Some compile fixes and a rename from gpu_wgpu to gpu_web, since wgpu
refers to a specific implementation of WebGPU and I'm really bad at
typing it for some reason.
Origin type used to be a query-able property of the VR system that
indicated whether the tracking was roomscale or seated-scale.
The t.headset.offset config value could be used to design an
origin-agnostic experience, which by default shifted content up 1.7
meters when tracking was seated-scale. That way, stuff rendered at
y=1.7m was always at "eye level". It worked pretty well.
It's getting replaced with a t.headset.seated flag.
- If seated is false (the default), the origin of the coordinate space
will be on the floor, enabling the y=1.7m eye level paradigm. If
tracking is not roomscale, a floor offset of 1.7m will be emulated.
- If seated is true, the origin of the coordinate space will be y=0
at eye level (where the headset was when the app started). This is
the case on both roomscale and seated-scale tracking.
So basically 'seated' is an opt-in preference for where the app wants
its vertical origin to be.
One advantage of this is that it's possible to consistently get a y=0
eye level coordinate space, which was not possible before. This makes
it easier to design simpler experiences that only need to render a
floating UI and don't want to render a full environment or deal with
offsetting everything relative to a 'floor'. This also makes it easier
to implement hybrid VR+flatscreen experiences, because the camera is at
y=0 when the headset module is disabled.
The opt-in nature of the flag, coupled with the fact that it is
consistent across all types of tracking and hardware, is hopefully a
more useful design.
