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// G4VExternalNavigation
//
// Class description:
//
// Pure virtual class to be specialised by the user for tracking with
// an external navigation

// Authors: V.Vlachoudis, G.Cosmo (CERN), 2019
// --------------------------------------------------------------------
#ifndef G4VEXTERNALNAVIGATION_HH
#define G4VEXTERNALNAVIGATION_HH 1

#include "G4LogicalVolume.hh"
#include "G4NavigationHistory.hh"
#include "G4ThreeVector.hh"
#include "G4VNavigation.hh"
#include "G4VPhysicalVolume.hh"
#include "G4VSolid.hh"

/**
 * @brief G4VExternalNavigation is a pure virtual class to be specialised
 * by the user for tracking with an external navigation.
 */

class G4VExternalNavigation : public G4VNavigation
{
  public:

    /**
     * Constructor and Destructor.
     */
    G4VExternalNavigation();
    ~G4VExternalNavigation() override;

    /**
     * Cloning method, pure virtual.
     */
    virtual G4VExternalNavigation* Clone() = 0;

    // Optional methods - may be necessary under particular circumstances

    /**
     * Special 'Inside' call that includes direction of next motion.
     * Provided for potential optimisations.
     *  @param[in] solid Solid to be considered.
     *  @param[in] position Point to be checked.
     *  @param[in] direction Not used.
     *  @returns Whether the point is inside the solid or not.
     */
    virtual EInside Inside( const G4VSolid*      solid,
                            const G4ThreeVector& position,
                            const G4ThreeVector& direction );

    /**
     * Updates any relevant internal state to take account that the location
     * has been moved to 'localPoint' and that it remains in the current
     * (mother) physical volume 'motherPhysical'.
     *  @note Default action is do-nothing; only implemented by the concrete
     *        navigator class.
     *  @param[in] motherPhysical Volume to be considered.
     *  @param[in] localPoint Point to be checked.
     */
     void RelocateWithinVolume( G4VPhysicalVolume* motherPhysical,
                                const G4ThreeVector& localPoint ) override;
};

#endif