First Start | Installation | Network Play | Configuration | FAQ | Redistribution

# Network Play

You can play Retrocycles over a LAN or the Internet. It uses the UDP connectionless communication mode of the IP protocol, so make sure you have TCP/IP installed and activated if you experience problems.

## Connecting

### LAN game

The fastest computer in your network should act as the server. There, go to the "Play Game"/"Multiplayer" menu and hit the "LAN Game"- menu item. After a second, Retrocycles should tell you that there are no servers currently available, but offer a "Host Game" item. Press Return on it. In the following menu, you can select a name for your server and the game options. The game options here are completely independent from those in single player mode. After everything is to your liking, you can hit the "Host Network Game" menu item and the game will start on the server and run just as in single player mode.

The other computers will be the clients. On them, you activate the "LAN Game" menu item, too. This time however, there should be the server you just started visible in the server browser. Just hit Return on it to connect.

### Internet game

An internet game works the same way; you just have to choose "Online Game" instead of "LAN Game" in the menu. Note that the number of users currently online on each server is displayed by the server browser, too.

While in the server browser, you use "cursor left/right" to change the sorting key, +/- to give individual servers a bias to the score (and thus their place with on the list if you sort by score which is the default). Add servers to your bookmarks with "b" and refresh all servers with "r".

Internet server browsing would not be possible without master servers. We currently use four masters, two run by Tank Program, two by Z-Man. DNS service for swapping out masters without you having to update your configuration is provided by Tank.

#### Current status

Current counts show about 200 active servers. If you're not picky about your fellow players, there should be someone to battle against on one of those. The problems start as soon as you develop a preference for certain server settings, because there are quite a number of flavors around.

### Bookmarks

You can access and edit your server bookmarks in the "Server Bookmarks" submenu of the "Network Game" menu. You can add bookmarks from the server browser or manually add bookmarks via the "Edit Bookmarks" menu. The only way to delete bookmarks currently is to edit out the server name of one, sorry for the inconvenience.

### Version Control

Server and client do not need to be of the same version. With default settings, the current server is compatible with clients down to 0.2.0, and the current client with servers down to 0.2.0. Obviously, some new settings were introduced since then; if you change them away from the default, three things can happen when an old client connects:

- Variant 0: Nothing. The old client is allowed to connect, and the setting stays like it was. It's the player's problem if something goes wrong.
- Variant 1: The offending setting automatically reverts to its default value.
- Variant 2: The old client is not allowed to connect. The player is already informed of that in the server browser.

You will be informed on the console when you change one of the affected settings which variant will be used for it, and clients up to which version are affected.

Settings are classified into five groups: Breaking, Bumpy, Annoying, Cheating and Visual. Settings of the "Breaking" group absolutely destroy the game for old clients when they are not on their default values; setting a custom map file is the perfect example. The "Bumpy" group allows basic play for old clients, but it's not likely to be a pleasant experience. Examples would be `CYCLE_DELAY` and `CYCLE_TURN_SPEED_FACTOR`. The "Annoying" group allows more or less pleasant gameplay with only little disturbances that feel a bit like small bugs. The `CYCLE_RUBBER_MINDISTANCE` setting family belongs to this group. When a client does not honor settings of the "Cheating" group, this is supposed to be considered cheating. An example is the `DOUBLEBIND_TIME` setting, and the `CAMERA_FORBID_` settings would fall into that category, too (but all clients know about them). Lastly, "Visual" settings only affect displayed information and have no influence on gameplay. And in fact, there is a sixth group where the behavior is hardcoded to either variant 1 or 0.

#### Customizing Version Control

Which of the three behavior variants is used for settings of the five categories is determined by the `SETTING_LEGACY_BEHAVIOR_` settings in settings.cfg. The default settings block old clients on Breaking, Bumpy and Cheating settings (Variant 2), and ignore possible conflicts for Annoying and Visual settings (Variant 0). To override the group defaults, you can define exceptions for single settings; if you want to revert the setting `FOO` to its default when an old client connects, then you set `FOO_OVERRIDE` to 1.

