Looks like this some NVIDIA guys have applied my authority management technique from my GDC lecture Networked Physics in a Large Streaming World
In general the use of additional physics for networked games requires network synchronization between the different clients. This is especially required for game play physics, e.g. rigid bodies which can block an opponent. There are different approaches to network synchronization, e.g. the server-client based model or an improved authority based model.
In case of a large synchronized rigid body world, an authority scheme can yield much better results in regards to synchronization problems (snapping). In the authority managed model, the server keeps track of game updates (default authority). In order to avoid snapping, the client can take authority over objects he interacts with. The server in this case accepts state changes for those objects from the client. If required, the server can overwrite the updates from the client to make sure that all state changes are properly in sync.
I’ve been meaning to write an article on authority management forever, but as soon as I’d finished up GDC this year it was crunch time on Mercs2 for the next 6 months.
Its a such a beautiful and simple technique. Its easier to code than a traditional client/server model, and has basically zero overhead on top of your existing simulation costs – the only caveat is that you must give limited authority to the client, which makes some cheats and exploits possible
Nothing you can’t handle on a closed platform like XBox-Live or PSN though!
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Seeing how more and more games are upping the amount of movable objects present in-game and getting more and more complicated physics systems, I’m kind of surprised that this technique hasn’t become standardized, as it makes insane amounts of sense.
I was playing the Forced Unleashed demo, a game with insane object physics, and I can imagine those guys running into a shit storm of trouble if they tried to network all that, especially without the client and server switching authority.
Yeah that would be super hard to pull off