Re: Modules split

On Mon, Aug 5, 2019 at 10:55 AM Rik Cabanier <rcabanier@magicleap.com>
wrote:

> On Mon, Aug 5, 2019 at 9:40 AM Brandon Jones <bajones@google.com> wrote:
>
>> I'm working on a more complete response, but I'm taking some time to make
>> sure that I'm not innacurately representing anyone's position or offering
>> any conflicting messages. But for the moment I want to make sure we're
>> clear on the use and purpose of *environmentBlendMode:*
>>
>> We heard from the HoloLens team that they wanted to have the ability to
>> display what was then the equivalent of *"immersive-vr"* content, but
>> provide developers a hint to determine how it would actually be shown in
>> order to allow them to either tweak the content for that scenario or
>> possibly optimize it by avoiding rendering certain things that wouldn't
>> display properly anyway (ie: certain shadow effects.) Thus by allowing
>> *"immersive-vr"* sessions to specify an *"additive"*
>> *environmentBlendMode* headsets like HoloLens or Magic Leap are allowed
>> to advertise support for VR content if they so choose. It's also perfectly
>> valid choice for a given platform to choose not to do that if they don't
>> feel the user experience will be a positive one, as you indicated.
>>
>
> It would be good to hear from Microsoft why they wanted this (and not just
> use 'immersive-ar').
> Maybe we can continue this on github? I filed an issue there.
>
> FWIW I think *environmentBlendMode *should only be meaningful in an
> 'immersive-ar' session. https://www.w3.org/TR/webxr/#xrsessionmode-enum already
> implies this
>

Just to avoid confusion, please keep in mind that the environmentBlendMode
is a read-only property that's set by the device depending on hardware
properties and the requested session type. It is NOT a developer choice
that's selected by an application.

There's no way for an application to request "immersive-vr with additive
blend mode". The application just asks for immersive-vr, and the UA either
picks the most-opaque blend mode that it supports (reporting this back to
the application through the blend mode property), or rejects the session if
it does not support immersive-vr.