//===========================================================================//
// File:	seqctl.cpp                                                          //
// Project: BattleTech           Brick: Mech animation                        //
// Contents: The Mech keyframe-animation player (leg / body gait clips)       //
//---------------------------------------------------------------------------//
// 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// This unpublished sourcecode is PROPRIETARY and CONFIDENTIAL               //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(SEQCTL_HPP)
#	include <seqctl.hpp>
#endif

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

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

#if !defined(APP_HPP)
#	include <app.hpp>
#endif

//
//#############################################################################
// Local helpers.
//#############################################################################
//

//
// Slot -> skeleton joint, through the clip's own index map.
//
Joint *
	SequenceController::GetAnimatedJoint(int slot) const
{
	if (jointSubsystem == NULL || jointIndices == NULL)
	{
		return NULL;
	}
	Verify(slot >= 0 && slot < jointCount);

	int
		joint_index = jointIndices[slot];
	if (joint_index < 0 || joint_index >= jointSubsystem->GetJointCount())
	{
		return NULL;
	}
	return jointSubsystem->GetJoint(joint_index);
}

//
// Component-wise ease between two orientations.
//
static EulerAngles
	InterpolateAngles(
		const EulerAngles	&from,
		const EulerAngles	&to,
		Scalar				 ratio
	)
{
	return EulerAngles(
		Radian((Scalar)from.pitch + ((Scalar)to.pitch - (Scalar)from.pitch) * ratio),
		Radian((Scalar)from.yaw   + ((Scalar)to.yaw   - (Scalar)from.yaw)   * ratio),
		Radian((Scalar)from.roll  + ((Scalar)to.roll  - (Scalar)from.roll)  * ratio));
}

//
//#############################################################################
//#############################################################################
//
SequenceController::SequenceController()
{
	keyframeCount		= 0;
	jointCount			= 0;
	footStepThreshold	= NULL;
	jointIndices		= NULL;
	keyframeTimes		= NULL;
	keyframeBase		= NULL;
	keyframeCursor		= NULL;
	keyframeData		= NULL;
	currentFrame		= 0;
	currentTime			= 0.0f;
	jointSubsystem		= NULL;
	owner				= NULL;
	clipResource		= NULL;
	finishedCallback	= NULL;
	callbackArg2		= 0;
	callbackArg3		= 0;
}

//
//#############################################################################
// Init  Bind the player to its owning mech and cache the joint subsystem the
// gait writes through.  Called from the Mech ctor for legAnimation/bodyAnimation.
//#############################################################################
//
void
	SequenceController::Init(Mech *owner_mech)
{
	Check(owner_mech);
	owner			= owner_mech;
	jointSubsystem	= owner_mech->GetJointSubsystem();
	clipResource	= NULL;
}

//
//#############################################################################
//#############################################################################
//
SequenceController::~SequenceController()
{
	//
	// Release the clip this controller holds locked.
	//
	if (clipResource != NULL)
	{
		((ResourceDescription *)clipResource)->Unlock();
		clipResource = NULL;
	}
}

//
//#############################################################################
// The clip resource layout, as SelectSequence parses it.  Offsets are the
// binary's (@004277a8):
//
//    int      frameCount                   hdr[0]
//    int      jointCount                   hdr[1]
//    Scalar   footStepThreshold            hdr[2]  -- authored contact height
//    int      jointIndices[jointCount]     keyframe slot -> skeleton joint
//    Scalar   frameTimes[frameCount]       keyframe timestamps, seconds
//    <pose>                                per frame, per joint, PACKED by DOF
//    Keyframe rootTranslations[frameCount] .stride == the forward step
//
// The pose block is packed by joint TYPE, so the root-translation table can
// only be located by walking the skeleton and summing the per-joint sizes --
// there is no count to seek by.  PoseSize is that walk's per-entry size.
//#############################################################################
//

static int
	PoseSize(Joint *joint)
{
	//
	// Hinge (X/Y/Z) = a Hinge; ball = EulerAngles; ball+translation = both.
	//
	if (joint == NULL)
	{
		return 0;
	}
	switch (joint->GetJointType())
	{
	case Joint::HingeXJointType:
	case Joint::HingeYJointType:
	case Joint::HingeZJointType:
		return sizeof(Hinge);

	case Joint::BallJointType:
		return sizeof(EulerAngles);

	case Joint::BallTranslationJointType:
		return sizeof(EulerAngles) + sizeof(Point3D);
	}
	return 0;
}

