way to reinitialize the space, to "undo" those center hmd calls?

[dsnopek]

Ah, that's great!

You can call XRServer.clear_reference_frame() to clear out anything that center_on_hmd() did.

However, if possible, switching your app to use a "Reference Space" of "Local Floor" (in Project Settings) would leave all the recentering up to the system, and then you wouldn't need to call center_on_hmd()? But I don't know if your app depends on using "Stage" as the reference space for some reason

[noahlessard]

I wasn't aware that changing to "Local Floor" handled that, but after some testing indeed it does. My reasoning for calling center_on_hmd() was to have it run when a user manually clicked a "recenter" button in the app's custom UI. Is there any way to emit a signal to the xr_interface/XRServer to make it call the system's way of recentering?

If not it's no big deal, this is back in the land of what I am comfortable trying to implement on my own and the main topic of this issue has been resolved. If you think any changes to the docs would be warranted, I can try to help with that, but this issue (which I will also be cross posting to the forum post mentioned earlier) might be enough for future people stumbling across the same issue.