IDENTIFICATION DIVISION.
PROGRAM-ID.	Droids.
*
* DATE-WRITTEN. March 15, 1985.
* AUTHOR. Ken Richardson.
*
* Written to the glory of God - 1 Corinthians 10:31
*

ENVIRONMENT DIVISION.

CONFIGURATION SECTION.

SPECIAL-NAMES.
	symbolic	control-g	is 08
			line-feed	is 11
			carriage-return	is 14
			shift-out	is 15
			shift-in	is 16
			control-r	is 19
			control-z	is 27
			escape		is 28
	.

SOURCE-COMPUTER. VAX-11.
OBJECT-COMPUTER. VAX-11.

INPUT-OUTPUT SECTION.
 
FILE-CONTROL.
	select	score-file
		assign to	"ci$games:droids.dat"
		organization is sequential
	.

DATA DIVISION.

FILE SECTION.
 
FD	score-file
	.

01  score-record.
    02  score-score				pic zzz,zz9.
    02  filler					pic x(02).
    02  score-date				pic x(11).
    02  filler					pic x(02).
    02  score-username				pic x(12).
 
WORKING-STORAGE SECTION.

01  constants.
    02  bell-char				pic x value control-g.
    02  line-feed-char				pic x value line-feed.
    02  carriage-return-char			pic x value carriage-return.
    02  control-r-char				pic x value control-r.
    02  control-z-char				pic x value control-z.
    02  difficulty-increment			pic s9(9) comp value 5.
    02  null-char				pic x value low-values.
    02  room-pieces.
	03  dead-human				pic x value "+".
	03  droid				pic x value "A".
	03  dust				pic x value "*".
	03  human				pic x value "X".
    02  score-file-title			pic x(34) value "======== Droids Champions ========".
    02	shift-out-character-set.
	03  filler				pic x value escape.
	03  special-graphics-set		pic x(2) value ")0".
    02  terminal-event-flag			pic s9(9) comp value 32.
    02  ws-false				pic x value "F".
    02  ws-true					pic x value "T".


01  display-item-sizes.
    02	clear-screen-size			pic s9(9) comp value 4.
    02	crlf-size				pic s9(9) comp value 2.
    02	display-square-size			pic s9(9) comp value 9.
    02	double-wide-size			pic s9(9) comp value 3.
    02	display-player-size			pic s9(9) comp value 8.
    02  home-cursor-size			pic s9(9) comp value 3.
    02  room-column-size			pic s9(9) comp.
    02  room-line-size				pic s9(9) comp.
    02  terminal-buffer-size			pic s9(9) comp value 1.


01  room-limits.
    02	north-limit				pic s9(9) comp value 1.
    02	south-limit				pic s9(9) comp value 24.
    02	east-limit				pic s9(9) comp value 40.
    02	west-limit				pic s9(9) comp value 1.


01  room-and-player.
    02	formatted-room-line occurs 24.
	03  room-line.
	    04	square occurs 40		pic x.
    02	display-player.
	03  filler				pic x value escape.
	03  filler				pic x value "[".
	03  display-player-y			pic 99.
	03  filler				pic x value ";".
	03  display-player-x			pic 99.
	03  filler				pic x value "H".


01  output-buffer.
    02	filler					pic x(4000).


01  display-square.
    02	filler					pic x value escape.
    02	filler					pic x value "[".
    02	display-square-y			pic 99.
    02	filler					pic x value ";".
    02	display-square-x			pic 99.
    02	filler					pic x value "H".
    02	display-square-char			pic x.


01  score-array.
    02	score-array-size			pic s9(9) comp.
    02	score-array-sub				pic s9(9) comp.
    02	score-array-limit			pic s9(9) comp	value  20.
    02  score-array-item					occurs 20.
	03  score-array-score			pic zzz,zz9.
	03  filler				pic x(02).
	03  score-array-date			pic x(11).
	03  filler				pic x(02).
	03  score-array-username		pic x(12).


01  character-sequences.
    02	clear-screen.
	03  filler				pic x(1) value escape.
	03  filler				pic x(3) value "[2J".
    02	crlf.
	03  filler				pic x value carriage-return.
	03  filler				pic x value line-feed.
    02	double-wide.
	03  filler				pic x(1) value escape.
	03  filler				pic x(2) value "#6".
    02	home-cursor.
	03  filler				pic x(1) value escape.
	03  filler				pic x(2) value "[H".


01  instructions-1.
    02	filler					pic x(55) value "You have landed on a space-station populated by droids.".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(42) value "Each room in the space-station is 40 x 24.".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(45) value "Each room contains progressively more droids.".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(63) value "These droids have just one function:  To destroy all intruders.".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(35) value "(Unfortunately, this includes you).".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(56) value "Droids are programmed to walk directly toward intruders.".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(51) value "They explode upon impact, leaving a pile of debris.".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.


