Socket Class

// <your_unigine_project>.cpp

/* ... */
// UDP port to be used
int UDP_PORT = 8889;

// UDP receive buffer size
int RECV_SIZE = 7;

// UDP send buffer size
int SEND_SIZE = 7;


/// Class representing the Server Socket
class ServerSocket {
	Socket socket;
	
	/// Server constructor
	ServerSocket() {
		// creating a UDP socket
		socket = new Socket(SOCKET_DGRAM);
		
		// opening a socket on the specified port with a specified broadcast address
		socket.open("127.255.255.255", UDP_PORT);

		// setting the size of the sending buffer
		socket.send(SEND_SIZE);

		// setting the socket as a broadcasting one
		socket.broadcast();

		// setting the socket as a non-blocking one
		socket.nonblock();
	}

	/// Server destructor
	~ServerSocket()
	{
		// closing the socket
		socket.close();

		// deleting the socket
		delete socket;
	}
	
	/// method sending a message to a certain client
	void send_message(int client_num, string msg)
	{
		// preparing a message to be received by a client with a given client_id
		Blob blob =  new Blob();
		blob.clear();
		blob.writeInt(client_num);
		int buf[SEND_SIZE];
		for(int i=0; i < strlen(msg); i++)
			buf[i] = msg[i];
		blob.write(buf, strlen(msg));

		// getting message size
		int size = blob.getSize();

		// setting current position to start
		blob.seekSet(0);

		// sending the message
		socket.writeStream(blob, size);

        delete blob;
	}
};

/// Class representing the Client Socket
class ClientSocket {
	Socket socket;
	int id = 0;

	/// Client constructor
	ClientSocket()
	{
		// creating a UDP socket
		socket = new Socket(SOCKET_DGRAM);

		// opening a socket on the specified port 
		socket.open(UDP_PORT);

		// setting the size of the receiving buffer
        socket.recv(RECV_SIZE);

		// binding the socket to an address figured out from the host used for socket initialization
		socket.bind();

		// setting the socket as a non-blocking one
		socket.nonblock();
	}

	/// Client destructor
	~ClientSocket()
	{
		// closing the socket
		socket.close();

		// deleting the socket
		delete socket;
	}
	
	void setID(int num)
	{
		// setting client's ID
		id = num;
	}
	
	/// method checking for received packes from the server
	int update()
	{
		// preparing a blob to read the message into
		Blob temp_blob = new Blob();
		temp_blob.clear();

		// reading data from the socket
		socket.readStream(temp_blob, RECV_SIZE);

		if (temp_blob.getSize() > 0){

			// setting current position to start
			temp_blob.seekSet(0);

			// getting client's ID
			int num_client = temp_blob.readInt();

			// checking if the received message is addressed to this particular client and processing it
			if (num_client == id){
               log.message("\nClient[%d] - OPERATION_CODE: %s", num_client, temp_blob.readLine());
			}
		}
		
		delete temp_blob;
		
		return 1;
	}
};

	// declaring client and server sockets
	ServerSocket server_socket;
	ClientSocket clients[5];
int init() {

	/* ... */

	// initializing server and clients
	server_socket = new ServerSocket();
	for (int i = 0; i < 5; i++)
	{
		clients[i] = new ClientSocket();
		clients[i].setID(i + 1);
	}
	
	return 1;
}

// start of the main loop
int update() {

	Controls controls = engine.game.getPlayer().getControls();

	// sending messages on keys pressed to clients 2 and 5
	if (controls.clearState(CONTROLS_STATE_USE) == 1 )
		server_socket.send_message(2, "SWT");
    else if (controls.clearState(CONTROLS_STATE_FORWARD) == 1)
		server_socket.send_message(5, "F");
    else if (controls.clearState(CONTROLS_STATE_BACKWARD) == 1)
		server_socket.send_message(5, "B");
    else if (controls.clearState(CONTROLS_STATE_MOVE_LEFT) == 1)
		server_socket.send_message(5, "L");
    else if (controls.clearState(CONTROLS_STATE_MOVE_RIGHT) == 1)
		server_socket.send_message(5, "R");

	// updating clients
	for (int i = 0; i < 5; i++)
		clients[i].update();

	return 1;
}

/* ... */

int shutdown() {
	// Write here code to be called on world shutdown: delete resources that were created during world script execution to avoid memory leaks.

	// performing cleanup
	for (int i = 0; i < 5; i++)
		delete clients[i];
		
	return 1;
}

/* ... */