TeslaRel410/restoration/source410/BT/BTDIRECT.CPP

//===========================================================================//
// Project: BattleTech                                                       //
//---------------------------------------------------------------------------//
// Copyright (C) 1995, Virtual World Entertainment, Inc.                     //
// 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// This unpublished sourcecode is PROPRIETARY and CONFIDENTIAL               //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

#if !defined(BTDIRECT_HPP)
#	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,
		"BTCameraDirector"
	);

BTCameraDirector::SharedData
	BTCameraDirector::DefaultData(
		BTCameraDirector::ClassDerivations,
		CameraDirector::MessageHandlers,
		CameraDirector::AttributeIndex,
		1,
		(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)
{
	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 *creation_message)
{
	BTCameraDirector
		*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();
}