subroutine b_generate_geometry

      implicit none
      save
      
      include 'bigcal_data_structures.cmn'
      include 'bigcal_geometry.cmn'

      integer ix,iy,icell,ixmin

      real xshift,yshift,xsize,ysize,xcenter,ycenter,xcell,diff
      real mindiff

      xshift = BIGCAL_PROT_SHIFT_X
      yshift = BIGCAL_PROT_SHIFT_Y + bigcal_height

      xsize = BIGCAL_PROT_SIZE_X
      ysize = BIGCAL_PROT_SIZE_Y
      

      do ix=1,BIGCAL_PROT_NX
         do iy=1,BIGCAL_PROT_NY
            icell = ix + (iy-1)*BIGCAL_PROT_NX
            xcenter = xshift + (ix - .5)*xsize
            ycenter = yshift + (iy - .5)*ysize

            BIGCAL_PROT_XCENTER(icell) = xcenter
            BIGCAL_PROT_YCENTER(icell) = ycenter
            bigcal_all_xcenter(icell) = xcenter
            bigcal_all_ycenter(icell) = ycenter
         enddo
      enddo

      xshift = BIGCAL_RCS_SHIFT_X
      yshift = BIGCAL_RCS_SHIFT_Y + bigcal_height

      xsize = BIGCAL_RCS_SIZE_X
      ysize = BIGCAL_RCS_SIZE_Y

      do ix=1,BIGCAL_RCS_NX
         do iy=1,BIGCAL_RCS_NY
            icell = ix + (iy-1)*BIGCAL_RCS_NX
            xcenter = xshift + (ix - .5)*xsize
            ycenter = yshift + (iy - .5)*ysize

            BIGCAL_RCS_XCENTER(icell) = xcenter
            BIGCAL_RCS_YCENTER(icell) = ycenter

            bigcal_all_xcenter(icell + bigcal_prot_maxhits) = xcenter
            bigcal_all_ycenter(icell + bigcal_prot_maxhits) = ycenter
         enddo
      enddo

      do ix=1,bigcal_prot_nx

         mindiff = 1000000.
         ixmin = 0

         xcenter = bigcal_prot_xcenter(ix + 31*32)
         do icell=1,30
            xcell = bigcal_rcs_xcenter(icell)
            diff = xcenter - xcell
            if(abs(diff).lt.mindiff) then
               mindiff = diff
               ixmin = icell
            endif
         enddo

         if(mindiff.lt.1000000..and.ixmin.ge.1.and.ixmin.le.30) then
            bigcal_ixclose_prot(ix) = ixmin
         else
            write(*,*) 'warning: could not find ixclose_prot, ix = ',ix
            write(*,*) 'something probably wrong with geometry database'
            bigcal_ixclose_prot(ix) = min(max(ix,1),30)
         endif     
      enddo

      do ix=1,bigcal_rcs_nx
         
         mindiff = 1000000.
         ixmin = 0

         xcenter = bigcal_rcs_xcenter(ix)
         do icell=1,32
            xcell = bigcal_prot_xcenter(icell + 31*32)
            diff = xcenter - xcell
            if(abs(diff).lt.mindiff) then
               mindiff = diff
               ixmin = icell
            endif
         enddo
         if(mindiff.lt.1000000..and.ixmin.ge.1.and.ixmin.le.32) then
            bigcal_ixclose_rcs(ix) = ixmin
         else
            write(*,*) 'warning: could not find ixclose_rcs, ix = ',ix
            write(*,*) 'something probably wrong with geometry database'
            bigcal_ixclose_rcs(ix) = min(max(ix,1),32)
         endif
      enddo 

      return
      end