NAME

atc — air traffic controller game

SYNOPSIS

DESCRIPTION

atc 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 (update time) and frequency of the planes depend on the difficulty of the chosen arena.

-f game

Play the named game. If the game listed is not one of the ones printed by the -l option, the default game is played.

-g game

Same as -f.

-l

Print a list of available games and exit. The first game name printed is the default game.

-p

Print the path to the special directory where atc expects to find its private files. This is used during the installation of the program.

-q

Play quietly (no bells).

-r seed

Set the random seed. This option can be used to replay a specific game.

-s

Print the score list (formerly the Top Ten list). The scoring information is the game time in “radar updates”, the wall-clock game time, and the number of planes that were successfully dealt with.

-t

Same as -s.

GOALS

Your goal in atc 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 (by instructing them to increase their altitude); land planes at airports (by instructing them to go to altitude zero when exactly over the airport); and maneuver planes out of exit points.

Several things will cause the end of the game. Each plane has a destination (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.

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 (except in the case of ties).

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?

THE DISPLAY

Depending on the terminal used, the atc 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.

INPUT

A command completion interface is built into the game. At any time, typing ‘?’ will list possible input characters. Typing a backspace (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 (somewhat) descriptive message will be printed under it.

The command syntax is broken into two parts: Immediate Only and Delayable commands. Immediate Only commands happen on the next update. Delayable commands also happen on the next update unless they are followed by an optional predicate called the Delay command.

In the following tables, the syntax [0-9] means any single digit, and <dir> refers to the keys around the ‘s’ key, namely “wedcxzaq”. In absolute references, ‘q’ refers to Northwest or 315 degrees, and ‘w’ refers to North, or 0 degrees. In relative references, ‘q’ refers to -45 degrees or 45 degrees left, and ‘w’ refers to 0 degrees, or no change in direction.

All commands start with a plane letter. This indicates the recipient of the command. Case is ignored.

OTHER INFORMATION

• Jets move every update; prop planes move every other update.
• All planes turn at most 90 degrees per movement.
• Planes enter at 7000 feet and leave at 9000 feet.
• Planes flying at an altitude of 0 crash if they are not over an airport.
• Planes waiting at airports can only be told to take off (climb in altitude).
• Pressing return (that is, entering an empty command) will perform the next update immediately. This allows the player to “fast forward” the game clock if nothing interesting is happening.

NEW GAMES

The 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.

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:

Variable may be one of: update, indicating the number of seconds between forced updates; newplane, indicating (about) the number of updates between new plane entries; width, indicating the width of the play field; or height, indicating the height of the play field.

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:

For beacons, a simple x, y coordinate pair is used (enclosed in parentheses). Airports and exits require a third value, a direction, which is one of “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.

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 exactly diagonal.

# 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 ) ] ;

ENVIRONMENT

LOGNAME

Name to be recorded in high score file.

FILES

Files are kept in a special directory, which can be shown by using the -p flag.

$HOME/.atc.scores

Score file.

/usr/share/games/atc/Game_List

The list of playable games.

AUTHORS

Ed James, UC Berkeley: edjames@ucbvax.berkeley.edu, ucbvax!edjames

This game is based on someone's description of the overall flavor of a game written for some unknown PC many years ago, maybe.

BUGS

The screen sometimes refreshes after you have quit.