BT412/context/open-questions.md

---
id: open-questions
title: "Open Questions — deferred systems, unknowns, get-from-Nick"
status: living
source_sections: "CLAUDE.md §9; docs/HARD_PROBLEMS.md; per-subsystem deferral notes"
related_topics: [source-completeness, subsystems, multiplayer, combat-damage, locomotion]
---

# Open Questions

Known unknowns + deliberately-deferred systems. For each: what's known, what's missing, what
would resolve it, status. Deferred ≠ broken — most are marked-and-guarded stand-ins with the
authentic path scoped.

## From Nick (external — gating for some paths)
- **[GATING] The BT game SOURCE CODE** — the missing implementation `.cpp` (mech, subsystems,
  mapper, HUD, app; see [[source-completeness]]). Without it, Route A (recompile original) is
  impossible; we reconstruct from the binary instead. Likely on a backup/dev drive. Status: OPEN.
- Confirmation the PodPC image is the complete content master. (Low priority — the runtime
  `BTL4.RES` already has 8 maps + the full mech anim set.) Status: OPEN.
- Pod specifics for Phase 8: the 7-monitor driver setup, the RIO cockpit I/O protocol, current
  Win10+wrapper pod config. Status: OPEN.

## Deferred subsystems / feeds (authentic path scoped, marked in code)
- **0xBD3 SubsystemMessageManager (WAVE 8)** — a per-mech **damage/explosion consolidation hub**
  (`ConsolidateAndSendDamage` Performance @0049b784, `weaponExplosions` queue, `CommonDamageInformation`;
  messmgr.hpp). ctor `FUN_0049bca4` (vtable 0x50b954, installs a Performance → ticks). The factory
  caches it to **`Mech[0x10d]` = byte 0x434**. What wiring it needs: an untangle — our reconstruction
  MISLABELED `Mech[0x10d]` as `controlsMapper` and `mech4`'s live drive reads it as the mapper, so the
  real messmgr can't land there until the drive is re-pointed to the true mapper (**roster slot 0**,
  installed by `SetMappingSubsystem`/`MakeViewpointEntity`; a `MechRIOMapper`). Payoff = authentic
  damage/explosion consolidation (a COMBAT-fidelity improvement) + fixing the mapper/messmgr conflation.
  ⚠ **CORRECTION (verified 2026-07):** 0xBD3 does NOT gate the valve/Myomers/MessageBoard — those read a
  DIFFERENT object at **`mech+0x190`** (both `FUN_004ac9c8` the valve guard `→+0x274` and `FUN_004ad7d4`
  the Myomers gate `→+0x260` deref `owner+0x190`, which ≠ the 0x434 messmgr cache). The earlier
  "0xBD3 gates 4 things" note was wrong.
- **✅ `mech+0x190` IDENTIFIED (2026-07): it is the owning `BTPlayer`** (`Mech::GetPlayerLink()`,
  `MECH_OWNING_PLAYER`; ENTITY.h:430). Set by `FUN_0049f624` (the mech↔player bind: `mech+0x190 = player`
  AND `player->playerVehicle(+0x1fc) = mech`), which resolves the player from the mission player registry
  (`app+0x2c+0x54`, `FUN_0041fd18`) by the pilot key. The valve/Myomers "gates" read the owning player's
  fields at `player+0x260` and `player+0x274` (the reconstruction maps this block as `showDamageReceived@0x25c
  / showKills@0x260 / showDamageInflicted@0x264 / roleClassIndex@0x274` in btplayer.hpp — from the SCORING
  work, so the names may NOT match the gate semantics; the true meaning + the WRITER of `player+0x260/0x274`
  are not yet pinned — part_013.c:4553-4660 is the TorsoSimulation, a different object, not the setter). So
  there is NO new subsystem to build. **The wiring (small):** point `MechSubsystem::IsDamaged()` (`FUN_004ac9c8`, valve
  guard) at `GetPlayerLink()->`(0x274) and `Myomers::OwnerAdvancedDamage()` (`FUN_004ad7d4`) at
  `GetPlayerLink()->`(0x260) — via NAMED members (databinding trap: our BTPlayer layout ≠ binary; do NOT
  raw-read `player+0x260`). ⚠ Resolve first: (a) a naming conflict — `FUN_004ad7d4` is labeled BOTH
  `HeatModelActive` (heat.hpp) AND `OwnerAdvancedDamage` (myomers.cpp); re-verify which body is which; (b)
  the true semantic of `player+0x260/0x274` vs the scoring-derived `showKills`/`roleClassIndex` names. NOTE:
  these are MODE flags — in the basic test mission the inert Myomers / dormant valve is likely AUTHENTIC
  (advanced damage off); wiring makes them RESPOND when a mission enables the mode, not necessarily change
  the basic-mission behavior. The MessageBoard feed is separate (StatusMessagePool, below).
- **StatusMessagePool (NULL stub, btstubs.cpp:62)** — the per-player status-message queue.
  BTPlayer+0x1dc is never populated → MessageBoard is empty (authentic for bring-up). What
  resolves it: wire the pool + decode `AddStatusMessage @0042e580` + the `Player__StatusMessage`
  record ({messageId@+0xc, nameEntity@+0x10}).
- **Gyroscope (0xBC4)** — layout + joint-I/O reconstructed, but the ctor field-init + the two
  integrators (IntegrateEyeJoint @004b2ec0 / IntegrateBody @004b30ec) are incomplete → writes NaN
  to the root joint. Reverted to a stub. A full subsystem-sim reconstruction (bigger than Torso).
- **MechControlsMapper look/eyepoint commit** — reconstructed but its offsets collide with declared
  members; arbitrate before enabling (no port consumer yet). The fire-trigger-through-mapper is
  still the `gBTWeaponTrigger` bring-up.
- **Myomers authentic coupling** — the structural un-stub is INERT (mover feed + heat-gen no-op).
  Real coupling needs the advanced-damage gate (`OwnerAdvancedDamage`/`FUN_004ad7d4` → the owning
  **BTPlayer** `mech+0x190`+0x260, NOT 0xBD3 — see the mech+0x190 item above) + `MoverAttach` routing
  into the LIVE JointedMover (must be reconciled with the gait cutover first).
- **SeekVoltageGraph** — 4 Seek* attrs unpublished (a cluster-child, not config-called; non-blocking).

