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Just Cause 2 Multiplayer: Behind the scenes with gaming's greatest hack

redbull.co.uk

11–20 of 45 posts

Re: Just Cause 2 Multiplayer: Behind the scenes with gaming's greatest hack

#11

I can't stop cracking up watching these videos. It's like a 3D visualization of Reddit or 4chan. "...in the last test players were killed 223,704 times, averaging out at 1.29 untimely ends per second."

This one's particularly great:

http://youtu.be/1-zhdU4GSBA

You can tell there are pretty often some weird syncing errors, but hey, it's worth it for stuff like this.

Re: Just Cause 2 Multiplayer: Behind the scenes with gaming's greatest hack

#12
post #7

About that 1800 players number. Based on posts by one of the developers, their server doesn't do any sort of calculation: > Our server is basically 'dumb', it doesn't do anything in the sorts of processing bullet trajectory, player line of sight or any hit detection at all. http://www.jc-mp.com/forums/index.php/topic,638.msg4783.html... Unlike other games which run a full simulation on the server-side, their server (…

>which is rather poor design for a competitive multiplayer game

Watching that video, I would guess the environment isn't so much competitive (even single player JC2 is very no-particular-goals-in-mind-just-blow-shit-up oriented) as it is mass chaos. It looked like what would happen if /b/ bought an island. So cheating is probably only a minor concern at this point.

Re: Just Cause 2 Multiplayer: Behind the scenes with gaming's greatest hack

#13
post #6

Would be great to see some articles on their technical approach, I assume they have used techniques to reach those scales based upon the fact the average pair of players are too far away from each other to be visible

i second that, immediately went to check if the source code is available, but sadly nothing.

It seems hard to general to get your hands on any modding code. Apparently the modding culture doesn't encourage opensource as much as other hacking circles.

Re: Just Cause 2 Multiplayer: Behind the scenes with gaming's greatest hack

#14
post #10
post #7

About that 1800 players number. Based on posts by one of the developers, their server doesn't do any sort of calculation: > Our server is basically 'dumb', it doesn't do anything in the sorts of processing bullet trajectory, player line of sight or any hit detection at all. http://www.jc-mp.com/forums/index.php/topic,638.msg4783.html... Unlike other games which run a full simulation on the server-side, their server (…

They could verify those things on other clients, instead of on the server. I think that's typical for pure P2P multiplayer games. They could use something like - every player sending their version of 'what happened' to the server which then decides the proper outcome. Btw, is it required to simulate everything on the server side? I know it is the conventional way to prevent cheating, but how about just randomly sampl…

"They could verify those things on other clients..."

But clients are not trustworthy. How do you decide which clients to trust? How long before your 'adversary' discovers your trust methods an replicates them in his client?

"...server which then decides the proper outcome."

This requires processing power. Random sampling is perhaps a possible solution, but if you're overwhelmed with nefarious client activity (50% perhaps) and you're only sampling, say, 10%, still 40% of your gameplay is cheating clients. If you increase your sampling based on finding increases in cheating, you start to overwhelm your server farm.

tl;dr - this is not an easy problem to solve

Re: Just Cause 2 Multiplayer: Behind the scenes with gaming's greatest hack

#15
post #7

About that 1800 players number. Based on posts by one of the developers, their server doesn't do any sort of calculation: > Our server is basically 'dumb', it doesn't do anything in the sorts of processing bullet trajectory, player line of sight or any hit detection at all. http://www.jc-mp.com/forums/index.php/topic,638.msg4783.html... Unlike other games which run a full simulation on the server-side, their server (…

On the other hand it's not like usual FPS have everything calculated on the server side, which is why there is a difference between most MMOs and FPSs and why there are still cheaters. There are various countermeasures. There are even a lot of MMOs that do a big part on the client side.

Maybe clients could also verify each other. There has been some thought on this topic, but I don't how far the research went.

