On 5/30/25 12:47 PM, Alex Cooper wrote:
> Can you say more why you think a TAG review isn't applicable here? I
see that TAG has reviewed a number of WebXR features in the past:
https://github.com/search?q=repo%3Aw3ctag%2Fdesign-reviews+webxr&type=issues
<https://github.com/search?q=repo%3Aw3ctag%2Fdesign-reviews+webxr&type=issues>
They have. By and large this is collectively 3 small updates to an
existing API that either follows the established patterns of the API
and/or are small enough features that can't really be done in another
way. Furthermore, there was already fairly substantial cross-vendor
iteration on this. Finally, it is my understanding that several of
these items have also already been implemented in the Meta Quest browser.
Thanks, that's helpful for non-WebXR experts. Which of the 3 were
already implemented by Meta?
> Could we file a position request at
https://github.com/WebKit/standards-positions/, and let them know
we're proposing to ship this? Or maybe it makes more sense to add a
comment to https://github.com/WebKit/standards-positions/issues/155 -
I'll leave that up to you.
We've typically been filing new issues. For what it's worth, the bulk
of the Depth API *is* shipped. This particular chromestatus is about
the three incremental features to allow for improved performance knobs
to be exposed to developers. I went ahead and filed the issue for the
overall API here though:
https://github.com/WebKit/standards-positions/issues/503
Thank you. And by "this" I'm referring the 3 updates you're proposing to
ship.
> I would assume remote debugging with DevTools works here, is that
correct?
I'm not sure what you mean? You can access all of the methods etc. via
the DevTools as with any API. We didn't do anything special to enable
debugging scenarios, but also nothing that would block default tooling
from working.
I'm responding to the "Debuggability: None" in your email and
chromestatus entry. It sounds like that should be updated to something
like "no special needs" or "existing tools cover debugging".
> Can you say more? I'm guessing just Android, but would be good to
confirm.
Technically OpenXR (one of the WebXR backends) *does* run on Windows;
but I know of no runtimes that expose the extensions we'd need there.
So while technically the features are supported on Windows and
Android, functionally they will only work on Android.
Can you update the chromestatus entry with this info (see the "Platform
Support Explanation" field)? Thanks.
On Fri, May 30, 2025 at 6:30 AM Mike Taylor <miketa...@chromium.org>
wrote:
On 5/22/25 1:45 PM, Chromestatus wrote:
Contact emails
alcoo...@chromium.org
Explainer
https://github.com/immersive-web/depth-sensing/blob/main/explainer.md
Specification
https://immersive-web.github.io/depth-sensing
Design docs
https://docs.google.com/document/d/1Nx3hCHqq8UZ6E1nxctmkr6BBQKwf3AgIai7WVsQ_nUM/edit?usp=sharing
Summary
Exposes several new mechanisms to customize the behavior of the
depth sensing feature within a WebXR session, with the goal of
improving the performance of the generation or consumption of the
depth buffer. The key mechanisms exposed are: the ability to
request the raw or smooth depth buffer, the ability to request
that the runtime stop or resume providing the depth buffer, and
the ability to expose a depth buffer that does not align with the
user's view exactly, so that the user agent does not need to
perform unnecessary re-projections every frame.
Blink component
Blink>WebXR
<https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3EWebXR%22>
TAG review
Cumulatively there are three changes represented by this feature.
All of which are small, cannot really feasibly be done in a
different way and went through multiple rounds of cross-vendor
discussion in the Immersive Web Working Group. Several of them
have already been implemented by Meta, who have begun updating
several of the well-known libraries (e.g. THREE.js) to consume
this new API shape. Great care was taken to ensure that existing
users of the API can also continue to use the API as it was
originally launched with zero impact from these new features.
They purely provide additive performance improvements to the pages.
TAG review status
Not applicable
Can you say more why you think a TAG review isn't applicable here?
I see that TAG has reviewed a number of WebXR features in the
past:
https://github.com/search?q=repo%3Aw3ctag%2Fdesign-reviews+webxr&type=issues
<https://github.com/search?q=repo%3Aw3ctag%2Fdesign-reviews+webxr&type=issues>
Risks
Interoperability and Compatibility
These features have been designed to work in a backwards
compatible way. Sites have to explicitly opt-in to receive any of
this new behavior.
/Gecko/: Defer
(https://github.com/mozilla/standards-positions/issues/487)
/WebKit/: No signal
(https://lists.webkit.org/pipermail/webkit-dev/2021-February/031695.html)
Could we file a position request at
https://github.com/WebKit/standards-positions/, and let them know
we're proposing to ship this? Or maybe it makes more sense to add
a comment to
https://github.com/WebKit/standards-positions/issues/155 - I'll
leave that up to you.
/Web developers/: Strongly positive Many of these changes have
been asked for by other developers
/Other signals/: Feature changes were developed in collaboration
with Meta in the Immersive Web Working Group to address their
needs as well.
WebView application risks
Does this intent deprecate or change behavior of existing APIs,
such that it has potentially high risk for Android WebView-based
applications?
None
Debuggability
None
I would assume remote debugging with DevTools works here, is that
correct?
Will this feature be supported on all six Blink platforms
(Windows, Mac, Linux, ChromeOS, Android, and Android
WebView)?
No
Can you say more? I'm guessing just Android, but would be good to
confirm.
Is this feature fully tested by web-platform-tests
<https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>?
Yes
https://wpt.fyi/results/webxr/depth-sensing?label=experimental&label=master&aligned
<https://wpt.fyi/results/webxr/depth-sensing?label=experimental&label=master&aligned>
Flag name on about://flags
webxr-depth-performance
Finch feature name
WebXRDepthPerformance
Rollout plan
Will ship enabled for all users
Requires code in //chrome?
False
Tracking bug
https://bugs.chromium.org/410607163
Availability expectation
Due to hardware restrictions certain features may only be
available on Chrome for the Forseeable future, but the rest are
either already implemented or should be implemented relatively
soon by Meta.
Adoption expectation
THREE.js has already received updates for some of these features,
and I have had developers explicitly ask for the rest of the
features.
Sample links
https://immersive-web.github.io/webxr-samples/layers-samples/proj-multiview-occlusion.html
https://immersive-web.github.io/webxr-samples/proposals/phone-ar-depth-gpu.html
https://immersive-web.github.io/webxr-samples/proposals/phone-ar-depth.html
Estimated milestones
Shipping on Android 139
Anticipated spec changes
Open questions about a feature may be a source of future web
compat or interop issues. Please list open issues (e.g. links to
known github issues in the project for the feature specification)
whose resolution may introduce web compat/interop risk (e.g.,
changing to naming or structure of the API in a
non-backward-compatible way).
None
Link to entry on the Chrome Platform Status
https://chromestatus.com/feature/5074096916004864?gate=5204438167584768
Links to previous Intent discussions
Intent to Prototype:
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/67fd96b4.170a0220.424d3.03b0.GAE%40google.com
This intent message was generated by Chrome Platform Status
<https://chromestatus.com>.
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