Game network programming
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This document discusses various approaches to network programming for multiplayer games. It begins by comparing synchronous peer-to-peer and client-server architectures. It then covers topics like latency, desync issues, client-side prediction, and authoritative servers. The document also discusses specific examples from games like Quake and strategies like UDP, TCP, snapshots, and web technologies like WebSockets. Overall it provides an overview of fundamental networking concepts for multiplayer games.
![Age of empires
1500 archers with a 28.8 modem [1]](https://image.slidesharecdn.com/gamenetworkprogramming-121204160301-phpapp02/85/Game-network-programming-22-320.jpg)
![References
■ [1] Age of empires paper
■ Synchronous RTS engines
■ Client / server tricks
■ Quake code reviews
■ Improving bandwidth for websockets
■ Unreal networking architecture
■ http://tools.ietf.org/html/rfc1323](https://image.slidesharecdn.com/gamenetworkprogramming-121204160301-phpapp02/85/Game-network-programming-92-320.jpg)
Game network programming
- 1. Game network programming PotHix (Willian Molinari) Diego Souza (marciano)
- 2. Why?
- 4. Skeleton Jigsaw: http://plaev.me/skeleton-jigsaw Shameless self promotion
- 5. To have fun, bro!
- 6. Agenda ■ Synchronous RTS ■ Peer to peer ■ Client / server ■ UDP ■ Quake strategy ■ TCP ■ Web and HTML5
- 8. RTS's and Supreme commander
- 9. Peer to peer
- 11. Two gameloops!
- 12. Latency My life for the horde!
- 13. Player1 Player2 Player3 tick 0ms tick 100ms tick 200ms tick 300ms tick 400ms
- 14. Player1 Player2 Player3 tick 0ms tick 100ms tick 200ms tick 300ms tick 400ms
- 15. Player1 Player2 Player3 tick 0ms tick 100ms tick 200ms tick 300ms tick 400ms
- 16. Player1 Player2 Player3 tick 0ms tick 100ms tick 200ms tick 300ms tick 400ms
- 17. butterfly effect
- 18. So...
- 19. Player1 Player2 Player3 tick 0ms tick 100ms tick 200ms tick 300ms tick 400ms
- 20. Player1 Player2 Player3 tick 0ms tick 100ms UI OK! tick 200ms tick 300ms tick 400ms
- 21. Desync
- 22. Age of empires 1500 archers with a 28.8 modem [1]
- 23. Client / Server
- 25. Client Server pos (0,0)
- 26. Client Server pos (0,0) pos (0,0)
- 27. Client Server pos (0,0) pos (0,0) move pos (1,0)
- 28. Client Server pos (0,0) pos (0,0) move pos (1,0) pos (1,0)
- 29. Smartass
- 30. Client Server pos (0,0)
- 31. Client Server pos (0,0) pos (0,0)
- 32. Client Server pos (0,0) pos (0,0) move pos (100,200)
- 33. Client Server pos (0,0) pos (0,0) move pos (100,200) pos (100,200)
- 35. Client Server pos (0,0)
- 36. Client Server pos (0,0) pos (0,0)
- 37. Client Server pos (0,0) pos (0,0) move right pos (1,0)
- 38. Client Server pos (0,0) pos (0,0) move right pos (1,0) pos (1,0)
- 39. Victory!
- 41. Client Server pos (0,0)
- 42. Client Server pos (0,0) pos (0,0)
- 43. Client Server pos (0,0) pos (0,0) move right pos (1,0)
- 44. Client Server pos (0,0) pos (0,0) move right pos (1,0) pos (1,0)
- 45. Client Server pos (0,0) pos (0,0) move right Latency pos (1,0) pos (1,0)
- 46. Client Server pos (0,0) pos (0,0) move right Animation pos (1,0) pos (1,0) Predicting
- 47. Client Server pos (0,0) pos (0,0) move right Animation pos (1,0) pos (1,0) Predicting
- 48. Client Server pos (0,0) pos (0,0) move right Animation pos (2,0) pos (1,0)
- 49. Client Server pos (0,0) pos (0,0) move right Animation pos (2,0) pos (1,0) Correction pos (2,0)
- 52. rcv_buf >= snd_buf All receive operations return only one packet watch out for MSG_TRUNC
- 53. auto ip_mtu_discover enabled by default EMSGSIZE signals packet too big
- 54. 65k max theoretical packet limit (headers included) rfc defines the size header to 16bits
- 55. however, 1472 is likely the max you may get, 576 to be sure MTU - headers
- 56. remember the TOS throughput, reliability, lowdelay (etc.)
- 58. All credits to Fabien Sanglard: http://fabiensanglard.net/quakeSource/quakeSourceNetWork.php Code: https://github.com/id-Software/Quake/blob/master/QW/client/net_chan.c
- 60. Snapshots based
- 61. All credits to Fabien Sanglard: http://fabiensanglard.net/quake3/network.php
- 62. All credits to Fabien Sanglard: http://fabiensanglard.net/quake3/network.php
- 63. All credits to Fabien Sanglard: http://fabiensanglard.net/quake3/network.php
- 64. All credits to Fabien Sanglard: http://fabiensanglard.net/quake3/network.php
- 65. All credits to Fabien Sanglard: http://fabiensanglard.net/quake3/network.php
- 66. All credits to Fabien Sanglard: http://fabiensanglard.net/quake3/network.php
- 68. TCP Streaming, reliable, connection oriented
- 69. TCP tuning
- 70. Long story short: use auto-tune You probably just need to tune the maximum values (system wide)
- 71. High-performance extensions refer to rfc1323
- 72. Bandwidth-delay product data link's capacity (in bits per second) and its end-to- end delay (in seconds).
- 73. 10Mbs x 1ms = 1.22 KB 10Mbs x 200ms = 244 KB rfc1323: huge buffers
- 74. CORK don't send partial frames
- 76. socket options
- 78. benchmarking
- 81. BBG* and HTML5 *Browser based games
- 82. The same thing... ...but not...
- 83. No TCP No UDP No peer to peer
- 85. HTTP
- 86. Websockets
- 87. Mozilla multiplayer game: http://browserquest.mozilla.org
- 88. Blackberry browser Chrome Opera Mobile safari Browsers IE Android browser Firefox Opera mini Safari
- 90. Socket.io Fallbacks all over the place
- 92. References ■ [1] Age of empires paper ■ Synchronous RTS engines ■ Client / server tricks ■ Quake code reviews ■ Improving bandwidth for websockets ■ Unreal networking architecture ■ http://tools.ietf.org/html/rfc1323
- 93. References ■ http://linux.die.net/man/7/udp ■ http://linux.die.net/man/7/ip ■ http://linux.die.net/man/7/socket ■ http://en.wikipedia.org/wiki/Nagle's_algorithm ■ http://en.wikipedia.org/wiki/Bandwidth- delay_product
- 95. Game over