This question is very generalised, but anyway... (btw if anyone remembers Carrier Command, then they''ll get the idea) If you were to design a real-time many-player flight sim, set on a virtual globe, in which each player orders a number of AI craft as well as piloting their own, what would the limiting factors be for speed and number of objects? Would the bottleneck be in the 56K modem link? And could this be avoided by using a large central server to handle position calculations and collisions, (especially for the AI craft), leaving clients free just to render graphics and transmit controller information? thanks george

You can pull it off with a 28.8 modem.

I say that with confidence, because SubSpace is a program just like you described with the only difference being that it's a 2D arcade-style shooter. But that's just a client-side difference. With a 28.8 modem, using UDP packets to transmit and receive player position, velocity, and events (like firing a gun) to a centralized server, you can get many players going at the same time.

SubSpace, which I heavily beta tested before it's brief commercial life (My name is on the retail CD), is able to host games with 80+ people playing together. Again, with nothing more than a 28.8 modem for clients (Of course, the server will need to be on a fast connection.)

The big problem is latency. There's internet latency, and there's also modem latency (two kinds.) Internet latency is the time it takes for your message to transmit from your ISP to the game server. Modem latency takes at least one of two forms. The first, unavoidable, is the time it takes to send the data over the line. The second, is buffering. Many modems, especially the 28.8k to 56k variety, will buffer outgoing data until a timeout expires or the buffer fills. Often, I beleive, it's a side-effect of having compression turned on in your modem; something you can turn off with the right 'AT' commands.

If you don't know what SubSpace is, and you're interested in seeing it in action, it's been hacked into "freeware". Even the creators of the game helped with that, as they were pretty much dumped by Virgin Interactive Entertainment (VIE) who sponsored them in the first place. I purchased a copy of the game at CompUSA when it came out, but it only lasted in the stores for about a month (that I remember.) It wasn't a hit "sale" wise, but it's a GREAT and addictive game. Playing against other people as cunning, conniving, and devious as you is a real treat! No game AI matches the real thing.

The site to go to is http://subspace.net

Download it from http://www.subspace.net/downloads.shtml

A couple notes (IMPORTANT)

(1) I think most servers are running v1.35A now, so download the upgrade from v1.34-v1.35a (strange, the copy I have is already 1.35A but I don't see it packaged that way on the download page.)

(2) It may not be obvious, but when you DO run the program select "Find Servers .." from the file menu to connect to a central server and download a list of currently running game servers. *** IMPORTANT *** Most likely the "Server Directory Address" will say "sscentral.vie.com" -- if it does, change it to "sscentral.vie.co.uk" or it won't work.


Happy Chillin' & Killin'
// CHRIS


Edited by - win32mfc on July 10, 2000 12:28:35 AM

Cheers for that - I''ll get on and have a go...

George