//===========================================================================//
// File:	torso.cpp                                                           //
// Project: BattleTech           Brick: Mech subsystems                       //
// Contents: Torso -- torso twist / weapon elevation                        //
//---------------------------------------------------------------------------//
// 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// This unpublished sourcecode is PROPRIETARY and CONFIDENTIAL               //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(TORSO_HPP)
#	include <torso.hpp>
#endif

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

#if !defined(JOINT_HPP)
#	include <joint.hpp>
#endif

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

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

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

	isDamagedCopy	= (owner->GetInstance() == Entity::ReplicantInstance);

	statusFlags					= 0;
	buttonAccelerationPerSecond	= r->buttonAccelerationPerSecond;
	buttonAccelerationStart		= r->buttonAccelerationStartValue;

	baseTwistRate		= r->horizontalRotationPerSecond * RAD_PER_DEG;
	baseElevationRate	= r->verticalRotationPerSecond   * RAD_PER_DEG;
	horizontalLimitRight= r->horizontalLimitRight * RAD_PER_DEG;
	horizontalLimitLeft	= r->horizontalLimitLeft  * RAD_PER_DEG;
	verticalLimitTop	= r->verticalLimitTop     * RAD_PER_DEG;
	verticalLimitBottom	= r->verticalLimitBottom  * RAD_PER_DEG;

	twistCenterHigh		= verticalLimitTop;
	twistCenterLow		= verticalLimitBottom;
	elevationCenter		= verticalLimitTop;
	elevationHalfBottom	= verticalLimitBottom * 0.5f;

	buttonRampActive	= 0;
	buttonRamp			= 0.0f;
	horizontalEnabled	= r->torsoHorizontalEnabled;

	//
	// Resolve the named torso-twist skeleton joints (twist body + shadow) from
	// the mech skeleton (now live).  A mech with a fixed torso, or one whose
	// joint name is absent from the skeleton, resolves NULL and simply never
	// twists.
	//
	horizontalJointNode			= owner->ResolveJoint(r->torsoHorizontalJoint);
	horizontalShadowJointNode	= owner->ResolveJoint(r->torsoHorizontalShadowJoint);

	if (getenv("BT_MECH_LOG"))
	{
		DEBUG_STREAM << "[torso] horizJoint '" << r->torsoHorizontalJoint
			<< "' -> " << (void *)horizontalJointNode;
		if (horizontalJointNode != NULL)
		{
			DEBUG_STREAM << " type=" << (int)horizontalJointNode->GetJointType();
		}
		DEBUG_STREAM << " enabled=" << (int)horizontalEnabled << endl << flush;
	}

	currentTwist		= 0.0f;
	currentElevation	= 0.0f;
	analogElevationAxis	= 0.0f;
	analogTwistAxis		= 0.0f;
	for (int i = 0; i < 22; ++i)
	{
		dynamicsState[i] = 0.0f;
	}

	//
	// Install the per-frame twist/elevation Performance (the replicant copy is
	// driven by console updates via TorsoCopySimulation instead, still staged).
	//
	if (owner->GetInstance() != Entity::ReplicantInstance)
	{
		SetPerformance(&Torso::TorsoSimulation);
	}

	Check_Fpu();
}

Torso::~Torso()
{
}

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

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

//
//#############################################################################
// TorsoSimulation -- per-frame torso twist / weapon-elevation integration.
//
// Slews the current elevation/twist toward the analog aim axes (written by
// MechControlsMapper::InterpretControls) at the resource base rates, clamped to
// the resource limits.  Authentic core (torso.cpp @004b6xxx): current += axis *
// baseRate * dt.  APPLYING the resolved angles onto the skeleton torso/gun
// joints (horizontalJointNode / the elevation joint) is deferred with the
// skeleton-link + render wave; here we advance the scalar aim state (read by the
// HUD reticle / weapon aim and, once wired, the joints).
//#############################################################################
//
void
	Torso::TorsoSimulation(Scalar time_slice)
{
	Check(this);

	//
	// Elevation (weapon pitch): slew toward the analog axis, clamp to limits.
	//
	currentElevation += analogElevationAxis * baseElevationRate * time_slice;
	{
		Scalar lo = (verticalLimitBottom < verticalLimitTop)
			? verticalLimitBottom : verticalLimitTop;
		Scalar hi = (verticalLimitBottom < verticalLimitTop)
			? verticalLimitTop : verticalLimitBottom;
		if (currentElevation < lo) currentElevation = lo;
		if (currentElevation > hi) currentElevation = hi;
	}

	//
	// Twist (horizontal torso rotation): only mechs with an enabled torso joint.
	//
	if (horizontalEnabled)
	{
		currentTwist += analogTwistAxis * baseTwistRate * time_slice;
		Scalar lo = (horizontalLimitLeft < horizontalLimitRight)
			? horizontalLimitLeft : horizontalLimitRight;
		Scalar hi = (horizontalLimitLeft < horizontalLimitRight)
			? horizontalLimitRight : horizontalLimitLeft;
		if (currentTwist < lo) currentTwist = lo;
		if (currentTwist > hi) currentTwist = hi;

		//
		// Push the twist onto the skeleton torso joint so the upper body rotates
		// on the model.  Hinge joints take the scalar angle about their axis;
		// ball joints take it as the yaw component.
		//
		if (horizontalJointNode != NULL)
		{
			Joint::JointType jt = horizontalJointNode->GetJointType();
			if (jt == Joint::HingeXJointType
				|| jt == Joint::HingeYJointType
				|| jt == Joint::HingeZJointType)
			{
				horizontalJointNode->SetRotation(Radian(currentTwist));
			}
			else if (jt == Joint::BallJointType)
			{
				horizontalJointNode->SetRotation(EulerAngles(0.0f, currentTwist, 0.0f));
			}
		}
	}

	Check_Fpu();
}

void
	Torso::TorsoCopySimulation(Scalar)
{
	Fail("Torso::TorsoCopySimulation -- torso.cpp not yet reconstructed");
}