/*************************************************************************

 *                                                                       *

 * Open Dynamics Engine, Copyright (C) 2001,2002 Russell L. Smith.       *

 * All rights reserved.  Email: russ@q12.org   Web: www.q12.org          *

 *                                                                       *

 * This library is free software; you can redistribute it and/or         *

 * modify it under the terms of EITHER:                                  *

 *   (1) The GNU Lesser General Public License as published by the Free  *

 *       Software Foundation; either version 2.1 of the License, or (at  *

 *       your option) any later version. The text of the GNU Lesser      *

 *       General Public License is included with this library in the     *

 *       file LICENSE.TXT.                                               *

 *   (2) The BSD-style license that is included with this library in     *

 *       the file LICENSE-BSD.TXT.                                       *

 *                                                                       *

 * This library is distributed in the hope that it will be useful,       *

 * but WITHOUT ANY WARRANTY; without even the implied warranty of        *

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the files    *

 * LICENSE.TXT and LICENSE-BSD.TXT for more details.                     *

 *                                                                       *

 *************************************************************************/

#ifndef _ODE_JOINT_H_

#define _ODE_JOINT_H_

#include "object.h"

#include <ode/contact.h>

#include "obstack.h"

// joint flags

enum {

  // if this flag is set, the joint was allocated in a joint group

  dJOINT_INGROUP = 1,

  // if this flag is set, the joint was attached with arguments (0,body).

  // our convention is to treat all attaches as (body,0), i.e. so node[0].body

  // is always nonzero, so this flag records the fact that the arguments were

  // swapped.

  dJOINT_REVERSE = 2,

  // if this flag is set, the joint can not have just one body attached to it,

  // it must have either zero or two bodies attached.

  dJOINT_TWOBODIES = 4

};

// there are two of these nodes in the joint, one for each connection to a

// body. these are node of a linked list kept by each body of it's connecting

// joints. but note that the body pointer in each node points to the body that

// makes use of the *other* node, not this node. this trick makes it a bit

// easier to traverse the body/joint graph.

struct dxJointNode {

  dxJoint *joint;		// pointer to enclosing dxJoint object

  dxBody *body;			// *other* body this joint is connected to

  dxJointNode *next;		// next node in body's list of connected joints

};

struct dxJoint : public dObject {

  // naming convention: the "first" body this is connected to is node[0].body,

  // and the "second" body is node[1].body. if this joint is only connected

  // to one body then the second body is 0.

  // info returned by getInfo1 function. the constraint dimension is m (<=6).

  // i.e. that is the total number of rows in the jacobian. `nub' is the

  // number of unbounded variables (which have lo,hi = -/+ infinity).

  struct Info1 {

    int m,nub;

  };

  // info returned by getInfo2 function

  struct Info2 {

    // integrator parameters: frames per second (1/stepsize), default error

    // reduction parameter (0..1).

    dReal fps,erp;

    // for the first and second body, pointers to two (linear and angular)

    // n*3 jacobian sub matrices, stored by rows. these matrices will have

    // been initialized to 0 on entry. if the second body is zero then the

    // J2xx pointers may be 0.

    dReal *J1l,*J1a,*J2l,*J2a;

    // elements to jump from one row to the next in J's

    int rowskip;

    // right hand sides of the equation J*v = c + cfm * lambda. cfm is the

    // "constraint force mixing" vector. c is set to zero on entry, cfm is

    // set to a constant value (typically very small or zero) value on entry.

    dReal *c,*cfm;

    // lo and hi limits for variables (set to -/+ infinity on entry).

    dReal *lo,*hi;

    // findex vector for variables. see the LCP solver interface for a

    // description of what this does. this is set to -1 on entry.

    // note that the returned indexes are relative to the first index of

    // the constraint.

    int *findex;

  };

  // virtual function table: size of the joint structure, function pointers.

