Hi,

I was just wondering how people go about representing fixed events in their client snapshot updates that might have occured for only a portion of the time between the updates.

For example, snapshot updates are sent from the server to the clients every 50ms. However, the player only crounched for 40ms (unlikely I know, but go with it for the example) and this happened between tick 1 and tick 2.

So in the tick 1 snapshot to the clients the player is not crouching, and nor are they in tick 2, meaning that other people will not see them crouch.

Do I have to decide what is important to the gameplay and make sure that these events are propogated to the client for the relevant tick, or is it normal just to ignore any events that are not impacting at the time the snapshot occurs?

Any thoughts or pointers on how other people accomplish this would be much appreciated!

I do it like this. I don't count "time", i count simulation frames - aka "ticks". Both my server and client run with 60 ticks / second, and I send data between them every third tick (~16.67 * 3 = ~50ms). The first four bytes in each packet is the current local tick of the machine at the time the packet was sent. I have three types of events: Reliable, Unreliable and UnreliableFrameSynchronized. Reliable and Unreliable dont care about what time they were sent, they are just executed whenever they arrive. The frame synced events are kept in "sync" with the senders tick, so it happens at the correct tick on the remote. I basically just write 2 bits for each frame synced event which tell how many frames "before" the packet tick this event was.

Thanks alot for the detailed reponse, I really apprecitate it.

Jus to make sure I've got it....

My player client sends data to the server that contains 3 lots of user input, one from each tick. The middle one of these contains an important event so is marked as frame synced.

The server gets this packet and processes each of the user inputs in turn.

On its 3rd tick it sends a snapshot to the clients. Now it knows that the input it got from the user from tick 2 was frame synced so it makes sure that when it sends its packet containing the server snapshot it marks the event that occured in this tick as happening 1 tick ago (as it happened in tick 2 from the client). The remote client can then push this into its interpolation of events it is using to represent that clients proxy at the correct point, ie 1 tick before it recieved the packet.

Does this make sense?

I have one further question, if I may.

When you bundle more than one ticks worth on input, from the client to server, is the server expecting the first, or last, tick in this packet? So would the server try and process all three ticks worth on the tick it receives the packet, or would it process them over the next three server ticks?

Thanks for all the help; it is slowly all sinking in!

Matt