01  instructions-2.
    02	filler					pic x(33) value "You have three choices of action:".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(65) value "    1.  You can move in any direction (including standing still).".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(37) value "    2.  You can teleport at any time.".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(50) value "        (careful; you may end up next to a droid).".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(63) value "    3.  You can use the ominous Sonic Zapper once in each room.".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(56) value "        (This disintegrates all droids adjacent to you).".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(54) value "Your goal is to destroy all droids, by causing them to".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(51) value "walk into each other or into piles of droid-debris.".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(14) value "Your controls:".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(43) value "    1-9     Move one step in any direction.".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(21) value "    T       Teleport.".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(25) value "    S       Sonic Zapper.".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(39) value "    L       Last stand (for this room).".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(27) value "    Ctrl-R  Refresh screen.".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(8) value "Scoring:".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(41) value "    10 points for each droid you explode.".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x(46) value "     1 point for each droid you Sonically Zap.".
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.
    02	filler					pic x value carriage-return.
    02	filler					pic x value line-feed.


01  totals.
    02	totals-base-position.
	03  filler				pic x value escape.
	03  filler				pic x value "[".
	03  totals-y				pic 99.
	03  filler				pic x value ";".
	03  totals-x				pic 99 value zero.
	03  filler				pic x value "H".
    02	totals-top-line.
	03  filler				pic x value shift-out.
	03  filler				pic x(27) value "lqqqqqqqqqqqqqqqqqqqqqqqqqk".
	03  filler				pic x value shift-in.
	03  filler				pic x value carriage-return.
	03  filler				pic x value line-feed.
    02	totals-room-line.
	03  left-border.
	    04	filler				pic x value shift-out.
	    04	filler				pic x value "x".
	    04	filler				pic x value shift-in.
	    04	filler				pic x value space.
	03  filler				pic x(17) value "Room #:".
	03  display-room-number			pic zz,zz9.
	03  right-border.
	    04	filler				pic x value space.
	    04	filler				pic x value shift-out.
	    04	filler				pic x value "x".
	    04	filler				pic x value shift-in.
	03  filler				pic x value carriage-return.
	03  filler				pic x value line-feed.
    02	totals-droids-line.
	03  left-border.
	    04	filler				pic x value shift-out.
	    04	filler				pic x value "x".
	    04	filler				pic x value shift-in.
	    04	filler				pic x value space.
	03  filler				pic x(17) value "Droids in room:".
	03  display-droids-in-room		pic zz,zz9.
	03  right-border.
	    04	filler				pic x value space.
	    04	filler				pic x value shift-out.
	    04	filler				pic x value "x".
	    04	filler				pic x value shift-in.
	03  filler				pic x value carriage-return.
	03  filler				pic x value line-feed.
    02	totals-score-line.
	03  left-border.
	    04	filler				pic x value shift-out.
	    04	filler				pic x value "x".
	    04	filler				pic x value shift-in.
	    04	filler				pic x value space.
	03  filler				pic x(17) value "Score this round:".
	03  display-score			pic zz,zz9.
	03  right-border.
	    04	filler				pic x value space.
	    04	filler				pic x value shift-out.
	    04	filler				pic x value "x".
	    04	filler				pic x value shift-in.
	03  filler				pic x value carriage-return.
	03  filler				pic x value line-feed.
    02	totals-running-score-line.
	03  left-border.
	    04	filler				pic x value shift-out.
	    04	filler				pic x value "x".
	    04	filler				pic x value shift-in.
	    04	filler				pic x value space.
	03  filler				pic x(14) value "Total score:".
	03  display-total-score			pic z,zzz,zz9.
	03  right-border.
	    04	filler				pic x value space.
	    04	filler				pic x value shift-out.
	    04	filler				pic x value "x".
	    04	filler				pic x value shift-in.
	03  filler				pic x value carriage-return.
	03  filler				pic x value line-feed.
    02	totals-bottom-line.
	03  filler				pic x value shift-out.
	03  filler				pic x(27) value "mqqqqqqqqqqqqqqqqqqqqqqqqqj".
	03  filler				pic x value shift-in.
	03  filler				pic x value carriage-return.
	03  filler				pic x value line-feed.


01  instruction-prompt				pic x(30) value "Do you want instructions? [n] ".
01  next-page-prompt				pic x(32) value "Press return for the next page: ".
01  press-return-prompt				pic x(25) value "Press return when ready: ".
01  game-over-message				pic x(12) value "Game over.  ".


