Open Source 3D Games

[Justin Dugger]

I'll try to describe, briefly, the problems of cheating and cheating
regulations.  First, the hacks themselves. These include aimbots, that
automatically aim at your enemies and kill them, even capable of
judging the trajectory of a grenade.  You've also got screenhacks,
that let you see through walls. These two combine nicely in games
where walls are sometimes bullet-permeable.  As an amusing example of
early internet technology, someone made a proxy between the client
playing the game and the server, that altered packets to correct a
person's aim.  These days packets are well encrypted.  There's also
hacks that let you move faster than should be possible, either through
strafe running (generally considered okay) or bunny-hopping (usually
requires a script and looks highly unnatural but allows you to move
wicked fast).

So now that we know about screenhacks, aimbots, and bunny-hoppers, I
can tell you how these are currently combatted.  In the case of
bunny-hoppers, you are correct in that the server should be able to
prevent that.  Counter-Strike I believe finally removed that stupid
hack.  On the other hand, aimbots don't do anything extraordinary or
out of the range of the possible.  Screenhacks don't even do anything
but reveal the extra information you've been given by the server. 
It's very difficult to combat aimbots and screenhacks.  The most
popular option is a program called PunkBuster.  This program basically
scans the player's computer for known cheats and hacks, and reports
unusual results back to a central repository.  Generally, when you get
detected, you'll be kicked.  I think that the BF2 version will
actually ban your userid on all rated servers, which acts as a nuclear
type deterrant.  Usually server software is free to the public, and
anyone can run one, even a rated one. The company behind BF2 actively
rents servers.  There are also "meta servers", which act as a
directory of public servers, and as a form of identification and
validation for individual users.  Steam, the software behind Halflife,
requires you to be authenticated by a metaserver before it will allow
you onto any server to play.

The problem with punkbuster and its friends is that it requires you to
run as admin, in order to let it examine all other programs running in
detail.  Furthermore, sometimes PB and antivirus software fight. 
Usually you get false positives for hacks by running norton or
something.  Furthermore, punkbuster actively fights many of the ideas
of open source.  By altering the software, you'll trigger a punkbuster
alert.

The safest solution is to do all processing server side, but you'll
have incredible amounts of video streaming for 32 players, which is
both processor and network intensive.  A safer solution is to do some
form of check to send out only information that the player could
observe, but that adds CPU overhead and should result in wierd pop in
because of lag. It may be that twitch games are simply doomed in an
open source environment.

Justin Dugger

On 8/13/05, Jack <quiet_celt at yahoo.com> wrote:
> --- Justin Dugger wrote:
> 
> >
> > Of course, there is also the concern over cheating
> > made simple with
> > open source.  ...
> > Personally,
> > I think that this is a failing of the server design.
> >  If a player is
> > being excessively disruptive, there should be a
> > social mechanism in
> > place via the server to manage, arbitrate and
> > facilitate the
> > curtailing of that disruptive player, either by
> > kick\bans or other
> > means of punishment.  This is probably one of the
> > most important
> > aspects of multiplayer gaming that has gone
> > unsolved, but not for a
> > lack of trying.
> 
> Not being a gamer [for health reasons. ;')], I don't
> know all the issues here, but it seems to me it should
> be fairly easy to deal with the cheaters. Of course it
> really does seem to depend on handling it at the
> servers. It seems that some fairly decent coders could
> write a routine to detect the cheaters and either ban
> them or strip their powers and points. Alternatively,
> it should also be possible for some decent coders to
> write a plug-in for users to download andinstall that
> could detect cheaters and take some action based on
> that, by any or all of:  posting to everyone in the
> game the "identity" of the cheater, cheating back
> against the cheater, using some force to terminate the
> cheater from the game, intercept the cheats and
> reverse them, etc. Now like I said I'm not a gamer but
> it seems some of these things should work, or I may
> just be uninformed to how it all works. I'm assuming
> all the servers are owned by the game vendors and thus
> out of the control of the players? It seems to me that
> this would be a good use for p2p to build rogue
> servers, with ligitimite clients. Should someone build
> a server that valdiated legitimite copies of the game
> software, then there really wouldn't be any angle the
> vendors could use to sue the servers/clients. I know
> that someone in St. Louis did build a server for some
> game, but I don't believe they included verification
> of clients, which of course just leads judges to
> believe they are up to something.
> 
> 
> just some random thoughts,
> Brian
> 
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