.\"	$OpenBSD: atc.6,v 1.18 2007/05/31 19:19:16 jmc Exp $
.\"
.\" Copyright (c) 1990, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" Ed James.
.\"
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.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\"
.\"	@(#)atc.6	8.1 (Berkeley) 5/31/93
.\"
.\" Copyright (c) 1986 Ed James. All rights reserved.
.\"
.Dd $Mdocdate: May 31 2007 $
.Dt ATC 6
.Os
.Sh NAME
.Nm atc
.Nd air traffic controller game
.Sh SYNOPSIS
.Nm atc
.Op Fl lpqstu?
.Op Fl f Ar game
.Op Fl g Ar game
.Op Fl r Ar seed
.Sh DESCRIPTION
.Nm
lets you try your hand at the nerve-wracking duties of an air traffic
controller without endangering the lives of millions of
travelers each year.
Your responsibilities require you to direct the flight of jets
and prop planes into and out of the flight arena and airports.
The speed
.Pq update time
and frequency of the planes depend on the
difficulty of the chosen arena.
.Bl -tag -width "-g gamex"
.It Fl f Ar game
Play the named
.Ar game .
If the game listed is not one of the ones printed by the
.Fl l
option, the default game is played.
.It Fl g Ar game
Same as
.Fl f .
.It Fl l
Print a list of available games and exit.
The first game name printed is the default game.
.It Fl p
Print the path to the special directory where
.Nm
expects to find its private files.
This is used during the installation of the program.
.It Fl q
Play quietly
.Pq no bells .
.It Fl r Ar seed
Set the random seed.
This option can be used to replay a specific game.
.It Fl s
Print the score list
.Pq formerly the Top Ten list .
The scoring information is the game time in
.Dq radar updates ,
the wall-clock game time, and the number of planes that were
successfully dealt with.
.It Fl t
Same as
.Fl s .
.It Fl u
Print the usage line and exit.
.It Fl \&?
Same as
.Fl u .
.El
.Sh GOALS
Your goal in
.Nm
is to keep the game going as long as possible.
There is no winning state, except to beat the times of other players.
You will need to: launch planes at airports
.Po
by instructing them to increase their altitude
.Pc ;
land planes at airports
(by instructing them to go to altitude zero when exactly over the airport);
and maneuver planes out of exit points.
.Pp
Several things will cause the end of the game.
Each plane has a destination
.Pq see information area ,
and sending a plane to the wrong destination is an error.
Planes can run out of fuel, or can collide.
Collision is defined as adjacency, horizontal or vertical.
A plane leaving the arena in any other way than through its correct
destination exit is an error as well.
.Pp
Scores are sorted in order of the number of planes safe.
The other statistics are provided merely for fun.
There is no penalty for taking longer than another player
.Pq except in the case of ties .
.Pp
Suspending a game is not permitted.
If you get a talk message, tough.
When was the last time an Air Traffic Controller got called away to
the phone?
.Sh "THE DISPLAY"
Depending on the terminal used, the
.Nm
screen will be divided into 4 areas.
It should be stressed that the terminal driver portion of the
game was designed to be reconfigurable, so the display format can vary
depending on the version you are playing.
The descriptions here are based on the ASCII version of the game.
The game rules and input format, however, should remain consistent.
Control-L redraws the screen, should it become muddled.
.Ss RADAR
The first screen area is the radar display, showing the relative locations
of the planes, airports, standard entry/exit points, radar
beacons, and
.Dq lines
which simply serve to aid you in guiding
the planes.
.Pp
Planes are shown as a single letter with an altitude.
If the numerical altitude is a single digit, then it represents
thousands of feet.
Some distinction is made between the prop planes and the jets.
On ASCII terminals, prop planes are
represented by an upper case letter, jets by a lower case letter.
.Pp
Airports are shown as a number and some indication of the direction
planes must be going to land at the airport.
On ASCII terminals, this is one of
.Sq ^ ,
.Sq \&> ,
.Sq \&< ,
or
.Sq v ,
to indicate
north
.Pq 0 degrees ,
east
.Pq 90 ,
west
.Pq 270 ,
and south
.Pq 180 ,
respectively.