01  variables.
    02  difficulty-level			pic s9(9) comp value 5.
    02	display-x				pic +999.
    02	display-y				pic +999.
    02	distance				pic s9(9) comp.
    02	droid-count				pic s9(9) comp.
    02	droid-x					pic s9(9) comp.
    02	droid-y					pic s9(9) comp.
    02	droids-moved-counter			pic s9(9) comp.
    02  ending-x				pic s9(9) comp.
    02  ending-y				pic s9(9) comp.
    02  formatted-total-score			pic zzz,zz9.
    02	hold-droid-count			pic s9(9) comp.
    02	line-sub				pic s9(9) comp.
    02	new-droid-x				pic s9(9) comp.
    02	new-droid-y				pic s9(9) comp.
    02  output-buffer-pointer			pic s9(9) comp.
    02	player-x				pic s9(9) comp.
    02	player-y				pic s9(9) comp.
    02	random-number-variables.
	03  ws-time				pic s9(18) comp.
	03  filler redefines ws-time.
	    04	random-number-seed		usage comp-1.
	    04	filler				usage comp-1.
	03  random-number			usage comp-1.
	03  random-x				pic s9(9) comp.
	03  random-y				pic s9(9) comp.
    02  room-line-sub				pic s9(9) comp.
    02  room-number				pic s9(9) comp value zero.
    02  score-file-tries			pic s9(9) comp.
    02  score-this-round			pic s9(9) comp.
    02  starting-x				pic s9(9) comp.
    02  starting-y				pic s9(9) comp.
    02  target-player-x				pic s9(9) comp.
    02  target-player-y				pic s9(9) comp.
    02	teleport-x-current			pic 99v999.
    02	teleport-x-difference			pic 99.
    02	teleport-x-increment			pic s99v999.
    02	teleport-y-current			pic 99v999.
    02	teleport-y-difference			pic 99.
    02	teleport-y-increment			pic s99v999.
    02	total-score				pic s9(9) comp value zero.
    02  username				pic x(12).


01  switches.
    02  ctrlc-entered-flag			pic x value "F".
    02  end-of-score-file-sw			pic x.
	88  end-of-score-file			value "T".
    02  last-stand-entered-sw			pic x.
	88  last-stand-entered			value "T".
    02  normal-command-entered-sw		pic x.
	88  normal-command-entered		value "T".
    02  player-is-dead-sw			pic x value "F".
	88  player-is-dead			value "T".
    02  sonic-screwdriver-used-up-sw		pic x.
	88  sonic-screwdriver-used-up		value "T".


01  terminal-related-data.
    02  terminal-buffer				pic x(1).
    02  terminal-channel			pic s9(9) comp.
    02  special-read-command			pic s9(9) comp.
    02  special-write-command			pic s9(9) comp.
    02  read-command				pic s9(9) comp value external io$_readvblk.
    02  cvtlow-read-modifier			pic s9(9) comp value external io$m_cvtlow.
    02  noecho-read-modifier			pic s9(9) comp value external io$m_noecho.
    02  nofiltr-read-modifier			pic s9(9) comp value external io$m_nofiltr.
    02  timed-read-modifier			pic s9(9) comp value external io$m_timed.
    02  trmnoecho-read-modifier			pic s9(9) comp value external io$m_trmnoecho.
    02  write-command				pic s9(9) comp value external io$_writevblk.
    02  noformat-modifier			pic s9(9) comp value external io$m_noformat.

    02  iosb.
	03  iobytes				pic s9(4) comp.
	03  ioterminator			pic s9(4) comp.
	03  ioterminator-size			pic s9(4) comp.


PROCEDURE DIVISION.

play-droids.
	perform	1-initialize-program
	perform 2-provide-instructions
	move	ws-false to player-is-dead-sw
	perform 3-play-one-round
		until	player-is-dead
			or
			ctrlc-entered-flag = ws-true
	perform 4-read-top-scores
	perform 5-update-top-scores
	display clear-screen, home-cursor
	call	"lib$do_command"
		using	by descriptor	"type ci$games:droids.dat"
	.


1-initialize-program.
	compute special-read-command =	read-command +
					cvtlow-read-modifier +
					noecho-read-modifier +
					nofiltr-read-modifier +
					trmnoecho-read-modifier
	compute special-write-command =	write-command +
					noformat-modifier
	call	"sys$assign"	using
		by descriptor	"sys$input:"
		by reference	terminal-channel,
		by value	0,
		by value	0

*	Enable a CTRL-C AST.
	call	"ci$enable_ctrlc_ast"
		using	by reference	ctrlc-entered-flag

	compute room-line-size = east-limit - west-limit + 1
	compute	room-column-size = south-limit - north-limit + 1

	move	1 to output-buffer-pointer

*	Initialize the G1 (shift-out) character set.
	display shift-out-character-set

*	Initialize the random number seed.
	call	"sys$gettim"
		using	by reference	ws-time
	.


