Naev Multiplayer Plugin

This plugin provides the necessary files to manage multiplayer in Naev. It requires the lua_enet configuration parameter to be set to true.

The plugin is fairly experimental and as such no backwards compatibility is guaranteed. It is recommended to play on the latest version of Naev (if compatible) and latest version of the plugin for all parties involved.

There are many features that haven't been implemented yet, and some that might just get brushed over. I like to stick to the principles that get us all the most amount of fun with the least amount of headaches, so let's make it fun and easy and we'll take it from there.

Some things to note:

• Expect some desync, but the server is authoritative
  • If you shoot on your client but there's nothing to shoot at, you don't lose energy because the server doesn't let you shoot
  • Missiles won't be in sync at all, but they are "predictably" out of sync, so it is a masterable skill
  • Beams are so out of sync that I removed them from equipopts, it's not even funny
  • If you enter a blocking state such as a menu or the chat, you will risk being disconnected by timeout
• When you die, the server should respawn you in a new ship, but sometimes you might need to reload a save and reconnect
  • If you "respawn" in the same ship, you probably just ate a missile on your client that the server said was a miss, just keep playing
• You can't configure weapons on the client, it doesn't do anything at all other than mess up what you see
• You can use afterburners and shield boosters (perhaps other modules too) and the effects will be synchronized between clients
• Autonav works
  • It should synchronize less often to save bandwidth on idling clients
  • Speedup does not work (and even if it did, the server would probably start teleporting you around or ask you to respawn)

The chat

There is a basic chat feature. You press your hail button and a text window pops up. Type a short message fast before you are disconnected.

Once you have sent your message, you will be resynchronized to where the server says you should be and can continue playing. Everyone will see your message if you are connected, you can confirm you are connected if your message appears in your message log.

This is mainly meant for short messages such as "go" or "attack goddard", but can be used for other things as well. Please be civil.

Question marks don't work, use something else instead. Perhaps your peers can decide on something like "ma" (a homage to Firefly, "ma" (嗎) is the Chinese equivalent of a question mark).

Configuration

In order to use the plugin, the lua_enet configuration parameter must be set to true. Insert the following line at the very end of your conf.lua: lua_enet = true

Server configuration

By default, you are free to use whatever port you like, but if you allow the original multiplayer to pick a port for you then you should start hosting on an ephemeral port. You will probably have to forward the server port in your router setting if you do not host on an ephemeral port.

If you decide to use port 0, a port will be selected for you as if by the original multiplayer. You will need to find out what ephemeral port was selected automatically with a tool of your choice, but you should be able to host a server without port forwarding in this case.

Starting a server

1. Start a new pilot or log into an existing pilot for this purpose (a server can't play and the nickname will be reserved so it is a good idea to pick a name like "Server" or "Host").
   • If you started a new pilot, you should do a save-load cycle to activate the multiplayer event
2. Click on the "Multiplayer" button
3. Click on the "Host Server" option in the conversation
4. You have a choice of selecting a custom port or picking one at random
   • You should try to use the same port consistently if you plan on hosting a server
   • You might need to forward the port that you choose
   • If you let the original multiplayer select the port for you, you can use a tool to find your port if you lose the message
5. Close everything and take off
6. Leave the server alone, as the simulation must run for the networking code to execute
   • The server cannot be seen by players -- please don't abuse this as the server is not meant to play but can be used to spectate
   • The server will announce the socket host (including the port, if you tried to get one automatically) in the console, message log, and as an omsg

Finding your port

Simply run the following command immediately after starting a server:

ss -tulpn | grep naev

The output will look something like this:

udp   UNCONN 0      0            0.0.0.0:60939      0.0.0.0:*    users:(("naev",pid=25833,fd=37))

This means that you are serving on port 60939. The next time you host a server, you can probably use that same port again. It is a good idea to make note of it, as your friends will have saved your server with this associated port after playing on your server.

Connecting to a server

1. Load a pilot with a suitable nickname (for obvious reasons, it's suggested to avoid using real world names on public servers, but special characters and numbers should be avoided as well).
2. Open the Info menu
3. Click on the "Multiplayer" button
4. Click on the "Connect" option in the conversation
5. Select "Add Server" to add a new server or select a recent server from the list
   • If you're adding a new server, you will have to first type a nickname (the label shown in the connect list) and then the host information (such as localhost 1337 or 127.0.0.1 48888)
6. Take off after the conversation has ended
   • Saving will now be disabled until you load again
   • If the connection is successful, the server will respawn you in a new ship
   • If there is an error, your ship will broadcast the error message
     • If the error is: nickname is reserved then you should come back later or join with another pilot (you're not playing on a live server anymore)
   • If you die on the server, the client tries to keep you alive so that you can respawn without reloading your save game
   • If you die on the client, you might still be alive on the server (for example if you dodged a missile by server law, but you thought it hit you on your client), just keep playing
   • If you die on the server and the client, just load a save and connect to the server again

Tips and Tricks

Adding a favorite server as a single-click button

If you have a favorite server (such as one hosted regularly by one of your friends), you might want to avoid the conversation with the original multiplayer every time you want to play. An easy way to get around that is to just create a new event like the one below, modified accordingly:

• Change the label on the connect button to something like "Connect to Favoured"
• Replace the placeholder values with your hard-coded values
• Change things like the name of the new event and any comments or labels you might want to personalize

If successful, it might look something like this:

--[[
<?xml version='1.0' encoding='utf8'?>
<event name="Multiplayer Handler - My favorite server">
 <location>load</location>
 <chance>100</chance>
 <unique />
</event>
--]]
--[[
   Multiplayer Event for my favorite server

   This event makes sure I can connect to my favorite server
--]]
local fmt           = require "format"
local mplayerclient = require "multiplayer.client"
-- luacheck: globals load (Hook functions passed by name)

function create ()
    hook.load("load")
end

local clientbtn

local function connectMultiplayer()
    local hostname = "192.168.1.254" -- note: not a real server
    local hostport = "6789"
    local localport = "0"

    local target = fmt.f( "{host}:{port}", { host = hostname, port = hostport } )

    fail = mplayerclient.start( hostname, hostport, localport )
    if fail then
        print("ERROR: " .. fail )
    else
        player.infoButtonUnregister( clientbtn )
    end
end

function load()
    clientbtn = player.infoButtonRegister( _("Connect to Favorite Server"), connectMultiplayer, 3)
end

If this was successful, you can now connect to your favorite server with the click of a button, in this case "Connect to Favorite Server" from the Info menu.

Removing the "Multiplayer" Button

If you only plan on playing on your button-click server as above, you might as well remove the regular "Multiplayer" button from your info menu. In this case, you can just remove the "dat/multiplayer.lua" event, since it is nothing more than a handy interface to connect and manage servers.