I'm new to StackOverflow lol, but I've been relying on this website for awhile. I have a question regarding a Java socket server that I created. Upon connection (client and server), my application creates a thread for that client. This is an MMORPG game server... at least trying to be. With one player, it doesn't lag that bad. With two, however, it began to show some lags...
If I was to spam left-right-left-right on one of the client, and move around normally with the other, the other would feel glitchy. I'm hoping to get some assistant since I've spent over a week and a half tangled up =) It's about time I ask for help.
The code is simple:
public static void main(String[] args) throws IOException{
serverRooms.put(roomNumber, new Room());
try {
System.out.println("Starting Server...");
serverSocket = new ServerSocket(9595, 20);
System.out.println("Server Started");
while(run){
Socket socket = serverSocket.accept(); // Check if we have a connection, otherwise wait
Player player = new Player(playerCount++, socket, roomNumber);
new Thread(player).start();
}
} catch (IOException e) {
e.printStackTrace();
}
}
That's how it is all started! On the Player object, it looks like :
public void run() {
while(playerIsConnected) {
try {
int msgid = input.readUnsignedByte();
messageHandler(this, msgid);
} catch (IOException e) {
System.err.println("Player have signed off");
playerIsConnected = false;
}
}
// If Player leaves, close socket, and end thread
try {
socket.close();
} catch (IOException e) {
System.out.println("We got an error while closing a socket on player " + pid + ".");
}
}
messageHandler happens to be a static method from a Final Static class. It is a global method that can be called by every thread (Can this be the cause of the lag??)
public final class MessageControl {
public static void messageHandler(Player player, int msgid) throws IOException{
DataInputStream input = player.getInputStream();
switch (msgid) {
case 10:
byte hspd = (byte) Math.signum(input.readByte());
byte vspd = (byte) Math.signum(input.readByte());
byte dir = input.readByte();
updatePlayerPosition(player);
byte spd = (byte) (hspd != 0 && vspd != 0 ? player.spd-1 : player.spd);
// Prepare packet and send to clients
ByteBuffer buffer = ByteBuffer.allocate(11);
buffer.put((byte) 10);
buffer.put(shortToByte_U16(player.pid));
buffer.put(shortToByte_U16(player.x));
buffer.put(shortToByte_U16(player.y));
buffer.put((byte)(hspd*spd));
buffer.put((byte)(vspd*spd));
buffer.put((byte)(dir));
sendPacketToAllClients(player, buffer, true);
// Update Player info
player.hspd = (byte) hspd;
player.vspd = (byte) vspd;
player.dir = dir;
player.lastUpdate = System.currentTimeMillis();
break;
}
private static void sendPacketToAllClients(Player player, ByteBuffer buffer, boolean includeMe){
for (Player otherPlayer : player.room.getPlayersInRoom()){
if (otherPlayer.pid != player.pid || includeMe){
sendPacketToClient(otherPlayer, buffer);
}
}
}
}
Regarding the shortToByte_U16(), I just created a simple method that conerts shorts to bytes (sending buffer packets via bytes to client). Example, I have about 5 of these conversions, which would include conversion for unsigned u16
public static byte[] shortToByte_16(int x){
short s = (short) x;
byte[] ret = new byte[2];
ret[0] = (byte)(s & 0xff);
ret[1] = (byte)((s >> 8) & 0xff);
return ret;
}
Looking at the following structure, any ideas why I be lagging?
EDIT : I think I improved it a lot by setting the setTcpNoDelay to true. The lag seems to still be there when I spam left/right on my end... the other player on my screen seems glitchy.
Socket socket = serverSocket.accept(); // Check if we have a connection, otherwise wait
socket.setTcpNoDelay(true); // This helped a lot!!!
Player player = new Player(playerCount++, socket, roomNumber);
new Thread(player).start();
From what I am seeing... my "spamming left/right" end seems to be missing the packet sent by the server.