2-provide-instructions.
	display instruction-prompt with no advancing
	accept	terminal-buffer
		at end
		move	ws-true to ctrlc-entered-flag
	end-accept
	if	ctrlc-entered-flag not = ws-true
		and
		(	terminal-buffer = "y"
			or
			terminal-buffer = "Y"
		)
	then
		display clear-screen, home-cursor, instructions-1, next-page-prompt with no advancing
		accept	terminal-buffer
			at end
			move	ws-true to ctrlc-entered-flag
		end-accept
		if	ctrlc-entered-flag not = ws-true
		then
			display clear-screen, home-cursor, instructions-2, press-return-prompt with no advancing
			accept	terminal-buffer
				at end
				move	ws-true to ctrlc-entered-flag
			end-accept
		end-if
	end-if
	.


3-play-one-round.
	perform 3-2-generate-room
	perform c-1-display-entire-room
	perform 3-3-play-one-move
		until	player-is-dead
			or
			droid-count = zero
			or
			ctrlc-entered-flag = ws-true
	add	score-this-round to total-score
	perform 3-4-display-running-score
	perform 3-5-increment-difficulty-level
	.


3-2-generate-room.
	add	1 to room-number
	perform varying line-sub from north-limit by 1
		until	line-sub > south-limit

		move	spaces to room-line ( line-sub )

	end-perform
	perform 3-2-1-generate-droid
		difficulty-level times
	move	difficulty-level to droid-count
	perform 3-2-2-generate-human
	move	ws-false to sonic-screwdriver-used-up-sw
	move	ws-false to last-stand-entered-sw
	move	zero to score-this-round
	.


3-2-1-generate-droid.
	perform c-4-generate-random-coordinates
		with	test after
		until	square ( random-y, random-x ) = space
	move	droid to square ( random-y, random-x )
	.


3-2-2-generate-human.
	perform c-4-generate-random-coordinates
		with	test after
		until	square ( random-y, random-x ) = space
	move	human to square ( random-y, random-x )
	move	random-x to player-x
	move	random-y to player-y
	.


3-3-play-one-move.
	if	not last-stand-entered
	then
		perform 3-3-1-get-command
	end-if
	if	ctrlc-entered-flag = ws-false
	then
		if	not last-stand-entered
		then
			perform 3-3-2-do-command
		end-if
		if	normal-command-entered
		then
			move	droid-count to hold-droid-count
			move	zero to droids-moved-counter
			perform 3-3-3-move-droids
				varying distance from 1 by 1
				until	droids-moved-counter = hold-droid-count
					or
					(	player-x - distance < west-limit
						and
						player-x + distance > east-limit
						and
						player-y - distance < north-limit
						and
						player-y + distance > south-limit
					)
			perform c-5-display-changed-squares
		end-if
	end-if
	.


3-3-1-get-command.
	move	null-char to terminal-buffer
        call	"sys$qiow" using
		by value	terminal-event-flag
		by value	terminal-channel
		by value	special-read-command
		by reference	iosb
		by value	zero
		by value	zero
		by reference	terminal-buffer
		by value	terminal-buffer-size
		by value	zero
		by value	zero
		by value	zero
		by value	zero
	.


3-3-2-do-command.
	move	ws-true to normal-command-entered-sw
	evaluate terminal-buffer
		when	"S"
			if	sonic-screwdriver-used-up
			then
				display	"" with no advancing
				move	ws-false to normal-command-entered-sw
			else
				perform 3-3-2-1-use-sonic-screwdriver
			end-if
		when	"T"
			perform 3-3-2-2-teleport-player
		when	"1"
			compute target-player-x = player-x - 1
			compute target-player-y = player-y + 1
			perform c-3-move-player
		when	"2"
			compute target-player-x = player-x
			compute target-player-y = player-y + 1
			perform c-3-move-player
		when	"3"
			compute target-player-x = player-x + 1
			compute target-player-y = player-y + 1
			perform c-3-move-player
		when	"4"
			compute target-player-x = player-x - 1
			compute target-player-y = player-y
			perform c-3-move-player
		when	"5"
			continue
		when	"6"
			compute target-player-x = player-x + 1
			compute target-player-y = player-y
			perform c-3-move-player
		when	"7"
			compute target-player-x = player-x - 1
			compute target-player-y = player-y - 1
			perform c-3-move-player
		when	"8"
			compute target-player-x = player-x
			compute target-player-y = player-y - 1
			perform c-3-move-player
		when	"9"
			compute target-player-x = player-x + 1
			compute target-player-y = player-y - 1
			perform c-3-move-player
		when	control-r-char
			perform c-1-display-entire-room
			move	ws-false to normal-command-entered-sw
		when	"L"
			move	ws-true to last-stand-entered-sw
		when	other
			display	"" with no advancing
			move	ws-false to normal-command-entered-sw
	end-evaluate
	.