//
//#############################################################################
// SelectSequence (@004277a8) -- bind a gait clip.  Stores the finished
// callback, rewinds playback, releases the previous clip, then finds, locks
// and parses the new one.
//
// The fetch is FindResourceDescription, NOT SearchList: the clip ID arriving
// here is already resolved, and SearchList would treat it as a resource LIST
// and walk the clip bytes as resource IDs.
//#############################################################################
//
void
	SequenceController::SelectSequence(
		int			clip_id,
		void		*finished_callback,
		unsigned	callback_arg2,
		unsigned	callback_arg3
	)
{
	Check_Pointer(this);

	finishedCallback	= finished_callback;
	callbackArg2		= callback_arg2;
	callbackArg3		= callback_arg3;
	currentTime			= 0.0f;
	currentFrame		= 0;

	if (clipResource != NULL)
	{
		((ResourceDescription *)clipResource)->Unlock();
		clipResource = NULL;
	}

	ResourceFile
		*resources = application->GetResourceFile();
	Check_Pointer(resources);

	ResourceDescription
		*description = resources->FindResourceDescription(clip_id);
	clipResource = description;
	if (description == NULL)
	{
		//
		// A mech whose skeleton omits this gait keeps an empty controller;
		// Advance below is guarded on keyframeCount so playback is inert.
		//
		keyframeCount	= 0;
		jointCount		= 0;
		return;
	}
	description->Lock();

	int
		*header = (int *)description->resourceAddress;
	Check_Pointer(header);

	keyframeCount		= header[0];
	jointCount			= header[1];
	footStepThreshold	= (Scalar *)(header + 2);

	int
		*cursor = header + 3;
	jointIndices	= cursor;
	cursor		   += jointCount;
	keyframeTimes	= (Scalar *)cursor;
	cursor		   += keyframeCount;
	keyframeBase	= cursor;
	keyframeCursor	= cursor;

	//
	// Walk the packed pose block to find the root-translation table behind it.
	//
	char
		*pose = (char *)cursor;
	int
		frame,
		slot;
	for (frame = 0; frame < keyframeCount; ++frame)
	{
		for (slot = 0; slot < jointCount; ++slot)
		{
			pose += PoseSize(GetAnimatedJoint(slot));
		}
	}
	keyframeData = (Keyframe *)pose;

	Check_Fpu();
}

//
//#############################################################################
// Advance (@0042790c) -- play the clip forward by time_slice and return the
// forward distance covered, which is what the gait feeds into the mech's
// motion.
//
// Two phases.  First SNAP through every keyframe whose timestamp the new time
// has passed, writing each animated joint's authored pose as it goes.  Then
// INTERPOLATE the remaining partial frame, easing every joint from where it
// is toward the next keyframe.
//
// move_joints == 0 advances the clock and accumulates distance WITHOUT
// touching the skeleton -- that is how the body channel measures a stride
// without fighting the leg channel for the same joints.
//#############################################################################
//
Scalar
	SequenceController::Advance(Scalar time_slice, int move_joints)
{
	Check_Pointer(this);

	Scalar
		target_time = currentTime + time_slice,
		distance = 0.0f;
	char
		*cursor = (char *)keyframeCursor;
	int
		slot;

	//
	// Phase 1 -- snap through the keyframes reached this frame.
	//
	while (
		currentFrame < keyframeCount &&
		keyframeTimes[currentFrame] <= target_time
	)
	{
		for (slot = 0; slot < jointCount; ++slot)
		{
			Joint
				*joint = GetAnimatedJoint(slot);

			switch (joint != NULL ? joint->GetJointType() : Joint::StaticJointType)
			{
			case Joint::HingeXJointType:
			case Joint::HingeYJointType:
			case Joint::HingeZJointType:
				if (move_joints)
				{
					joint->SetHinge(*(const Hinge *)cursor);
				}
				cursor += sizeof(Hinge);
				break;

			case Joint::BallJointType:
				if (move_joints)
				{
					joint->SetRotation(*(const EulerAngles *)cursor);
				}
				cursor += sizeof(EulerAngles);
				break;

			case Joint::BallTranslationJointType:
				if (move_joints)
				{
					joint->SetRotation(*(const EulerAngles *)cursor);
				}
				cursor += sizeof(EulerAngles);
				if (move_joints)
				{
					joint->SetTranslation(*(const Point3D *)cursor);
				}
				cursor += sizeof(Point3D);
				break;