## Locomotion / combat polish (non-gating)
- Authentic per-mech TURN-RATE constant (currently a bring-up constant rate).
- Body-callback gimp handlers (states 16-19, targets 0x70b2/0x7161 undecoded → fall back to stand);
  airborne callbacks (`FUN_004a6344`/`FUN_004a7970`).
- Wall-block-vs-climb tuning; collision DAMAGE application (computed, not applied — blocked on the
  cylinder hit-location model / STEP 6, below, to resolve the impact point → zone; else aim a fixed zone).
- **Cylinder hit-location (STEP 6)** — the Mech override that maps an unaimed hit's impactPoint → a damage
  zone. Investigated 2026-07 (see [[combat-damage]]): the table (list of 0x30-byte entries, `FUN_0049e740`,
  resource type 0x1d) IS built (recon `StandingAnimation` @Mech[0x111], but with an EMPTY name → 0 entries);
  the lookup + `Mech::TakeDamageMessageHandler` override are NOT in the exported decomp (need disassembly).
  Meatier than a captured-fn reconstruction — the cited `FUN_004a0230`/`FUN_0049ed0c` don't exist.
- Death: reconstruct `DeathShutdown` (RP `VTV::DeathShutdown` analog) + collapse anim + destroyed
  skin. The wreck-stays behavior we ship is faithful; do NOT issue DestroyEntityMessage on death.

## Multiplayer (Phase 7 / P6)
- Cross-pod COMBAT (target a replicant + route damage to the owning master).
- Replicant GAIT animation (replicants don't animate joints yet — derive from replicated velocity).
- The pod-LAN config (real IPs, bare-IP pilot entries). The WinSock2 TCP stack (L4NET.CPP) is
  reconstructed + smoke-tested on one box (two instances share a world, movement replicates).

## Rendering follow-ups (non-blocking)
- Replacement-LOD selection for NON-additive multi-LOD models (needs the board's hot-spot/
  reference-point semantics; leads: `s_dplobject.lod_ranges[16]/lod_hot_spot`, 0x2047/0x2048).
- Day/night MATERIAL path priority (BMF/IMG) — infrastructure done, gated `BT_MATPRI` (over-applies
  to shared terrain mats); needs the terrain-material model understood.
- RGBA4444 alpha (TREE.BSL cutout) decoded but not alpha-tested outside punch batches; VTX/TGA paths.

## Content build sub-project (low priority)
- Lab/other-build maps (`des`/`burnt`/`frstrm`) are source-only (`.map` in CONTENT/BT/MAPS/); would
  need compiling into a RES via the DOS `btl4tool.exe`. The 8 RES maps cover testing.

## Key Relationships
- Feeds from: every subsystem/render topic (their deferral notes collect here).
- Gating master: [[source-completeness]] (the missing BT source).