3-3-2-1-use-sonic-screwdriver.
	compute starting-x = player-x - 1
	perform varying droid-x from starting-x by 1
		until	droid-x > player-x + 1

		compute starting-y = player-y - 1
		perform varying droid-y from starting-y by 1
			until	droid-y > player-y + 1

			if	(	droid-x not = player-x
					or
					droid-y not = player-y
				)
				and
				droid-x not < west-limit
				and
				droid-x not > east-limit
				and
				droid-y not < north-limit
				and
				droid-y not > south-limit
			then
				if	square ( droid-y, droid-x ) = droid
				then
					move	space to square ( droid-y, droid-x )
					move	space to display-square-char
					move	droid-x to display-square-x
					move	droid-y to display-square-y
					move	display-square to output-buffer ( output-buffer-pointer : display-square-size )
					add	display-square-size to output-buffer-pointer

					add	1 to score-this-round
					subtract 1 from droid-count
					display	"" with no advancing
				end-if
			end-if
		end-perform
	end-perform
	move	ws-true to sonic-screwdriver-used-up-sw
	.


3-3-2-2-teleport-player.
*	Find new space for human
	perform c-4-generate-random-coordinates
		with	test after
		until	square ( random-y, random-x ) = space

*	Eliminate human from current square
	move	space to square ( player-y, player-x )

*	Make it dramatic on screen
	perform 3-3-2-2-1-display-teleportation

*	Put human into new square
	move	human to square ( random-y, random-x )
	move	random-x to player-x
	move	random-y to player-y
	.


3-3-2-2-1-display-teleportation.
	if	player-y < random-y
	then
		move	+1 to teleport-y-increment
	else
		move	-1 to teleport-y-increment
	end-if

	if	player-x < random-x
	then
		move	+1 to teleport-x-increment
	else
		move	-1 to teleport-x-increment
	end-if

*	These differences are unsigned.
	compute teleport-y-difference = player-y - random-y
	compute teleport-x-difference = player-x - random-x

	if	teleport-y-difference > teleport-x-difference
	then
		compute teleport-x-increment = teleport-x-increment * ( teleport-x-difference / teleport-y-difference )
		perform 3-3-2-2-1-1-enteleport-by-y
		perform 3-3-2-2-1-2-deteleport-by-y
	else
		if	teleport-x-difference > teleport-y-difference
		then
			compute teleport-y-increment = teleport-y-increment * ( teleport-y-difference / teleport-x-difference )
			perform 3-3-2-2-1-3-enteleport-by-x
			perform 3-3-2-2-1-4-deteleport-by-x
		else
			if	teleport-y-difference not = zero
			then
				compute teleport-y-increment = teleport-y-increment * ( teleport-y-difference / teleport-x-difference )
				perform 3-3-2-2-1-3-enteleport-by-x
				perform 3-3-2-2-1-4-deteleport-by-x
			else
*				( Both differences = zero )
				continue
			end-if
		end-if
	end-if
	.

3-3-2-2-1-1-enteleport-by-y.
	compute teleport-x-current = player-x + teleport-x-increment
	compute teleport-y-current = player-y + teleport-y-increment

	move	human to display-square-char

	perform	with test after
		varying teleport-y-current from teleport-y-current by teleport-y-increment
		until	teleport-y-current = random-y

		move	teleport-y-current to display-square-y
		compute	display-square-x rounded = teleport-x-current

*		Display human in intermediate square
		move	display-square to output-buffer ( output-buffer-pointer : display-square-size )
		add	display-square-size to output-buffer-pointer

		compute teleport-x-current = teleport-x-current + teleport-x-increment

	end-perform
	.

3-3-2-2-1-3-enteleport-by-x.
	compute teleport-x-current = player-x + teleport-x-increment
	compute teleport-y-current = player-y + teleport-y-increment

	move	human to display-square-char

	perform	with test after
		varying teleport-x-current from teleport-x-current by teleport-x-increment
		until	teleport-x-current = random-x

		move	teleport-x-current to display-square-x
		compute	display-square-y rounded = teleport-y-current

*		Display human in intermediate square
		move	display-square to output-buffer ( output-buffer-pointer : display-square-size )
		add	display-square-size to output-buffer-pointer

		compute teleport-y-current = teleport-y-current + teleport-y-increment

	end-perform
	.

3-3-2-2-1-2-deteleport-by-y.
	move	player-x to teleport-x-current
	perform	with test before
		varying teleport-y-current from player-y by teleport-y-increment
		until	teleport-y-current = random-y

		move	teleport-y-current to display-square-y
		compute	display-square-x rounded = teleport-x-current

*		Redisplay actual intermediate-square contents
		move	square ( display-square-y, display-square-x ) to display-square-char
		move	display-square to output-buffer ( output-buffer-pointer : display-square-size )
		add	display-square-size to output-buffer-pointer

		compute teleport-x-current = teleport-x-current + teleport-x-increment

	end-perform
	.

