source: code/archive/environment2/src/external/bullet/BulletDynamics/ConstraintSolver/btPoint2PointConstraint.h

/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2006 Erwin Coumans  http://continuousphysics.com/Bullet/

This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, 
including commercial applications, and to alter it and redistribute it freely, 
subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/

#ifndef POINT2POINTCONSTRAINT_H
#define POINT2POINTCONSTRAINT_H

#include "LinearMath/btVector3.h"
#include "btJacobianEntry.h"
#include "btTypedConstraint.h"

class btRigidBody;


#ifdef BT_USE_DOUBLE_PRECISION
#define btPoint2PointConstraintData     btPoint2PointConstraintDoubleData
#define btPoint2PointConstraintDataName "btPoint2PointConstraintDoubleData"
#else
#define btPoint2PointConstraintData     btPoint2PointConstraintFloatData
#define btPoint2PointConstraintDataName "btPoint2PointConstraintFloatData"
#endif //BT_USE_DOUBLE_PRECISION

struct  btConstraintSetting
{
        btConstraintSetting()   :
                m_tau(btScalar(0.3)),
                m_damping(btScalar(1.)),
                m_impulseClamp(btScalar(0.))
        {
        }
        btScalar                m_tau;
        btScalar                m_damping;
        btScalar                m_impulseClamp;
};

enum btPoint2PointFlags
{
        BT_P2P_FLAGS_ERP = 1,
        BT_P2P_FLAGS_CFM = 2
};

/// point to point constraint between two rigidbodies each with a pivotpoint that descibes the 'ballsocket' location in local space
ATTRIBUTE_ALIGNED16(class) btPoint2PointConstraint : public btTypedConstraint
{
#ifdef IN_PARALLELL_SOLVER
public:
#endif
        btJacobianEntry m_jac[3]; //3 orthogonal linear constraints
        
        btVector3       m_pivotInA;
        btVector3       m_pivotInB;
        
        int                     m_flags;
        btScalar        m_erp;
        btScalar        m_cfm;
        
public:

        ///for backwards compatibility during the transition to 'getInfo/getInfo2'
        bool            m_useSolveConstraintObsolete;

        btConstraintSetting     m_setting;

        btPoint2PointConstraint(btRigidBody& rbA,btRigidBody& rbB, const btVector3& pivotInA,const btVector3& pivotInB);

        btPoint2PointConstraint(btRigidBody& rbA,const btVector3& pivotInA);


        virtual void    buildJacobian();

        virtual void getInfo1 (btConstraintInfo1* info);

        void getInfo1NonVirtual (btConstraintInfo1* info);

        virtual void getInfo2 (btConstraintInfo2* info);

        void getInfo2NonVirtual (btConstraintInfo2* info, const btTransform& body0_trans, const btTransform& body1_trans);

        void    updateRHS(btScalar      timeStep);

        void    setPivotA(const btVector3& pivotA)
        {
                m_pivotInA = pivotA;
        }

        void    setPivotB(const btVector3& pivotB)
        {
                m_pivotInB = pivotB;
        }

        const btVector3& getPivotInA() const
        {
                return m_pivotInA;
        }

        const btVector3& getPivotInB() const
        {
                return m_pivotInB;
        }

        ///override the default global value of a parameter (such as ERP or CFM), optionally provide the axis (0..5). 
        ///If no axis is provided, it uses the default axis for this constraint.
        virtual void    setParam(int num, btScalar value, int axis = -1);
        ///return the local value of parameter
        virtual btScalar getParam(int num, int axis = -1) const;

        virtual int     calculateSerializeBufferSize() const;

        ///fills the dataBuffer and returns the struct name (and 0 on failure)
        virtual const char*     serialize(void* dataBuffer, btSerializer* serializer) const;


};

///do not change those serialization structures, it requires an updated sBulletDNAstr/sBulletDNAstr64
struct  btPoint2PointConstraintFloatData
{
        btTypedConstraintData   m_typeConstraintData;
        btVector3FloatData      m_pivotInA;
        btVector3FloatData      m_pivotInB;
};

///do not change those serialization structures, it requires an updated sBulletDNAstr/sBulletDNAstr64
struct  btPoint2PointConstraintDoubleData
{
        btTypedConstraintData   m_typeConstraintData;
        btVector3DoubleData     m_pivotInA;
        btVector3DoubleData     m_pivotInB;
};


SIMD_FORCE_INLINE       int     btPoint2PointConstraint::calculateSerializeBufferSize() const
{
        return sizeof(btPoint2PointConstraintData);

}

        ///fills the dataBuffer and returns the struct name (and 0 on failure)
SIMD_FORCE_INLINE       const char*     btPoint2PointConstraint::serialize(void* dataBuffer, btSerializer* serializer) const
{
        btPoint2PointConstraintData* p2pData = (btPoint2PointConstraintData*)dataBuffer;

        btTypedConstraint::serialize(&p2pData->m_typeConstraintData,serializer);
        m_pivotInA.serialize(p2pData->m_pivotInA);
        m_pivotInB.serialize(p2pData->m_pivotInB);

        return btPoint2PointConstraintDataName;
}

#endif //POINT2POINTCONSTRAINT_H