Gitea #46: ammo bay fire now DETONATES and KILLS (+ #47 fire icon) -- three stacked kill-switches removed, the fuse decoded, and a vptr-alias corruption caught by regression

Field report (night 3): "two ammo bay fires and no death" (Cyd + RajelAran; one
purged, one left burning).  Root cause = THREE independent kill-switches stacked
on the same path, all in ammobin.cpp:

  1. `GameClock::Now() { return 0; }` -- `cookOffTime < Now()` was `0 < 0`, so
     an ARMED bay fire never detonated.
  2. `InjectHeat(void*) {}` -- the detonation body was a no-op.
  3. The bin's Damage record was never stamped -- 0 damage of type 0 (which the
     mech TakeDamage handler drops) even if 1+2 had fired.

THE FUSE (raw disasm, scratchpad/disammo.py): the old "RandomDelay" was a Ghidra
carve artifact -- FUN_004dcd94 is __ftol and the export DROPPED the caller's x87
expression.  The real bytes @004bd450: fld 10.0 / fmul [ticksPerSecond] /
fadd 0.5 / __ftol -- a FIXED 10.0-SECOND fuse in clock ticks.  New gotcha #19
(reconstruction-gotchas.md) documents the __ftol export blind spot.

THE DAMAGE RECORD: bin+0x1F0..0x21C is a real engine `Damage` (FUN_0041db7c IS
Damage::Damage(), byte-matched to T0 DAMAGE.cpp).  The linked ProjectileWeapon's
ctor @004bc3fc stamps it from weapon->damageData @0x3A8 via
owner->roster[0x128][res+0x1C0] -- projweap.cpp's old comment called this "the
bin's HUD display block ... wired in the AmmoBin family"; both halves were wrong
and it was wired nowhere.  Now stamped (before MissileLauncher's ctor divides by
missileCount -- a missile bin authentically holds the per-SALVO amount).

THE DETONATION (@004ac274 = MechSubsystem::DistributeCriticalHit -- the old
"HeatableSubsystem::InjectHeat" label was wrong, and the old reconstruction
iterated a stand-in CriticalChain whose First()/Next() returned 0):
statusAlarm pulse Exploding(2)->Destroyed(1) (slot 13 = the printSimulationState
state PRINT @004ac8c0, not an "explosion notify"), own private zone pinned
destroyed, then collect the mech DamageZones whose crit entries plug the bin
(the binary filters plug classID 0x4E = DamageZoneClassID -- VDATA.h idx 78,
cross-checked via idx 28 = AudioStateTrigger), split the amount evenly, and send
the OWNER one full Entity::TakeDamageMessage per zone: inflictingEntity = SELF,
damageZone = the zone index, inflictingSubsystemID = the bin (the message-
manager explosion-bundling key, ENTITY3.h's own NOTE), printing the binary's
exact "ammo explosion damaging <zoneName>" @0050df61.
Port shape: Mech::AmmoExplosionFanOut (mechdmg.cpp) behind a databinding bridge;
guarded deviation: zoneCount==0 warns instead of the binary's unguarded divide.
CriticalChain/CriticalEntry stand-ins DELETED from mechrecon.hpp.

VERIFIED LIVE (BT_BAYTEST hook = message 1, the crit-induced arm channel):
  scratchpad/baytest.py : arm -> 10s -> "20 rounds x 35 = 700 (type 2)" ->
    "ammo explosion damaging dz_ltorso" -> zone cascade -> mech DESTROYED
    (authentic death list).
  scratchpad/baypurge.py: arm -> eject-hold purge -> "bay fire EXTINGUISHED
    (bin empty)", no detonation.
  scratchpad/sim3.py    : the HEAT route arms organically in combat (overheated
    AFC100), detonates "11 x 25 = 275 (type 1)" split across dz_larm + dz_lgun.
  BAYBOOM matchlog record added for MP field forensics.

FIX-OF-THE-FIX (caught by the sim3 regression, would have shipped a crash):
MechSubsystem's ReconDamageZone proxy puts structureLevel at OFFSET 0 -- which
ALIASES THE REAL DamageZone's VTABLE POINTER (the private zone is `new
DamageZone`, mechsub.cpp:154; mechsub.hpp:260 documents the alias).  My first
DistributeCriticalHit kept the old body's `damageZone->structureLevel = 1.0f`
and OVERWROTE THE ZONE'S VPTR with 0x3F800000; the respawn sweep's virtual
SetGraphicState (vtable+0xC) then called through it -> AV at 0x3f80000c in
RespawnRepair, one frame after a bay-fire death.  ALL EIGHT proxy-view sites in
mechsub.cpp swept to the engine view (((DamageZone*)damageZone)->damageLevel
@0x158) -- including two silently-wrong LIVE readers: GetStatusFlags (vptr as
float -> always "intact") and ApplyDamageAndMeasure (the crit cascade's
measure).  Ruled out first by evidence: the weapon->bin stamps were all clean
(six stamps, all classID 0xbcb, logged).

