TeslaRel410/restoration/source410/BT/MECH-LAYOUT.md

MECH.HPP staging worksheet (opened 2026-07-19)

The working ledger for growing the literal MECH.HPP alongside the mech-family TU reconstructions. The period compiler is the layout authority: ../layout_probe.cpp compiled+run under BC4.52 with the authentic OPT.MAK flags (-a4 alignment) measures the 1995 base-class sizes from the SURVIVING engine headers.

Probe results (2026-07-19) — methodology VALIDATED 3/3

class	sizeof	validation
Simulation	0x0D0
Entity	0x1C4	(⇒ Entity-own fields span 0x0D0–0x1C4: playerLink@0x190 ✓, subsystem roster @0x124/0x128 ✓)
Mover	0x300	(⇒ Mover-own 0x1C4–0x300: localOrigin@0x260 ✓)
JointedMover	0x328	⇒ Mech's own region = 0x328–0x854 (0x52C bytes)
Mission	0x0E4	BTMission's experienceLevel @+0xE4 = first BT member ✓
BTMission	0x0FC	== the binary's new(0xfc) (BTL4Mission alloc) ✓
ModeManager / BTL4ModeManager	0x00C	== the binary's new(0xc) ✓
BTRegistry	0x010	== the binary's new(0x10) ✓

Three independent allocation-size matches against the shipped binary ⇒ headers + compiler + flags reproduce 1995 layout exactly. Any future header where the probe disagrees with a binary alloc size is WRONG and must be fixed before use.

Consequences for MECH.HPP staging

• Every binary offset < 0x328 is a BASE-CLASS field, not a Mech member. The port's mech.hpp declares several pose members in that range (orientation@0xD0, bodyRotation@0x100, turretBase@0x1C4, headPitch@0x1CC, torsoTwist@0x1DC, legAngle@0x1F4, hipAngle@0x200, torsoAim*@0x298/0x2C8, netOrientation@0x2D4) — in the 1995 header these belong to Simulation/Entity/Mover/JointedMover (or their equivalents) and must be RE-ATTRIBUTED by checking the surviving engine headers' member lists at those offsets (probe with offsetof where members are public).
• Mech-own members with binary offsets ≥ 0x328 (from the port/CLASSMAP, to be laid out with reserved[] filler between mapped runs): reduceButton@0x340, forwardCycleRate@0x344, legCycleSpeed@0x348, reverseStrideLength@0x34C, gimpStrideLength@0x350, mechName@0x360, masterAlarm@0x39C(+legStateAlarm), legAnimationState@0x3B0, unstablePercentage@0x3F0, airborne@0x3F4, radar block @0x3F8–0x40C, rearFiring@0x410, missionReview@0x414, messageManager@0x434, torsoCache@0x438, lastInflictingID@0x43C, damageLookupTable@0x444, weaponCount@0x448, collisionTemporaryState@0x44C, heatAlarm@0x450–0x464, throttleState@0x4A4, fallDirection@0x4A8, fallScalar@0x4B4(+collisionSpeed), templateBottomLift@0x4B8, stabilityAlarm@0x4C4–0x4D8, standing/duckedTemplateMaxY@0x518/0x51C (≡heatLevel/Capacity — CONFLICT, resolve), gyroSubsystem@0x528, gait caps @0x52C–0x548, look angles @0x564–0x570, turn rates @0x574/0x578, jump flags @0x580–0x588, motionEventName@0x598, motionEventArmed@0x5A4, time scales @0x5A8–0x5B0, hudSubsystem@0x5B4, cycle rates @0x5B8–0x5C0, gyroRumbleTimer@0x5C4, footStepRootJoint@0x5C8, animationClips@0x5CC(+namedClip alias @0x5E0, crash clips @0x5D4–0x5DC), gimpBaseClip@0x64C, deathAnimationLatched@0x650, leg/bodyResetLatch@0x654/0x658, legAnimation@0x65C, controllableSubsystems@0x65C(CONFLICT — one is a chain @0x65C, resolve), bodyTargetSpeed@0x6B4, bodyCycleSpeed@0x6B8, bodyAnimation@0x6BC(≡watchedSubsystems CONFLICT), statusAlarm/bodyStateAlarm@0x714, bodyAnimationState@0x728, deadband block @0x768–0x770, creationTime@0x778, poseSyncLatch@0x77C, heatLevelSnapshot@0x780, unstable tuning @0x784–0x798, reverseSpeedMax2@0x7A0, heatableSubsystems@0x7AC, weaponRoster@0x7BC, damageableSubsystems@0x7CC, sensorSubsystem@0x7DC, telemetryFilter@0x7E0, linearSpeed@0x81C, resource names @0x844–0x84C, deathHandler@0x850, end 0x854.
• The flagged CONFLICTs are port-side double-attributions to untangle against the decomp before the first staged MECH.HPP is written.
• Real 1995 types to substitute for the port proxies: ReconChain→ChainOf<Subsystem*>? / AlarmIndicator→the engine alarm type / ReconSeq→the SequenceController analog / BTVal→per case — settle each against the surviving engine headers + sizes via the probe.

