BT410 5.3.116: the spectator camera direats -- BTCameraDirector reconstructed from a disassembly gap, and the donor's inverted pick caught

The two Performance bodies fell in a Ghidra gap (@004c11b3..@004c1408), so
BeABTDirector came straight off ndisasm of the shipped CODE section. The
verdict corrects the BT411 donor twice more: FUN_0049fb54 is not
'IsLiveMech' -- it is the mech DEATH-TRANSITION test (simulation state 2 or
9; its other callers strip update-record motion bits and halt motion
integration while it holds, and our own MovementMode ledger already said
so) -- and the donor's pick loop breaks on a DYING vehicle where the
binary's jz breaks on a LIVE one. The true 1995 behavior: the camera
lingers on its mech while the 30s timer runs, cuts away THE MOMENT the
followed mech starts dying, picks the first of four ranked players with a
live vehicle, and refreshes the lock during mission end. The 'BT-specific
0x15/0x34 track message' the port invented an engine substitute for IS the
engine's CameraShip::DirectionMessage -- ID 0x15 == Entity::NextMessageID,
0x34 bytes, byte-for-byte; the RP engine's own BeADirector source
(DIRECTOR.CPP survives) is the literal structural template BT overrode
(rank-0-only, 10s, no offset -> four ranks, 30s, (0,5,0) eye).

Mech::InDeathTransition lands in mech.cpp per the census (@0049fb54, 32
bytes). The ctor's replicant gate uses the binary's own flag test --
entity-side simulationFlags arrive live via the MakeMessage, unlike the
subsystem masters still waiting on the stream builders.

Stubs: 11 across 9 files (the 8 authoring CSS fns + the L4NET trio).
Pod-role soak clean; the director's live test rides the operator's
camera-egg / mission-review session.

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

restoration/source410/BT/BTDIRECT.CPP

@@ -5,6 +5,34 @@
 // All Rights reserved worldwide                                             //
 // This unpublished sourcecode is PROPRIETARY and CONFIDENTIAL               //
 //===========================================================================//
+//
+// BTCameraDirector -- the spectator/live-cam director (camera-role eggs).
+// The surviving BTDIRECT.HPP is ground truth for the interface.  The two
+// Performance bodies fell in a Ghidra gap (@004c11b3..@004c1408) and were
+// recovered by direct disassembly of the shipped exe (ndisasm of the CODE
+// section); the construction family comes from the decomp (part_013.c).
+//
+//   ctor                @004c1408   (chains CameraDirector @0042eec8)
+//   Make                @004c1454   (new 0x238 + ctor)
+//   ~BTCameraDirector   @004c1484
+//   TestInstance        @004c14b0
+//   CreateBTCameraShip  @004c13d4   initial Performance
+//   BeABTDirector       @004c1230   steady Performance
+//
+// The engine base (RP DIRECTOR.CPP survives) is the literal template:
+// CameraDirector::BeADirector = PlayerSimulation + UpdateHUD + a 10s
+// rotation onto FindPlayerByRank(0)'s vehicle.  The BT override widens the
+// scan to the first four ranks, stretches the rotation to 30s, offsets the
+// camera eye (0, 5, 0), refreshes the lock while the mission ends -- and
+// CUTS AWAY from the followed mech the moment it enters the death
+// transition (Mech::InDeathTransition, binary @0049fb54).  NOTE: the BT411
+// donor's pick loop is inverted here (it breaks on a DYING vehicle); the
+// disassembly's pick breaks on jz -- the first LIVE vehicle wins.
+//
+// The "BT-specific" track message turns out to be the engine's own
+// CameraShip::DirectionMessage (ID 0x15 == Entity::NextMessageID, 0x34
+// bytes) -- no BT message class exists.
+//
 
 #include <bt.hpp>
 #pragma hdrstop
@@ -13,6 +41,17 @@
 #	include <btdirect.hpp>
 #endif
 
+#if !defined(CAMSHIP_HPP)
+#	include <camship.hpp>		// CameraShip::DirectionMessage (the track)
+#endif
+
+#if !defined(APP_HPP)
+#	include <app.hpp>			// application state gates
+#endif
+
+#define CAMERA_SWITCH_INTERVAL	30.0f	// 0x41f00000 -- BT stretches the base 10s
+#define CAMERA_EYE_HEIGHT		 5.0f	// 0x40a00000 -- fixed eye offset
+
 Derivation
 	BTCameraDirector::ClassDerivations(
 		CameraDirector::ClassDerivations,
@@ -28,22 +67,162 @@ BTCameraDirector::SharedData
 		(Entity::MakeHandler)BTCameraDirector::Make
 	);
 
+//
+//#############################################################################
+// Construction / Destruction
+//
+// @004c1408 -- chains the engine CameraDirector ctor; a non-replicant copy
+// gets CreateBTCameraShip as its initial Performance.  The replicant test is
+// the entity flag pair (simulationFlags & 0xC) == 4 -- these flags arrive
+// via the MakeMessage's instance flags, so the binary's own gate works here
+// (unlike the subsystem masters, whose 0xC/0x100 seeding still waits on the
+// mech stream builders).
+//#############################################################################
+//
 BTCameraDirector::BTCameraDirector(
 	MakeMessage	*creation_message,
 	SharedData	&shared_data
 ):
 	CameraDirector(creation_message, shared_data)
 {
-	Fail("BTCameraDirector -- btdirect.cpp not yet reconstructed");
+	Check(this);
+
+	if ((simulationFlags & 0xC) != 4)
+	{
+		SetPerformance(&BTCameraDirector::CreateBTCameraShip);
+	}
+
+	Check_Fpu();
 }
 
