OpenXR's grip +X is normal to the palm but points away from it on the left hand
and into it on the right, which is exactly what makes both grips carry the same
orientation when the hands hold a wheel symmetrically. The fingers therefore run
along -Y on both hands, and it is the geometry across the palm that mirrors.
Building the right hand's fingers on +Y instead left them pointing at the player
while the real hand faced forward.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The Quest offers XR_FB_hand_tracking_mesh without the app declaring hand
tracking, so a Quest 3 draws the runtime's own hand mesh rather than the
procedural gloves, and its fingers bent backwards on grip: the mesh's
joints point -Z towards the fingertip and +Y out of the back of the hand,
so flexion is negative about the joint's own X, on both hands. Fix and
test by the repository owner; OPENXR.md said the Quest always drew the
gloves, which was wrong.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
On a Quest 3 the gloves' fingers pointed up out of the fist and bent out
of the back of the hand as the grip closed: they were built along the
grip's -Z, which runs up the tube the curled fingers form towards the
thumb, and curled towards -Y, which is backwards on the right hand.
The fingers now run along Y, forwards out of the palm (+Y on the right
hand, -Y on the left, the frame being right-handed), and close towards
+X, the palm's outward normal, with the thumb on the -Z side of both
hands. A test pins the reach, the closing direction and that nothing
bends out of the back of the hand.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
A stereo packet can now carry an AuroraCockpit: tracked hands and, when the
vehicle's own wheel cannot be animated, a synthetic steering wheel or
handlebar, all in metres in the seated frame. Each eye draws it inside the
scene's pass just before the first virtual-screen draw, depth-tested with
the world's own depth mapping (captured from a full-view world draw), so
the kart and track occlude the hands and the 2D layer cannot hide them.
Hands use a runtime-provided hand mesh when one is supplied and a
procedural glove otherwise.
aurora_set_stereo_scene_anchor_scaled lets the sealed frame own its world
scale: each eye's head translation is rescaled from the packet's scale to
the frame's. A non-finite cockpit is dropped with one warning; the frame
still renders.
Ported from heurazy's mario-kart-wii-VR-port (GPL-3.0-or-later).