3-3-2-2-1-4-deteleport-by-x.
	move	player-y to teleport-y-current
	perform	with test before
		varying teleport-x-current from player-x by teleport-x-increment
		until	teleport-x-current = random-x

		move	teleport-x-current to display-square-x
		compute	display-square-y rounded = teleport-y-current

*		Redisplay actual intermediate-square contents
		move	square ( display-square-y, display-square-x ) to display-square-char
		move	display-square to output-buffer ( output-buffer-pointer : display-square-size )
		add	display-square-size to output-buffer-pointer

		compute teleport-y-current = teleport-y-current + teleport-y-increment

	end-perform
	.

3-3-3-move-droids.
	compute droid-y = player-y - distance
	if	droid-y not < north-limit
	then
		perform 3-3-3-1-move-north-droids
	end-if

	compute droid-x = player-x + distance
	if	droid-x not > east-limit
	then
		perform 3-3-3-2-move-east-droids
	end-if

	compute droid-y = player-y + distance
	if	droid-y not > south-limit
	then
		perform 3-3-3-3-move-south-droids
	end-if

	compute droid-x = player-x - distance
	if	droid-x not < west-limit
	then
		perform 3-3-3-4-move-west-droids
	end-if
	.


3-3-3-1-move-north-droids.
* droid-y was already computed before calling this paragraph.
	compute starting-x = player-x - distance + 1
	if	starting-x < west-limit
	then
		move	west-limit to starting-x
	end-if
	compute ending-x = player-x + distance
	if	ending-x > east-limit
	then
		move	east-limit to ending-x
	end-if
	perform varying droid-x from starting-x by 1
		until droid-x > ending-x

		if	square ( droid-y, droid-x ) = droid
		then
			if	droid-x < player-x
			then
				compute new-droid-x = droid-x + 1
			else
				if	droid-x = player-x
				then
					compute new-droid-x = droid-x
				else
***					[ droid-x > player-x ]
					compute new-droid-x = droid-x - 1
				end-if
			end-if
			compute new-droid-y = droid-y + 1
			perform c-2-move-droid
		end-if
	end-perform
	.


3-3-3-2-move-east-droids.
* droid-x was already computed before calling this paragraph.
	compute starting-y = player-y - distance + 1
	if	starting-y < north-limit
	then
		move	north-limit to starting-y
	end-if
	compute ending-y = player-y + distance
	if	ending-y > south-limit
	then
		move	south-limit to ending-y
	end-if
	perform varying droid-y from starting-y by 1
		until droid-y > ending-y

		if	square ( droid-y, droid-x ) = droid
		then
			if	droid-y < player-y
			then
				compute new-droid-y = droid-y + 1
			else
				if	droid-y = player-y
				then
					compute new-droid-y = droid-y
				else
***					[ droid-y > player-y ]
					compute new-droid-y = droid-y - 1
				end-if
			end-if
			compute new-droid-x = droid-x - 1
			perform c-2-move-droid
		end-if
	end-perform
	.


3-3-3-3-move-south-droids.
* droid-y was already computed before calling this paragraph.
	compute starting-x = player-x + distance - 1
	if	starting-x > east-limit
	then
		move	east-limit to starting-x
	end-if
	compute ending-x = player-x - distance
	if	ending-x < west-limit
	then
		move	west-limit to ending-x
	end-if
	perform varying droid-x from starting-x by -1
		until droid-x < ending-x

		if	square ( droid-y, droid-x ) = droid
		then
			if	droid-x < player-x
			then
				compute new-droid-x = droid-x + 1
			else
				if	droid-x = player-x
				then
					compute new-droid-x = droid-x
				else
***					[ droid-x > player-x ]
					compute new-droid-x = droid-x - 1
				end-if
			end-if
			compute new-droid-y = droid-y - 1
			perform c-2-move-droid
		end-if
	end-perform
	.


3-3-3-4-move-west-droids.
* droid-x was already computed before calling this paragraph.
	compute starting-y = player-y + distance - 1
	if	starting-y > south-limit
	then
		move	south-limit to starting-y
	end-if
	compute ending-y = player-y - distance
	if	ending-y < north-limit
	then
		move	north-limit to ending-y
	end-if
	perform varying droid-y from starting-y by -1
		until droid-y < ending-y

		if	square ( droid-y, droid-x ) = droid
		then
			if	droid-y < player-y
			then
				compute new-droid-y = droid-y + 1
			else
				if	droid-y = player-y
				then
					compute new-droid-y = droid-y
				else
***					[ droid-y > player-y ]
					compute new-droid-y = droid-y - 1
				end-if
			end-if
			compute new-droid-x = droid-x + 1
			perform c-2-move-droid
		end-if
	end-perform
	.


