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Author Topic: Anyone here have a project made using SFML for networking?  (Read 11622 times)

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Mars_999

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Anyone here have a project made using SFML for networking?
« on: March 31, 2012, 05:53:35 pm »
I am about ready to jump off a cliff... I am having a hell of a time getting a server/client chat log going in my main menu using SFML and threads...

This is TCP, but right now could care less what it uses as long as it works...

So I started looking around and see libs like ClanLIb and such  have networking, but I would rather use SFML. So I though has anyone coded up a nice networking lib for chatting and sending game data using SFML as the only lib needed?

Thanks!

Groogy

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Re: Anyone here have a project made using SFML for networking?
« Reply #1 on: April 01, 2012, 02:53:58 am »
The whole socket interface will still be the same. And you can mix the usage of TCP and UDP depending on the importance of the package.

I don't think changing library will help you much if you are having problem grasping the concept. I haven't used SFML for this myself but I have made a chat client using sockets and TCP yes. Though I have no idea why you are having problem or what you are getting stuck on.

Should we start simple? From the start? Are you capable of doing a manual handshake? Have a client sending a connect message to a server at intervals until the server responds? If you can, then try and extend this so it can handle several clients at the same time.

This is probably the key to get it to work for you, small steps, one at a time. Otherwise you will just trip and fall ;)
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Walker

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Re: Anyone here have a project made using SFML for networking?
« Reply #2 on: April 01, 2012, 03:23:29 am »
There are networking libraries around. Some are relatively simple socket wrappers (like SFML) and some have higher-level features like client/server stuff.

I tried some game networking libs when I first wanted to make networked games and it didn't help at all. I have had far more success using raw sockets then writing a wrapper over it to support extra stuff I wanted like compression.

Bottom line:
I don't think changing library will help you much if you are having problem grasping the concept.

If you post your actual problem in the networking part of the forum, people will definitely help you out. But a few tips: Use the console. Don't use threads.

Mars_999

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Re: Anyone here have a project made using SFML for networking?
« Reply #3 on: April 01, 2012, 03:43:42 am »
Thanks guys for the help....

AFAIK I need to use threads... The whole app stalls when I run the server client stuff and not what I want to happen for obvious reason.

I can connect to each other stuff like that but I need it threaded unless you a simple example where their is no stalling while waiting for client to send or receive ect.. and same for server. When I use the simple example and drop it into my GUI chat interface due to blocking the user can't go back or do anything... This is the issue and then with threading I need to use mutexes correct for the data I am sharing to update...

e.g. a string for the chat log that gets received will need to be locked/unlocked

Thanks!

Groogy

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Re: Anyone here have a project made using SFML for networking?
« Reply #4 on: April 01, 2012, 04:04:44 am »
Yes you need to use threads in order to have asynchronous sockets.

But you aren't giving us much information. But I will still stand with the advice that you should take small baby steps forward. So if you revert back to only having a threaded handshake/connection and disconnection working. Make sure it works and then we can take it from there to see where your problem is.

You have to understand that with networking is that a thousand things can go wrong without it even giving an effect until later. And so on and so on. That's why I recommend taking small steps to ensure that what you have done right now works as intended.
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Tank

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Re: Anyone here have a project made using SFML for networking?
« Reply #5 on: April 01, 2012, 01:14:38 pm »
Yes you need to use threads in order to have asynchronous sockets.
That's not quite true. Sockets can be set to non-blocking and especially that makes sense in games where you have a loop running all the time.

The question one always has to ask himself: Is a thread *really* needed? If you can go with polling then do it, it saves a lot of time and trouble and in the end you don't benefit from threading as you're entering critical sections anyways mostly all the time.

That's different when your application's main thread is blocking, e.g. if you have a console application waiting for user input or even a GUI application that's blocking on events.

Groogy

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Re: Anyone here have a project made using SFML for networking?
« Reply #6 on: April 01, 2012, 03:47:00 pm »
If sockets are set to be asynchronous/non-blocking then the socket API provides the thread and queuing construct for you. There's always a thread ;) The difference is if you are doing it yourself or if the API is doing it. There's some pro's for doing it yourself as the queuing can be done in several ways and most often is decided on how your application looks.
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Laurent

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Re: Anyone here have a project made using SFML for networking?
« Reply #7 on: April 01, 2012, 04:07:01 pm »
Quote
If sockets are set to be asynchronous/non-blocking then the socket API provides the thread and queuing construct for you. There's always a thread
I don't think that there are threads involved when you use non-blocking sockets.
Laurent Gomila - SFML developer

Mars_999

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Re: Anyone here have a project made using SFML for networking?
« Reply #8 on: April 01, 2012, 05:49:27 pm »
Tank or anyone else... I don't see anything in SFML for using a polling system. And I think my issue is all having to do with threading as its nightmare to keep straight! :(

Tank

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Re: Anyone here have a project made using SFML for networking?
« Reply #9 on: April 01, 2012, 05:53:59 pm »
@Groogy:
That's again not true. ;) Sockets are simple streaming file I/O and have nothing to do with threads themselves. The difference between blocking and non-blocking sockets is how the operating system (or better speaking of the kernel) notifies the application of events. When blocking, it waits for a proper interrupt before giving back control, when non-blocking the current state is polled and control is given back to the caller immediately.

So when you run a loop at a high frequency (like being done in games) there's often no need use a separate thread for socket I/O.

