Which pattern is good for bullets hit test in game that need server validates?

I would like to design a PvP game uses flash in client and java socket server, but I do need server validates trajectory and if bullets hit target from cheating.开发者_如何学C

Is there any tutorial or paper provides how to do this ?

To do it you need to have a server-side logic.

Mainly you will use clients just to show gamestates that are sent by server (if you want you can also let your clients show whatever they think is right until a new gamestate is received and synch to it) and to send to the servers just actions that are done (clicks or key presses) while your server should take care of everything else..

clients should be mainly frontends for the world representation..

The general idea for a uncheatable multiplayer game is:

You should only send the keys the user is pressing, the server stores it and after some intervals, it processes the informations and send a snapshot of the current position of all objects in the game.

Maybe if you don't want to waste too much network traffic:

You could save everything's position for 2 seconds, record the last user input (with the input, he may also send his last snapshot id), then send only what differs from the position now and what the user have.

Since you asked for patterns, I am assuming you understand the kind of logic you want to write on server side, but not sure about how to organize your code. You should look at strategy pattern (http://en.wikipedia.org/wiki/Strategy_pattern) once. Since in this problem based on various locations on the screen, you need to change the way server validates the data, strategy pattern is a good fit for the problem.

@Jack: +1, and you should not actually do physical exercises at server,server just check start point, end point, range and time ect... if they are reasonable!