3-4-display-running-score.
	move	room-number to display-room-number
	move	difficulty-level to display-droids-in-room
	move	score-this-round to display-score
	move	total-score to display-total-score
*	The number (8) is:	the number of totals lines (including borders), plus the press-return-prompt, plus one (1).
	if	player-y < north-limit + 8
	then
		compute totals-y = south-limit - 8
	else
		compute totals-y = north-limit
	end-if
	if	player-is-dead
		or
		ctrlc-entered-flag = ws-true
	then
		display	totals, game-over-message, press-return-prompt, bell-char, bell-char, bell-char, bell-char with no advancing
	else
		display	totals, press-return-prompt, bell-char, bell-char, bell-char, bell-char with no advancing
	end-if
	accept	terminal-buffer
		at end
		move	ws-true to ctrlc-entered-flag
	end-accept
	.


3-5-increment-difficulty-level.
	add	difficulty-increment to difficulty-level
	.


4-read-top-scores.
	open	i-o	score-file
	move	ws-false to end-of-score-file-sw
*	Read past the title record.
	perform c-7-read-score-record
	if	not end-of-score-file
	then
		perform c-7-read-score-record
	end-if
	move	zero to score-array-sub
	perform until	score-array-sub = score-array-limit
			or
			end-of-score-file
		add	1 to score-array-sub
		move	score-record to score-array-item ( score-array-sub )
		perform c-7-read-score-record
	end-perform
	move	score-array-sub to score-array-size
	close	score-file
	.


5-update-top-scores.
	move	total-score to formatted-total-score
	perform varying score-array-sub from score-array-size by -1
		until	score-array-sub = zero
			or
			score-array-score ( score-array-sub ) not < formatted-total-score
		if	score-array-sub not = score-array-limit
		then
			move	score-array-item ( score-array-sub ) to score-array-item ( score-array-sub + 1 )
		end-if
	end-perform
	if	score-array-size < score-array-limit
	then
		add	1 to score-array-size
		perform 5-1-load-score-into-array
		perform 5-2-rewrite-score-array
	else
		if	score-array-sub < score-array-limit
		then
			perform 5-1-load-score-into-array
			perform 5-2-rewrite-score-array
		end-if
	end-if
	.


5-1-load-score-into-array.
	move	spaces to score-array-item ( score-array-sub + 1 )
	move	total-score to score-array-score ( score-array-sub + 1 )
	call	"lib$date_time"
		using	by descriptor	score-array-date  ( score-array-sub + 1 )
	call	"ci$get_vax_username"
		using	by reference	score-array-username ( score-array-sub + 1 )
	.


5-2-rewrite-score-array.
	open	i-o	score-file
	move	ws-false to end-of-score-file-sw
	perform 5-2-1-position-score-file
	move	score-file-title to score-record
	perform	c-8-write-score-record
	perform varying score-array-sub from 1 by 1
		until	score-array-sub > score-array-size
		perform 5-2-1-position-score-file
		move	score-array-item ( score-array-sub ) to score-record
		perform c-8-write-score-record
	end-perform
	close	score-file
	.


5-2-1-position-score-file.
	if	not end-of-score-file
	then
		perform c-7-read-score-record
		if	not end-of-score-file
		then
			continue
		else
			close	score-file
			open	extend	score-file
		end-if
	end-if
	.


c-1-display-entire-room.
	move	clear-screen to output-buffer ( output-buffer-pointer : clear-screen-size )
	add	clear-screen-size to output-buffer-pointer

	move	home-cursor to output-buffer ( output-buffer-pointer : home-cursor-size )
	add	home-cursor-size to output-buffer-pointer

	perform varying room-line-sub from north-limit by 1
		until room-line-sub > south-limit

		move	double-wide to output-buffer ( output-buffer-pointer : double-wide-size )
		add	double-wide-size to output-buffer-pointer

		move	room-line ( room-line-sub ) to output-buffer ( output-buffer-pointer : room-line-size )
		add	room-line-size to output-buffer-pointer

		if	room-line-sub not = south-limit
		then
			move	crlf to output-buffer ( output-buffer-pointer : crlf-size )
			add	crlf-size to output-buffer-pointer
		end-if

	end-perform

	move	player-x to display-player-x
	move	player-y to display-player-y
	move	display-player to output-buffer ( output-buffer-pointer : display-player-size )
	add	display-player-size to output-buffer-pointer

	perform	c-6-write-buffer
	.


