GEANT321/cgpack/cgvedg.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 CGVEDG(NT,P1,P2,IVIS)
  13 ************************************************************************
  14 *                                                                      *
  15 *     Name: CGVEDG                                                     *
  16 *     Author: E. Chernyaev                       Date:    08.08.88     *
  17 *                                                Revised:              *
  18 *                                                                      *
  19 *     Function: Compute ALL about edge:                                *
  20 *               parametric equations X=X1+T(X2-X1), Y=Y1+T(Y2-Y1)      *
  21 *               edge line equation   Ax+By+C=0                         *
  22 *               edge min-max                                           *
  23 *                                                                      *
  24 *     References: none                                                 *
  25 *                                                                      *
  26 *     Input: NT - number of transformation to screen coordinates       *
  27 *            P1(3) - 1-st edge point                                   *
  28 *            P2(3) - 2-nd edge point                                   *
  29 *                                                                      *
  30 *     Output: IVIS = -1 for very small edges                           *
  31 *                                                                      *
  32 *     Errors: none                                                     *
  33 *                                                                      *
  34 ************************************************************************
  35 #include "geant321/cgdelt.inc"
  36 #include "geant321/cgctra.inc"
  37 #include "geant321/cgcedg.inc"
  38       REAL    P1(3),P2(3)
  39 *-
  40       DO 100 I=1,3
  41         AA(I) = P1(1)*TSCRN(1,I,NT) + P1(2)*TSCRN(2,I,NT) +
  42      +          P1(3)*TSCRN(3,I,NT) + TSCRN(4,I,NT)
  43         BB(I) = P2(1)*TSCRN(1,I,NT) + P2(2)*TSCRN(2,I,NT) +
  44      +          P2(3)*TSCRN(3,I,NT) + TSCRN(4,I,NT)
  45         DELTA(I) = BB(I) - AA(I)
  46   100   CONTINUE
  47 *
  48       IVIS   =-1
  49       AXDELT=ABS(XDELT)
  50       AYDELT=ABS(YDELT)
  51       IF ((AXDELT.LE.EESCR).AND.(AYDELT.LE.EESCR))GOTO 999
  52       IVIS   = 0
  53 *           C O M P U T E   E D G E   E Q U A T I O N
  54       Q        = XDELT*XDELT + YDELT*YDELT
  55       ABC(1,1) = XDELT/Q
  56       ABC(2,1) = YDELT/Q
  57       ABC(3,1) =-(XDELT*XA + YDELT*YA)/Q
  58       XXXQ        = SQRT(Q)
  59       ABC(1,2) =-YDELT/XXXQ
  60       ABC(2,2) = XDELT/XXXQ
  61       ABC(3,2) = (YDELT*XA - XDELT*YA)/XXXQ
  62 *           C O M P U T E   E D G E   M I N - M A X
  63       DEDGE(1) =-MAX(XA,XB)
  64       DEDGE(2) =-MAX(YA,YB)
  65       DEDGE(3) = MIN(XA,XB)
  66       DEDGE(4) = MIN(YA,YB)
  67       DEDGE(5) = MIN(ZA,ZB)
  68 *
  69       NPART  = 0
  70       TDEL   = EESCR / XXXQ
  71   999 RETURN
  72       END