btGeneric6DofConstraint.hpp

//! Rotation Limit structure for generic joints
class btRotationalLimitMotor
{
public:
    //! limit_parameters
    //!@{
    btScalar m_loLimit;//!< joint limit
    btScalar m_hiLimit;//!< joint limit
    btScalar m_targetVelocity;//!< target motor velocity
    btScalar m_maxMotorForce;//!< max force on motor
    btScalar m_maxLimitForce;//!< max force on limit
    btScalar m_damping;//!< Damping.
    btScalar m_limitSoftness;//! Relaxation factor
    btScalar m_normalCFM;//!< Constraint force mixing factor
    btScalar m_stopERP;//!< Error tolerance factor when joint is at limit
    btScalar m_stopCFM;//!< Constraint force mixing factor when joint is at limit
    btScalar m_bounce;//!< restitution factor
    bool m_enableMotor;

    //!@}

    //! temp_variables
    //!@{
    btScalar m_currentLimitError;//!  How much is violated this limit
    btScalar m_currentPosition;     //!  current value of angle 
    int m_currentLimit;//!< 0=free, 1=at lo limit, 2=at hi limit
    btScalar m_accumulatedImpulse;
    //!@}

    btRotationalLimitMotor()
    {
    	m_accumulatedImpulse = 0.f;
        m_targetVelocity = 0;
        m_maxMotorForce = 0.1f;
        m_maxLimitForce = 300.0f;
        m_loLimit = 1.0f;
        m_hiLimit = -1.0f;
		m_normalCFM = 0.f;
		m_stopERP = 0.2f;
		m_stopCFM = 0.f;
        m_bounce = 0.0f;
        m_damping = 1.0f;
        m_limitSoftness = 0.5f;
        m_currentLimit = 0;
        m_currentLimitError = 0;
        m_enableMotor = false;
    }

    btRotationalLimitMotor(const btRotationalLimitMotor & limot)
    {
        m_targetVelocity = limot.m_targetVelocity;
        m_maxMotorForce = limot.m_maxMotorForce;
        m_limitSoftness = limot.m_limitSoftness;
        m_loLimit = limot.m_loLimit;
        m_hiLimit = limot.m_hiLimit;
		m_normalCFM = limot.m_normalCFM;
		m_stopERP = limot.m_stopERP;
		m_stopCFM =	limot.m_stopCFM;
        m_bounce = limot.m_bounce;
        m_currentLimit = limot.m_currentLimit;
        m_currentLimitError = limot.m_currentLimitError;
        m_enableMotor = limot.m_enableMotor;
    }



	//! Is limited
    bool isLimited()
    {
    	if(m_loLimit > m_hiLimit) return false;
    	return true;
    }

	//! Need apply correction
    bool needApplyTorques()
    {
    	if(m_currentLimit == 0 && m_enableMotor == false) return false;
    	return true;
    }

	//! calculates  error
	/*!
	calculates m_currentLimit and m_currentLimitError.
	*/
	int testLimitValue(btScalar test_value);

	//! apply the correction impulses for two bodies
    btScalar solveAngularLimits(btScalar timeStep,btVector3& axis, btScalar jacDiagABInv,btRigidBody * body0, btRigidBody * body1);

};