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() {}
 
    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