GEANT321/cgpack/cgvhed.F

   1 *
   2 * $Id$
   3 *
   4 * $Log$
   5 * Revision 1.1.1.1  1995/10/24 10:19:45  cernlib
   6 * Geant
   7 *
   8 *
   9 #include "geant321/pilot.h"
  10 *CMZ :  3.21/02 29/03/94  15.41.32  by  S.Giani
  11 *-- Author :
  12       SUBROUTINE CGVHED(XYZ,IFACE,IPF,DFACE,ITREE,ISTACK,ALEFT,ARIGHT)
  13 ************************************************************************
  14 *                                                                      *
  15 *     Name: CGVHED                                                     *
  16 *     Author: E. Chernyaev                       Date:    08.08.88     *
  17 *                                                Revised:              *
  18 *                                                                      *
  19 *     Function: Hidden line removal algorithm                          *
  20 *               (tree search is used for min-max test)                 *
  21 *                                                                      *
  22 *     References: CGVEDG, CGVTEF                                       *
  23 *                                                                      *
  24 *     Input: XYZ(3,*) - nodes coordinates                              *
  25 *         IFACE(*) - faces                                             *
  26 *           IPF(*) - pointers to faces beginings                       *
  27 *       DFACE(6,*) - faces min-max                                     *
  28 *       ITREE(4,*) - tree of faces min-max                             *
  29 *        ISTACK(*) - stack for tree search                             *
  30 *         ALEFT(*) - min-max of left subtrees                          *
  31 *        ARIGHT(*) - min-max of rigth subtrees                         *
  32 *                                                                      *
  33 *     Output: none                                                     *
  34 *                                                                      *
  35 *     Errors: none                                                     *
  36 *                                                                      *
  37 ************************************************************************
  38 #include "geant321/cgcedg.inc"
  39       REAL            XYZ(3,*),DFACE(6,*),ALEFT(*),ARIGHT(*)
  40 *SG
  41       INTEGER         IPF(*)
  42       INTEGER         IFACE(*)
  43       INTEGER         ISTACK(*),ITREE(4,*)
  44       INTEGER         INDLFT(5),INDRGT(5)
  45 *SG
  46       DATA            INDLFT/3,4,5,1,2/,INDRGT/3,4,1,2,1/
  47 *-
  48       JS     = 0
  49       JT     = 1
  50 *           T R E E   S E A R C H
  51   200 NF     = ITREE(1,JT)
  52       IND    = ITREE(4,JT)
  53       IF (DEDGE(IND) .GT. DFACE(IND,NF))      GOTO 300
  54       DO 210 I=1,5
  55         IF (DEDGE(I) .GT. DFACE(I,NF))        GOTO 220
  56   210   CONTINUE
  57       NIPF=IPF(NF)
  58       CALL CGVTEF(IFACE(NIPF),XYZ,IVIS)
  59       IF (IVIS .LT. 0)                        GOTO 900
  60 *           S T O R E   L E F T   L I N K   I N   S T A C K  (IF NEED)
  61   220 IF (DEDGE(INDLFT(IND)) .GT. ALEFT(JT))  GOTO 300
  62       JS     = JS + 1
  63       ISTACK(JS) = ITREE(2,JT)
  64 *           S T E P   T O   R I G H T
  65   300 IF (DEDGE(INDRGT(IND)) .GT. ARIGHT(JT)) GOTO 400
  66       JT     = ITREE(3,JT)
  67       GOTO 200
  68 *           R E S T O R E   L E F T   L I N K   F R O M   S T A C K
  69   400 IF (JS .EQ. 0)                          GOTO 999
  70       JT     = ISTACK(JS)
  71       JS     = JS - 1
  72       GOTO 200
  73 *
  74   900 NPART = -1
  75   999 RETURN
  76       END