WebXR Anchors Module

[bialpio]

Request for Mozilla Position on an Emerging Web Specification

• Specification Title: WebXR Anchors Module
• Specification or proposal URL: https://immersive-web.github.io/anchors/
• Caniuse.com URL (optional):
• Bugzilla URL (optional):
• Mozillians who can provide input (optional): @Manishearth, @kearwood, @blairmacintyre

Other information

This is an extension of WebXR Device API that allows applications to ask the underlying XR systems to track particular poses over time & query for the latest pose as the system's understanding of the real world evolves. The specification efforts are happening in Immersive Web Community Group.

TAG review thread

[dbaron]

Also cc @avadacatavra @martinthomson.

[martinthomson]

@Manishearth mentioned this on #218 saying:

The anchors module by itself doesn't really do more here, but when paired with hit-test it can be used to track how real-world objects move over time. It requires an additional permission.

I'm not seeing the additional permission in the specification. From what I can see, the security and privacy considerations reduce to those of the Hit Testing API (which we deferred in #259). In many ways, this API would appear to be an extension of that. It is almost possible to use the Hit Testing API to obtain the information that this API provides, albeit with less precision.

My understanding was that the concerns with Hit Testing were not about functionality, but execution, so this might be more acceptable. I will defer to the folks who are closer to this in that regard.

[Manishearth]

@martinthomson the extra permission is in https://immersive-web.github.io/anchors/#anchor-feature-descriptor , each XR feature descriptor typically requires user consent

[martinthomson]

Thanks. The fact that WebXR has a new abstraction for describing and managing user consent is deeply concerning to me, but not strictly a problem for this specification. However, as we don't have a settled position on WebXR yet, and this seems to be for immersive-ar sessions (which is another specification we have no position for, and it depends on the WebXR permission model, I am lacking the information I need to assess this. Maybe we can see if we can make progress on the central issues first.

[Manishearth]

@martinthomson this is not a new abstraction, it operates within the permissions API as subpermissions of the xr permission. The core spec describes this integration.