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////////////////////////////////////////////////////////////////////////
// Optical Photon Boundary Process Class Definition
////////////////////////////////////////////////////////////////////////
//
// File:        G4OpBoundaryProcess.hh
// Description: Discrete Process -- reflection/refraction at
//                                  optical interfaces
// Version:     1.1
// Created:     1997-06-18
// Modified:    2005-07-28 add G4ProcessType to constructor
//              1999-10-29 add method and class descriptors
//              1999-10-10 - Fill NewMomentum/NewPolarization in
//                           DoAbsorption. These members need to be
//                           filled since DoIt calls
//                           aParticleChange.SetMomentumChange etc.
//                           upon return (thanks to: Clark McGrew)
//              2006-11-04 - add capability of calculating the reflectivity
//                           off a metal surface by way of a complex index
//                           of refraction - Thanks to Sehwook Lee and John
//                           Hauptman (Dept. of Physics - Iowa State Univ.)
//              2009-11-10 - add capability of simulating surface reflections
//                           with Look-Up-Tables (LUT) containing measured
//                           optical reflectance for a variety of surface
//                           treatments - Thanks to Martin Janecek and
//                           William Moses (Lawrence Berkeley National Lab.)
//              2013-06-01 - add the capability of simulating the transmission
//                           of a dichronic filter
//              2017-02-24 - add capability of simulating surface reflections
//                           with Look-Up-Tables (LUT) developed in DAVIS
//
// Author:      Peter Gumplinger
//              adopted from work by Werner Keil - April 2/96
//
////////////////////////////////////////////////////////////////////////

#ifndef G4OpBoundaryProcess_h
#define G4OpBoundaryProcess_h 1

#include "G4RandomTools.hh"
#include "G4VDiscreteProcess.hh"
#include "G4OpticalSurface.hh"
#include "G4OpticalPhoton.hh"

enum G4OpBoundaryProcessStatus
{
  Undefined,
  Transmission,
  FresnelRefraction,
  FresnelReflection,
  TotalInternalReflection,
  LambertianReflection,
  LobeReflection,
  SpikeReflection,
  BackScattering,
  Absorption,
  Detection,
  NotAtBoundary,
  SameMaterial,
  StepTooSmall,
  NoRINDEX,
  PolishedLumirrorAirReflection,
  PolishedLumirrorGlueReflection,
  PolishedAirReflection,
  PolishedTeflonAirReflection,
  PolishedTiOAirReflection,
  PolishedTyvekAirReflection,
  PolishedVM2000AirReflection,
  PolishedVM2000GlueReflection,
  EtchedLumirrorAirReflection,
  EtchedLumirrorGlueReflection,
  EtchedAirReflection,
  EtchedTeflonAirReflection,
  EtchedTiOAirReflection,
  EtchedTyvekAirReflection,
  EtchedVM2000AirReflection,
  EtchedVM2000GlueReflection,
  GroundLumirrorAirReflection,
  GroundLumirrorGlueReflection,
  GroundAirReflection,
  GroundTeflonAirReflection,
  GroundTiOAirReflection,
  GroundTyvekAirReflection,
  GroundVM2000AirReflection,
  GroundVM2000GlueReflection,
  Dichroic
};

class G4OpBoundaryProcess : public G4VDiscreteProcess
{
 public:
  explicit G4OpBoundaryProcess(const G4String& processName = "OpBoundary",
                               G4ProcessType type          = fOptical);
  virtual ~G4OpBoundaryProcess();

  virtual G4bool IsApplicable(
    const G4ParticleDefinition& aParticleType) override;
  // Returns true -> 'is applicable' only for an optical photon.

  virtual G4double GetMeanFreePath(const G4Track&, G4double,
                                   G4ForceCondition* condition) override;
  // Returns infinity; i. e. the process does not limit the step, but sets the
  // 'Forced' condition for the DoIt to be invoked at every step. However, only
  // at a boundary will any action be taken.

  G4VParticleChange* PostStepDoIt(const G4Track& aTrack,
                                  const G4Step& aStep) override;
  // This is the method implementing boundary processes.

  virtual G4OpBoundaryProcessStatus GetStatus() const;
  // Returns the current status.

  virtual void SetInvokeSD(G4bool);
  // Set flag for call to InvokeSD method.

  virtual void PreparePhysicsTable(const G4ParticleDefinition&) override;

  virtual void Initialise();

 private:
  G4OpBoundaryProcess(const G4OpBoundaryProcess& right) = delete;
  G4OpBoundaryProcess& operator=(const G4OpBoundaryProcess& right) = delete;

  G4bool G4BooleanRand(const G4double prob) const;

  G4ThreeVector GetFacetNormal(const G4ThreeVector& Momentum,
                               const G4ThreeVector& Normal) const;

  void DielectricMetal();
  void DielectricDielectric();

  void DielectricLUT();
  void DielectricLUTDAVIS();

  void DielectricDichroic();

  void ChooseReflection();
  void DoAbsorption();
  void DoReflection();

