Game Network Programming

@CoreyClarkPhD @GameTheoryLabs

!

What I Did?

What I Do Now Crowd Sourced

Games

Distributed Computing MMOs

FoldIt Crowd Process

GTL

Determinism & Lock Step

Authoritative Server

Mid-Game Join

Floating point

Latency vs Lag

Fight Lag

!  What is the Cause?

!  Slower But Consistent Frame Rate

!  Animations

!  Client Side Prediction

!  Learning Algorithms !  Markov Models

!  Artificial Neural Networks

Client Side Prediction

Linear Interpolation

Jitter / Wobble

The Internets …

Peer To Peer (P2P)

Client / Server

Mesh

Network Stack

Sockets

!   Extends Network Layer (Host to Host)

!   End – to – End (App to App)

!   APIs: WinSock & Berkley (BSD)

TCP vs UDP

TCP

!   Connection Based

!   Delivery Guarantee

!   Order Guarantee

!   Flow Control

!   Duplicates Deleted

UDP

!   Connectionless

!   No Delivery Guarantee

!   No Order Guarantee

!   No Flow Control

!   Duplicates

TCP/IP Network

Host

App

Socket

TCP

IP

Channel Channel

Host

App

Socket

TCP

IP

Ethernet, WiFi, Bluetooth

Addresses

External Address

Internal Address

MAC Address

ISP Geo Referenced

Router

Hardware IEEE Regulated

Ports

!   Communication End Point

!   Port Forwarding !   Internal Static IP

!   Stay above 1024

!   Common Ports !   20: FTP

!   80: HTTP

!   443: HTTPS

!   Registered Ports !   7778: Unreal

!   26000: Quake

!   27010: Half-Life

!   27960: Quake III

Programming Sockets

!   Blocking

!   Non-Blocking

!   Overlapped I/O !   Event Handle

!   Completion Port

WinSock Procedure

Client

!   WinSock Init

!   Create Socket

!   Connect

!   Send/Recv

!   Close Socket

!   WinSock Clean Up

Server

!   WinSock Init

!   Create Socket

!   Bind

!   Listen

!   Accept (New Socket)

!   Send /Recv

!   Close Socket

!   WinSock Clean Up

TCP Procedure

Create Socket Bind Listen Accept

Create Socket Connect

Send Recv

Send Recv

Byte Order

Endianness

!   Big Endian !   MSB in Smallest Addr

!   Intel

!   Little Endian !   LSB in Smallest Addr

!   Motorola

Host vs Network

!   Host Byte Order (Intel (Big-Endian)

!   Network Byte Order (Big-Endian)

! htons, htonl

! ntohs, ntohl

SockAddr.sin_port = htons(nPort);

Startup & Cleanup

WSAStartup( MAKEWORD(2,2), &WSADATA)

WSACleanup()

Create Socket

socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

socket(AF_INET, SOCK_DGRAM,

IPPROTO_UDP);

Connect

connect(SOCKET tcp, const struct sockaddr* SockAddr,

sizeof(SockAddr))

Send

int send( SOCKET s, const char *buf, int len, int flags);

Demo

NodeJS Server Web Viewer

C++ TCP Client WebSocket Client

Help Me Out

gametheorylabs.com/smu Go To:

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Set Color

Questions?