GEANT321/gdraw/gdthrz.F

   1 *
   2 * $Id$
   3 *
   4 * $Log$
   5 * Revision 1.1.1.1  1995/10/24 10:20:28  cernlib
   6 * Geant
   7 *
   8 *
   9 #include "geant321/pilot.h"
  10 *CMZ :  3.21/02 29/03/94  15.41.27  by  S.Giani
  11 *-- Author :
  12       SUBROUTINE GDTHRZ(XYZ)
  13 C.
  14 C.    ******************************************************************
  15 C.    *                                                                *
  16 C.    *       Routine processing R-Z projection of tracks and hits     *
  17 C.    *                                                                *
  18 C.    *       XYZ    = Array of X,Y,Z coordinates (input/output)       *
  19 C.    *                                                                *
  20 C.    *    ==>Called by : GDFR3D                                       *
  21 C.    *       Author : P.Zanarini   *********                          *
  22 C.    *                                                                *
  23 C.    ******************************************************************
  24 C.
  25 #include "geant321/gcdraw.inc"
  26 #include "geant321/gcflag.inc"
  27 #include "geant321/gcnum.inc"
  28       DIMENSION XYZ(3),ITRSGN(20),ITRFLG(20)
  29       LOGICAL BTEST
  30       SAVE MAXITR,EPS,LIDEVT,LITR3D,ITRSGN,ITRFLG,IFACT
  31       DATA MAXITR/20/,EPS/0.0001/,LIDEVT/0/
  32 C.
  33 C.    ------------------------------------------------------------------
  34 C.
  35       CALL UCTOH('360 ',I360,4,4)
  36 C
  37 C             If ITHRZ='ON  ' or '180 ' then use positive or negative ra
  38 C             else if ITHRZ='360 ' then use only positive radius
  39 C
  40       IF (ITHRZ.EQ.I360) THEN
  41          XYZ(2)=SQRT(XYZ(2)*XYZ(2)+XYZ(3)*XYZ(3))
  42          GO TO 999
  43       ENDIF
  44 C
  45 C             IDEVT  = Event number (in common GCFLAG)
  46 C             LIDEVT = Last event number
  47 C
  48       IF (IDEVT.NE.LIDEVT) THEN
  49          DO 10 I=1,MAXITR
  50             ITRSGN(I)=0
  51             ITRFLG(I)=0
  52    10    CONTINUE
  53          LIDEVT=IDEVT
  54       ENDIF
  55 C
  56 C             NBIT   = Number of bit per machine word (in common GCNUM)
  57 C             MAXITR = A maximum of NBIT*MAXITR significant track signs
  58 C                      can be stored (after that all signs will be posit
  59 C             IWORD  = 1,2,...,MAXITR
  60 C             IOFSET = 0,1,...,NBIT-1
  61 C
  62       IWORD=(IABS(ITR3D)/NBIT)+1
  63       IOFSET=MAX(MOD(IABS(ITR3D),NBIT)-1,0)
  64 C
  65       IF (IWORD.GT.MAXITR) THEN
  66          IFACT=1
  67          XYZ(2)=IFACT*SQRT(XYZ(2)*XYZ(2)+XYZ(3)*XYZ(3))
  68          GO TO 999
  69       ENDIF
  70 C
  71 C             If being drawing an hit, with sign already
  72 C             set by previous track, then use that sign
  73 C
  74       IF (IOBJ.EQ.3.AND.BTEST(ITRFLG(IWORD),IOFSET)) THEN
  75          IF(BTEST(ITRSGN(IWORD),IOFSET)) THEN
  76             IFACT=1
  77          ELSE
  78             IFACT=-1
  79          ENDIF
  80          XYZ(2)=IFACT*SQRT(XYZ(2)*XYZ(2)+XYZ(3)*XYZ(3))
  81          GO TO 999
  82       ENDIF
  83 C
  84       IF (ITR3D.LT.0) THEN
  85 C
  86 C             First call to GDFR3D/GDTHRZ : initialize LITR3D and make I
  87 C
  88          ITR3D=-ITR3D
  89          IF (.NOT.BTEST(ITRFLG(IWORD),IOFSET)) THEN
  90             ITRFLG(IWORD) = IBSET(ITRFLG(IWORD),IOFSET)
  91             LITR3D=0
  92          ENDIF
  93       ENDIF
  94 C
  95       IF (ITR3D.GT.0) THEN
  96 C
  97 C             LITR3D contains the last ITR3D value,
  98 C             or zero if last point was at U-V origin (0,0,...)
  99 C
 100          IF (ITR3D.EQ.LITR3D) THEN
 101 C
 102 C             Old track : get R sign from ITRSGN into IFACT
 103 C
 104             IF(BTEST(ITRSGN(IWORD),IOFSET)) THEN
 105                IFACT=1
 106             ELSE
 107                IFACT=-1
 108             ENDIF
 109 C
 110          ELSE
 111 C
 112 C             New track : set R sign into ITRSGN and IFACT
 113 C
 114             IF (ABS(XYZ(2)).GT.EPS) THEN
 115                IF (XYZ(2)/ABS(XYZ(2)).GT.0.) THEN
 116                   ITRSGN(IWORD) = IBSET(ITRSGN(IWORD),IOFSET)
 117                   IFACT=1
 118                ELSE
 119                   ITRSGN(IWORD) = IBCLR(ITRSGN(IWORD),IOFSET)
 120                   IFACT=-1
 121                ENDIF
 122             ENDIF
 123 C
 124             LITR3D=ITR3D
 125             IF ((ABS(XYZ(1)).LT.EPS).AND.(ABS(XYZ(2)).LT.EPS)) LITR3D=0
 126 C
 127          ENDIF
 128 C
 129    20    CONTINUE
 130          XYZ(2)=IFACT*SQRT(XYZ(2)*XYZ(2)+XYZ(3)*XYZ(3))
 131 C
 132       ENDIF
 133   999 RETURN
 134       END