  // we do it this way instead of using C++ virtual functions because

  // sometimes we need to allocate joints ourself within a memory pool.

  typedef void init_fn (dxJoint *joint);

  typedef void getInfo1_fn (dxJoint *joint, Info1 *info);

  typedef void getInfo2_fn (dxJoint *joint, Info2 *info);

  struct Vtable {

    int size;

    init_fn *init;

    getInfo1_fn *getInfo1;

    getInfo2_fn *getInfo2;

    int typenum;		// a dJointTypeXXX type number

  };

  Vtable *vtable;		// virtual function table

  int flags;			// dJOINT_xxx flags

  dxJointNode node[2];		// connections to bodies. node[1].body can be 0

  dJointFeedback *feedback;	// optional feedback structure

  dReal lambda[6];		// lambda generated by last step

};

// joint group. NOTE: any joints in the group that have their world destroyed

// will have their world pointer set to 0.

struct dxJointGroup : public dBase {

  int num;		// number of joints on the stack

  dObStack stack;	// a stack of (possibly differently sized) dxJoint

};			// objects.

// common limit and motor information for a single joint axis of movement

struct dxJointLimitMotor {

  dReal vel,fmax;		// powered joint: velocity, max force

  dReal lostop,histop;		// joint limits, relative to initial position

  dReal fudge_factor;		// when powering away from joint limits

  dReal normal_cfm;		// cfm to use when not at a stop

  dReal stop_erp,stop_cfm;	// erp and cfm for when at joint limit

  dReal bounce;			// restitution factor

  // variables used between getInfo1() and getInfo2()

  int limit;			// 0=free, 1=at lo limit, 2=at hi limit

  dReal limit_err;		// if at limit, amount over limit

  void init (dxWorld *);

  void set (int num, dReal value);

  dReal get (int num);

  int testRotationalLimit (dReal angle);

  int addLimot (dxJoint *joint, dxJoint::Info2 *info, int row,

		const dVector3 ax1, int rotational);

};

// ball and socket

struct dxJointBall : public dxJoint {

  dVector3 anchor1;		// anchor w.r.t first body

  dVector3 anchor2;		// anchor w.r.t second body

};

extern struct dxJoint::Vtable __dball_vtable;

// hinge

struct dxJointHinge : public dxJoint {

  dVector3 anchor1;		// anchor w.r.t first body

  dVector3 anchor2;		// anchor w.r.t second body

  dVector3 axis1;		// axis w.r.t first body

  dVector3 axis2;		// axis w.r.t second body

  dQuaternion qrel;		// initial relative rotation body1 -> body2

  dxJointLimitMotor limot;	// limit and motor information

};

extern struct dxJoint::Vtable __dhinge_vtable;

// universal

struct dxJointUniversal : public dxJoint {

  dVector3 anchor1;		// anchor w.r.t first body

  dVector3 anchor2;		// anchor w.r.t second body

  dVector3 axis1;		// axis w.r.t first body

  dVector3 axis2;		// axis w.r.t second body

  dQuaternion qrel1;	// initial relative rotation body1 -> virtual cross piece

  dQuaternion qrel2;    // initial relative rotation virtual cross piece -> body2

  dxJointLimitMotor limot1;	// limit and motor information for axis1

  dxJointLimitMotor limot2;	// limit and motor information for axis2

};

extern struct dxJoint::Vtable __duniversal_vtable;

/**

 * The axisP must be perpendicular to axis2

 * <PRE>

 *                                        +-------------+

 *                                        |      x      |

 *                                        +------------\+

 * Prismatic articulation                   ..     ..

 *                       |                ..     ..

 *                      \/              ..      ..

 * +--------------+    --|        __..      ..  anchor2

 * |      x       | .....|.......(__)     ..

 * +--------------+    --|         ^     <

 *        |----------------------->|

 *            Offset               |--- Rotoide articulation

 * </PRE>

 */

struct dxJointPR : public dxJoint {

  dVector3 anchor2;         ///< @brief Position of the rotoide articulation

                            ///<        w.r.t second body.

                            ///< @note Position of body 2 in world frame +

                            ///< anchor2 in world frame give the position

                            ///< of the rotoide articulation

  dVector3 axisR1;          ///< axis of the rotoide articulation w.r.t first body.