You can also lock out old clients independently of incompatible settings; use the variable `BACKWARD_COMPATIBILITY` for that. Setting it to 0 will only allow the most current clients to connect. You can also disable some new features to be activated by setting `NEW_FEATURE_DELAY` to some positive value. If both configuration variables are set to the same value, no feature will be enabled or disabled just because an old client connects/disconnects. The numbers these two settings refer to are raw network protocol versions; see here for a table comparing them with release versions.

## Interpersonals

Please behave like a human being on the game grid. Don't use offensive language when asked, sometimes there are children online. Help newbies into the game. Follow the rules of the server administrator or change the server you play on.

### Chat

Send your fellow players messages by hitting the chat key configurable in the "Player Setup" menu (defaults to "Enter"). Usually, the message will go out to all players. Servers from 0.2.8.0 on support IRC style extensions: By starting your message with "/msg ", you can send selected players personal messages. With "/me", you can tell the others what you do; "/me falls asleep" will print "Walruss walls asleep" if you're Walruss. "/team" sends messages to your teammates only; if you're a spectator, those will be the other spectators. Some servers make that the default chat mode even without command prefix; on those, you may be allowed to address all players by using "/shout".

If another player annoys you, the silencing menu comes in handy: it can be reached by pressing ESC, then selecting "Player Police/Silence Menu". If you're annoyed by chat in general, edit settings.cfg and activate SILENCE_DEFAULT (add the line SILENCE_DEFAULT 1). This has the effect that new players get silenced by default and have to be unsilenced if you want to hear them. If you really never want to hear chat, add the line ENABLE_CHAT 0.

#### Instant Chat

By default, the game lets you say some predefined things when you press F1 to F12 or 1 to Backspace. Beware, the default settings for those can get you in trouble. Change them in "Player Setup/Player 1 Settings/Instant Chat Setup", and change the keybindings used in the player input configuration. If you are already in chat mode and hit one of the instant chat keys not associated with a printable character, like the F keys, the corresponding instant chat will be inserted where you type. If an instant chat string ends in a backslash "\", pressing the corresponding key will not send the string immediately, but will let you append to it first.

## Authentication

### The old way: ADMIN_PASS

This paragraph applies if your server was compiled without --enable-armathentication.

The server administrator can allow selected players to control the server settings through chat commands; the setting `ADMIN_PASS` has to be modified to a nondefault value. Whoever knows this value can log in by saying "/login <password>". After that, it's possible to issue regular console commands by saying "/admin <command>" or to log out again with "/logout".
WARNING: currently, chat messages and therefore the password are sent unencrypted. This means that everyone with physical access to the network flow, which is, among others, anyone on the server's or the player's LAN, can steal the password.

### The new way

This paragraph applies if your server was compiled with --enable-armathentication.

The new authentication code allows you to securely log into servers using various accounts; check out the Wiki FAQ for details. The quick and simple way to get an account you can use is if you sign up on the Forums; pick a simple username without fancy characters. Your Global ID (GID) associated with that account will then be "<your username>@forums". Enter that in the "Global ID" field of your "Player Setup" menu and activate "Auto Login". Every time you enter a server that supports authentication, you'll be prompted for your forum password.

If you administer a server with --enable-armathentication compiled in, you can grant yourself remote admin rights with the configuration line `USER_LEVEL <your GID> 0`. Replace the 0 with your desired access level: 0 gives full access, 1 admin access (a few things like QUIT are locked, then) and 2 is moderator access, blocking most setting changes and only leaving commands required to moderate a server.

### Kicking and Banning

You can kick players with the `KICK user` command; it accepts either the network user ID or the user name (currently the nickname, filtered so you can actually type it) of the player to kick; you can get a list of both with the command `PLAYERS`. You can ban them from the server with `BAN user` or `BAN user time`; the time duration is given in minutes and defaults to 60 minutes if not present. The `user` argument of `BAN` is interpreted exactly as with `KICK`.

