server/client performance

[sunnyl]

I asked this one a while ago, just asking again to see if there's any fresh opinions.

I'm writing a DX based multiplayer game (for LAN). If for example, the client fires a projectile, I think I have two options:

- The client calculates and updates the position of the projectile and sends to the server, which will only relay this to the other clients.

or

- The server will be told that a projectile has been fired, and it is up to the server to recalculate the projectile's position and relay it to the clients as well.

Opinions welcome...

[chenko]

if the client works the position, and there pc is slow, it will slow down everyone... If the server does it the game speed will be affected by server speed. But its really best IMO to let the client do it.

[Michael Woolsey]

If you are concerned with hackers (any commercial game should be) then you will have to have the data all calculated on the server side.

Anything that is left on the client side will be hacked and modifed for some reason or another. Hackers seem to take great pleasure out of cheating.

You may want to pass the server the fire signal and all the specifics like initial speed, angle, etc and have the server do the rest. This useally means you need a "bigger" server, but in the long run I think it is worth it.

I heard of a game (I can't remember which one) that left a small amount of what seemed like harmless data on the client side for speed of updates, when the hackers found it they managed to manipulate it for their own ends thus making the developers change the code.

Just something to think about.
Michael