The planes will also take off in this direction.
.Pp
Beacons are represented as circles or asterisks and a number.
Their purpose is to offer a place of easy reference to the plane pilots.
See
.Sx The Delay Command
under the input section of this manual.
.Pp
Entry/exit points are displayed as numbers along the border of the
radar screen.
Planes will enter the arena from these points without warning.
These points have a direction associated with them, and
planes will always enter the arena from this direction.
On the ASCII version of
.Nm atc ,
this direction is not displayed.
It will become apparent what this direction is as the game progresses.
.Pp
Incoming planes will always enter at the same altitude: 7000 feet.
For a plane to depart successfully through an entry/exit point,
it must be flying at 9000 feet.
It is not necessary for the planes to be flying in any particular
direction when they leave the arena
.Pq yet .
.Ss "INFORMATION AREA"
The second area of the display is the information area, which lists
the time
.Pq number of updates since start
and the number of planes you
have directed safely out of the arena.
Below this is a list of planes currently in the air, followed by a
blank line, and then a list of planes on the ground
.Pq at airports .
Each line lists the plane name and its current altitude,
an optional asterisk indicating low fuel, the plane's destination,
and the plane's current command.
Changing altitude is not considered
to be a command and is therefore not displayed.
The following are some possible information lines:
.Pp
.Dl B4*A0: Circle @ b1
.Pp
.Dl g7 E4: 225
.Pp
The first example shows a prop plane named
.Sq B
that is flying at 4000
feet.
It is low on fuel (note the
.Sq * ) .
Its destination is
Airport #0.
The next command it expects
to do is circle when it reaches Beacon #1.
The second example shows a jet named
.Sq g
at 7000 feet, destined for
Exit #4.
It is just now executing a turn to 225 degrees
.Pq Southwest .
.Ss "INPUT AREA"
The third area of the display is the input area.
It is here that your input is reflected.
See the
.Sx INPUT
heading of this manual for more details.
.Ss "AUTHOR AREA"
This area is used simply to give credit where credit is due. :-)
.Sh INPUT
A command completion interface is built into
the game.
At any time, typing
.Sq \&?
will list possible input characters.
Typing a backspace
.Pq your erase character
backs up, erasing the last part of the command.
When a command is complete, a return enters it, and
any semantic checking is done at that time.
If no errors are detected, the command is sent to the appropriate plane.
If an error is discovered
during the check, the offending statement will be underscored and a
.Pq somewhat
descriptive message will be printed under it.
.Pp
The command syntax is broken into two parts:
.Em Immediate Only
and
.Em Delayable
commands.
.Em Immediate Only
commands happen on the next
update.
.Em Delayable
commands also happen on the next update unless they
are followed by an optional predicate called the
.Em Delay
command.
.Pp
In the following tables, the syntax
.Em [0\-9]
means any single digit, and
.Em <dir>
refers to the keys around the
.Sq s
key, namely
.Dq wedcxzaq .
In absolute references,
.Sq q
refers to Northwest or 315 degrees, and
.Sq w
refers to North, or 0 degrees.
In relative references,
.Sq q
refers to \-45 degrees or 45 degrees left, and
.Sq w
refers to 0 degrees, or no change in direction.
.Pp
All commands start with a plane letter.
This indicates the recipient of the command.
Case is ignored.
.Ss "IMMEDIATE ONLY COMMANDS"
.Bd -ragged
.Bl -tag -width "aaaa"
.It Sy "a [ cd+- ]" Em number
Altitude:
Affect a plane's altitude, possibly requesting takeoff.
.Sq \&+
and
.Sq \&-
are the same as
.Sq c
and
.Sq d .
.Bl -tag -width "aaaaaaaaaa" -compact
.It Sy a [0\-9]
Go to the given altitude
.Pq thousands of feet .
.It Sy c [0\-9]
Climb:
Relative altitude change
.Pq thousands of feet .
.It Sy d [0\-9]
Descend:
Relative altitude change
.Pq thousands of feet .
.El
.It Sy m
Mark:
Display in highlighted mode.
Plane and command information is displayed normally.
.It Sy i
Ignore:
Do not display highlighted.