  G4double GetIncidentAngle();
  // Returns the incident angle of optical photon

  G4double GetReflectivity(G4double E1_perp, G4double E1_parl,
                           G4double incidentangle, G4double RealRindex,
                           G4double ImaginaryRindex);
  // Returns the Reflectivity on a metalic surface

  void CalculateReflectivity(void);

  void BoundaryProcessVerbose(void) const;

  // Invoke SD for post step point if the photon is 'detected'
  G4bool InvokeSD(const G4Step* step);

  G4double thePhotonMomentum;

  G4ThreeVector OldMomentum;
  G4ThreeVector OldPolarization;

  G4ThreeVector NewMomentum;
  G4ThreeVector NewPolarization;

  G4ThreeVector theGlobalNormal;
  G4ThreeVector theFacetNormal;

  G4Material* Material1;
  G4Material* Material2;

  G4OpticalSurface* OpticalSurface;

  G4MaterialPropertyVector* fRealRIndexMPV;
  G4MaterialPropertyVector* fImagRIndexMPV;

  G4double Rindex1;
  G4double Rindex2;

  G4double cost1, cost2, sint1, sint2;

  G4OpBoundaryProcessStatus theStatus;

  G4OpticalSurfaceModel theModel;

  G4OpticalSurfaceFinish theFinish;

  G4double theReflectivity;
  G4double theEfficiency;
  G4double theTransmittance;

  G4double theSurfaceRoughness;

  G4double prob_sl, prob_ss, prob_bs;

  G4int iTE, iTM;

  G4double kCarTolerance;

  size_t idx, idy;
  G4Physics2DVector* DichroicVector;

  G4bool fInvokeSD;

  size_t idx_rindex1        = 0;
  size_t idx_rindex_surface = 0;
  size_t idx_reflect        = 0;
  size_t idx_eff            = 0;
  size_t idx_trans          = 0;
  size_t idx_lobe           = 0;
  size_t idx_spike          = 0;
  size_t idx_back           = 0;
  size_t idx_rindex2        = 0;
  size_t idx_groupvel       = 0;
  size_t idx_rrindex        = 0;
  size_t idx_irindex        = 0;
};

////////////////////
// Inline methods
////////////////////

inline G4bool G4OpBoundaryProcess::G4BooleanRand(const G4double prob) const
{
  /* Returns a random boolean variable with the specified probability */
  return (G4UniformRand() < prob);
}

inline G4bool G4OpBoundaryProcess::IsApplicable(
  const G4ParticleDefinition& aParticleType)
{
  return (&aParticleType == G4OpticalPhoton::OpticalPhoton());
}

inline G4OpBoundaryProcessStatus G4OpBoundaryProcess::GetStatus() const
{
  return theStatus;
}

inline void G4OpBoundaryProcess::SetInvokeSD(G4bool flag) { fInvokeSD = flag; }

inline void G4OpBoundaryProcess::ChooseReflection()
{
  G4double rand = G4UniformRand();
  if(rand >= 0.0 && rand < prob_ss)
  {
    theStatus      = SpikeReflection;
    theFacetNormal = theGlobalNormal;
  }
  else if(rand >= prob_ss && rand <= prob_ss + prob_sl)
  {
    theStatus = LobeReflection;
  }
  else if(rand > prob_ss + prob_sl && rand < prob_ss + prob_sl + prob_bs)
  {
    theStatus = BackScattering;
  }
  else
  {
    theStatus = LambertianReflection;
  }
}

inline void G4OpBoundaryProcess::DoAbsorption()
{
  theStatus = Absorption;

  if(G4BooleanRand(theEfficiency))
  {
    // EnergyDeposited =/= 0 means: photon has been detected
    theStatus = Detection;
    aParticleChange.ProposeLocalEnergyDeposit(thePhotonMomentum);
  }
  else
  {
    aParticleChange.ProposeLocalEnergyDeposit(0.0);
  }

  NewMomentum     = OldMomentum;
  NewPolarization = OldPolarization;

  aParticleChange.ProposeTrackStatus(fStopAndKill);
}

inline void G4OpBoundaryProcess::DoReflection()
{
  if(theStatus == LambertianReflection)
  {
    NewMomentum    = G4LambertianRand(theGlobalNormal);
    theFacetNormal = (NewMomentum - OldMomentum).unit();
  }
  else if(theFinish == ground)
  {
    theStatus = LobeReflection;
    if(fRealRIndexMPV && fImagRIndexMPV)
    {
      //
    }
    else
    {
      theFacetNormal = GetFacetNormal(OldMomentum, theGlobalNormal);
    }
    G4double PdotN = OldMomentum * theFacetNormal;
    NewMomentum    = OldMomentum - (2. * PdotN) * theFacetNormal;
  }
  else
  {
    theStatus      = SpikeReflection;
    theFacetNormal = theGlobalNormal;
    G4double PdotN = OldMomentum * theFacetNormal;
    NewMomentum    = OldMomentum - (2. * PdotN) * theFacetNormal;
  }
  G4double EdotN  = OldPolarization * theFacetNormal;
  NewPolarization = -OldPolarization + (2. * EdotN) * theFacetNormal;
}

#endif /* G4OpBoundaryProcess_h */