source: JEM-EUSO/esaf_lal/tags/v1_r0/esaf/packages/simulation/detector/optics/src/FastFocalPlane.cc @ 117

// ESAF : Euso Simulation and Analysis Framework
// class FastFocalPlane
// $Id: FastFocalPlane.cc 2849 2010-11-11 11:59:41Z biktem $
//

#include <math.h>
#include "FastFocalPlane.hh"
#include "ElectronicsFactory.hh"
#include "EusoElectronics.hh"
#include "MacroCell.hh"
#include "Photomultiplier.hh"
#include "PmtGeometry.hh"
#include "Config.hh"
#include "IdealFocalSurface.hh"
#include "EConst.hh"

ClassImp(FastFocalPlane)
using namespace EConst;

//______________________________________________________________________________
FastFocalPlane::FastFocalPlane() {
    //
    // Constructor
    //
}

//______________________________________________________________________________
FastFocalPlane::~FastFocalPlane() {
    //
    // Destructor
    //
}

//______________________________________________________________________________
Photon *FastFocalPlane::Transport(Photon *p) const {
    //
    // Transport the photon through the optics
    //

    if (!fElectronics)
        FatalError("No electronics defined.");
    // photon position relative to local coordinate system
    p->pos -= fPos;
    MacroCellGeometry *g;
    Photon *pOld = p;

    for(Int_t i=0; i<fElectronics->NumCell(); i++) {
        g=fElectronics->Cell(i)->Geometry();
        if ( ( g->IsHit( *p ) ) > kTolerance ){
            p = HitMC( p, g );

            // photon can be either dead
            if (!p) {
                pOld->pos += fPos;
                return 0;
            }
            // or can have reached successfully a macrocell
            if ( p->MChit) {
                p->pos += fPos;
                return p;
            }
        }
    }

    if(p && !p->MChit) {
        if(p->dir[Z] > 0) {
            // photon going up
            p->pos += fPos;
            Double_t DL = CylinderIntersection( p );

            if ( DL < kTolerance ) {
                p->history = kWalls;
                return 0;
            }

            p->pos+=DL*p->dir.Unit();
            p->time+=DL/Clight();
            p->history = kWalls;
            return 0;
        } else {
            // reflected photon
            EVector dummy=p->dir*((p->pos[Z]-Bottom())/fabs(p->dir[Z]));
            p->pos+=dummy;
            p->time+=dummy.Mag()/Clight();
            p->pos[Z]=Bottom();
            p->pos += fPos;
            return p;
        }
    }

    return 0;
}

//#define DEBUG
//______________________________________________________________________________
Photon* FastFocalPlane::HitMC(Photon *p, MacroCellGeometry *g) const {
        Photomultiplier *HitPMT = g->FindHitPmt( *p );
        if (!HitPMT){

            return p;
        }
        p->MChit=true;

        Double_t DL = HitPMT->Geometry()->GetOA()->IsHit(*p);

        p->pos+=p->dir.Unit()*DL;
        p->time+=DL/Clight();
        p->hit=true;
#ifdef DEBUG
        cout<<"-------- MACROCELL HIT ---------"<<endl;
        //cout<<"Hit MacroCell "<<i<<endl;

        cout<<"relposition = "<<p->pos - g->GetCenter()<<endl;
        cout<<"position = "<<p->pos<<endl;
        cout<<"g->GetNormal() = "<<g->GetNormal()<<endl;
        cout<<"direction = "<<p->dir<<endl;
        if(HitPMT) {
            cout<<"Hit PMT "<<endl;
            cout<<"Hit PMT "<<HitPMT->Id()<<endl;
            cout <<"Hit PMT position "<<HitPMT->Geometry()->Position()<<endl;
            cout <<"Hit PMT distance "<< DL <<endl;
        } else {
            cout<<"missed PMT"<<endl;
        }

        cout<<"hit ifs "<<p->hitIfs<<" "<<p->posOnIfs<<endl;
        cout<<"pos "<<Position()<<endl;
#endif /* DEBUG */
        //p->posOnIfs=p->pos;
        p=HitPMT->Geometry()->GetOA()->Transport(p);

        // when we get here there are two possibility:
        // p==0 if the photon is not reflected by the cathode
        // p!=0 if the photon is reflected back
        if(p){
#ifdef DEBUG
                cerr<<"FastFocalPlane: photon reflected back by the chatode"<<endl;
#endif /* DEBUG */
                p=Transport(p);
        }
        return p;
}