Command information is displayed as a line of dashes if there is no command.
.It Sy u
Unmark:
Same as ignore, but if a delayed command is processed,
the plane will become marked.
This is useful if you want to forget about a plane during part, but not
all, of its journey.
.El
.Ed
.Ss "DELAYABLE COMMANDS"
.Bd -ragged
.Bl -tag -width "aaaa"
.It Sy c
Circle:
Have the plane circle.
.It Sy "t [ l-r+LR ] [ dir ]" No or Sy "tt [ abe* ]" Em number
Turn:
Change direction.
.Bl -tag -width "aaaaaaaaaa" -compact
.It Sy t<dir>
Turn to the absolute compass heading given.
The shortest turn will be taken.
.It Sy tl
Left:
Turn counterclockwise
.Pq 45 degrees by default .
.Bl -tag -width "tl <dir>" -compact
.It Sy tl <dir>
Turn ccw the given number of degrees.
Zero degrees
.Pq Sq w
is no turn; 45 degrees ccw is
.Sq e .
The shortest turn will be taken; for instance, if you specify
a ccw turn of 315 degrees
.Pq Sq q ,
which should take several turns,
the plane will really turn 45 cw, which takes only one turn.
.El
.It Sy tr
Right:
Turn clockwise
.Pq 45 degrees by default .
.Bl -tag -width "tl <dir>" -compact
.It Sy tr <dir>
Analogous to turn left <dir>.
.El
.It Sy tL
Turn counterclockwise 90 degrees.
.It Sy tR
Turn clockwise 90 degrees.
.It Sy "tt [abe*]"
Towards:
Turn towards a beacon, airport or exit.
The turn is just an estimate.
.Bl -tag -width "aaaaaaaaaa" -compact
.It Sy ttb Em number
Turn towards the specified beacon.
.It Sy tt* Em number
Equivalent to
.Sy ttb .
.It Sy tte Em number
Turn towards the specified exit.
.It Sy tta Em number
Turn towards the specified airport.
.El
.El
.El
.Ed
.Ss "THE DELAY COMMAND"
The
.Em Delay
(a/@)
command may be appended to any
.Em Delayable
command.
It allows the controller to instruct a plane to do an action
when the plane reaches a particular beacon
.Pq or other objects in future versions .
.Bd -ragged -offset indent
.Bl -tag -width indent -compact
.It Sy a/@
At:
Do the given delayable command when the plane reaches the given beacon.
.Bl -tag -width "aaaaaaaaaa" -compact
.It Sy ab Em number
The letter is redundant to allow for expansion.
.Sq \&@
can be used instead of
.Sq a .
.El
.El
.Ed
.Ss "MARKING, UNMARKING AND IGNORING"
Planes are
.Em marked
by default when they enter the arena.
This means they are displayed in highlighted mode on the radar display.
A plane may also be either
.Em unmarked
or
.Em ignored .
An
.Em unmarked
plane is drawn in unhighlighted mode, and a line of dashes is displayed in
the command field of the information area.
The plane will remain this way until a mark command has been issued.
Any other command will be issued,
but the command line will return to a line of dashes when the command
is completed.
.Pp
An
.Em ignored
plane is treated the same as an unmarked plane, except that it will
automatically switch to
.Em marked
status when a delayed command has been processed.
This is useful if you want to forget about a plane for a while,
but its flight path has not yet been completely set.
.Pp
As with all of the commands, marking, unmarking and ignoring will take effect
at the beginning of the next update.
Do not be surprised if the plane does
not immediately switch to unhighlighted mode.
.Ss EXAMPLES
.Bd -ragged -offset indent
.Bl -tag -width "gtte4ab2"
.It atlab1
Plane A: turn left at beacon #1
.It cc
Plane C: circle
.It gtte4ab2
Plane G: turn towards exit #4 at beacon #2
.It ma+2
Plane M: altitude: climb 2000 feet
.It stq
Plane S: turn to 315
.It xi
Plane X: ignore
.El
.Ed
.Sh "OTHER INFORMATION"
.Bl -bullet
.It
Jets move every update; prop planes move every other update.
.It
All planes turn at most 90 degrees per movement.
