CydandClaude Fable 5
06bc863b33
Not code -- evidence. The mech's master Performance was never decompiled because Ghidra sized the stream-builder's strcmp resolver at 6.6KB and swallowed everything behind it; the ctor's member-pointer constants prove @004a9b5c (master) and @004ab9d8 (replicant, hidden the same way inside @004ab430's range). One body, one ret, 1509 instructions, and its 111-call skeleton maps block-for-block onto our fragment-built Mech::Simulate -- validating the 5.3.90-104 arc -- while locating exactly what remains staged: the duck driver (three SetAnim/Mark/SetLevel arms), the status->mode limp promotion, the gyro rumble feed points, and twenty FUN_004a4c54 update-record dirty marks our empty ForceUpdate never makes. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
117 lines
6.7 KiB
Markdown
117 lines
6.7 KiB
Markdown
# MECH4 — pre-TU reconstruction notes
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**Status: no MECH4.CPP exists yet.** The ground snap, frame rejection,
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knockdown stagger and collision economy that the binary keeps in mech4's
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master performance are currently RE-HOSTED inside `Mech::Simulate`
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([[MECH]], 5.3.98–100) at seams marked STAGED. This file carries the decode
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work for the pieces not yet written, so it survives session boundaries.
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## Mech::ProcessCollision (@004abb40) — decoded, not yet reconstructed
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The override of the engine's protected virtual (`MOVER.CPP:1354`), called
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per contact by `Mover::ProcessCollisionList`. The decomp
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(part_012.c:15206–15416) reads as the BASE function plus four additions:
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1. **The base head, verbatim**: `collisionVolume->ProcessCollision(collision,
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worldLinearVelocity, lastCollisionList, &damage->surfaceNormal,
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&penetration)`; on a miss NOTHING runs. Clamp penetration to the slice,
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ratio = pen/dt, `damage->damageAmount = StaticBounce(old, dt, r, normal,
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&elasticity, minimumBounceSpeed, &friction)` with the elasticity/friction
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locals seeded from the mover's coefficients.
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2. **The Mover-family branch** (owner = the collided solid's owner entity,
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solid+0x1c; family test FUN_0041a1a4 against the "Mover" derivation GUID
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@0x4e4518):
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* SEPARATING-CONTACT GATE: `(ourWorldVel − other->WorldVel[vtbl+0x20])
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· normal < −1e-4` (`_DAT_004ac044`) → return, no damage, no dispatch.
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* If the other's classID == **0xbb9** (mech), build a TakeDamage message
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(raw wire shape `{id, len, inflictor = DAT_0050b9ac global, zone −1,
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the Damage verbatim}`) and Dispatch it AT THE OTHER — the mech-vs-mech
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ram. Use our `Entity::TakeDamageMessage` ctor as the weapon path does.
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3. **The CulturalIcon branch** (GUID @0x4e7038):
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* `stopping = other->instanceFlags & 0x8000` (the StoppingCollisionVolume
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flag, entity+0x28).
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* Same separating gate against a ZERO other-velocity (icons are static).
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* Dispatch the crunch TakeDamage at the icon (crushable props have no
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zones → their base handler no-ops it, but the dispatch is real).
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* If NOT stopping: `damage->damageAmount = 0.00123f` (bits 0x3aa137f4) —
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the WALK-THROUGH SENTINEL. The caller (the response block in Simulate)
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must treat exactly 0.00123f as "the move stands": restore the post-snap
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saves, zero the amount, feed the gyro crunch (torque 0.4 along the
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normalized force, upward impulse 0.2 — binary @4aa81e/@4aa86c).
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4. **The material tail**: the elasticity/friction OUT values from
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StaticBounce are compared against `_DAT_004ac048`; sets
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`collisionTemporaryState` (+0x44c) to 1, or 2 when both match and the
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state was 0. The state is pushed into the `collisionState` StateIndicator
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once per frame by the response block (0→1 fires the impact sound). Needs
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the `_DAT_004ac048` constant identified before writing (likely the
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default-material coefficient — check the literal pool at 0x4ac048).