You can get a list of currently banned IP addresses with `BAN_LIST`. To unban one of these, use `UNBAN_IP ip`. To ban an IP address explicitly, use `BAN_IP ip`. Bans are persistent when you shut down and restart the server; the data is stored in var/bans.txt.

#### Autobanning

When a user gets kicked often (by you or by kick votes), he will be banned automatically. It is measured how often a user gets kicked per hour (KPH); this value is not persistent across runs of the server. KPH can't get larger than `NETWORK_AUTOBAN_MAX_KPH`. When a user gets kicked, the duration of the automatic ban in minutes is determined as (KPH - `NETWORK_AUTOBAN_OFFSET`) * `NETWORK_AUTOBAN_FACTOR`; the user is not banned if this value is negative. You can disable automatic banning by setting `NETWORK_AUTOBAN_OFFSET` larger than `NETWORK_AUTOBAN_MAX_KPH`.

### Voting

Sometimes, votes on important topics will be cast by players. If a vote is pending, a menu will automatically pop up between rounds and remind you to vote. You can accept or reject a suggestion, or explicitly say you don't care about it.
For example, to start a kick vote, press ESC and enter the "Player Police/Kick Menu" menu and select the player you want kicked. Prepare to get kicked yourself if you abuse the system.

### Synchronization Settings

The two `CYCLE_SYNC_INTERVAL_` settings determine the interval at which sync commands are sent for cycles. `CYCLE_SYNC_INTERVAL_SELF` determines the time between syncs to the owner of a cycle itself, and `CYCLE_SYNC_INTERVAL_ENEMY` determines the interval for everyone else.

## Advanced Topics

New clients since 0.2.7.1 send the time of turn commands to the server. This makes it possible to avoid grinding lag sliding (you move towards a wall, grind it shortly and turn away again, and you'll slide) by letting the cycle on the server turn not before the time sent by the client. At the low speeds before the grind, the positional command interpretion is inaccurate and will usually turn the cycle too early. Now, old clients don't send the command time, so this code can't work. The lag sliding is a clear disadvantage, but the earlier turn is an advantage in some situations because it makes you cover more ground, so both the new and the old players have plenty of reason to complain if they are not treated equally. Therefore, when CYCLE_FAIR_ANTILAG is set to 1 and old clients are present, this code is deactivated.

When a cycle turns in free space, the server will try to follow the client's request by matching the turn position as closely as possible. Sometimes however there are large desyncs and clients sent silly turns halfway across the grid from their current position. So, for clients that send the command time, the server will execute turns only in a time window around that command time. The width of that window is determined by CYCLE_TIME_TOLERANCE.

I observed that old clients ( 0.2.7.0 and earlier ) would be more likely to pass through walls when they received a sync from the server shortly before. So, if you set CYCLE_AVOID_OLDCLIENT_BAD_SYNC to 1, the server will not send those syncs. Whether this helps or makes matters worse by not sending enough syncs is unknown, that's why it is a setting.

You are not limited to one player per computer; on each of them you can play with up to four people. In the precompiled version, there is a limit of 16 clients. You can set the configuration variable `MAX_CLIENTS` to limit it further. If you compile your Retrocycles server yourself, you can increase the limit if you configure it with

    CXXFLAGS="-DMAXCLIENTS=X" ./configure

where X is the number of clients you want to support.

If you are behind a masquerading firewall (such as a DSL router or the Microsoft connection sharing), you cannot act as a server; your computer is then unreachable from the outside unless you manage to forward port 4534 UDP connections from the firewall to your server. Most software solutions and some standalone DSL routers offer this option, so you may be lucky.

The client may be behind a firewall as long as it allows outgoing UDP connections on the Retrocycles port.

