File indexing completed on 2024-10-13 06:32:54

 /*
     SPDX-FileCopyrightText: 2007 Vladimir Kuznetsov <ks.vladimir@gmail.com>
     SPDX-FileCopyrightText: 2014 Inge Wallin <inge@lysator.liu.se>
 
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 
 /** \file joint.h
  *  \brief Contains the Joint object.
  */
 
 #ifndef STEPCORE_JOINT_H
 #define STEPCORE_JOINT_H
 
 
 // stdc++
 #include <vector> // XXX: Replace if Qt is enabled.
 
 // Stepcore
 #include "types.h"
 #include "item.h"
 
 
 namespace StepCore
 {
 
 
 /** \ingroup joints
  *  Constraints information structure
  *  XXX: Move it to constraintsolver.h
  */
 struct ConstraintsInfo
 {
     int                variablesCount;      ///< Number of dynamic variables
     int                constraintsCount;    ///< Number of constraints equations
     int                contactsCount;       ///< Number of additional constrains 
                                             ///< equations due to contacts
 
     VectorXd           value;               ///< Current constraints values (amount of brokenness)
     VectorXd           derivative;          ///< Time-derivative of constraints values
     DynSparseRowMatrix jacobian;            ///< Position-derivative of constraints values
     DynSparseRowMatrix jacobianDerivative;  ///< Time-derivative of constraintsJacobian
     VectorXd           inverseMass;         ///< Diagonal coefficients of the inverse mass matrix of the system
 
     MappedVector       position;            ///< Positions of the bodies
     MappedVector       velocity;            ///< Velocities of the bodies
     MappedVector       acceleration;        ///< Accelerations of the bodies before applying constraints
 
     VectorXd           forceMin;            ///< Constraints force lower limit
     VectorXd           forceMax;            ///< Constraints force upper limit
 
     VectorXd           force;               ///< Resulting constraints force
 
     bool               collisionFlag;       ///< True if there is a collision to be resolved
 
     ConstraintsInfo(): variablesCount(0), constraintsCount(0), contactsCount(0),
                        position(nullptr,0), velocity(nullptr,0), acceleration(nullptr,0) {}
 
     /** Set variablesCount, constraintsCount and reset contactsCount,
      *  resize all arrays appropriately */
     void setDimension(int newVariablesCount, int newConstraintsCount, int newContactsCount = 0);
 
     /** Clear the structure */
     void clear();
 
 private:
     ConstraintsInfo(const ConstraintsInfo&);
     ConstraintsInfo& operator=(const ConstraintsInfo&);
 };
 
 
 /** \ingroup joints
  *  \brief Interface for joints
  */
 class Joint : public Item
 {
     STEPCORE_OBJECT(Joint)
 
 public:
     virtual ~Joint() {}
 
     /** Get count of constraints */
     virtual int constraintsCount() = 0;
 
     /** Fill the part of constraints information structure starting at offset */
     virtual void getConstraintsInfo(ConstraintsInfo* info, int offset) = 0;
 
 #if 0
     /** Get current constraints value (amount of brokenness) and its derivative */
     virtual void getConstraints(double* value, double* derivative) = 0;
 
     /** Get force limits, default is no limits at all */
     virtual void getForceLimits(double* forceMin STEPCORE_UNUSED, double* forceMax STEPCORE_UNUSED) {}
 
     /** Get constraints jacobian (space-derivatives of constraint value),
      *  its derivative and product of inverse mass matrix by transposed jacobian (wjt) */
     virtual void getJacobian(GmmSparseRowMatrix* value, GmmSparseRowMatrix* derivative, int offset) = 0;
 #endif
 };
 
 
 /** List of pointers to Joint */
 typedef std::vector<Joint*> JointList;
 
 
 } // namespace StepCore
 
 
 #endif