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## Two hazards the donor fought that DO NOT apply here
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* **Compounded StaticBounce reflections**: our engine's
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`Mover::ProcessCollisionList` (MOVER.CPP:1203) restores
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`worldLinearVelocity = initial_velocity` and position PER CONTACT before
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each ProcessCollision call, and averages the results. The port's
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`frameEntryWorldVelocity` economy guard has no counterpart hazard in this
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engine — do not import it.
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* **The AlarmIndicator ODR split**: a port-only problem; our tree reads
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`MovementMode()` / the alarms directly.
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## Already re-hosted in Mech::Simulate (move here when mech4.cpp exists)
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| piece | binary | landed |
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|---|---|---|
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| ground probe + snap | @4aa630–4aa6cc | 5.3.98 |
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| frame rejection + crash self-damage + knockdown | @4aa6cf–4aab0b | 5.3.99 |
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| collision economy divert + distributor | @0x4a0368 → @0049ffcc | 5.3.100 (in the damage hub, where the binary has it) |
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| status→mode limp promotion | master perf (un-decompiled) | 5.3.97, STAGED |
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| forwardCycleRate re-pick (ground/airborne) | IntegrateMotion head | partially — the ctor sets it once; the per-frame re-pick needs +0x3f4 |
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## Still to decode
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* `FUN_004a9b5c` — the master performance. **ISOLATED AND MAPPED
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(2026-08-04):** one single 5,676-byte body @004a9b5c..@004ab168 (one
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`ret`), hidden inside the manifest's mis-sized @004a9770 entry (that fn
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is really the stream-builder's 6.6KB name→SharedData strcmp resolver,
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and Ghidra swallowed everything to @004ab188 behind it). Registration
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proven from the ctor decomp: `(flags & 0xC) == 4` → replicant perf
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@004ab9d8 (also hidden, inside @004ab430's claimed range); else master
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@004a9b5c. Recipe: extract CODE bytes (va 0x1000 → file 0xe00),
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`ndisasm -b 32 -o 0x4a9b5c`.
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**The ordered call skeleton (111 calls)** — blocks in execution order,
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matching our Simulate's structure and locating every staged gap:
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1. controls/demand intake (mech.cpp helpers 0x4a4eab/0x4a4ee9/0x4a4f9e)
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2. three cerr+SetLevel triplets — illegal-state alarm guards
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3. **THE DUCK DRIVER**: three arms of {mech2 SetAnim 0x4a7fc4,
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MarkUpdate ×2, AlarmIndicator::SetLevel} — duck down/hold/up
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4. verify-guarded state read (mech4 accessors + Fail 0x40385c)
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5. gyro feed a (vec pair → gyro_b 0x4b2de4, gyro_a 0x4b2d8c)
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6. death arm: InDeathTransition 0x49fb54 → the 1.9KB mech2 advancer
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0x4a71f4 under it (death-clip arming)
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7. **status→mode LIMP PROMOTION** (0x4a5028 + SetAnim/Mark/SetLevel)
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8. update-record block (0x421bac/0x40e5f0/0x4227e0/0x41db7c/0x422bac +
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Point3D copies) — the dead-reckon/update writer
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9. collision → gyro crunch (gyro feeds + alarms)
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10. knockdown/bump arms (EntityID pair + two SetAnim/Mark/SetLevel arms)
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11. IntegrateMotion @004ab1c8 + position dirty marks
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12. pose/joint tail: gyro_d/gyro_c → **Torso::UpdateJoints @004b66b4** →
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five StateIndicator::SetState publishes + four GetState reads
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13. frame close (position latch)
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**MarkUpdate = FUN_004a4c54 (×20!)** — the update-record dirty-mask OR
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(death strips motion bits); our `ForceUpdate(int)` is an EMPTY STUB, so
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none of these marks exist in our tree yet (MP replication feed).
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Next sitting: instruction-level read of blocks 3 and 7 (the two STAGED
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items), then the mark masks.
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* `@004ab430` ReplicantPerformance (1432B) — the replicant-side interior.
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* `@004ab1c8` IntegrateMotion — decoded (see 5.3.95 notes) but only
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partially re-hosted: the local-velocity/orientation integration and the
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dead-reckon latency fold (+0x778/+0x77c) remain. **`+0x598` is a Point3D**
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(its replicant branch writes it with a vector subtract), so
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`motionEventName` in MECH.HPP is mistyped as CString — fix when this
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lands.
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