Next actions

1. Extend layout_probe.cpp with offsetof checks on public base members to re-attribute the sub-0x328 pose fields to their true base classes.
2. Untangle the three offset CONFLICTs above (decomp reads).
3. Write the first staged MECH.HPP (interface + mapped runs + reserved[] filler) and compile-verify sizeof(Mech)==0x854 with the probe.

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ADDENDUM 2026-07-19 (later) — spawn factory reached the Mech ctor; proxy layer resolved

The boot ladder now runs the full spawn factory (CreatePlayerVehicle -> Mech::MakeMessage -> MakeAndLinkViewpointEntity -> registry -> Mech::Make -> new Mech -> JointedMover base streams the model) and halts at the Mech ctor. So the ctor is the live frontier and this worksheet is the active blocker.

Proxy layer resolved (BT411 mechrecon.hpp -> real 1995 types)

Settles the open item in the "Real 1995 types" bullet above:

BT411 alias	real type	in 4.10 archive?
ReconAlarm (AlarmIndicator)	AlarmIndicator (multi-level, N levels sets size)	❌ MISSING
ReconSeq	SequenceController (animation sequence)	❌ MISSING
ReconFiltered / FilteredScalar	AverageOf (15-sample running avg)	❌ MISSING
ReconFiltered (mechNameFilter)	NameFilter	❌ MISSING
ReconChain<Subsystem*>	ChainOf<Subsystem*>	✅ CHAIN.HPP
ReconMatrix / Matrix34	AffineMatrix / Matrix	✅
StateIndicator	StateIndicator	✅ STATE.HPP
Reticle	Reticle	✅ RETICLE.HPP
BTVal (turretBase, mechName, torsoAim*, aimRate, headPitch, torsoTwist)	animated value/quaternion — UNIDENTIFIED; BT411 BTVal is a no-op placeholder. Most BTVal members are < 0x328 = BASE-class pose fields (re-attribute per §"Consequences"), so their type is a base concern, not Mech's.

CRITICAL new finding — embedded helper classes are ALSO missing

AlarmIndicator, SequenceController, NameFilter, AverageOf do not exist anywhere in the 4.10 CODE archive (confirmed by full-tree grep). They are additional helper classes the milestone must reconstruct, and their sizes set the embedded-member offsets — so the masterAlarm@0x39C/heatAlarm@0x450/stabilityAlarm@0x4C4/statusAlarm@0x714 spacing DERIVES the AlarmIndicator per-level size (e.g. masterAlarm 33 levels spans 0x39C..0x450 = 0xB4; heatAlarm 3 levels spans 0x450..0x4C4 = 0x74 — a fixed header + N-level array; solve the two equations for header size + per-level stride). Same method sizes AverageOf from telemetryFilter[5]@0x7E0..0x81C (0x3C/5 = 0xC each) and SequenceController from the legAnimation/bodyAnimation spacing.

Subsystem roster source availability (VDATA 0xBxx ClassIDs)

• Full .CPP/.HPP in 4.10: GAUSS, PPC, SENSOR
• .TCP partial survivors (authoritative where present): AMMOBIN, EMITTER, GNRATOR, HEAT, MISSILE, PROJTILE, PROJWEAP
• Decomp-only (BT411): MechSubsystem base, gyro, torso, hud, myomers, mechweap, mislanch, powersub, + the rest of the "917 missing functions".

Revised reconstruction order

1. Helper classes (block the layout): AlarmIndicator, SequenceController, NameFilter, AverageOf — sizes solved from the offset-spacing equations above; identify BTVal.
2. MechSubsystem base + roster (GAUSS/PPC/SENSOR + .TCP partials + decomp).
3. Finalize MECH.HPP per the offset map; probe sizeof(Mech)==0x854.
4. Mech ctor (@004a1674): embedded construction + segment-table walk.
5. Per-frame path (mech2/3/4) + damage/weapon handlers.