Comments on: Virtual Connection over UDP

By: Glenn Fiedler

Glenn Fiedler — Fri, 09 Dec 2011 19:16:35 +0000

I think eventually I’ll leave these original articles online but sell an ebook for the rest of the articles that I’ll write over the next ten years (hopefully a full books’ worth…) with updated example source code under BSD licence.

By: Glenn Fiedler

Glenn Fiedler — Fri, 09 Dec 2011 19:14:38 +0000

I would eventually like to write a book on networking, once work calms down a bit (if it ever does), I’d like to take all my GDC talks and articles and combine it into a e-book. I think I’ll maybe kickstarter it.

By: Glenn Fiedler

Glenn Fiedler — Sun, 12 Dec 2010 16:52:36 +0000

actually it will work provided the server (the one being connected to) is not behind NAT. if you need to establish P2P connections then you’ll need to use NAT-punchthrough. cheers

By: The-Snake

The-Snake — Fri, 10 Dec 2010 20:42:39 +0000

Well… this isn’t a connection over udp…
This won’t work unless the client is directly connected to the Internet… right ?

I mean, if all you have is an IP and a port, the server will send answers to the device who sent the packages… which is your client ONLY when you’re not using a router (and almost everybody use routers nowadays).

When using a TCP connection, you don’t have such problems (you still can’t connect to a device which is not directly connected to the Internet, unless the router makes a redirection)… using UDP is a whole other matter.
I am actually wondering how games such as Warcraft III deal with that stuff : why is the server the ONLY ONE who has to be directly connected to Internet (or have his router re-route packages from one port to him) ?

By: Dr.Kappa

Dr.Kappa — Thu, 03 Jun 2010 08:40:03 +0000

Yes you’re right… and deallocation is automatic.

By: Glenn Fiedler

Glenn Fiedler — Wed, 02 Jun 2010 20:25:53 +0000

for such a small allocation, it’s better to allocate on the stack via alloca, at least where I come from working on game consoles

By: Dr.Kappa

Dr.Kappa — Wed, 02 Jun 2010 13:18:30 +0000

You don’t need a pointer-to-pointer since:

unsigned char *packet;
packet = new unsigned char[size+4];

should be enough… the rest of code is pretty much the same.

By: Christopher Cubells

Christopher Cubells — Sun, 17 Jan 2010 17:06:25 +0000

When using Visual Studio Express 2010 Beta 2 to compile your example Client/Server code, there is an issue with the dynamic packet array in the Net.h header file.

unsigned char packet[size+4];

needs to be changed to:

unsigned char **packet;
packet = new unsigned char*[size+4];

and in the if statement below the cast of (unsigned char) needs to be changed to (unsigned char*)

These changes need to be applied to both ReceivePacket and SendPacket functions.

By: Glenn Fiedler

Glenn Fiedler — Tue, 08 Dec 2009 15:14:37 +0000

Thanks, yep there are more articles coming – cheers

By: Tomas Herman

Tomas Herman — Tue, 08 Dec 2009 12:06:32 +0000

I know you published this quite a while ago but dude, each one of your articles is more useful then 5x2hour lessons on our uni…thx a lot and pls keep publishing them ;]