Comments on: What every programmer needs to know about game networking

By: rts

rts — Sun, 20 Jun 2010 01:28:34 +0000

thanks that makes sense. i’m on linux right now, but its easy enough to apply this.

By: Glenn Fiedler

Glenn Fiedler — Sun, 20 Jun 2010 01:11:28 +0000

game consoles usually have two levels of security. the closed platform itself (cannot modify the executable) and encrypted communications over UDP to avoid sniffing packets, modifying packets or injecting fake packets.

if you are a PC you can encrypt your communications but remember, never trust the client.

if you are on a PS3 you can trust that client slightly more

cheers

By: rts

rts — Sat, 19 Jun 2010 13:00:29 +0000

really enjoyed this – you’ve got me trying this out at home – very slowly

any suggestions on security? udp seems pretty easy to pick up on . do you create your own authentication tokens to reverify after each event?

is connected udp an kind of solution? it seems light enough to use for a game connection and i can see who is sending what.
- does that present any issues – do you feel you have to home roll authentication too?

By: Glenn Fiedler

Glenn Fiedler — Tue, 20 Apr 2010 18:25:17 +0000

Re Geo about deterministic lockstep model:

http://www.gamasutra.com/view/feature/3374/the_internet_sucks_or_what_i_.php
http://www.gamasutra.com/view/feature/3094/1500_archers_on_a_288_network_.php

By: Geo

Geo — Mon, 19 Apr 2010 14:35:56 +0000

Hello! I can’t find any good documentation about lock-step with client/server. The classic lock step model would need a very long delay in responsivness until the ack for a command goes all the way back. Also, because the server must initiate all ‘locks’ the delay gets even bigger. A way to reduce this delay would be to send a full snapshot of the world for resync each time a command did not arrive in time – but a full snapshot is a lot of data.

Toadcop mentioned something about lagger’s don’t affect gameplay and local speed increasing technic is not covered in the web. Is there a way to find out more about it?

Thank’s a lot!

By: Toadcop

Toadcop — Thu, 25 Feb 2010 17:08:38 +0000

awesome B-)

By: Glenn Fiedler

Glenn Fiedler — Wed, 24 Feb 2010 19:05:04 +0000

New article: Floating Point Determinism

By: Glenn Fiedler

Glenn Fiedler — Tue, 23 Feb 2010 21:04:18 +0000

no worries, i’ve been studying up on this stuff for the past few days – you are just super-lucky you asked this question at exactly the right time!

By: Toadcop

Toadcop — Tue, 23 Feb 2010 20:59:01 +0000

wow ! tnx ALOT !
now i need some time to study this =)

By: Glenn Fiedler

Glenn Fiedler — Tue, 23 Feb 2010 07:36:45 +0000

Here are some good links about floating point determinism and IEEE 754:

http://www.box2d.org/forum/viewtopic.php?f=3&t=1800
http://www.nccs.nasa.gov/images/FloatingPoint%5Fconsistency.pdf
http://www.christian-seiler.de/projekte/fpmath/
http://www.gamedev.net/community/forums/topic.asp?topic_id=499435
http://software.intel.com/en-us/forums/showthread.php?t=48339
http://gamesfromwithin.com/back-to-the-future-part-1
http://developer.apple.com/hardwaredrivers/ve/sse.html
http://download.intel.com/technology/itj/q41999/pdf/ia64fpbf.pdf
http://www.intel.com/standards/floatingpoint.pdf
http://cache-www.intel.com/cd/00/00/34/76/347605_347605.pdf
http://download.intel.com/technology/itj/Q21999/PDF/simd_ext.pdf
http://msdn.microsoft.com/en-us/library/aa289157(VS.71).aspx
http://bulletphysics.org/Bullet/phpBB3/viewtopic.php?f=4&t=3435
http://docs.sun.com/source/819-3693/ncg_math.html#pgfId-405
http://stackoverflow.com/questions/968435/
http://docs.sun.com/source/806-3568/ncg_goldberg.html
http://www.mathworks.com/support/solutions/en/data/1-7AST0R/index.html