//*-- Author : V.Pechenov (18/04/2010)

//_HADES_CLASS_DESCRIPTION
////////////////////////////////////////////////////////////////////////////
//  HMdcKickPlane
//
//  Descriptor of the magnetic kick plane of HADES.
//  Contains a parametrization of the kick plane.
//  Parametrization and parameters of the kick plane is the copy 
//  of HSurfPlaneTriV parameters from HKickPlane2 (detPartName: MDC3)
////////////////////////////////////////////////////////////////////////////

#include "hmdckickplane.h"

ClassImp(HMdcKickPlane)

void HMdcKickPlane::setDefaultParam(void) {
  // Plane equation: y=fDx*x + fDz[i]*z + fC[i]
  // This parameters is the copy of HSurfPlaneTriV parameters
  // from HKickPlane2 (detPartName: MDC3)
  fDzLimit[1] =  400.;        // =fDzLimit[1] in HSurfPlaneTriV 
  fDzLimit[0] =  1100.;       // =fDzLimit[1] in HSurfPlaneTriV 
  fDx         =  0.124811;  
  fDz[2]      = -0.6546;      // =fDz[0] in HSurfPlaneTriV 
  fDz[1]      = -0.82008;     // =fDz[1] in HSurfPlaneTriV 
  fDz[0]      = -1.1989;      // =fDz[2] in HSurfPlaneTriV 
  fC[2]       =  1295.53;     // =fDc[0] in HSurfPlaneTriV 
  
  fC[1]  = fC[2] + (fDz[2]-fDz[1])*fDzLimit[1]; // =fDc[1] in HSurfPlaneTriV 
  fC[0]  = fC[1] + (fDz[1]-fDz[0])*fDzLimit[0]; // =fDc[2] in HSurfPlaneTriV 
}

void HMdcKickPlane::calcIntersection(Double_t x1,Double_t y1,Double_t z1,
                                     Double_t x2, Double_t y2, Double_t z2,
                                     Double_t& x, Double_t& y, Double_t& z) const { 
  // Calcul. a cross of the line with plane       y=fDx*x+fDz*z+fC
  Double_t dX = x2-x1;
  Double_t dY = y2-y1;
  Double_t dZ = z2-z1;
  
  for(Int_t i=0;i<3;i++) {
    Double_t c2  = fDz[i]*dZ;
    Double_t c3  = y1-fC[i];
    
    Double_t cDx = fDx;
    Double_t c1  = cDx*dX-dY;
    Double_t div = 1/(c1+c2);
    Double_t cx  = dX*(c3-fDz[i]*z1)+ x1*(c2-dY);
    x = cx*div;
    if(x<0) {
      cDx = -fDx;
      c1  = cDx*dX-dY;
      div = 1/(c1+c2);
      x   = cx*div;
    }   
    z = (dZ*(c3-cDx*x1) + z1*c1)*div;
    if(i<2 && z<fDzLimit[i]) continue;
    y = cDx*x+fDz[i]*z+fC[i];
    break;
  }
}