			default:
				break;
			}
		}

		distance +=
			(keyframeTimes[currentFrame] - currentTime) *
			keyframeData[currentFrame].stride;
		currentTime = keyframeTimes[currentFrame];
		++currentFrame;
	}

	if (currentFrame == keyframeCount)
	{
		//
		// End of clip.  The finished callback picks the next gait state and
		// RE-ARMS this controller through SelectSequence (which rewinds us to
		// frame 0), then advances the leftover time itself -- so on return the
		// controller is already playing the next clip and its distance folds
		// into ours.  A NULL callback simply parks the clip at its end.
		//
		if (finishedCallback != NULL && keyframeCount > 0)
		{
			Scalar
				carryover = target_time - keyframeTimes[keyframeCount - 1];

			distance += (*(ClipFinishedCallback)finishedCallback)(
				owner, callbackArg2, carryover, move_joints);
		}
	}
	else
	{
		//
		// Phase 2 -- the partial frame.
		//
		keyframeCursor = cursor;

		Scalar
			span = keyframeTimes[currentFrame] - currentTime,
			ratio = (span > 0.0f) ? (target_time - currentTime) / span : 0.0f;

		for (slot = 0; slot < jointCount; ++slot)
		{
			Joint
				*joint = GetAnimatedJoint(slot);

			switch (joint != NULL ? joint->GetJointType() : Joint::StaticJointType)
			{
			case Joint::HingeXJointType:
			case Joint::HingeYJointType:
			case Joint::HingeZJointType:
				if (move_joints)
				{
					Scalar
						from = (Scalar)joint->GetRadians(),
						to = (Scalar)((const Hinge *)cursor)->rotationAmount;
					joint->SetRotation(Radian(from + (to - from) * ratio));
				}
				cursor += sizeof(Hinge);
				break;

			case Joint::BallJointType:
				if (move_joints)
				{
					joint->SetRotation(
						InterpolateAngles(
							joint->GetEulerAngles(),
							*(const EulerAngles *)cursor,
							ratio));
				}
				cursor += sizeof(EulerAngles);
				break;

			case Joint::BallTranslationJointType:
				if (move_joints)
				{
					joint->SetRotation(
						InterpolateAngles(
							joint->GetEulerAngles(),
							*(const EulerAngles *)cursor,
							ratio));
				}
				cursor += sizeof(EulerAngles);
				if (move_joints)
				{
					const Point3D
						&to = *(const Point3D *)cursor;
					Point3D
						from = joint->GetTranslation();
					Point3D
						blended(
							from.x + (to.x - from.x) * ratio,
							from.y + (to.y - from.y) * ratio,
							from.z + (to.z - from.z) * ratio);
					joint->SetTranslation(blended);
				}
				cursor += sizeof(Point3D);
				break;

			default:
				break;
			}
		}

		distance += (target_time - currentTime) * keyframeData[currentFrame].stride;
		currentTime = target_time;
	}

	Check_Fpu();
	return distance;
}

//
//#############################################################################
// Reset (@004283b8) -- return every animated joint to its neutral pose.  Only
// the loop form does anything; the mech calls it when a gait is abandoned
// (fall, death, respawn) so the skeleton does not keep the last frame of a
// clip that is no longer playing.
//#############################################################################
//
void
	SequenceController::Reset(int loop)
{
	Check_Pointer(this);

	if (loop == 0)
	{
		return;
	}

	EulerAngles
		neutral_angles(Radian(0.0f), Radian(0.0f), Radian(0.0f));
	Point3D
		neutral_point(0.0f, 0.0f, 0.0f);
	int
		slot;

	for (slot = 0; slot < jointCount; ++slot)
	{
		Joint
			*joint = GetAnimatedJoint(slot);
		if (joint == NULL)
		{
			continue;
		}
		switch (joint->GetJointType())
		{
		case Joint::HingeXJointType:
		case Joint::HingeYJointType:
		case Joint::HingeZJointType:
			joint->SetRotation(Radian(0.0f));
			break;

		case Joint::BallJointType:
			joint->SetRotation(neutral_angles);
			break;

		case Joint::BallTranslationJointType:
			joint->SetRotation(neutral_angles);
			joint->SetTranslation(neutral_point);
			break;

		default:
			break;
		}
	}

	Check_Fpu();
}