BT411/context/subsystems.md

id, title, status, source_sections, related_topics, key_terms, open_questions

id	title	status	source_sections	related_topics	key_terms	open_questions
subsystems	Subsystems — the factory + the reconstruction waves	established	PROGRESS_LOG.md §10d; docs/SUBSYS_PLAN.md; docs/VEHICLE_SUBSYSTEMS.md; docs/RESOURCE_AUDIT.md	decomp-reference reconstruction-gotchas combat-damage gauges-hud	subsystem factory ClassID subsystem-roster PoweredSubsystem bridge	Myomers coupling (gates on owning-player @mech+0x190); 0xBD3 damage-hub untangle (WAVE 8)

Subsystems

The mech's components (heat/power/weapons/sensor/gyro/torso/myomers/…), built by the Mech-ctor factory. Full per-family plan: docs/SUBSYS_PLAN.md; the engineering-cluster panels: docs/VEHICLE_SUBSYSTEMS.md; the layout audit: docs/RESOURCE_AUDIT.md. ClassID map: decomp-reference §2.

The factory

The Mech ctor switches on the resource ClassID to build each subsystem into the subsystem-roster (subsystemArray@0x128). The case <Name>ClassID LABELS are systematically MISLABELED — the real class is the // FUN_004xxxxx ctor-address comment reconciled via CLASSMAP.md, not the case name (e.g. 0xBBE case="Sensor" is actually AggregateHeatSink). Each real class is wired via a Create<Class>Subsystem(Mech*,int,void*) bridge in the class's own .cpp (do NOT #include the real subsystem headers into mech.cpp — the local stubs collide). Keep the alloc SIZE + special-cache. [T2]

Class hierarchy (two branches, shared only at MechSubsystem)

• Heat leaf: PoweredSubsystem : HeatSink : HeatableSubsystem : MechSubsystem. Emitter/PPC/ Sensor/Myomers/ProjectileWeapon/MissileLauncher/GaussRifle chain here. Uses 0xC SubsystemConnection
  • 0x54 GaugeAlarm54 (alarm level at +0x14). [T1]
• Watcher branch: Torso/Gyroscope/Searchlight/ThermalSight/HUD : PowerWatcher : HeatWatcher : MechSubsystem; AmmoBin : HeatWatcher. Uses a 0xC WatchedConnection + 0x54 WatcherGaugeAlarm. [T1] Making a base byte-exact GROWS every subclass — they must be re-based TOGETHER in one build, each static_assert-locked (the P7 alarm-unification: HeatSink 0x1D0 → PoweredSubsystem 0x31C → MechWeapon 0x3F0 → Emitter 0x478). [T2]

Reconstruction waves (state: ALL 20 factory cases wired to real classes — 0xBD3 = the real SubsystemMessageManager since task #7, 2026-07-11; the mapper lives in roster slot 0)

• WAVE 1 — HeatableSubsystem re-based onto MechSubsystem (de-shadow cascade).
• WAVE 2 — heat family (Condenser/AggregateHeatSink/Reservoir) + HUD + MechTech (un-swap).
• WAVE 3 — power bus (Generator/PoweredSubsystem) + Emitter/PPC fire-path (end-to-end fire; heat conducts to the central sink via the linked-sink roster).
• WAVE 4 — standalone readouts: Sensor/Searchlight/ThermalSight/AmmoBin (de-shim, gate fixes).
  • ⚠ Searchlight has an ORIGINAL latent bug [T1, task #63]: SearchlightSimulation (@004b841c) reads requestedOn@0x1E0 (never written) while ToggleLamp (@004b860c) toggles commandedOn@0x1DC — no bridge, so lightState@0x1D8 is perpetually 0 (lamp never lights). Present in the 1995 binary (sibling ThermalSight reads the field it toggles, 0x1DC); the port reproduces it faithfully. Left as-is by decision; it makes the searchlight→fog swap inert. See open-questions + rendering fog.
• WAVE 5 — Torso (aim twist/elevation; joint-I/O reconstructed; the BLH record disables torso → faithfully no visible twist).
• WAVE 6 — Myomers (mover-coupled; structural un-stub is INERT — no live mover/heat coupling).
• WAVE 7 — projectile/missile weapons (byte-exact; flying projectiles are a PORT reconstruction — the 2007 Entity is 0x1BC vs the binary's 0x300, so raw base-offset reads fail).
• TASK #56 (2026-07-11) — Gyroscope LIVE byte-exact (ctor @004b3778, sizeof 0x3D0 locked; integrators + FUN_004b2980 damage fan-out; joint dispatch from the Mech performance tail @0x4aaf74/83; BT_GYRO_LOG/BT_GYRO_TRACE) — see cockpit-view.
• DEFERRED — SubsystemMessageManager 0xBD3 (WAVE 8 — a damage/explosion consolidation hub cached to Mech[0x10d]=0x434; recon MISLABELS the slot controlsMapper + the drive squats there while the real mapper is roster slot 0, so wiring it needs an untangle. NOT the valve/advanced-damage gate — that's the owning BTPlayer @mech+0x190, see combat-damage/open-questions). [T2]

