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