btTypedConstraint.h

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/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2010 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 BT_TYPED_CONSTRAINT_H
#define BT_TYPED_CONSTRAINT_H

class btRigidBody;
#include "LinearMath/btScalar.h"
#include "btSolverConstraint.h"

class btSerializer;

//Don't change any of the existing enum values, so add enum types at the end for serialization compatibility
enum btTypedConstraintType
{
        POINT2POINT_CONSTRAINT_TYPE=3,
        HINGE_CONSTRAINT_TYPE,
        CONETWIST_CONSTRAINT_TYPE,
        D6_CONSTRAINT_TYPE,
        SLIDER_CONSTRAINT_TYPE,
        CONTACT_CONSTRAINT_TYPE,
        D6_SPRING_CONSTRAINT_TYPE,
        MAX_CONSTRAINT_TYPE
};


enum btConstraintParams
{
        BT_CONSTRAINT_ERP=1,
        BT_CONSTRAINT_STOP_ERP,
        BT_CONSTRAINT_CFM,
        BT_CONSTRAINT_STOP_CFM
};

#if 1
        #define btAssertConstrParams(_par) btAssert(_par) 
#else
        #define btAssertConstrParams(_par)
#endif


class btTypedConstraint : public btTypedObject
{
        int     m_userConstraintType;

        union
        {
                int     m_userConstraintId;
                void* m_userConstraintPtr;
        };

        btScalar        m_breakingImpulseThreshold;
        bool            m_isEnabled;


        bool m_needsFeedback;

        btTypedConstraint&      operator=(btTypedConstraint&    other)
        {
                btAssert(0);
                (void) other;
                return *this;
        }

protected:
        btRigidBody&    m_rbA;
        btRigidBody&    m_rbB;
        btScalar        m_appliedImpulse;
        btScalar        m_dbgDrawSize;

        btScalar getMotorFactor(btScalar pos, btScalar lowLim, btScalar uppLim, btScalar vel, btScalar timeFact);
        
        static btRigidBody& getFixedBody();

public:

        virtual ~btTypedConstraint() {};
        btTypedConstraint(btTypedConstraintType type, btRigidBody& rbA);
        btTypedConstraint(btTypedConstraintType type, btRigidBody& rbA,btRigidBody& rbB);

        struct btConstraintInfo1 {
                int m_numConstraintRows,nub;
        };

        struct btConstraintInfo2 {
                // integrator parameters: frames per second (1/stepsize), default error
                // reduction parameter (0..1).
                btScalar 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.
                btScalar *m_J1linearAxis,*m_J1angularAxis,*m_J2linearAxis,*m_J2angularAxis;

                // 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.
                btScalar *m_constraintError,*cfm;

                // lo and hi limits for variables (set to -/+ infinity on entry).
                btScalar *m_lowerLimit,*m_upperLimit;

                // 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;
                // number of solver iterations
                int m_numIterations;

                //damping of the velocity
                btScalar        m_damping;
        };

        virtual void    buildJacobian() {};

        virtual void    setupSolverConstraint(btConstraintArray& ca, int solverBodyA,int solverBodyB, btScalar timeStep)
        {
        (void)ca;
        (void)solverBodyA;
        (void)solverBodyB;
        (void)timeStep;
        }
        
        virtual void getInfo1 (btConstraintInfo1* info)=0;

        virtual void getInfo2 (btConstraintInfo2* info)=0;

        void    internalSetAppliedImpulse(btScalar appliedImpulse)
        {
                m_appliedImpulse = appliedImpulse;
        }
        btScalar        internalGetAppliedImpulse()
        {
                return m_appliedImpulse;
        }


        btScalar        getBreakingImpulseThreshold() const
        {
                return  m_breakingImpulseThreshold;
        }

        void    setBreakingImpulseThreshold(btScalar threshold)
        {
                m_breakingImpulseThreshold = threshold;
        }

        bool    isEnabled() const
        {
                return m_isEnabled;
        }

        void    setEnabled(bool enabled)
        {
                m_isEnabled=enabled;
        }


        virtual void    solveConstraintObsolete(btRigidBody& /*bodyA*/,btRigidBody& /*bodyB*/,btScalar  /*timeStep*/) {};

        
        const btRigidBody& getRigidBodyA() const
        {
                return m_rbA;
        }
        const btRigidBody& getRigidBodyB() const
        {
                return m_rbB;
        }

        btRigidBody& getRigidBodyA() 
        {
                return m_rbA;
        }
        btRigidBody& getRigidBodyB()
        {
                return m_rbB;
        }

        int getUserConstraintType() const
        {
                return m_userConstraintType ;
        }

        void    setUserConstraintType(int userConstraintType)
        {
                m_userConstraintType = userConstraintType;
        };

        void    setUserConstraintId(int uid)
        {
                m_userConstraintId = uid;
        }