The watcher electrical chain (task #57, 2026-07-13 — the torso power gate)

The Watcher branch is POWERED indirectly: a watcher WATCHES another roster subsystem and mirrors its electrical state. The full chain, byte-verified [T1]:

• Data: the model entry WatchedSubsystem=<name> → segment index +2 at resource+0xE4 (HeatWatcher::CreateStreamedSubsystem @004aec54); the ctor @004aeb40 stores it at watcher+0x128 (watchedSubsystem).
• Bind (factory post-roster loop 1): vtable slot 14 (+0x38) — @004aee2c (HeatWatcher) / @004b1a40 (PowerWatcher/Torso override, byte-identical); Ghidra missed both function starts (recovered from raw bytes; the vtables.tsv rows have GAPS where the exporter skipped slots — dump the exe bytes at vtable+slot*4 when a slot looks missing). Master-gated ((owner->simulationFlags & 0xC)==0 && (flags & 0x100)); binds watchedLink(+0x114).Add( owner->roster[+0x128][watchedSubsystem]). Port: BTWatcherWatchedIndex/BTWatcherBindTarget bridges (heatfamily_reslice.cpp) called from the mech.cpp factory loop.
• Tick: @004b181c = the REAL PowerWatcher Performance (PTR @0050f5fc → 004b181c) = UpdateWatch(): heat mirror (FUN_004aeac4) + watchdogAlarm.SetLevel(watched->electrical level @+0x278) + brownout downgrade to 1 when gen->outputVoltage(+0x1DC) <= minVoltage(+0x180) × gen->ratedVoltage(+0x1D8). The Torso sims (@004b5cf0/@004b65f8) call it first-line. (@004b1804 is slot-10 ResetToInitialState, NOT the Simulation — old recon mislabel, fixed.)
• MinVoltageScale = 0.01 — a 10-byte x87 literal at 0x4b1924 (0a d7 a3 70 3d 0a d7 a3 f8 3f); the port had 1.0f, making minVoltage 100× too big → the brownout latched every watchdog at 1.
• PowerWatcher::GetClassDerivations chains HeatWatcher (real base) — the old HeatableSubsystem stand-in broke IsDerivedFrom(HeatWatcher) for Torso/Searchlight/ThermalSight and silently skipped them in the connect pass.
• Effect: Torso::ElectricalStateLevel()==Ready(4) un-gates effectiveTwistRate — the MadCat torso twists at its authored 50°/s (±140° limits, roster 17 watching 15 → generator @10000V); the BLH is authentically fixed (horizontalEnabled=0, limits ±0.01°). [T2 live-verified]
• STILL DEAD: factory loops 2-4 (heatable/weapon/damageable capability rosters) go through the SubProxy stub whose IsDerivedFrom returns 0 — they add NOTHING. See open-questions.

The four systemic checks (every subsystem)

See reconstruction-gotchas: (1) shadowing (re-declared engine-base fields), (2) the Wword trap, (3) message-handler chaining, (4) entity validity. Plus resource-struct layout (must mirror the class hierarchy, byte-exact — the RESOURCE_AUDIT found 8 bugs) and object-layout (alias/phantom/interior fields). A +0x128-style owner offset is the ROSTER, not the segment table (the heat-link type confusion that caused a heap-corruption via OOB ConductHeat writes). [T2]

Engineering cluster panels (vehicleSubSystems)

Not a widget — a per-subsystem FACTORY (FUN_004cbaf0) building a status CLUSTER onto one of 12 aux MFD positions, dispatching on classID → HeatSinkCluster/MyomerCluster/EnergyWeaponCluster/ BallisticWeaponCluster. Reads PoweredSubsystem::auxScreenNumber/Placement/Label (res +0x104/8/C) via the BTGetSubsystemAuxScreen bridge. See docs/VEHICLE_SUBSYSTEMS.md + gauges-hud. [T2]

Key Relationships

• Data: decomp-reference (ClassIDs/hierarchy). Bugs: reconstruction-gotchas.
• Feeds: combat-damage (weapons/damage), gauges-hud (attribute state).
• Plan: docs/SUBSYS_PLAN.md.