Re: Just Cause 2 Multiplayer: Behind the scenes with gaming's greatest hack

#16
post #13
post #6

Earlier quoted context omitted.

i second that, immediately went to check if the source code is available, but sadly nothing.

It seems hard to general to get your hands on any modding code. Apparently the modding culture doesn't encourage opensource as much as other hacking circles.

Modding seems very 'credit-heavy' and it can be difficult to get credit for your work when a bigger, better team can simply fork your code and call it their own. Then again I don't have any experience in this field so I could be completely off-target.

Re: Just Cause 2 Multiplayer: Behind the scenes with gaming's greatest hack

#17

I can't stop cracking up watching these videos. It's like a 3D visualization of Reddit or 4chan. "...in the last test players were killed 223,704 times, averaging out at 1.29 untimely ends per second."

This one's particularly great: http://youtu.be/1-zhdU4GSBA You can tell there are pretty often some weird syncing errors, but hey, it's worth it for stuff like this.

As per the recent test, I think a lot of latency issues have become less pronounced. Only in 'Dome Deathmatch' did I really see any glaring movement issues.

There are still plenty of funny movement related issues because of latency, but they don't really affect the game too much.

And it's totally worth it. I sat there laughing for a good long while after someone dumped a jet right into the ground, taking at least 5 people with him.

Re: Just Cause 2 Multiplayer: Behind the scenes with gaming's greatest hack

#18
I used to play Multi Theft Auto a lot years ago on GTA: Vice City, which was similarly buggy but excellent fun. This just looks completely insane.

Impressive work by the developers - even though they've effectively piggy-backed onto an existing game, presumably the engine etc is closed-source and therefore their efforts are worthy of admiration.

I wonder if Multi Theft Auto is still going, I still have my Vice City disc somewhere...

Re: Just Cause 2 Multiplayer: Behind the scenes with gaming's greatest hack

#19
post #7

About that 1800 players number. Based on posts by one of the developers, their server doesn't do any sort of calculation: > Our server is basically 'dumb', it doesn't do anything in the sorts of processing bullet trajectory, player line of sight or any hit detection at all. http://www.jc-mp.com/forums/index.php/topic,638.msg4783.html... Unlike other games which run a full simulation on the server-side, their server (…

>which is rather poor design for a competitive multiplayer game Watching that video, I would guess the environment isn't so much competitive (even single player JC2 is very no-particular-goals-in-mind-just-blow-shit-up oriented) as it is mass chaos. It looked like what would happen if /b/ bought an island. So cheating is probably only a minor concern at this point.

While cheating may not be a problem in a noncompetitive sandbox environment, griefing is. Consider a dumb client that fakes logging in to the game server and sends thousands of explosions to a player's screen at once, or drops hundreds of jets or explosive barrels everywhere instantaneously. There is practically no limit to sending these hand crafted packets in comparison to how fast the GPU will be able to render the resulting actions. So now, you have a massive DoS problem on your hands. Ideally nobody will do this, but my point is lots of problems can come up when you trust the client.

Re: Just Cause 2 Multiplayer: Behind the scenes with gaming's greatest hack

#20
post #7

About that 1800 players number. Based on posts by one of the developers, their server doesn't do any sort of calculation: > Our server is basically 'dumb', it doesn't do anything in the sorts of processing bullet trajectory, player line of sight or any hit detection at all. http://www.jc-mp.com/forums/index.php/topic,638.msg4783.html... Unlike other games which run a full simulation on the server-side, their server (…

>which is rather poor design for a competitive multiplayer game Watching that video, I would guess the environment isn't so much competitive (even single player JC2 is very no-particular-goals-in-mind-just-blow-shit-up oriented) as it is mass chaos. It looked like what would happen if /b/ bought an island. So cheating is probably only a minor concern at this point.

DayZ is also not "competitive" at its core (and Arma2 even has anti-cheat measures built in -> BattleEye)... this doesnt stop script kiddies from server-hopping and killing/teleporting every one (even though they have no benefit from it beside the "lulz")..
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