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Locomotion: wire the AUTHENTIC per-mech turn-rate lerp (task #64b)

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The master-perf disasm (0x4aa3d3-0x4aa4ff) computes the yaw rate as
lerp(walkingTurnRate@0x574, runningTurnRate@0x578) by ground speed, not a
constant. Wired it into the drive, replacing the bring-up constant kDriveTurnRate:

- walkingTurnRate/runningTurnRate are now REAL named members. The ctor's
  `Wword(0x15d)/(0x15e) = model->...TurnRate * DegreesToRadians` writes were
  NO-OPS -- Wword() returns a shared static scratch cell, so the rates were
  silently discarded. Now stored + read by name.
- The drive (mech4.cpp) computes authTurnRate: base = walkingTurnRate; above
  reverseSpeedMax(0x538) lerp walk->run across [walkStride 0x534 .. topSpeed
  0x34c] with an over-run falloff runningTurnRate/t^2; clamp >=0; zeroed in the
  death/limbo/airborne leg states (1/2/3) or when deathAnimationLatched(0x650) is
  set. Falls back to kDriveTurnRate if the model gave no rates.

The lerp is a RUN-speed refinement -- below reverseSpeedMax (walk / turn-in-place)
the rate is the constant walkTR base; runningTurnRate < walkingTurnRate (a running
mech is less maneuverable). Verified headless (DEV mech, BT_TURN_LOG): walkTR
1.309 rad/s (75 deg/s), runTR 0.873 (50 deg/s), turn-in-place + walk yaw at walkTR,
no crash. [T1 logic / T2 runtime]

