SUBROUTINE BULLET
C
C	THIS SUBROUTINE CONTROLS THE MOTION OF A BULLET ON THE SCREEN.
C	IT CALLS BULCOL TO TEST FOR AND CONTROL COLLISIONS WITH TARGETS.
C
      IMPLICIT INTEGER(A - Z)
      PARAMETER MAXCNT = 24
C SCREEN BOUNDARIES
      PARAMETER LMAR = 2, RMAR = 30, TMAR = 2, BMAR = 23, GMAR = 18
C DIRECTIONALS
      PARAMETER HALT = 0, UP = 1, DOWN = 2, LEFT = 4, RIGHT = 8
      PARAMETER UPL = 10, UPR = 9, DOWNL = 12, DOWNR = 11
C DISPLAYABLE CHARACTERS
	PARAMETER GUNCHR="166, CBODY="140, MSHCHR="146, BULCHR="170
	PARAMETER SPICHR="173, FLECHR="175, SCOCHR="142, PSNCHR="052
	PARAMETER CLHEAD="074, CRHEAD="076, CDHEAD="126
	PARAMETER SHFIN="17, SHFOUT="16, SPACE="40
C QIO FUNCTION CODES
	PARAMETER IOATA="1410, IOWVB="11000, SFSMC="2440
C
      INTEGER*4SCORE, FRESCO, TIMER, SEED, FLETIM, SPITIM, SCOTIM, CNTTI
     *M
      DIMENSION PRL(6), CX(MAXCNT, 12), CY(MAXCNT, 12)
      DIMENSION CLEN(MAXCNT), CDIR(MAXCNT), CRISE(MAXCNT), CBOT(MAXCNT)
      BYTE CNTBRD(BMAR, RMAR), MSHBRD(BMAR, RMAR), PSNBRD(BMAR, RMAR)
      COMMON/DIRCOM/DIRCOD, FIRCOD
      COMMON/CNTCOM/PRL, SCORE, TIMER, SEED, CX, CY, CLEN, CDIR, CRISE, 
     *CBOT, GUNX, GUNY, FRESCO, CNTBRD, MSHBRD, PSNBRD, BULACT, BULX, BU
     *LY, FLETIM, FLEACT, FLEX, FLEY, SPITIM, SPIACT, SPIX, SPIY, SPILR,
     * SCOTIM, SCOACT, SCOX, SCOY, SCODIR, GUNCNT, CNTTIM, BOARD, CNTWAV
C
C	VT100 DISPLAY CONTROL PARAMETER DEFINITIONS
C
CCURSOR POSITION REPORT
CCURSOR UP
CCURSOR DOWN
CCURSOR FORWARD
CCURSOR BACK
CDOUBLE WIDTH LINE
      PARAMETER CUP = 1, CUU = 2, CUD = 3, CUF = 4, CUB = 5, DECDWL = 6,
     * DECDHL = 7, DECRC = 8, DECSC = 9, DECSWL = 10, ED = 11, EL = 12, 
     *SGR = 13, NEL = 14, SCS = 15, SM = 16, RM = 17, ANSI = 18, CPP=19
CCHECK FOR COLLISIONS
      CALL BULCOL
      IF (.NOT.(BULACT .EQ. 0)) GOTO 2000
CBULLET HAS HIT SOMETHING
        RETURN
C
C	BLANK OUT OLD BULLET LOCATION AND MOVE BULLET UP ONE SPACE
C
2000  CONTINUE
      CALL UVT100(CPP, BULX, BULY, SPACE)
      BULX = BULX - 1
      IF (.NOT.(BULX .LT. TMAR)) GOTO 2020
CBULLET OFF TOP OF SCREEN
        BULACT = 0
        RETURN
2020  CONTINUE
CCHECK FOR COLLISIONS AT NEW LOC.
      CALL BULCOL
C
C	IF BULLET HAS COLLIDED WITH SOMETHING, RETURN.
C	OTHERWISE DISPLAY BULLET AT NEW LOCATION.
C
      IF (.NOT.(BULACT .NE. 0)) GOTO 2040
        CALL UVT100(CPP, BULX, BULY, BULCHR)
2040  CONTINUE
      RETURN
      END