Multiplayer Netcode

Buffer the server's snapshots, render remote players a little in the past, and blend between them - the loop that keeps online games smooth over a jittery, lossy network.

Your own character cannot wait a round trip for every key. The client moves at once, keeps the inputs the server has not yet seen, and replays them on each state, so only a real disagreement snaps.

A shooter aims at a picture of the past, so the server keeps a short history and rewinds the target to the moment the shooter saw before testing the shot. Hence hits after reaching cover.

Two machines run the same game, so a frame needs both players' presses. Guess the late one, run anyway, and when the guess was wrong, roll back and run every frame since again.