Author:

• Name: Kevin Pulo
  Location: AU - Commonwealth of Australia (Australia)

To build:

    make

There is another version which lets you use the arrow keys rather than the more awkward , and . keys. See Alternate code below.

Bugs and (Mis)features:

The current status of this entry is:

STATUS: INABIAF - please DO NOT fix

For more detailed information see 2001/kev in bugs.html.

To use:

    ./kev # in one terminal

    ./kev hostname # in another terminal

NOTE: each player’s paddle is at the bottom and the opponent at the top.

Try:

    ./kev                   # in one terminal

    ./kev localhost         # in another terminal on the same host

If you need to change the speed you can reconfigure it like (say for over a network and not the same host):

    make clobber SPEED=50 all # original default value which is very fast

If you wish to change the port you can do so like:

    make clobber PORT=3773 all

Of course if you want a port < 1024 you’ll need to be root so don’t do that.

And if you know what you’re doing you can redefine the call to the socket(2) syscall with the l_ macro, changing the L variable like one would PORT. Of course you can do more than one at the same time. For instance to change the speed and port:

    make clobber SPEED=512 PORT=3773 all

If you have xterm try on one system:

    xterm -geometry 80x40 -fg green -bg black -fn 9x15bold -e ./kev &

and then the other, the client system:

    xterm -geometry 80x40 -fg green -bg black -fn 9x15bold -e ./kev localhost&

This might look nicer than just the terminal itself.

Alternate code:

This version allows you to use arrow keys on the keyboard rather than the more awkward , and . keys to move your paddle.

Alternate build:

    make alt

You can reconfigure the macros described above in the same way.

Alternate use:

Use kev.alt as you would kev.

What happens if you use both, one in one terminal and the other in another terminal?

Alternate try:

If you have xterm try on one system:

    xterm -geometry 80x40 -fg green -bg black -fn 9x15bold -e ./kev.alt &

and then the other, the client system:

    xterm -geometry 80x40 -fg green -bg black -fn 9x15bold -e ./kev.alt localhost&

Judges’ remarks:

Continuing with this year’s “retro game” theme, this is another old game; arguably, one of the oldest. Requires a functioning network, and curses.

The graphics aren’t the impressive part; the graphics and network are. How many games come out at $50 and still require you to wait for a patch to come out before you can play multiplayer? This one works out of the box.

Author’s remarks:

NETWORK PONG!

REQUIREMENTS

• TCP sockets
• curses
• usleep(3)

DESCRIPTION

This program is a two-player networked version of the eighties arcade classic, Pong. It uses standard TCP sockets to communicate over the net, and ncurses for display. It supports variable terminal sizes (though both players must have the same terminal size) and game speeds. Each player has a paddle to hit the ball, and you get points for getting the ball past your opponent’s paddle. It’s pretty fun! :)

RUNNING

Run the server first without any command line arguments, i.e.

    ./kev

Then run the client with a single command line argument which is the name of the machine running the server, e.g.

    ./kev localhost

Make sure that the terminals on both ends are the same size. Also, the TCP port number (by default 5455) specified in the Makefile mustn’t be blocked by a firewall.

Here’s a good quick example to see it in action on your own machine, assuming you have Xwindows:

    xterm -geometry 80x40 -fg green -bg black -fn 9x15bold -e ./kev &
    xterm -geometry 80x40 -fg green -bg black -fn 9x15bold -e ./kev localhost&

PLAYING

Your paddle is the one at the bottom of the screen, your opponent is at the top. To move your paddle left, hold down , (i.e. < but don’t press shift). To move your paddle right, hold down .. To quit, either player may press q.

The current score is shown on the left side of the halfway line. Your score is the lower number, your opponents score is the upper number. Your score is the number of times your opponent has missed the ball.

You can control the speed of the ball by the motion of your paddle when the ball hits it. If your paddle is still, then the ball just bounces normally off it. If your paddle is moving in the same direction as the ball, then the ball’s speed in that direction will increase. If your paddle is moving in the opposite direction to the ball, then the ball’s speed in that direction will decrease (or if the ball is going slowly enough, it’ll turn around).

You might want to increase your keyboard repeat rate before playing. On the Linux console try kbdrate -r 24.0 -d 250 (kbdrate might be “hidden” from normal users in /sbin, and you might need to be root anyway), in Xwindows try xset r rate 250 24 (find out your current rate first with xset q, so that you can reset it later).

Look below in the Building section for info on how to speed up or slow down the game (useful if you increase or decrease the terminal size).

BUILDING

Just run make to use the Makefile as above. The SPEED variable in the Makefile controls the speed of the game (defaults to 50). This speed is the delay between frames in milliseconds. Thus a value of 0 will make the game go as fast as your network can handle, and values less than 50 are useful for larger terminals or more exciting games. The program needs bandwidth equal to 1/s bytes per second (where s is the speed value). Any latency on the network will be added to s - so you should probably subtract any latency from the value of s you want to have. Given that loopback and fast Ethernet LANs are both much less than 1ms of latency, you should only need to worry about this if you plan on playing over a slower link like a cable modem, DSL, or (God-forbid) dial-up.

The TCP port to use for network communications is specified by the PORT variable in the Makefile. If the default of 5455 is blocked for whatever reason, you can change it to something else. Of course if you use a port < 1024, you’ll need to be root.

OBFUSCATION

The program’s broad structure is fairly straightforward, but individual tasks are rarely done in a straightforward manner. ;)

Identifier names have mostly been chosen to resemble paddles and balls, and to generally decrease readability.

The source has been cleverly formatted to resemble one of the paddles from the game, rotated 90 degrees. ;) (The “source paddle” has approximately the same aspect ratio as the game at 80 columns wide, which is 1:10.)

Finally, the number of “non-whitespace characters” (as defined by the rules) in the file is exactly 2048, which I think is rather unexpectedly cool. :)

BUGS

There are 3 warnings when I compile with gcc 2.95.3 (-Wall -ansi -pedantic) on my Linux system, but all are completely harmless.

I don’t like the curses and/or termcaps/terminfos on IRIX and Solaris (the only two non-Linux systems I have access to). Despite calling timeout(0);, notimeout(win, TRUE);, nodelay(win, TRUE); and/or keypad(win, FALSE);, it still seems to force a delay into calls to getch() - I’m guessing at a termcap/terminfo level. At any rate, I can’t seem to force no delay. This is a shame, because it basically plays havoc with the input code, particularly the read-ahead canceller. It still works, but not nearly as well (key presses are dodgy and holding down keys doesn’t always work), and so I much prefer and recommend Linux libncurses.

Sometimes when q is pressed in one, the other will crash out with Broken pipe.

If the specified port can’t be bound or connected to, the program segfaults.

If your terminal is too wide (we’re talking gigantic here - over 500 characters wide) then the program can segfault. It’s also possible to crash the program a player scores over a billion points (1e9). Maybe you can consider that the goal… ;)

If you run the client and server on different architectures, both architectures need to have the same character systems (i.e. don’t try mixing ASCII and EBCDIC). It is independent of endianness though.

Primary files

• kev.c - entry source code
• Makefile - entry Makefile
• kev.alt.c - alternate source code
• kev.orig.c - original source code

Secondary files

• 2001_kev.tar.bz2 - download entry tarball
• README.md - markdown source for this web page
• .entry.json - entry summary and manifest in JSON
• .gitignore - list of files that should not be committed under git
• .path - directory path from top level directory
• index.html - this web page

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