Finishes the coupled IntegrateMotion path the decomp workflow (wh1h5gnmc, 3
make-or-break claims CONFIRMED by adversarial verify) proved authentic:
- Peer LINEAR position is SINGLE-SOURCE gait: IntegrateMotion integrates the
body-channel cycleDistance into projectedOrigin.linear@0x260, copied verbatim
to localOrigin -- NOT velocity dead-reckon (that is angular/heading ONLY).
0x260 'motionDelta' and 'projectedOrigin' are literally the same field; the
'contradiction' was our reconstruction's two misnamed shadows.
- Master and peer run the SAME predictor; the master's SEND-mirror must run it
too (binary FUN_004a9b5c @0x4aab9c) so a gait-driven peer stays anchored. Our
mirror used the constant-velocity deadReckoner + overwrote bodyTargetSpeed
live every frame -> could not model a gait peer (the tug-of-war).
- T4 CONFIRMED: both channels pose the full skeleton (same JointedMover); keep
the peer LEG channel (our body channel is unbound on the peer).
CHANGES (all behind BT_MASTER_GAITMIRROR / BT_ROOT_POS, DEFAULT OFF -- zero
change to shipped behavior until visually confirmed):
- mech4.cpp: send-mirror advances projectedOrigin by the mj=0 body channel
travel (mirrorBodyAdv) rotated by heading + last-sent angular vel, re-seeded
to localOrigin on each send, instead of the deadReckoner; and stops the
per-frame live bodyTargetSpeed overwrite so the mirror slews toward last-sent.
- mech.hpp/mech.cpp: mirrorBodyAdv member.
Measured A/B (autonomous through-zero sweep circle, the speed-change regime):
velocity two-source (current default): ratio 1.0022 BUT user-visible glitch
coupled, NO mirror (dense): ratio 1.86 (tug-of-war)
coupled + gait mirror, dense OFF: ratio 1.14, back-steps 0.1%
coupled + gait mirror, dense ON: ratio 1.043, back-steps 0.1%, maxStep 2.9u
The single-source coupling is proven (backward-stepping 0.1% vs the split's
churn). Residual 2.9u occasional snap = leg(peer)-vs-body(mirror) channel
mismatch, second-order. Awaiting visual confirmation before default promotion.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
