Thread: opengl and networking on win32

I'm making a OpenGL game and i want to add some networking code to it. For example i have a rotating cube. if i block in read() it cannot rotate, right? So how can i have my app talking over the net and drawing GL at the same time?

ohh, and another quick question. If i add a menu (but no net code) will my app freeze when i click a menu item?

Well, first off you must understand that you cannot have your application communicating on the network and drawing at exactly the same time. It's virtually the same time, and there will most likely be some hiccups.

Second of all, there are some functions that will assist you in pushing your drawing routine down the graphics pipeline faster (since you're depending on a socket here). If I remember correctly, one of them is glFlush().

Needless to say, all of this depends on your network code. If you code it right, everything should work just fine (even if you don't use glFlush or similar functions to stop the wait time). So unless I can see some code...I can't determine why your GL routine isn't drawing.

As for your menu question, most likely your GL drawing routine will freeze up when it recieves that message (since it will be stuck looping through that menu code). That's how all of my apps have been like. However, there are probably ways for you to counter this effect. How to do it though...I'm not entirely sure. I've always just created my own UI that I render with OpenGL ontop of the rest of my rendering routine. Creating your own menus can counteract the issue of your menus freezing up your rendering routine.

Hi and thanks for the reply.
Well, the networking code is ok i think, but from what i understand everything will heavily depend on how fast the reply from the server comes in. If there's no data, i'm blocked in read() and the loop with drawing doesn't spin. I've just remembered there's a net function select() which has a timeout, i suppose i can use that. i'll also look up glFlush() and see if i can use it.
About the menu...Making my own would be quite difficult especially since i'm new to GL, so using win32 menu wold be better for me i think.

Ahh, then I strongly suggest sticking to Win32 menus until the remainder of your OpenGL knowledge (Until you get to things like double buffers, transparency and possibly tesselation).

As for the timeout issue, yeah that's always a problem. There's a couple of options you could do here, and I think the first is the best and most common: 1) Let the animation pause until the function recieves the data off of the network. 2) Continue the motion of your triangle while you wait for the function to recieve the data off of the network.

The second option is of course a little bit more tricky, but if the movement is predictable enough, then you can get away with this fairly easily. Depending on your expected network load though, this might be a very worthwhile option to investigate. It sort of..tricks the user into thinking nothing is lagging for a short time.

WSAAsyncSelect() sounds right. I'm not completely sure though x.x. I'm actually just starting to use Windows Sockets myself. I found a really good tutorial if anyone wants it. Beej's guide annoyed me to no end x.x.

yeah, i'm new to winsock myself, but not bsd sockets.
As i remember select() can have a timeout and if it's 0, it just checks if there's data to be read and if not it doesn't block. I dont' know what WSAAsyncSelect() does though, i'll look it up