# MISSILE.CPP / SEEKER.CPP / MISTHRST.CPP / PROJTILE.CPP — the flying rounds

**Status: PARTIAL (5.3.18) — the guided flight loop is LIVE-VERIFIED through
DETONATE (spawn → fly → home → proximity fuse → cluster damage lands once),
but the death-row TEARDOWN page-faults, so the spawn path is opt-in
(`BT_MISSILE_FLIGHT=1`); the default delivery remains the 5.3.18a instant-hit
cluster message.**

## Interfaces

- `SEEKER.HPP` + `MISTHRST.HPP` are AUTHENTIC survivors (CODE/BT/BT/). The
  Subsystem base chain is the NAME ctor (binary FUN_0041c52c) with the
  shipped strings "Seeker" @00512e1e and **"MissleThruster"** @00512e25 (the
  1995 misspelling is authentic — keep it).
- `MISSILE.HPP` / `PROJTILE.HPP` are STAGED (only MISSILE.TCP / PROJTILE.TCP
  survive). Binary chain: Entity → Projectile (@004be1bc, 0x340) → Missile
  (@004bf5b4, vtable @00512f2c, 0x368). Our staged chain matches:
  Projectile : Mover (make-message path), Missile : Projectile.

## What is verified live (BT_MISSILE_FLIGHT=1 fight run)

ONE cluster Missile entity per SRM salvo, spawned through the real Mover make
machinery mid-weapon-sim (the Entity ctor self-registers — the engine
tolerates mid-roster-walk creation, as the binary did); flight telemetry
shows thruster acceleration (150→153 u/s) and closing range; the proximity
fuse (rangeToTarget <= 20u staged) delivers `damageData` (salvo-split amount,
burstCount=missileCount) exactly once via TakeDamageMessage with the LAUNCHER
as inflictor; lifetime fizzle retires unexploded rounds. Guidance constants
are binary-decoded (steer deadband 1e-4, turn gain 4.0, seeker loft
200/50/300/0.1 — .rdata @004bec18/@004bf594).

## THE OPEN CRASH (the 5.3.18 frontier)

After the first detonated round's `~Missile` completes (dtor log proves it),
the frame page-faults with EIP IN THE HEAP (0x9FEAEF-style) — something
calls through freed missile memory or a base-dtor releases a structure
wrongly. The Seeker/MissileThruster are the FIRST SUBSYSTEMS and the Missile
the FIRST ENTITY ever DESTROYED in the reconstructed sim — the whole
~Entity/~Mover/~Subsystem teardown path is virgin. Checked already: NOT
AlwaysExecute (flag-only), NOT interestZoneID (message base NULLs it), NOT
the subsystemArray idiom (matches ~Entity's expectations exactly), Sensor
holds no pointers. Latent bug FIXED on the way: the Subsystem NAME ctor left
`damageZone` UNINITIALIZED (the resource ctor NULLs it) — garbage for every
name-built subsystem. Next suspects: ~Mover's collision/interest release
(collisionLists array delete), the executive's per-frame entity chain vs
mid-frame delete (FryDeathRow one-per-frame), the host-manager update-record
writer touching a condemned entity.

## Engine truths learned (load-bearing)

- `ResourceFile::SearchList(id, type)` CRASHES (@0x414938) when `id` is not
  in the top-level directory — it derefs its inner FindResourceDescription
  unconditionally. `FindResourceDescription(int)` is the NULL-safe probe.
- Resource IDs in MakeMessages must be FAMILY ids: the Mover base ctor runs
  its own `SearchList(resourceID, GameModelResourceType)`, and member
  resources resolve only through their family head.
- The streamed `explosionModelFile` is a small INDEX (SRM6 reads 17), a
  model-list indirection like voltageSourceIndex/ammoBinIndex — decoding it
  into the real projectile family is the projectile-model brick. Until then
  the round spawns on the OWNER's family (GameModel member provably present;
  our staged flight reads none of the Mover mass/drag).

## Staged / deferred

- Muzzle = mech origin; the authored MuzzleVelocity arc through the MOUNT
  segment world frame (fire builder @0x4bcc60:8758-64, z NEGATED + mech
  velocity) is the muzzle wave.
- Flight envelope defaults (lifetime 10s, burn 2s @120 u/s², launch 150 u/s,
  fuse 20u) pending the missile GameModel record decode (model +0x44
  lifetime, +0x48 thrust, +0x50 detonation mode).
- Cluster SPLASH + explosion entity (ClassID 0x5C @004be078), world-geometry
  collision (@0042291c), target-velocity intercept lead, Missile
  WriteUpdateRecord (tag 0x78) for MP replication.