c-2-move-droid.
	add	1 to droids-moved-counter
	move	space to square ( droid-y, droid-x )
	move	space to display-square-char
	move	droid-x to display-square-x
	move	droid-y to display-square-y
	move	display-square to output-buffer ( output-buffer-pointer : display-square-size )
	add	display-square-size to output-buffer-pointer
	evaluate square ( new-droid-y, new-droid-x )
		when	space
			move	droid to square ( new-droid-y, new-droid-x )
			move	droid to display-square-char
			move	new-droid-x to display-square-x
			move	new-droid-y to display-square-y
			move	display-square to output-buffer ( output-buffer-pointer : display-square-size )
			add	display-square-size to output-buffer-pointer
		when	droid
			move	dust to square ( new-droid-y, new-droid-x )
			move	dust to display-square-char
			move	new-droid-x to display-square-x
			move	new-droid-y to display-square-y
			move	display-square to output-buffer ( output-buffer-pointer : display-square-size )
			add	display-square-size to output-buffer-pointer
			add	20 to score-this-round
			subtract 2 from droid-count
		when	dust
			add	10 to score-this-round
			subtract 1 from droid-count
		when	dead-human
			add	10 to score-this-round
			subtract 1 from droid-count
		when	human
			move	dead-human to square ( new-droid-y, new-droid-x )
			move	dead-human to display-square-char
			move	new-droid-x to display-square-x
			move	new-droid-y to display-square-y
			move	display-square to output-buffer ( output-buffer-pointer : display-square-size )
			add	display-square-size to output-buffer-pointer
			add	10 to score-this-round
			subtract 1 from droid-count
			move	ws-true to player-is-dead-sw
		when	other
			move new-droid-x to display-x
			move new-droid-y to display-y
			display	"Problem square `"
				square ( new-droid-y, new-droid-x )
				"' in c-2-move-droid at ("
				display-y
				","
				display-x
				").  Press RETURN when ready:  " with no advancing
			accept	terminal-buffer
				at end
				move	ws-true to ctrlc-entered-flag
			end-accept
	end-evaluate
	.


c-3-move-player.
	if	target-player-x < west-limit
	then
		move	ws-false to normal-command-entered-sw
	else
		if	target-player-x > east-limit
		then
			move	ws-false to normal-command-entered-sw
		end-if
	end-if
	if	target-player-y < north-limit
	then
		move	ws-false to normal-command-entered-sw
	else
		if	target-player-y > south-limit
		then
			move	ws-false to normal-command-entered-sw
		end-if
	end-if
	if	normal-command-entered
	then
		move	space to square ( player-y, player-x )
		move	space to display-square-char
		move	player-x to display-square-x
		move	player-y to display-square-y
		move	display-square to output-buffer ( output-buffer-pointer : display-square-size )
		add	display-square-size to output-buffer-pointer
		evaluate square ( target-player-y, target-player-x )
			when	space
				move	human to square ( target-player-y, target-player-x )
				move	human to display-square-char
				move	target-player-x to display-square-x
				move	target-player-y to display-square-y
				move	display-square to output-buffer ( output-buffer-pointer : display-square-size )
				add	display-square-size to output-buffer-pointer
			when	droid
				add	10 to score-this-round
				subtract 1 from droid-count
				move	ws-true to player-is-dead-sw
				move	dead-human to display-square-char
				move	target-player-x to display-square-x
				move	target-player-y to display-square-y
				move	display-square to output-buffer ( output-buffer-pointer : display-square-size )
				add	display-square-size to output-buffer-pointer
			when	dust
				move	ws-true to player-is-dead-sw
				move	dead-human to display-square-char
				move	target-player-x to display-square-x
				move	target-player-y to display-square-y
				move	display-square to output-buffer ( output-buffer-pointer : display-square-size )
				add	display-square-size to output-buffer-pointer
			when	other
				move target-player-x to display-x
				move target-player-y to display-y
				display	"Problem square `"
					square ( target-player-y, target-player-x )
					"' in c-3-move-player at ("
					display-y
					","
					display-x
					").  Press RETURN when ready:  " with no advancing
				accept	terminal-buffer
					at end
					move	ws-true to ctrlc-entered-flag
				end-accept
		end-evaluate
		move	target-player-x to player-x
		move	target-player-y to player-y
	else
		display	"" with no advancing
	end-if
	.


c-4-generate-random-coordinates.
	call	"mth$random"
		using	by reference	random-number-seed
		giving	random-number
	compute	random-x = ( random-number * ( room-line-size ) ) + 1
	call	"mth$random"
		using	by reference	random-number-seed
		giving	random-number
	compute	random-y = ( random-number * ( room-column-size ) ) + 1
	.


c-5-display-changed-squares.
	move	player-x to display-player-x
	move	player-y to display-player-y
	move	display-player to output-buffer ( output-buffer-pointer : display-player-size )
	add	display-player-size to output-buffer-pointer
	perform	c-6-write-buffer
	.


c-6-write-buffer.
	compute	output-buffer-pointer = output-buffer-pointer - 1
        call	"sys$qiow" using
		by value	terminal-event-flag
		by value	terminal-channel
		by value	special-write-command
		by reference	iosb
		by value	zero
		by value	zero
		by reference	output-buffer
		by value	output-buffer-pointer
		by value	zero
		by value	zero
		by value	zero
		by value	zero

	move	1 to output-buffer-pointer
	.


c-7-read-score-record.
	read	score-file
		at end
		move	ws-true to end-of-score-file-sw
	end-read
	.


c-8-write-score-record.
	if	not end-of-score-file
	then
		rewrite	score-record
	else
		write	score-record
	end-if
	.