                            ///< @note This is considered as axis1 from the parameter

                            ///< view.

  dVector3 axisR2;          ///< axis of the rotoide articulation w.r.t second body.

                            ///< @note This is considered also as axis1 from the

                            ///< parameter view

  dVector3 axisP1;          ///< axis for the prismatic articulation w.r.t first body.

                            ///< @note This is considered as axis2 in from the parameter

                            ///< view

  dQuaternion qrel;         ///< initial relative rotation body1 -> body2.

  dVector3 offset;          ///< @brief vector between the body1 and the rotoide

                            ///< articulation.

                            ///<

                            ///< Going from the first to the second in the frame

                            ///<  of body1.

                            ///< That should be aligned with body1 center along axisP

                            ///< This is calculated whe the axis are set.

  dxJointLimitMotor limotR; ///< limit and motor information for the rotoide articulation.

  dxJointLimitMotor limotP; ///< limit and motor information for the prismatic articulation.

};

extern struct dxJoint::Vtable __dPR_vtable;

// slider. if body2 is 0 then qrel is the absolute rotation of body1 and

// offset is the position of body1 center along axis1.

struct dxJointSlider : public dxJoint {

  dVector3 axis1;		// axis w.r.t first body

  dQuaternion qrel;		// initial relative rotation body1 -> body2

  dVector3 offset;		// point relative to body2 that should be

				// aligned with body1 center along axis1

  dxJointLimitMotor limot;	// limit and motor information

};

extern struct dxJoint::Vtable __dslider_vtable;

// contact

struct dxJointContact : public dxJoint {

  int the_m;			// number of rows computed by getInfo1

  dContact contact;

};

extern struct dxJoint::Vtable __dcontact_vtable;

// hinge 2

struct dxJointHinge2 : public dxJoint {

  dVector3 anchor1;		// anchor w.r.t first body

  dVector3 anchor2;		// anchor w.r.t second body

  dVector3 axis1;		// axis 1 w.r.t first body

  dVector3 axis2;		// axis 2 w.r.t second body

  dReal c0,s0;			// cos,sin of desired angle between axis 1,2

  dVector3 v1,v2;		// angle ref vectors embedded in first body

  dxJointLimitMotor limot1;	// limit+motor info for axis 1

  dxJointLimitMotor limot2;	// limit+motor info for axis 2

  dReal susp_erp,susp_cfm;	// suspension parameters (erp,cfm)

};

extern struct dxJoint::Vtable __dhinge2_vtable;

// angular motor

struct dxJointAMotor : public dxJoint {

  int num;			// number of axes (0..3)

  int mode;			// a dAMotorXXX constant

  int rel[3];			// what the axes are relative to (global,b1,b2)

  dVector3 axis[3];		// three axes

  dxJointLimitMotor limot[3];	// limit+motor info for axes

  dReal angle[3];		// user-supplied angles for axes

  // these vectors are used for calculating euler angles

  dVector3 reference1;		// original axis[2], relative to body 1

  dVector3 reference2;		// original axis[0], relative to body 2

};

extern struct dxJoint::Vtable __damotor_vtable;

struct dxJointLMotor : public dxJoint {

  int num;

  int rel[3];

  dVector3 axis[3];

  dxJointLimitMotor limot[3];

};

extern struct dxJoint::Vtable __dlmotor_vtable;

// 2d joint, constrains to z == 0

struct dxJointPlane2D : public dxJoint

{

    int                 row_motor_x;

    int                 row_motor_y;

    int                 row_motor_angle;

    dxJointLimitMotor   motor_x;

    dxJointLimitMotor   motor_y;

    dxJointLimitMotor   motor_angle;

};

extern struct dxJoint::Vtable __dplane2d_vtable;

// fixed

struct dxJointFixed : public dxJoint {

  dQuaternion qrel;		// initial relative rotation body1 -> body2

  dVector3 offset;		// relative offset between the bodies

};

extern struct dxJoint::Vtable __dfixed_vtable;

// null joint, for testing only

struct dxJointNull : public dxJoint {

};

extern struct dxJoint::Vtable __dnull_vtable;

#endif