.It
Planes enter at 7000 feet and leave at 9000 feet.
.It
Planes flying at an altitude of 0 crash if they are not over an airport.
.It
Planes waiting at airports can only be told to take off
.Pq climb in altitude .
.It
Pressing return
.Pq that is, entering an empty command
will perform the next update immediately.
This allows the player to
.Dq fast forward
the game clock if nothing interesting is happening.
.El
.Sh "NEW GAMES"
The
.Pa Game_List
file lists the currently available play fields.
New field description file names must be placed in this file to be
playable.
If a player specifies a game not in this file, his score will not be logged.
.Pp
The game field description files are broken into two parts.
The first part is the definition section.
Here, the four tunable game parameters must be set.
These variables are set with the syntax:
.Pp
.Dl "variable = number;"
.Pp
Variable may be one of:
.Li update ,
indicating the number of seconds between forced updates;
.Li newplane ,
indicating
.Pq about
the number of updates between new plane entries;
.Li width ,
indicating the width of the play field; or
.Li height ,
indicating the height of the play field.
.Pp
The second part of the field description files describes the locations
of the exits, the beacons, the airports and the lines.
The syntax is as follows:
.Bd -ragged -offset indent
.Bl -tag -width "airport:" -compact
.It beacon :
(x y) ... ;
.It airport :
(x y direction) ... ;
.It exit :
(x y direction) ... ;
.It line :
[ (x1 y1) (x2 y2) ] ... ;
.El
.Ed
.Pp
For beacons, a simple x, y coordinate pair is used
.Pq enclosed in parentheses .
Airports and exits require a third value, a direction, which is one
of
.Dq wedcxzaq .
For airports, this is the direction that planes must be going to take
off and land, and for exits, this is the direction that planes will be going
when they enter
the arena.
This may not seem intuitive, but as there is no restriction on
direction of exit, this is appropriate.
Lines are slightly different, since they need two coordinate pairs to
specify the line endpoints.
These endpoints must be enclosed in square brackets.
.Pp
All statements are semi-colon (;) terminated.
Multiple item statements accumulate.
Each definition must occur exactly once, before any
item statements.
Comments begin with a hash (#) symbol
and terminate with a newline.
The coordinates are between zero and width-1 and height-1
inclusive.
All of the exit coordinates must lie on the borders, and
all of the beacons and airports must lie inside of the borders.
Line endpoints may be anywhere within the field, so long as
the lines are horizontal, vertical or
.Em exactly
diagonal.
.Ss "FIELD FILE EXAMPLE"
.Bd -literal -offset indent
# This is the default game.

update = 5;
newplane = 5;
width = 30;
height = 21;

exit:		( 12  0 x ) ( 29  0 z ) ( 29  7 a ) ( 29 17 a )
		(  9 20 e ) (  0 13 d ) (  0  7 d ) (  0  0 c ) ;

beacon:		( 12  7 ) ( 12 17 ) ;

airport:	( 20 15 w ) ( 20 18 d ) ;

line:		[ (  1  1 ) (  6  6 ) ]
		[ ( 12  1 ) ( 12  6 ) ]
		[ ( 13  7 ) ( 28  7 ) ]
		[ ( 28  1 ) ( 13 16 ) ]
		[ (  1 13 ) ( 11 13 ) ]
		[ ( 12  8 ) ( 12 16 ) ]
		[ ( 11 18 ) ( 10 19 ) ]
		[ ( 13 17 ) ( 28 17 ) ]
		[ (  1  7 ) ( 11  7 ) ] ;
.Ed
.Sh FILES
Files are kept in a special directory, which can be shown by using the
.Fl p
flag.
.Pp
.Bl -tag -width "/usr/share/games/atc/Game_List" -compact
.It Pa /var/games/atc_score
Score file.
.It Pa /usr/share/games/atc/Game_List
The list of playable games.
.El
.Sh AUTHORS
Ed James, UC Berkeley: edjames@ucbvax.berkeley.edu, ucbvax!edjames
.Pp
This game is based on someone's description of the overall flavor
of a game written for some unknown PC many years ago, maybe.
.Sh BUGS
The screen sometimes refreshes after you have quit.