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Locomotion: replace task-#64 trn stand-ins with the AUTHENTIC dispatcher (disasm-decoded)

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The turn-in-place dispatcher lives in the master-perf gap 0x4a9b5c-0x4ab188 that
Ghidra never lifted. Disassembled it with objdump (scratchpad/masterperf.asm) and
hand-decoded the real logic, replacing the two [T3] stand-ins I had invented:

- Entry gate was `commandedSpeed < 0.25*standSpeed` (a near-zero guess). AUTHENTIC
  (0x4aa505): arm trn when TURNING (|angVel|>1e-4, port proxy = turnDemand deadband)
  AND speed in the FULL [0, standSpeed] sub-walk range AND turnCapable. trn is gated
  on TURNING, not on being slow.
- Case-4 exit had a ×4 fast-forward + SetLegAnimation(5) invention. Restored the
  VERBATIM decompiled leg-SM exits (part_012.c:12013): standSpeed<spd or reverse ->
  Standing, else advance the pivot. Added the master-perf turn-STOP exit (0x4aa5c6):
  turn stopped -> Standing + legResetLatch=1 (folded into case 4 since the port has
  no separate master-perf frame).
- Body case-4 twin mirrors the authentic exits (mj=0, tracks state for lockstep).

The fast-forward was invented to dodge a turn->walk stutter that was ACTUALLY the
body channel leaking joints (mj=1) -- already root-caused + fixed by mj=0. The
trn->walk seam (legFrm7 cycle-end -> swr legFrm1) is the authentic pose-matched
boundary and the same seam the fast-forward version hit, just at the correct release
speed. Also decoded (documented, not yet wired) the authentic turn-RATE lerp
(walkingTurnRate@0x574 -> runningTurnRate@0x578 by speed; angVel = turnDemand*rate);
the bring-up drive still yaws at the constant kDriveTurnRate.

Headless-verified (BT_AUTODRIVE/BT_FORCE_TURN/BT_WALK_DELAY/BT_GAIT_TRACE): turn-in-
place enters state 4, ramp past standSpeed -> 4->stand->swr->walk, both channels in
lockstep. Feel re-verification pending. [T1 logic / T2 runtime]