        int getUserConstraintId() const
        {
                return m_userConstraintId;
        }

        void    setUserConstraintPtr(void* ptr)
        {
                m_userConstraintPtr = ptr;
        }

        void*   getUserConstraintPtr()
        {
                return m_userConstraintPtr;
        }

        int getUid() const
        {
                return m_userConstraintId;   
        } 

        bool    needsFeedback() const
        {
                return m_needsFeedback;
        }

        void    enableFeedback(bool needsFeedback)
        {
                m_needsFeedback = needsFeedback;
        }

        btScalar        getAppliedImpulse() const
        {
                btAssert(m_needsFeedback);
                return m_appliedImpulse;
        }

        btTypedConstraintType getConstraintType () const
        {
                return btTypedConstraintType(m_objectType);
        }
        
        void setDbgDrawSize(btScalar dbgDrawSize)
        {
                m_dbgDrawSize = dbgDrawSize;
        }
        btScalar getDbgDrawSize()
        {
                return m_dbgDrawSize;
        }

        virtual void    setParam(int num, btScalar value, int axis = -1) = 0;

        virtual btScalar getParam(int num, int axis = -1) const = 0;
        
        virtual int     calculateSerializeBufferSize() const;

        virtual const char*     serialize(void* dataBuffer, btSerializer* serializer) const;

};

// returns angle in range [-SIMD_2_PI, SIMD_2_PI], closest to one of the limits 
// all arguments should be normalized angles (i.e. in range [-SIMD_PI, SIMD_PI])
SIMD_FORCE_INLINE btScalar btAdjustAngleToLimits(btScalar angleInRadians, btScalar angleLowerLimitInRadians, btScalar angleUpperLimitInRadians)
{
        if(angleLowerLimitInRadians >= angleUpperLimitInRadians)
        {
                return angleInRadians;
        }
        else if(angleInRadians < angleLowerLimitInRadians)
        {
                btScalar diffLo = btFabs(btNormalizeAngle(angleLowerLimitInRadians - angleInRadians));
                btScalar diffHi = btFabs(btNormalizeAngle(angleUpperLimitInRadians - angleInRadians));
                return (diffLo < diffHi) ? angleInRadians : (angleInRadians + SIMD_2_PI);
        }
        else if(angleInRadians > angleUpperLimitInRadians)
        {
                btScalar diffHi = btFabs(btNormalizeAngle(angleInRadians - angleUpperLimitInRadians));
                btScalar diffLo = btFabs(btNormalizeAngle(angleInRadians - angleLowerLimitInRadians));
                return (diffLo < diffHi) ? (angleInRadians - SIMD_2_PI) : angleInRadians;
        }
        else
        {
                return angleInRadians;
        }
}

struct  btTypedConstraintData
{
        btRigidBodyData         *m_rbA;
        btRigidBodyData         *m_rbB;
        char    *m_name;

        int     m_objectType;
        int     m_userConstraintType;
        int     m_userConstraintId;
        int     m_needsFeedback;

        float   m_appliedImpulse;
        float   m_dbgDrawSize;

        int     m_disableCollisionsBetweenLinkedBodies;
        char    m_pad4[4];
        
};

SIMD_FORCE_INLINE       int     btTypedConstraint::calculateSerializeBufferSize() const
{
        return sizeof(btTypedConstraintData);
}



class btAngularLimit
{
private:
        btScalar 
                m_center,
                m_halfRange,
                m_softness,
                m_biasFactor,
                m_relaxationFactor,
                m_correction,
                m_sign;

        bool
                m_solveLimit;

public:
        btAngularLimit()
                :m_center(0.0f),
                m_halfRange(-1.0f),
                m_softness(0.9f),
                m_biasFactor(0.3f),
                m_relaxationFactor(1.0f),
                m_correction(0.0f),
                m_sign(0.0f),
                m_solveLimit(false)
        {}

        void set(btScalar low, btScalar high, btScalar _softness = 0.9f, btScalar _biasFactor = 0.3f, btScalar _relaxationFactor = 1.0f);

        void test(const btScalar angle);

        inline btScalar getSoftness() const
        {
                return m_softness;
        }

        inline btScalar getBiasFactor() const
        {
                return m_biasFactor;
        }

        inline btScalar getRelaxationFactor() const
        {
                return m_relaxationFactor;
        }

        inline btScalar getCorrection() const
        {
                return m_correction;
        }

        inline btScalar getSign() const
        {
                return m_sign;
        }

        inline btScalar getHalfRange() const
        {
                return m_halfRange;
        }

        inline bool isLimit() const
        {
                return m_solveLimit;
        }

        void fit(btScalar& angle) const;

        btScalar getError() const;

        btScalar getLow() const;

        btScalar getHigh() const;

};



#endif //BT_TYPED_CONSTRAINT_H