 BTCameraDirector::~BTCameraDirector()
 {
 }
 
+//
+// @004c1454 -- the registered MakeHandler: allocate (0x238) and construct.
+//
 BTCameraDirector*
-	BTCameraDirector::Make(CameraDirector::MakeMessage *)
+	BTCameraDirector::Make(CameraDirector::MakeMessage *creation_message)
 {
-	Fail("BTCameraDirector::Make -- btdirect.cpp not yet reconstructed");
+	BTCameraDirector
-	return NULL;
+		*director = new BTCameraDirector(creation_message);
+	Register_Object(director);
+	return director;
+}
+
+//
+// @004c14b0
+//
+Logical
+	BTCameraDirector::TestInstance() const
+{
+	return IsDerivedFrom(ClassDerivations);
+}
+
+//
+//#############################################################################
+// CreateBTCameraShip -- @004c13d4, the initial Performance.  One-shot: let
+// the engine base spawn the spectator camera ship and wire its viewport,
+// then hand the per-frame work to the steady director.
+//#############################################################################
+//
+void
+	BTCameraDirector::CreateBTCameraShip(Scalar time_slice)
+{
+	Check(this);
+
+	CameraDirector::CreateCameraShip(time_slice);
+
+	SetPerformance(&BTCameraDirector::BeABTDirector);
+}
+
+//
+//#############################################################################
+// BeABTDirector -- @004c1230, the steady Performance (disassembly-verified).
+//
+// Per frame: the inherited player-side update and viewpoint/HUD work, then
+// the pick.  While the rotation timer runs during a live mission the camera
+// stays put -- UNLESS the followed mech has entered its death transition,
+// in which case the re-pick happens immediately (the cut away from the
+// kill).  On a re-pick the first of the four ranked players whose vehicle
+// is alive wins; a switch restarts the 30s timer and sends the camera ship
+// a DirectionMessage with the (0, 5, 0) eye offset.  While the mission is
+// ending the lock refreshes even if the target is unchanged.
+//#############################################################################
+//
+void
+	BTCameraDirector::BeABTDirector(Scalar time_slice)
+{
+	Check(this);
+
+	Player::PlayerSimulation(time_slice);
+	UpdateHUD(time_slice);
+
+	Logical
+		mission_ending = False;
+
+	if (
+		timeLeftOnPlayer > 0.0f &&
+		application->GetApplicationState() == Application::RunningMission
+	)
+	{
+		if (!Mech::InDeathTransition(GetGoalEntity()))
+		{
+			timeLeftOnPlayer -= time_slice;
+			return;
+		}
+		// the followed mech is dying -- fall through and cut now
+	}
+	else if (application->GetApplicationState() == Application::EndingMission)
+	{
+		mission_ending = True;
+	}
+
+	//
+	// The first ranked player (0..3) with a live vehicle wins the camera.
+	//
+	Player
+		*player = NULL;
+	Entity
+		*vehicle = NULL;
+	int
+		rank;
+	for (rank = 0; rank < 4; rank++)
+	{
+		player = FindPlayerByRank(rank);
+		if (player != NULL)
+		{
+			vehicle = player->GetPlayerVehicle();
+			if (vehicle != NULL && !Mech::InDeathTransition(vehicle))
+			{
+				break;
+			}
+		}
+	}
+	if (player == NULL || vehicle == NULL)
+	{
+		return;
+	}
+
+	if (vehicle == GetGoalEntity() && !mission_ending)
+	{
+		return;
+	}
+
+	SetGoalEntity(vehicle);
+	timeLeftOnPlayer = CAMERA_SWITCH_INTERVAL;
+
+	CameraShip::DirectionMessage
+		track(
+			CameraShip::DirectionMessageID,
+			sizeof(CameraShip::DirectionMessage),
+			GetGoalEntity()->GetEntityID(),
+			CAMERA_SWITCH_INTERVAL,
+			Point3D(0.0f, CAMERA_EYE_HEIGHT, 0.0f)
+		);
+	Check(cameraShip);
+	cameraShip->Dispatch(&track);
+
+	Check_Fpu();
 }

restoration/source410/BT/MECH.CPP

@@ -796,6 +796,20 @@ Mech::~Mech()
 {
 }
 
+//
+//#############################################################################
+// InDeathTransition -- binary @0049fb54 (32 bytes): simulation state 2 or 9.
+//#############################################################################
+//
+Logical
+	Mech::InDeathTransition(Entity *vehicle)
+{
+	Check(vehicle);
+	return
+		vehicle->GetSimulationState() == 2 ||
+		vehicle->GetSimulationState() == 9;
+}
+
 //
 //#############################################################################
 // TakeDamageMessageHandler -- the Mech override of the Entity damage entry

restoration/source410/BT/MECH.HPP

@@ -597,6 +597,19 @@
 		Subsystem*
 			GetSensorSubsystem()	{ Check(this); return sensorSubsystem; }
 
+		//
+		// The death-transition test (binary @0049fb54, mech.cpp): True while
+		// the simulation state is 2 or 9 -- the two death-transition states
+		// in the MovementMode ledger.  Multiple families key off it: update
+		// records strip their motion bits while it holds (@004a4c54), motion
+		// stops integrating (mech4 dead-reckon head), and the spectator
+		// camera director cuts AWAY from a mech the moment it starts dying
+		// (BeABTDirector @004c1230).  Takes the ENTITY view because callers
+		// hold vehicles as Entity* (the state field is the Simulation base's).
+		//
+		static Logical
+			InDeathTransition(Entity *vehicle);
+
 	//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 	// Locomotion parameters (read by MechControlsMapper::InterpretControls to
 	// shape the demands, and by the drive in Simulate).  reverseStrideLength is