btWheelInfo.h

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/*
 * Copyright (c) 2005 Erwin Coumans http://continuousphysics.com/Bullet/
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies.
 * Erwin Coumans makes no representations about the suitability 
 * of this software for any purpose.  
 * It is provided "as is" without express or implied warranty.
*/
#ifndef BT_WHEEL_INFO_H
#define BT_WHEEL_INFO_H

#include "LinearMath/btVector3.h"
#include "LinearMath/btTransform.h"

class btRigidBody;

struct btWheelInfoConstructionInfo
{
        btVector3       m_chassisConnectionCS;
        btVector3       m_wheelDirectionCS;
        btVector3       m_wheelAxleCS;
        btScalar        m_suspensionRestLength;
        btScalar        m_maxSuspensionTravelCm;
        btScalar        m_wheelRadius;
        
        btScalar                m_suspensionStiffness;
        btScalar                m_wheelsDampingCompression;
        btScalar                m_wheelsDampingRelaxation;
        btScalar                m_frictionSlip;
        btScalar                m_maxSuspensionForce;
        bool m_bIsFrontWheel;
        
};

struct btWheelInfo
{
        struct RaycastInfo
        {
                //set by raycaster
                btVector3       m_contactNormalWS;//contactnormal
                btVector3       m_contactPointWS;//raycast hitpoint
                btScalar        m_suspensionLength;
                btVector3       m_hardPointWS;//raycast starting point
                btVector3       m_wheelDirectionWS; //direction in worldspace
                btVector3       m_wheelAxleWS; // axle in worldspace
                bool            m_isInContact;
                void*           m_groundObject; //could be general void* ptr
        };

        RaycastInfo     m_raycastInfo;

        btTransform     m_worldTransform;
        
        btVector3       m_chassisConnectionPointCS; //const
        btVector3       m_wheelDirectionCS;//const
        btVector3       m_wheelAxleCS; // const or modified by steering
        btScalar        m_suspensionRestLength1;//const
        btScalar        m_maxSuspensionTravelCm;
        btScalar getSuspensionRestLength() const;
        btScalar        m_wheelsRadius;//const
        btScalar        m_suspensionStiffness;//const
        btScalar        m_wheelsDampingCompression;//const
        btScalar        m_wheelsDampingRelaxation;//const
        btScalar        m_frictionSlip;
        btScalar        m_steering;
        btScalar        m_rotation;
        btScalar        m_deltaRotation;
        btScalar        m_rollInfluence;
        btScalar        m_maxSuspensionForce;

        btScalar        m_engineForce;

        btScalar        m_brake;
        
        bool m_bIsFrontWheel;
        
        void*           m_clientInfo;//can be used to store pointer to sync transforms...

        btWheelInfo(btWheelInfoConstructionInfo& ci)

        {

                m_suspensionRestLength1 = ci.m_suspensionRestLength;
                m_maxSuspensionTravelCm = ci.m_maxSuspensionTravelCm;

                m_wheelsRadius = ci.m_wheelRadius;
                m_suspensionStiffness = ci.m_suspensionStiffness;
                m_wheelsDampingCompression = ci.m_wheelsDampingCompression;
                m_wheelsDampingRelaxation = ci.m_wheelsDampingRelaxation;
                m_chassisConnectionPointCS = ci.m_chassisConnectionCS;
                m_wheelDirectionCS = ci.m_wheelDirectionCS;
                m_wheelAxleCS = ci.m_wheelAxleCS;
                m_frictionSlip = ci.m_frictionSlip;
                m_steering = btScalar(0.);
                m_engineForce = btScalar(0.);
                m_rotation = btScalar(0.);
                m_deltaRotation = btScalar(0.);
                m_brake = btScalar(0.);
                m_rollInfluence = btScalar(0.1);
                m_bIsFrontWheel = ci.m_bIsFrontWheel;
                m_maxSuspensionForce = ci.m_maxSuspensionForce;

        }

        void    updateWheel(const btRigidBody& chassis,RaycastInfo& raycastInfo);

        btScalar        m_clippedInvContactDotSuspension;
        btScalar        m_suspensionRelativeVelocity;
        //calculated by suspension
        btScalar        m_wheelsSuspensionForce;
        btScalar        m_skidInfo;

};

#endif //BT_WHEEL_INFO_H