FSCKING LAG

Video Games!

Multi-player video games!

Server

Server Client Client Client

Server Client

Server Client “I just killed player 1”

Server Client “I just killed player 1” “ok”

Server Client “I just killed player 1” “ok” BAD

Server Client “I pressed these buttons” “This is where things
are”

Server Client “I pressed these buttons” “This is where things
are” BETTER

PROBLEM

1 2 Lag = 1 second Lag = 0.1 seconds

1 2 Shoots! Runs! FROM PLAYER 1’S PERSPECTIVE:

Server Player 1 Player 2

Server Player 1 Player 2 “I’m shooting!” (1 second ago)

Server Player 1 Player 2 “I’m shooting!” (1 second ago)
“I’m running around the corner!” (0.1 second ago)

Server Player 1 has shot, and Player 2 is around
the corner. Player 1’s shot missed.

Server Player 1 Player 2 “Player 2 is now around
the corner. Player 1 shot, but missed.”

Counter-Strike

Server Player 1 shot, and at the time, they were
aiming at Player 2. Their should would have hit.

Server Player 1 Player 2 “Player 1 shot Player 2.”

“Oh, and Player 2 still ran around the corner. lol.”

“Oh, and Player 2 still ran around the corner. lol.” wtf

Age of Empires

1500 Archers on a 28.8: Network Programming in Age of
Empires and Beyond Mark Terrano, Paul Bettner

PROBLEM: 1500 archers Each one has a position Each one
is moving

Each position is about 4 bytes each

4 bytes ✕ 1500 = 6000 bytes

6000 bytes ✕ 30 frames/sec = 175 kB/s

SOLUTION:

DON’T SYNC STATE

SYNC PLAYER INTENT

Client Client Client

Client Client Client “I told my archers to move.”

Client Client Client “I told my archers to move.” “I
told a villager to gather wood.”

Client Client Client Wait for everyone to ﬁnish this frame….

Client Client Client Archers are moving, and the villager is
gathering wood.

NOT PERFECT

RUNS AT THE SLOWEST PLAYER

DESYNCS

@thesecretlab rocketboxgame.tumblr.com

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