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
arcattack
2026-07-14 00:31:56 -05:00
co-authored by Claude Fable 5
parent bfdd41bb9d
commit 35c30bda67
2 changed files with 107 additions and 84 deletions
Download Patch File Download Diff File Expand all files Collapse all files
game/reconstructed/mech2.cpp
+63 -60
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@@ -595,22 +595,26 @@ Scalar
else
{
distance = 0.0f;
// TURN-IN-PLACE entry. The authentic entry DISPATCHER lives in the
// un-decompiled master-perf gap (0x4a9b5c-0x4ab188), the sole reader of
// turnDemand(+0x12c) + turnCapable(+0x588); the decompiled lifecycle is
// case-4 advance/exit (below) + the clip-finish drop-to-stand. The
// authentic gate is turn-IN-PLACE == NEAR-ZERO commanded speed. The old
// stand-in gated on `ZeroSpeed <= commandedSpeed` -- i.e. it re-armed trn
// for ANY forward speed in [0, standSpeed~6.83], so pushing forward mid-
// turn SWALLOWED the throttle (the mech kept pivoting) until spd crossed
// standSpeed, then lurched to walk (task #64 user-reported stutter). Gate
// on near-zero speed instead: the instant real throttle is applied the trn
// re-arm stops, the in-flight pivot finishes to Standing, and case 0 hands
// off to walk normally. turnEntrySpeed = 0.25*standSpeed is a STAND-IN for
// the gap's threshold constant [T3]; the deadband mirrors the replicant's.
const Scalar turnEntrySpeed = standSpeed * 0.25f;
// TURN-IN-PLACE entry -- AUTHENTIC, decoded from the master-perf disasm
// (0x4aa505-0x4aa588, task #64b). The dispatcher lives in the master perf
// FUN_004a9b5c (Ghidra never decompiled it -> objdump); it arms trn from
// Standing when: the mech is TURNING (|angularVelocity| > 1e-4, ds:0x4ab16c
// -- angularVelocity = turnDemand * turnRate, so turnDemand outside a tiny
// deadband) AND 0 <= speedDemand <= standSpeed (the FULL sub-walk range,
// ds:0x4ab178=0 .. mech[0x530]) AND turnCapable(mech[0x588]) AND the
// legResetLatch(mech[0x654]) debounce is clear. CORRECTS the task-#64a
// stand-in `commandedSpeed < 0.25*standSpeed` (that near-zero gate was a
// guess; the binary allows the full [0,standSpeed] range -- trn is gated on
// TURNING, not on being slow). [T1 from disasm] The turnDemand deadband
// (0.05) is the port proxy for the |angVel|>1e-4 test. NOTE: the disasm's
// legResetLatch gate is a master-perf ONE-FRAME debounce (cleared every
// frame at 0x4a9bff, set on wind-down/turn-stop) -- it does NOT map onto
// the port's split leg-SM (wind-down + trn-entry run in different frames/
// cases and the port never per-frame-clears the latch), so gating entry on
// it here would wrongly block trn after every walk. Omitted by design;
// see locomotion.md "turn-in-place dispatcher".
if (hasCrashSet != 0 && mppr != 0
&& commandedSpeed >= ZeroSpeed && commandedSpeed < turnEntrySpeed
&& commandedSpeed >= ZeroSpeed && commandedSpeed <= standSpeed
&& (mppr->turnDemand > 0.05f
|| mppr->turnDemand < -0.05f)
&& bodyAnimationState == StandingAnimation) // weld: enter only when BOTH can
@@ -664,47 +668,41 @@ Scalar
case 4: // TURN-IN-PLACE (trn clip)
// state 4 is the turn-in-place animation (animationClips[4] = the "trn" clip,
// loaded under turnCapable@0x588). THE POSE-SNAP RULE (task #64, root-caused
// from the user's BT_GAIT_TRACE): this engine has NO pose blending -- every
// authored transition is pose-MATCHED at its boundary (swr starts from the
// stand pose; the walk clips alternate at matched extremes). Any exit that
// abandons the pivot MID-CLIP (SetLevel(0) or SetLegAnimation(5)) hard-resets
// the next clip to frame 0 while the legs are mid-step -> the legs TELEPORT
// (legFrm 7->1 in the trace) = the 100%-repro turn-then-walk stutter. Three
// prior fixes all failed because each still cut the clip mid-step, just at a
// different speed threshold.
// loaded under turnCapable@0x588). AUTHENTIC exits, restored VERBATIM from the
// decompiled leg SM (part_012.c:12013 == FUN_004a5028 case 4 [T1]):
// * standSpeed < commandedSpeed -> SetLevel(0)+ForceUpdate(8): walk takes over
// * commandedSpeed < ZeroSpeed -> SetLevel(0)+ForceUpdate(8): reverse
// * else -> goto advance_normally: advance the pivot at idleStrideScale.
// PLUS the master-perf turn-STOP exit (disasm 0x4aa5c6-0x4aa5e6 [T1], which the
// leg SM does NOT contain -- it lives in the un-decompiled master perf that the
// port has no separate frame for, so it folds in here): when the turn stops
// (|angularVelocity| <= 1e-4, i.e. turnDemand back inside the deadband) ->
