source: code/archive/tutorial5/src/external/bullet/BulletDynamics/Vehicle/btRaycastVehicle.h

/*
 * 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_RAYCASTVEHICLE_H
#define BT_RAYCASTVEHICLE_H

#include "BulletDynamics/Dynamics/btRigidBody.h"
#include "BulletDynamics/ConstraintSolver/btTypedConstraint.h"
#include "btVehicleRaycaster.h"
class btDynamicsWorld;
#include "LinearMath/btAlignedObjectArray.h"
#include "btWheelInfo.h"
#include "BulletDynamics/Dynamics/btActionInterface.h"

class btVehicleTuning;

///rayCast vehicle, very special constraint that turn a rigidbody into a vehicle.
class btRaycastVehicle : public btActionInterface
{

                btAlignedObjectArray<btVector3> m_forwardWS;
                btAlignedObjectArray<btVector3> m_axle;
                btAlignedObjectArray<btScalar>  m_forwardImpulse;
                btAlignedObjectArray<btScalar>  m_sideImpulse;
        
                ///backwards compatibility
                int     m_userConstraintType;
                int     m_userConstraintId;

public:
        class btVehicleTuning
                {
                        public:

                        btVehicleTuning()
                                :m_suspensionStiffness(btScalar(5.88)),
                                m_suspensionCompression(btScalar(0.83)),
                                m_suspensionDamping(btScalar(0.88)),
                                m_maxSuspensionTravelCm(btScalar(500.)),
                                m_frictionSlip(btScalar(10.5)),
                                m_maxSuspensionForce(btScalar(6000.))
                        {
                        }
                        btScalar        m_suspensionStiffness;
                        btScalar        m_suspensionCompression;
                        btScalar        m_suspensionDamping;
                        btScalar        m_maxSuspensionTravelCm;
                        btScalar        m_frictionSlip;
                        btScalar        m_maxSuspensionForce;

                };
private:

        btScalar        m_tau;
        btScalar        m_damping;
        btVehicleRaycaster*     m_vehicleRaycaster;
        btScalar                m_pitchControl;
        btScalar        m_steeringValue; 
        btScalar m_currentVehicleSpeedKmHour;

        btRigidBody* m_chassisBody;

        int m_indexRightAxis;
        int m_indexUpAxis;
        int     m_indexForwardAxis;

        void defaultInit(const btVehicleTuning& tuning);

public:

        //constructor to create a car from an existing rigidbody
        btRaycastVehicle(const btVehicleTuning& tuning,btRigidBody* chassis,    btVehicleRaycaster* raycaster );

        virtual ~btRaycastVehicle() ;


        ///btActionInterface interface
        virtual void updateAction( btCollisionWorld* collisionWorld, btScalar step)
        {
        (void) collisionWorld;
                updateVehicle(step);
        }
        

        ///btActionInterface interface
        void    debugDraw(btIDebugDraw* debugDrawer);
                        
        const btTransform& getChassisWorldTransform() const;
        
        btScalar rayCast(btWheelInfo& wheel);

        virtual void updateVehicle(btScalar step);
        
        
        void resetSuspension();

        btScalar        getSteeringValue(int wheel) const;

        void    setSteeringValue(btScalar steering,int wheel);


        void    applyEngineForce(btScalar force, int wheel);

        const btTransform&      getWheelTransformWS( int wheelIndex ) const;

        void    updateWheelTransform( int wheelIndex, bool interpolatedTransform = true );
        
//      void    setRaycastWheelInfo( int wheelIndex , bool isInContact, const btVector3& hitPoint, const btVector3& hitNormal,btScalar depth);

        btWheelInfo&    addWheel( const btVector3& connectionPointCS0, const btVector3& wheelDirectionCS0,const btVector3& wheelAxleCS,btScalar suspensionRestLength,btScalar wheelRadius,const btVehicleTuning& tuning, bool isFrontWheel);

        inline int              getNumWheels() const {
                return int (m_wheelInfo.size());
        }
        
        btAlignedObjectArray<btWheelInfo>       m_wheelInfo;


        const btWheelInfo&      getWheelInfo(int index) const;

        btWheelInfo&    getWheelInfo(int index);

        void    updateWheelTransformsWS(btWheelInfo& wheel , bool interpolatedTransform = true);

        
        void setBrake(btScalar brake,int wheelIndex);

        void    setPitchControl(btScalar pitch)
        {
                m_pitchControl = pitch;
        }
        
        void    updateSuspension(btScalar deltaTime);

        virtual void    updateFriction(btScalar timeStep);



        inline btRigidBody* getRigidBody()
        {
                return m_chassisBody;
        }

        const btRigidBody* getRigidBody() const
        {
                return m_chassisBody;
        }

        inline int      getRightAxis() const
        {
                return m_indexRightAxis;
        }
        inline int getUpAxis() const
        {
                return m_indexUpAxis;
        }

        inline int getForwardAxis() const
        {
                return m_indexForwardAxis;
        }

        
        ///Worldspace forward vector
        btVector3 getForwardVector() const
        {
                const btTransform& chassisTrans = getChassisWorldTransform(); 

                btVector3 forwardW ( 
                          chassisTrans.getBasis()[0][m_indexForwardAxis], 
                          chassisTrans.getBasis()[1][m_indexForwardAxis], 
                          chassisTrans.getBasis()[2][m_indexForwardAxis]); 

                return forwardW;
        }

        ///Velocity of vehicle (positive if velocity vector has same direction as foward vector)
        btScalar        getCurrentSpeedKmHour() const
        {
                return m_currentVehicleSpeedKmHour;
        }

        virtual void    setCoordinateSystem(int rightIndex,int upIndex,int forwardIndex)
        {
                m_indexRightAxis = rightIndex;
                m_indexUpAxis = upIndex;
                m_indexForwardAxis = forwardIndex;
        }


        ///backwards compatibility
        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;
        }

};

class btDefaultVehicleRaycaster : public btVehicleRaycaster
{
        btDynamicsWorld*        m_dynamicsWorld;
public:
        btDefaultVehicleRaycaster(btDynamicsWorld* world)
                :m_dynamicsWorld(world)
        {
        }

        virtual void* castRay(const btVector3& from,const btVector3& to, btVehicleRaycasterResult& result);

};


#endif //BT_RAYCASTVEHICLE_H