//===========================================================================//
// File:	hud.cpp                                                             //
// Project: BattleTech           Brick: Mech subsystems                       //
// Contents: HUD -- head-up display / targeting reticle                      //
//---------------------------------------------------------------------------//
// Copyright (C) 1995, Virtual World Entertainment, Inc.                     //
// All Rights reserved worldwide                                             //
// This unpublished sourcecode is PROPRIETARY and CONFIDENTIAL               //
//===========================================================================//

#include <bt.hpp>
#pragma hdrstop

#if !defined(HUD_HPP)
#	include <hud.hpp>
#endif

#if !defined(MECH_HPP)
#	include <mech.hpp>
#endif

static const Point3D HudZeroVector(0.0f, 0.0f, 0.0f);

Derivation
	HUD::ClassDerivations(
		PowerWatcher::ClassDerivations,
		"HUD"
	);

HUD::SharedData
	HUD::DefaultData(
		HUD::ClassDerivations,
		Subsystem::MessageHandlers,
		Subsystem::AttributeIndex,
		Subsystem::StateCount
	);

HUD::HUD(
	Mech				*owner,
	int					subsystem_ID,
	SubsystemResource	*subsystem_resource,
	SharedData			&shared_data
):
	PowerWatcher(owner, subsystem_ID, subsystem_resource, shared_data)
{
	Check(owner);
	Check_Pointer(subsystem_resource);

	flickerRate					= 0.0f;
	rotationOfTorsoHorizontal	= 0.0f;
	torsoLimitRight				= 0.0f;
	torsoLimitLeft				= 0.0f;
	torsoSpeed					= 0.0f;
	rangeToTarget				= 0.0f;
	scratch1F0					= 0;
	visible						= True;
	lockFlag					= False;
	hotBoxVector				= HudZeroVector;
	threatVector				= HudZeroVector;
	compassHeading				= 0.0f;
	blinkTimer					= 0.0f;
	flickerTimer				= 0.0f;
	blinkState					= True;
	transitionFlag				= False;
	previousHorizontal			= 0.0f;

	statusAlarm.Initialize(2);

	freeAimSlew					= 0.0f;
	scratch290					= 0.0f;
	horizontalTorsoOffset		= 0.0f;

	flickerRate					= subsystem_resource->flickerRate;
	horizontalMovementPerSecond	= subsystem_resource->horizontalMovementPerSecond;
	horizontalLimit				= subsystem_resource->horizontalLimit;

	//
	// The torso-orientation source is a Mech link not yet live at
	// construction time; HudSimulation refreshes these per-frame.
	//
	linkedEntity				= 0;
	flickerActive				= 0;

		//
	// The master instance runs the HUD per-frame.
	//
	if (owner->GetInstance() != Entity::ReplicantInstance)
	{
		SetPerformance(&HUD::HudSimulation);
	}

Check_Fpu();
}

HUD::~HUD()
{
}

Logical
	HUD::TestClass(Mech &)
{
	return True;
}

Logical
	HUD::TestInstance() const
{
	return IsDerivedFrom(ClassDerivations);
}

//
//#############################################################################
// @004b7830 -- the per-frame HUD, PARTIAL: the base tick, the heat/voltage
// page gating and the blink are reconstructed (the donor's confident half);
// the reticle / target-lock / torso-horizon math (its blocks 4-6) survives
// only as summarised offsets in the recovered shard and stays STAGED --
// the page visibility is the cockpit-bound behaviour, and it is real.
//
// The blink comparison is >= (the decomp shard's literal != would toggle
// every tick through float inequality; the shard's own banner describes
// "compared against flickerRate; on expiry ... toggles").
//#############################################################################
//
void
	HUD::HudSimulation(Scalar time_slice)
{
	Check(this);

	PowerWatcher::Simulation(time_slice);

	//
	// Page gating off our own mirrored alarms (the watchers, 5.3.109):
	// a heat failure or an unpowered watched subsystem hides the page.
	//
	Logical
		page_visible = True;

	if (watchdogAlarm.GetLevel() != PoweredSubsystem::Ready)
	{
		page_visible = False;
	}
	if (heatAlarm.GetLevel() == HeatSink::FailureHeat)
	{
		page_visible = False;
	}

	//
	// The blink.
	//
	if (transitionFlag == 0)
	{
		blinkTimer += time_slice;
		if (blinkTimer >= flickerRate)
		{
			blinkTimer = 0.0f;
			blinkState = (blinkState == 0);
		}
	}
	else if (transitionFlag == 1)
	{
		blinkState = True;
	}

	visible = (page_visible && blinkState) ? 1 : 0;

	//
	// STAGED (donor blocks 4-6): engine/start flag mirror, target lock +
	// sliding range + compass, and the torso-horizon slew -- summarised
	// offsets only in the recovered shard (part_013.c @004b7830).
	//

	Check_Fpu();
}