Avian’s Blog

Here you can see the server running in the upper left window. I've removed all functions that were drawing the radar screen from the server code. Maybe I'll implement some kind of a command line in the future. Currently the server only outputs some status messages to the terminal.

Other three windows on the above screen shot are clients connected to the server. The lower left client just ordered plane "a" to change heading to 0 degrees. The upper right client ordered the same plane to turn to 90 degrees and the last client ordered airplane "b" to climb to 9000 feet.

I'm using the Simple Network Layer library for networking. It is very simple to use (contains only 4 functions) and as far as I can see it works perfectly. The only problem I've found is that I can't use telnet to directly talk to the server (the library returns "buffer allocation error") even though the network protocol I use is plain ASCII.

This is a screenshot of the first kind-of-working version of my multiplayer ATC hack.

ATC (Air Traffic Controller) is a simple game by Ed James which lets you try your hand at the nerve wracking duties of the air traffic controller without endangering the lives of millions of travelers each year. The original only supports one player and uses simple ncurses-based monochrome ASCII graphics.

Loopus and I got the idea at What The Hack to make a multiplayer version that could be played over the internet and perhaps use SDL for better graphics.

In the screenshot above, the top window is running the server. Any number of clients (one can be seen running in the bottom window) can then connect to the server and they can all send commands to all airplanes on the radar screen.

I'll release the source code as soon as I'll get this even remotely playable. I still have problems with sending commands over the network connection (the game uses a quite interesting state machine for entering commands for airplanes).

I'll post some more details tommorow.

If your tcpdump isn't showing any packets when you know it should be (like, you can ping another machine, but tcpdump doesn't show any packets on the wire), then the problem can be that it can't get a reverse DNS look up for the IPs in the packets it is receiving. You can use the -n option to turn off reverse lookups and solve this problem (or better, fix your DNS configuration).