@Mars_999:
sf::Socket::setBlocking

Mars_999

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Re: Anyone here have a project made using SFML for networking?
« Reply #10 on: April 01, 2012, 06:14:23 pm »
So if I set the socket to non blocking I can basically put

if(socket->receive(packet) != sf::Socket::Done)

in the event loop like any other event? e.g. Draw() or Upate() for say game objects?

while(true)//game loop
{
GetPackets();//if(socket->receive(packet) != sf::Socket::Done) is in here...
PhysicsUpdate();
LogicUpdate();
Draw();
TimerUpdate();
}

Hope you are following me, in saying I can just treat the receive() as if it were a polled event in a switch() for sf::Events....

Tank

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Re: Anyone here have a project made using SFML for networking?
« Reply #11 on: April 01, 2012, 07:11:15 pm »
Yup.

Mars_999

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Re: Anyone here have a project made using SFML for networking?
« Reply #12 on: April 07, 2012, 06:24:54 pm »
Sigh, this is what I have so far and works, but the issue is I can't get the Client() to allow messages from the Server to be updated each time one is sent... It's like they are blocked....

Code: [Select]
#include "stdafx.h"

const unsigned short PORT = 5000;
const std::string IPADDRESS("127.0.0.1");

bool quit = false;
std::ofstream fout("test.txt");

template<class T>
class SharedType
{
public:
std::vector<T> data;
sf::Mutex mutex;

SharedType(){}
~SharedType(){}
void Push(const T& t)
{
mutex.lock();
data.push_back(t);
mutex.unlock();
}
T Get(void)
{
T t;
mutex.lock();
if(!data.empty())
t = data.back();
mutex.unlock();
return t;
}
void Pull(std::vector<T>& v)
{
mutex.lock();
v = data;
data.clear();
mutex.unlock();
}
void Clear(void)
{
mutex.lock();
data.clear();
mutex.unlock();
}
};
SharedType<std::string> data;

void Server(void)
{
std::list<sf::TcpSocket*> clients;
sf::SocketSelector selector;
sf::TcpListener listener;

listener.listen(PORT);
selector.add(listener);

while(!quit)
{
if(selector.wait(sf::seconds(2.0f)))
{
if(selector.isReady(listener))
{
sf::TcpSocket* client = new sf::TcpSocket;
if(listener.accept(*client) == sf::Socket::Done)
{
clients.push_back(client);
selector.add(*client);
            }
        }
else
{
//receive messages from clients
for(std::list<sf::TcpSocket*>::iterator it = clients.begin(); it != clients.end(); ++it)
{
sf::TcpSocket& client = **it;
if(selector.isReady(client))
{
sf::Packet packet;
std::string clientMsg;
                    if(client.receive(packet) == sf::Socket::Done)
{
packet >> clientMsg;
std::cout << "\nClient said: " << clientMsg << std::endl;
clientMsg.clear();
}
}
}
}
}
//send messages?
for(std::list<sf::TcpSocket*>::iterator it = clients.begin(); it != clients.end(); ++it)
{
sf::TcpSocket& client = **it;
if(selector.isReady(client))
{
sf::Packet packet;
std::string s;
s = data.Get();
data.Clear();
if(!s.empty())
{
packet << s;
if(client.send(packet) == sf::Socket::Done)
{
std::cout << "\nMessage sent to client: " << s << std::endl;
}
}
}
}
}
for(std::list<sf::TcpSocket*>::iterator it = clients.begin(); it != clients.end(); ++it)
{
if(*it)
delete *it;
}
}
void Client(void)
{
std::string s;
sf::Packet packet;
sf::TcpSocket socket;
socket.setBlocking(false);
while(true)
{
if(quit)
break;
socket.connect(IPADDRESS, PORT);
if(socket.getRemotePort())
break;
}
while(!quit)
{
if(socket.receive(packet) == sf::Socket::Done)
{
packet >> s;
std::cout << "\nThe server said: " << s << std::endl;
}
packet.clear();
s.clear();

s = data.Get();
data.Clear();
if(!s.empty())
{
packet << s;
if(socket.send(packet) == sf::Socket::Done)
{
std::cout << "\nMessage sent to server: " << s << std::endl;
}
}
packet.clear();
s.clear();
}
}
void GetInput(void)
{
std::string s;
std::cout << "\nEnter \"exit\" to quit or message to send: ";
std::cin >> s;
data.Push(s);
if(s == "exit")
quit = true;
}
int main(int argc, char* argv[])
{
sf::Thread* thread = 0;

char who;
    std::cout << "Do you want to be a server (s) or a client (c) ? ";
    std::cin  >> who;

    if(who == 's')
thread = new sf::Thread(&Server);
else
thread = new sf::Thread(&Client);

thread->launch();

while(!quit)
{
GetInput();
}
if(thread)
{
thread->wait();
delete thread;
}

std::vector<std::string> temp;
data.Pull(temp);
for(unsigned int i = 0; i < temp.size(); ++i)
fout << temp[i] << std::endl;

return 0;
}

Mars_999

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Re: Anyone here have a project made using SFML for networking?
« Reply #13 on: April 08, 2012, 01:05:37 am »
Anyone wants to, the code posted above is complete and should be drop and compile to test for yourself... after you update the IP to whatever you need....

I am not sure if this is a bug or what...

Mars_999

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Re: Anyone here have a project made using SFML for networking?
« Reply #14 on: April 08, 2012, 06:13:54 am »
Anyone?????

 

anything