***********************************************************************

      SUBROUTINE REFSTEP
c
c  12-july 99  R. Schicker 

***********************************************************************

      implicit none

#include "geant321/gcflag.inc"
#include "geant321/gckine.inc"
#include "geant321/gcking.inc"
#include "geant321/gclist.inc"
#include "geant321/gcsets.inc"
#include "geant321/gctmed.inc"
#include "geant321/gctrak.inc"
#include "geant321/gcvolu.inc"
#include "geant321/gconst.inc"
#include "user.inc"
#include "mdcdconst.inc"

      integer numl(4),i,i1,i2,iac1,j1,j2,nmdc,ihit,icref,kcoun
      real xl(3),xll(3),xlll(3),pl(3),pll(3),hit(15),theg
      real d1,d2,d3,the,themdc,phimdc,themdcp,phimdcp,plx,ply,plz
      character*4 ac1,ac2
      equivalence(iac1,ac1)
      data numl/1,1,1,1/
      save icref,kcoun


c      if(kcoun.eq.0)then
c         do i1=1,4
c            write(6,701)i1,(mdcdy(i2,i1),i2=1,6)
c 701        format(' mdc ',i4,' mdcy = ',6f8.3)
c        end do
c      end if

      kcoun=kcoun+1

      if(inwvol.eq.1)then
      iac1=names(nlevel)
      if(ac1.eq."D4S6")istop=1
      if(ac1(3:4).eq."C4")then
      nmdc=ichar(ac1(2:2))-48
c      write(6,101)itra,sleng,step,inwvol,ac1,numed,nmdc
c 101  format(' ref101',i4,' sl=',2f8.4,' iw=',i2,' ac1=',a4,' med=',2i4)

c      write(6,101)itra,sleng,step,inwvol,ac1,numed
c 101  format(' ref101',i4,' sl=',2f8.4,' iw=',i2,' ac1=',a4,' med=',i4)

      do i=1,3
         xl(i)=vect(i)
         pl(i)=vect(i+3)
      end do

      call gmtod(xl,xll,1)
      call gmtod(pl,pll,2)
      
      do i=1,3
         pll(i)=pll(i)*vect(7)
      end do

      d1=sqrt(xl(1)**2+xl(2)**2)
      the=raddeg*atan2(d1,xl(3))

c      write(6,102)(xll(i),i=1,3),(pll(i),i=1,3),the
c 102  format(' ref102: xll ',3f8.4,' pll ',3f8.4,' the=',f6.2)

      xlll(1)=-xll(1)
      xlll(2)=xll(3)+mdcdy(4,nmdc)
      xlll(3)=xll(2)

      plx=-pll(1)
      ply=pll(3)
      plz=pll(2)

      d1=sqrt(plx**2+ply**2)
      themdc=atan2(d1,plz)

      if(themdc.lt.0.)then
         themdcp=themdc+twopi
c         write(6,301)themdc,themdcp
c 301     format(' refstep 301: the ',2f8.3)
         else
            themdcp=themdc
      end if

      phimdc=atan2(ply,plx)
      if(phimdc.lt.0.)then
         phimdcp=phimdc+twopi
c         write(6,302)phimdc,phimdcp
c 302     format(' refstep 302: phi ',2f8.3)
         else
            phimdcp=phimdc
      end if

c      write(6,103)(xlll(i),i=1,3),(plll(i),i=1,3),the
c 103  format(' ref103: xlll ',3f8.4,' plll ',3f8.4,' the=',f6.2)

c      do j1=1,4
c         write(6,201)j1,(mdcdx(j2,j1),j2=1,6)
c 201     format(' mdcdx ',i4,2x,6f8.4)
c      end do

c      do j1=1,4
c         write(6,202)j1,(mdcdy(j2,j1),j2=1,6)
c 202     format(' mdcdy ',i4,2x,6f8.4)
c      end do


c      write(6,104)
c 104  format('    ')

c      hit(1)=vect(1)
c      hit(2)=vect(2)
c      hit(3) =vect(3)

      hit(1)=plx
      hit(2)=ply
      hit(3)=plz

      hit(4)=vect(4)*vect(7)
      hit(5)=vect(5)*vect(7)
      hit(6)=vect(6)*vect(7)
      hit(7)=xlll(1)
      hit(8)=xlll(2)
      hit(9)=1.e9*tofg
      hit(10)=1.e3*getot
      hit(11)=float(ipart)
      hit(12)=sleng
      hit(13)=themdcp
      hit(14)=phimdcp
      hit(15)=float(number(3))

      if(hit(13).lt.0.)then

      write(6,401)themdc,themdcp,phimdc,phimdcp
 401  format(' the ',2f8.3,' phi ',2f8.3)
      
      write(6,402)(hit(j1),j1=1,7)
 402  format(' refstep 402: ',3f9.3,3f9.4,f9.3)

      write(6,403)(hit(j1),j1=8,14)
 403  format(' refstep 403: ',5f9.3,2f9.5)

      write(6,404)nlevel,(numbv(j1),j1=1,6)
 404  format(' refstep 404: nlevel = ',i4,' numbv ',6i5)

      do j1=1,8
         iac1=names(j1)
         j2=number(j1)
         write(6,405)j1,ac1,j2
 405     format(' level ',i4,' name ',a4,' number ',i4)
      end do

      end if

      icref=icref+1

c      write(6,111)icref
c 111  format('  NOW IN REFSTEP GSAHIT ',i4)

      call gsahit(iset,idet,itra,numbv,hit,ihit)


      end if
      end if

      return 
      end