RE: [GD-General] Online Gaming
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From: <phi...@pl...> - 2003-01-24 17:38:09
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AFAIK SOCOM is a classic client/server model, with centralised servers,= while TMB online is P2P, although only in that one of the clients also = acts as a server. Another client can become the server, if the host-client d= rops out (AKA host migration), I believe that this means that each client is= running full physics and logic, but discarding results upon receipt of = data from the server. I think the more direct client interaction a game recquires, the worse = the network experience generally is. Both of those games suffer on that fro= nt, but it could be worse. I once worked on an online 1-on-1 fighting game.= Lag's kinda fatal in that environment... Cheers, Phil = =20 "Mick West" <mi...@ne...> = =20 Sent by: To: = <gam...@li...> =20 gam...@li...urc cc: = =20 eforge.net Fax to= : =20 Subjec= t: RE: [GD-General] Online Gaming =20 = =20 01/23/2003 03:25 PM = =20 Please respond to gamedevlists-general = =20 = =20 = =20 c) it's not really P2P. Clients are deterministic, and ignore what's happening on other clients.=A0 One "client" is also a "server", which arbitrates scoring and collision between clients.=A0 The server tells = the clients when they have been hit, and they fall over.=A0=A0 The clients= tell the server where they are and what they look like, and the server rela= y this to the other clients, who just display the other skaters at a few= frames before their last known good position, extrapolating only if da= ta fails to arrive in good time. It only works because there is very little interaction between clients= (they don't shoot each other, and most of=A0our online games don't rel= y on=A0skater-skater interactions).=A0 Also there are no moving objects = in mutli-player games, so we dont have to worry about crates or vehicles.= It's pretty specific to our type of game, and is probably not what the= y use in SOCOM. MIck =A0-----Original Message----- From: gam...@li... [mailto:gam...@li...] On Behalf Of Andrew Sharpe Sent: Thursday, January 23, 2003 1:43 PM To: gam...@li... Subject: [GD-General] Online Gaming After getting my PS2 network adaptor I've been playing SOCOM online for= the past few days. Today though I put on a copy of Tony Hawk4 and was pretty surprised with how it played online. Even on what I'd consider to be laggy servers (200-250 ping) the game seemed remarkably fluent and consistent, i.e no warping players. Althou= gh I've played lots of FPS games which usually use a client/server architecture I'd never really played a fast-paced peer-to-peer game an= d always assumed that on anything other than LAN or fast broadband the g= ame would suffer. Although I'm familiar with how C/S architectures work and how the effec= ts of latency can be compensated for, I've never really given P2P much tho= ught before in terms of how games can achieve a smooth playing experience, o= r even how their network update is structured. Possibilities I can think of for fast action games using P2P: a) Clients are fully deterministic and perform a lock-stepped update b= ased on inputs from all clients. For instance all clients perform their phy= sics update based on inputs from clients during frame 180 and obtain identi= cal results. Problems: this means that there's a delay between input & response, even on the local client, of around half the ping time to the= slowest machine. Not too good I'd imagine on a slow connection. b) All clients send their essential information (position, orientation,= etc) and run their physics based on the last, or extrapolated details o= f other players. Problems: clients may come up with slightly different results due to extrapolated data for other players (e.g the client coliding with another vehicle). There's also the problem of non-player= entities in the world, for instance a crate, which may end up with different positions on different machines if some form of correction i= s not performed to remove errors due to the above problem. There's probably other problems or solutions I've not thought of thoug= h! I'd be very interested in comments from people who've implemented P2P solutions in games aimed at the online market though, especially to do= with how they handled gameworld physics and physical non-player entiti= es. Very fascinating subject. Thanks, Andrew With Yahoo! Mail you can get a bigger mailbox -- choose a size that fi= ts your needs = |