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
arcattack
2026-07-14 05:48:51 -05:00
co-authored by Claude Fable 5
parent 35c30bda67
commit a83995a755
4 changed files with 67 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files
game/reconstructed/mech.cpp
+7 -8
View File
@@ -1325,14 +1325,13 @@ Mech::Mech(
<< " turnVel=" << updateTurnVelocityDeadband
<< " turnAngle=" << updateTurnAngleDeadband << " (rad)" << std::endl;
Wword(0x10c) = model->timeDelay; // rec+0xA4 -> mech+0x430
// NOTE: the decomp writes word slots this[0x15d]/this[0x15e]. Routed to the
// scratch bank (unnamed pose-angle fields) -- writing through (float*)(this +
// 0x15d) would be typed-pointer arithmetic on Mech* (== this + 0x15d*sizeof(Mech)).
// The AUTHENTIC per-mech turn rates (rec+0x60/0x64, deg->rad ->
// mech+0x574/0x578) -- still absorbed pending the turn-code wiring
// (locomotion polish item: the port turns at a bring-up constant rate).
Wword(0x15d) = model->walkingTurnRate * DegreesToRadians;
Wword(0x15e) = model->runningTurnRate * DegreesToRadians;
// The AUTHENTIC per-mech turn rates (rec+0x60/0x64, deg->rad -> mech+0x574/0x578).
// The decomp writes word slots this[0x15d]/this[0x15e] (== 0x574/0x578); stored in
// real named members now (task #64b) -- read by the master-perf turn-rate lerp in
// the drive (mech4.cpp) that yaws at lerp(walkingTurnRate, runningTurnRate) by speed
// instead of the old bring-up constant kDriveTurnRate.
walkingTurnRate = model->walkingTurnRate * DegreesToRadians;
runningTurnRate = model->runningTurnRate * DegreesToRadians;
//
// SHADOW JOINT resolve (task #20; CORRECTED -- the earlier draft misread
game/reconstructed/mech.hpp
+2
View File
@@ -848,6 +848,8 @@ protected:
Scalar jumpWalkSpeedMax; // @0x540
Scalar jumpRunStrideLength; // @0x544
Scalar jumpWalkStrideLength; // @0x548
Scalar walkingTurnRate; // @0x574 (WalkingTurnRate, rad/s) -- the master
Scalar runningTurnRate; // @0x578 (RunningTurnRate, rad/s) perf turn-rate lerp
Scalar groundCycleRate; // @0x5b8
Scalar airborneCycleRate; // @0x5bc
// Forward-throttle scale read by the controls mapper (@004afd10:
game/reconstructed/mech4.cpp
+43 -6
View File
@@ -2614,18 +2614,55 @@ void
if (!gDriveSeeded) { gDriveHeading = 0.0f; gDriveSeeded = 1; }
// --- AUTHENTIC turn rate (master-perf disasm 0x4aa3d3-0x4aa4ff [T1]) ---------
// The yaw rate is per-mech lerp(walkingTurnRate, runningTurnRate) by GROUND
// SPEED, not the old bring-up constant kDriveTurnRate. spd = horizontal speed
// (last frame's worldLinearVelocity); base = walkingTurnRate; above the low
// gate (reverseSpeedMax@0x538) lerp walk->run across [walkStride 0x534 ..
// topSpeed 0x34c], with an over-run falloff runningTurnRate/t^2 past topSpeed;
// clamp >=0. angularVelocity = turnDemand * turnRate, ZEROED in the death/
// limbo/airborne leg states (1/2/3) or when the death-anim latch is set.
// Falls back to the bring-up constant if the model supplied no rates.
Scalar authTurnRate = kDriveTurnRate;
if (walkingTurnRate > 0.0f)
{
const Scalar spd = (Scalar)sqrtf(worldLinearVelocity.x * worldLinearVelocity.x
+ worldLinearVelocity.z * worldLinearVelocity.z);
authTurnRate = walkingTurnRate; // base (walk / idle / turn-in-place)
if (spd >= reverseSpeedMax) // 0x538 low gate
{
const Scalar den = reverseStrideLength - walkStrideLength; // topSpeed - walkStride
const Scalar t = (den != 0.0f) ? (spd - walkStrideLength) / den : 0.0f;
if (t <= 1.0f)
authTurnRate = walkingTurnRate + (runningTurnRate - walkingTurnRate) * t; // walk->run
else
authTurnRate = runningTurnRate / (t * t); // over-run falloff
}
if (authTurnRate < 0.0f) authTurnRate = 0.0f;
const int ls = legAnimationState; // 0x3b0
if (deathAnimationLatched != 0 || ls == 1 || ls == 2 || ls == 3)
authTurnRate = 0.0f; // no yaw in death/limbo/airborne
}
if (getenv("BT_TURN_LOG"))
DEBUG_STREAM << "[turnrate] walkTR=" << walkingTurnRate
<< " runTR=" << runningTurnRate << " spd="
<< (Scalar)sqrtf(worldLinearVelocity.x*worldLinearVelocity.x
+ worldLinearVelocity.z*worldLinearVelocity.z)
<< " -> authTurnRate=" << authTurnRate
<< " (kDrive=" << kDriveTurnRate << ")\n" << std::flush;
// --- turn: integrate heading, write it onto the body orientation -----
gDriveHeading += turn * kDriveTurnRate * dt; // scalar mirror (drive log + fallback)
gDriveHeading += turn * authTurnRate * dt; // scalar mirror (drive log + fallback)
if (s_realControls)
{
// AUTHENTIC ORIENTATION INTEGRATION (the IntegrateMotion-tail form):
// compose the yaw RATE into the pose quaternion via the engine
// integrate op (Quaternion::Add == FUN_00409f58) -- the same op the
// binary's motion tail uses -- instead of rebuilding the orientation
// from a scalar heading. The rate SCALE (kDriveTurnRate) remains a
// bring-up constant; the authentic per-mech turn-rate parameter is
// part of the deferred full-IntegrateMotion work.
Vector3D angStep(0.0f, turn * kDriveTurnRate * dt, 0.0f);
// from a scalar heading. The rate SCALE is now the AUTHENTIC per-mech
// turn rate (authTurnRate above) -- lerp(walkingTurnRate, runningTurnRate)
// by ground speed, master-perf 0x4aa3d3 [T1].
Vector3D angStep(0.0f, turn * authTurnRate * dt, 0.0f);
Quaternion prevPose = localOrigin.angularPosition;
localOrigin.angularPosition.Add(prevPose, angStep);
}
@@ -3059,7 +3096,7 @@ void
worldLinearVelocity.x * worldLinearVelocity.x +
worldLinearVelocity.z * worldLinearVelocity.z);
localVelocity.linearMotion = Vector3D(0.0f, worldLinearVelocity.y, -fwdSpeed);
localVelocity.angularMotion = Vector3D(0.0f, turn * kDriveTurnRate, 0.0f);
localVelocity.angularMotion = Vector3D(0.0f, turn * authTurnRate, 0.0f);
// CRASH motion suppression (spec: the binary zeroes localVelocity while
// crashed). While the stagger clip (legState 0x20) plays, freeze the