Decomp-verified via multi-agent investigation (workflow wv1km7lvc, adversarially
checked against reference/decomp/all/part_012.c + engine T0).
ROOT CAUSE (D3 CONFIRMED): the peer's leg channel FUN_004a5028 reads its speed
demand from mapper->speedDemand (**(mech+0x128)+0x128, part_012.c:11947/11975/
12028). The reconstruction FABRICATED that input from the noisy dead-reckoned
velocity magnitude and PINNED it flat with a standSpeed*1.05 floor across the
walk threshold -- the leg stutter/skip + cadence-vs-travel desync, worst on
accel/decel. The authentic input is the replicated commanded speed
bodyTargetSpeed@0x6b4 -- the master's own throttle-commanded speedDemand
(mechmppr.cpp:749), stamped into every record (mech.cpp:2036) and read back on
the peer (mech.cpp:1833/1841/1871). It is the IDENTICAL value the master's leg
channel consumes, so the peer clears the stand->walk gate exactly when the master
does and ramps cadence continuously through accel/decel.
Confirms the 07-13/07-14 regression: bb795e2 (smooth, 07-12) fed raw derived
speed with NO floor; the floor added in the task-#64/#50 spiral is what pinned
the cadence.
CHANGES (mech4.cpp replicant branch):
- Change 1 (D3): replMppr->speedDemand = bodyTargetSpeed (was derived velocity
+ standSpeed*1.05 floor). Old path kept behind BT_REPL_VEL for A/B.
- Turning: authentic peer turning is net-driven (angular slerp in DeadReckon,
MOVER.cpp:521-525, D8). Removed the flickery bare +-0.02 yawRate->turnDemand.
The visible turn-STEP (authentically from the body channel replaying the
type-3 turn state; we run the leg channel per D2) is reproduced by arming the
trn clip from the replicated yaw rate with HYSTERESIS (enter >0.08, hold until
<0.03) so the clip no longer chatters. BT_REPL_NOTURN = decomp-strict, no step.
REFUTED (kept as-is): D1/D5 -- peer POSITION authentically comes from the engine
velocity dead-reckoner (Mover::DeadReckon, T0), NOT the gait travel; the
body-channel switch DEVIATES (double-authors position + T4 leg-bone risk) and was
NOT taken. D4 -- bodyTargetSpeed is non-zero tracking throttle (0 only on coast,
which authentically winds down to stand).
Verified live: walking + accel/decel + in-place pivot all smooth (user-confirmed).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
