How we solved an infamous sliding bug
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How we solved an infamous sliding bug
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Re: How we solved an infamous sliding bug
#2How do you stop clients from cheating in a peer-to-peer game like Awesomenauts?
Re: How we solved an infamous sliding bug
#3Problem: Lag + collision detection = characters slide.
Solution: Turn off collision detection.
I was sincerely hoping for an actual technical solution for dealing with peer-to-peer networking and lag. I feel somewhat cheated out of the time it took me to read that article. While it did explain the problem very nicely, the solution was to just disable the feature outright.
Re: How we solved an infamous sliding bug
#4How does the player with the lower objectID detect that the sliding bug is happening? The way it was described, only the player with the higher objectID would be able to figure that out. Did they change it so both players sends the message? Or does the player with the higher objectID simply send a message when they detect the bug, meaning they turn off their collision first? Or something else entirely?
Re: How we solved an infamous sliding bug
#5How do you stop clients from cheating in a peer-to-peer game like Awesomenauts?
You probably can't. If stopping cheating is a goal you need to go for client-server were you host the servers yourself. A lot of developers are not prepared to take that on.
Re: How we solved an infamous sliding bug
#6It seems like this solution implicitly acknowledges (and fails to resolve) the fact that their game has frequent, pervasive desyncs. The bug being described is only possible when in a state of persistent desync - that's a little scary in a competitive or semi-competitive game (like most games in the 'MOBA' genre are, including Awesomenauts).
I wonder what their reasons were for going with peer-to-peer instead of anointing a player as the 'server' as many other console multiplayer games do (Awesomenauts started out on console, IIRC)? That would solve a lot of these desync problems because the server would be responsible for resolving all the collisions.
Re: How we solved an infamous sliding bug
#7Problem: Lag + collision detection = characters slide. Solution: Turn off collision detection. I was sincerely hoping for an actual technical solution for dealing with peer-to-peer networking and lag. I feel somewhat cheated out of the time it took me to read that article. While it did explain the problem very nicely, the solution was to just disable the feature outright.
Well, the first paragraph did say
> The solution we finally managed to come up with is also a good example of how very incorrect workarounds can actually be a really good solution to a complex problem.
So you knew they were presenting a "very incorrect workaround"---which, counterintuitively, worked better than some of the more "correct" things they tried.
Re: How we solved an infamous sliding bug
#8How do you stop clients from cheating in a peer-to-peer game like Awesomenauts?
You probably can't. If stopping cheating is a goal you need to go for client-server were you host the servers yourself. A lot of developers are not prepared to take that on.
In many RTS peer-2-peer games like Starcraft or Age of Empires, they use a lock-step model, which can stop the majority of cheating.
Every player uses a tick-engine (ie tick every 0.1s) that performs the same commands on the same ticks. When a player issues a command, such as "Build Unit X", it sends it to every other player to run a couple ticks ahead (how far ahead is based on average lag or whatever). If anyone performs differently, then a de-synchronization occurs and the game is over.
It's explained much better here http://www.gamasutra.com/view/feature/3094/1500_archers_on_a... "Because the game's outcome depended on all of the users executing exactly the same simulation, it was extremely difficult to hack a client (or client communication stream) and cheat. Any simulation that ran differently was tagged as "out of sync" and the game stopped. Cheating to reveal information locally was still possible, but these few leaks were relatively easy to secure in subsequent patches and revisions. Security was a huge win. "
Re: How we solved an infamous sliding bug
#9Problem: Lag + collision detection = characters slide. Solution: Turn off collision detection. I was sincerely hoping for an actual technical solution for dealing with peer-to-peer networking and lag. I feel somewhat cheated out of the time it took me to read that article. While it did explain the problem very nicely, the solution was to just disable the feature outright.
Well, the first paragraph did say > The solution we finally managed to come up with is also a good example of how very incorrect workarounds can actually be a really good solution to a complex problem. So you knew they were presenting a "very incorrect workaround"---which, counterintuitively, worked better than some of the more "correct" things they tried.
>So you knew they were presenting a "very incorrect workaround"
It actually made it a bit more enticing, I was expecting a horrific chain of gotos or some other cliche programming paradigm being completely violated for the sake of pragmatism.
What we got instead was, "This is a hard problem, let's just not solve it." which was written up with a title of "How we solved a hard problem"
Re: How we solved an infamous sliding bug
#10Earlier quoted context omitted.
Well, the first paragraph did say > The solution we finally managed to come up with is also a good example of how very incorrect workarounds can actually be a really good solution to a complex problem. So you knew they were presenting a "very incorrect workaround"---which, counterintuitively, worked better than some of the more "correct" things they tried.
>So you knew they were presenting a "very incorrect workaround" It actually made it a bit more enticing, I was expecting a horrific chain of gotos or some other cliche programming paradigm being completely violated for the sake of pragmatism. What we got instead was, "This is a hard problem, let's just not solve it." which was written up with a title of "How we solved a hard problem"
They did solve the problem, the solution was to turn of collision detection.