// SetLevel(0) + legResetLatch(mech[0x654])=1. Without it the trn clip would
// shuffle in place forever after the stick re-centers.
//
// The reconstruction: when forward is commanded past the turn-in-place band,
// FAST-FORWARD the pivot to completion (accelerated advance) -- the feet
// hurry down to the plant, the clip's own finished-callback (case 4 ->
// SetLevel(0), the DECOMPILED one-shot tail) drops to Standing AT THE STAND
// POSE, and the normal pose-matched stand->walk path takes over. No mid-clip
// cut anywhere. trn has zero root translation, so the fast-forward moves no
// distance. [T3: the release threshold (0.25*standSpeed) + hurry rate (4x)
// stand in for the un-decompiled master-perf dispatcher constants (gap
// 0x4a9b5c); the completion->Standing tail itself is T1 decompiled.]
//
// The decompiled REVERSE abort is kept verbatim; the decompiled standSpeed
// abort is deliberately SUBSUMED by the hurry (it was the mid-clip pose cut
// itself -- any spd above the band fast-forwards to the plant instead, and
// Standing picks up the walk one frame after the callback). [T3 deviation
// from the literal case-4 exit, in service of the pose-match invariant.]
if (commandedSpeed < ZeroSpeed)
// The task-#64 fast-forward (4x) + 0.25*standSpeed early-release were STAND-INS
// invented to dodge a turn->walk stutter that was ACTUALLY the body channel
// leaking joints into the rendered skeleton (mj=1); root-caused + fixed by the
// body-channel mj=0 change (AdvanceBodyAnimation, mech4.cpp). With the body no
// longer writing joints the authentic mid-clip cut renders cleanly, so the
// inventions are removed. trn has zero root translation -> distance stays 0.
if (standSpeed < commandedSpeed || commandedSpeed < ZeroSpeed)
{
legStateAlarm.SetLevel(0);
legStateAlarm.SetLevel(0); // -> Standing (leg-SM exit)
ForceUpdate(8); // type-3 record
distance = 0.0f;
break;
}
if (mppr == 0
|| (mppr->turnDemand <= 0.05f && mppr->turnDemand >= -0.05f))
{
Scalar trnRate = 1.0f;
if (standSpeed * 0.25f < commandedSpeed)
trnRate = 4.0f; // forward commanded: hurry the plant [T3]
distance = legAnimation.Advance( // same advance advance_normally does,
time_slice * globalTimeScale * idleStrideScale * trnRate, 1); // rate-scaled
legCycleSpeed = distance / time_slice; // trn z=0 -> stays 0 (no travel)
legStateAlarm.SetLevel(0); // turn stopped -> Standing (master-perf exit)
ForceUpdate(8);
legResetLatch = 1; // mech[0x654] (master perf sets it here, 0x4aa5e1)
distance = 0.0f;
break;
}
break;
goto advance_normally; // still turning, sub-walk -> advance the pivot
case 6: case 7: // WalkToRun
//
@@ -918,27 +916,32 @@ Scalar
// the SAME live speedDemand, so both clips complete on the same frame and
// both channels re-enter walk on the same frame. Without this the body
// entered walk ~7-20 frames apart from the leg and the two walk cycles ran
// permanently out of phase -- the body's pose flashes through on the leg's
// clip-boundary frames (body advances mj=1 FIRST, leg overwrites LAST;
// boundary frames the leg doesn't write) = the rhythmic gait skip + halved
// bob the user reproduced 100% from turn-then-walk (standstill starts weld
// the phases, which is why they never stuttered). [T3 rates/threshold; the
// per-channel case-4 machinery itself is T1 decompiled.]
// permanently out of phase. Exits mirror the leg twin VERBATIM
// (part_012.c:12013 [T1]): speed exits + the master-perf turn-stop exit.
// The body does NOT set legResetLatch (leg-channel/master-perf state, set
// once by the leg twin). Since the body no longer writes joints (mj=0,
// AdvanceBodyAnimation) this channel only tracks state so both channels
// re-enter walk on the same frame.
{
MechControlsMapper *bm = MappingMapper();
const Scalar bspd = (bm != 0) ? bm->speedDemand : 0.0f;
if (bspd < ZeroSpeed) // reverse abort (leg-symmetric)
if (standSpeed < bspd || bspd < ZeroSpeed) // walk / reverse (leg-symmetric)
{
bodyStateAlarm.SetLevel(0);
ForceUpdate(8);
distance = 0.0f;
break;
}
Scalar trnRate = 1.0f;
if (standSpeed * 0.25f < bspd)
trnRate = 4.0f; // hurry the plant (leg-symmetric)
distance = bodyAnimation.Advance(
time_slice * globalTimeScale * idleStrideScale * trnRate, loop);
if (bm == 0
|| (bm->turnDemand <= 0.05f && bm->turnDemand >= -0.05f))
{
bodyStateAlarm.SetLevel(0); // turn stopped (leg-symmetric)
ForceUpdate(8);
distance = 0.0f;
break;
}
distance = bodyAnimation.Advance( // still turning -> advance the pivot
time_slice * globalTimeScale * idleStrideScale, loop);
bodyCycleSpeed = distance / time_slice;
}
break;