The multiplayer Game Jam
@OpherV
Fullstack2gether 2017
Can we make this experience
easier? faster?
realtime multiplayer game running in the browser
@opherv
Hi! I'm Opher
I'm a creative developer at Eko
http://lance.gg
Lance is:
@opherv
Multiplayer server + client library
Written entirely in JavaScript
Open source and free to use
Makes multiplayer games on the web easy(ish) and fun!
anatomy of a game
@opherv
while (true)
{
processInput();
updateGameState();
render();
}
Input
0
1
2
3
4
5
6
7
render
game step
8
9
10
11
12
13
14
15
@opherv
peer-to-peer
Why do you even need a server?
Because your players suck
@opherv
if cheating can happen,
it will happen
authoritative server
@opherv
authoritative server
Run game world
Receive input request
Validate input
Broadcast game state
13,759 km
299,792,458 m / s
Speed of Light
45 milliseconds
Tel Aviv -> Melbourne
Round Trip Time (RTT) > 90ms
@opherv
Tel Aviv
Melbourne
Request - 45ms
Reply - 45ms
LAG
Syncing the game world
Game Loop
Render Loop
@opherv
Broadcast Loop
Input
0
1
2
3
4
5
6
7
Broadcast
game step
8
9
10
11
12
13
14
15
Server view
Option 1
client step N
X: 200
client step M
X: 50
Interpolation
30
31
32
33
34
35
36
37
38
39
26
27
28
29
30
31
32
33
34
35
The client is in the past
Real Time Strategy *
Role Playing Games
"client side prediction"
Player presses "up"
Running the same game code,
both on the server and the client
@opherv
The client is in the past
but also... kinda in the future
"bending"
Physics based games
First person shooters
But what about...
Option 2: Extrapolation
30
31
32
33
34
35
36
37
38
39
30
31
32
33
34
35
36
37
38
39
Input
game state
extrapolated
steps
Interpolation
Faster, less precise
Smoother movement at the cost of delay
Extrapolation
Requires heavier simulation
Essential for physics-based games
@opherv
All must implement:
Client side prediction
Bending
@opherv
@opherv
@opherv
@opherv
more info: http://lance.gg
@opherv
Free Stickers!
follow me @OpherV
Lets start!
@OpherV
opherv.com
Multiplayer Game Jam
By Opher Vishnia