#47 (half 1 -- the FIRE ICON): BallisticWeaponCluster::Execute @004c9a38 reads
bin+0x18C = cookOffArmed into the btefire.pcc TwoState, and while armed computes
(Now - cookOffTime)/ticksPerSecond -- the COOK-OFF COUNTDOWN -- into the numeric
beside it.  The old reconstruction misread 0x18C as "the reload state" and
bridged the icon to BTAmmoBinFeeding, so it blinked on every feed and never lit
on a bay fire (RajelAran: "it doesn't").  Now driven by the
BTAmmoBinCookOffArmed/CookOffTime complete-type bridges.  [T2 -- the data path
is rig-verified; the pixels await the next live session.]

#47 (half 2 -- the ENG-BUTTON FLASH): fully mapped, deliberately NOT built this
session.  The authored data SHIPS (BTL4.RES carries exactly one type-31
GaugeAlarmStream); the chain is alarm SetLevel -> gauge-watcher socket ->
Renderer msg 7 -> GaugeAlarmManager::Activate @00448d00 (T0) -> the BTL4
override @004cc148..@004cc2fc (btl4galm.cpp's provenance note claiming "no
override body exists" is WRONG -- corrected in-file) -> LampManager::FindLamp
@00444c80 -> Lamp::SetAlertState @00444e64 (flash counter) -> the L4 flush
@00474e94 emitting flashFast states 0x37/0x13 (== T0 L4LAMP.cpp:234-239).
Missing: the override bodies, the gauge-watcher sender, the aux-button lamps.
3-piece plan in context/open-questions.md.

Also logged: HandleMessage is vtable slot 8/9 in the binary but NON-virtual
across 10 reconstruction classes (bit the BT_BAYTEST hook; typed call used, gap
documented in open-questions).

KB: combat-damage.md (the full cook-off section), decomp-reference.md (the
cluster addresses + the GaugeAlarm/lamp map + BT_BAYTEST env), gauges-hud.md
(the fire-icon correction), reconstruction-gotchas.md #19 (__ftol),
open-questions.md (2 entries), btl4galm.cpp provenance correction.
checkctx CLEAN.  40 LNK2019 unchanged (the two pre-existing families).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

game/reconstructed/projweap.cpp

@@ -334,9 +334,31 @@ ProjectileWeapon::ProjectileWeapon(
 	{
 		Subsystem *roster_bin = OwnerSubsystem(owner, subsystem_resource->ammoBinIndex);	// +0x128 table
 		ammoBinLink.Connect(roster_bin);		// (**bin.vtbl[1])(...)
-		// CROSS-FAMILY (mech/ammobin): the shipped ctor also primed the bin's HUD
-		// display block (iVar1+0x1f0/0x1f4/0x1f8/0x210) from this weapon; wired in
-		// the AmmoBin family.
+
+		// @004bc3fc (Gitea #46): stamp the bin's COOK-OFF DAMAGE RECORD from this
+		// weapon's own Damage -- bin+0x1F0..0x21C <- weapon->damageData @0x3A8:
+		//     *(bin+0x1f0) = this[0xea]   damageType        *(bin+0x1f4) = this[0xeb] damageAmount
+		//     *(bin+0x1f8..) = force      *(bin+0x204..) = normal   *(bin+0x210..) = impact
+		//     *(bin+0x21c) = this[0xf5]   burstCount
+		// The old comment here called this "the bin's HUD display block ... wired
+		// in the AmmoBin family" -- BOTH halves were wrong: it is the Damage record
+		// the bay-fire detonation multiplies by ammoCount (CookOff @004bd300), and
+		// it had never been wired anywhere, so the record stayed all-zero and even
+		// a detonating cook-off would have dealt 0 damage of type 0 (which the
+		// mech TakeDamage handler drops).  NOTE the sequencing is authentic and
+		// load-bearing: this runs INSIDE the ProjectileWeapon ctor, BEFORE
+		// MissileLauncher's chained ctor divides its own damageData by
+		// missileCount -- so a missile bin holds the per-SALVO amount.  The
+		// binary writes the roster slot UNGUARDED (no AmmoBin type check).
+		if (getenv("BT_AMMO_LOG"))
+			DEBUG_STREAM << "[ammo] stamp " << GetName() << " -> roster["
+				<< subsystem_resource->ammoBinIndex << "]="
+				<< (roster_bin ? roster_bin->GetName() : "NULL")
+				<< " classID=0x" << std::hex
+				<< (roster_bin ? (int)roster_bin->GetClassID() : 0) << std::dec
+				<< " dmg={t=" << (int)damageData.damageType
+				<< " a=" << damageData.damageAmount << "}\n" << std::flush;
+		((AmmoBin *)roster_bin)->StampCookOffDamage(damageData);
 	}
 
 	AmmoBin *bin = (AmmoBin*)ammoBinLink.Resolve();	// FUN_00417ab4(this+0x43c)