## The dedicated server

Following the model of Quake 1-3 and NOT Modern Warfare 2, there is a special binary version of the game available for download (or compile it yourself giving the option --disable-glout to configure) that has all input/output features disabled. If you start it, it will read the normal configuration files and set up a network game according to the settings in the game menu (Number of AI players, game mode and finish mode). A dedicated server takes input from the keyboard and interprets it just the way it does with the configuration files. Additionally to the usual configuration files, the dedicated server will read the file everytime.cfg from the var directory before each round; it may be comfortable to place quickly changing settings there. You can join the game on the dedicated server just the way described above.

The advantages of this solution are:

- there is no longer a "privileged" player; all players are clients to the dedicated server.
- the dedicated server can use it's full computing power just to manage the game; it does not have to bother about input or 3d rendering. So, the game is a bit smoother for all players.
- the dedicated server should run on any 32 Bit Windows and about any UNIX; it does not need any special library installed (OpenGL, SDL, ...) , so it is easy to set up public internet servers.
- The dedicated server uses less CPU power than a client because it does not have to care about graphics and sound. It can be run on an older PC.

### Controlling network input

Often, it is desireable to not only specify the port Retrocycles listens on, but also the IP address. Examples include LAN servers that run on a machine with connection to the internet or servers on a server farm where each host is shared between many users and has a multitude of IP addresses. For this purpose, the `SERVER_IP` setting has been introduced. Documentation with example usage is provided in settings_dedicated.cfg.

## Ping Charity

Ping charity can be configured along with your network bandwidth and other settings in the "Network Setup" submenu in the "Network Game" menu.

It is the configurable part of the "equal ping" technology. In short, if you have low ping and your opponent has high ping (ping: the time it takes a message to travel from your computer to the server and back, usually measured in milliseconds), you can take over some of his ping to make the situation more equal. So, if you have ping 60, your opponent has ping 160 and you set the ping charity to at least 50 (more does not change the situation), you will take over 50 ms of his ping, giving you both ping 110. If you set your ping charity to 20, you will end up with ping 80, your opponent with ping 140. Of course, you may be greedy and set ping charity to zero, but I suggest leaving it at the default value 100.

How does that "equal ping" thing work? It is not that complicated, but for now, I rather keep the secret buried in the source code (too lazy to explain it right now...).

## Spectator Mode

In the player menu, there is the "Spectator mode" toggle; If you just want to watch an internet game, connect to the server with spectator mode enabled, or enable it while already online and you will leave active play. You can also bind a key to toggling spectator mode in your player keyboard setup, that allows you to enter and leave quickly.

## Scores

In a multiplayer game, every crucial action makes you gain or lose points; after

- a fixed number of rounds has been played
- a fixed time elapsed or
- a fixed score is reached

the team with the most points wins the match. If two or more teams share the first place, the fight continues until there is a unique winner.
You can configure the score/time/rounds-limits in the file settings.cfg; scores and winners are logged in the file scorelog.txt on the server.

If you are the only person on a dedicated server, a special single player game is started (its parameters are determined in the SP_* variables in settings.txt on the server) to keep you busy until someone else connects; the highscores in this mode may be published by the server administrator.
The highest scores collected in a single player game are collected in the file highscores.txt, the people with the most won multiplayer rounds/matches are stored in won_rounds.txt and won_matches.txt. A ladder is stored in ladder.txt.
Note: these statistics have all not been adapted to team play and most of them will store very odd results.

## BIG BROTHER

As in any software downloaded for free, you can't be completely sure whether Retrocycles has secret functions that, for example, spy on your system internals, exploit known Windows bugs to get to your ISP's password, etc... and send this information to the author. Of course, Retrocycles does not do such a thing, and you can check that in the source code.
But Retrocycles DOES send some information out: If you connect to the master server for the first time, Retrocycles will send

- Your Operating system and Retrocycles/SDL version
- the information the OpenGL system offers, telling me which graphic card you use
- if you are running Retrocycles fullscreen or windowed

and nothing else, especially no personal information. I hope you understand that there is a good reason to collect this information. If you don't want to reveal these facts, simply edit your Retrocycles-0.2.9.3.0 configuration file user.cfg and change
`BIG_BROTHER 1`
to
`BIG_BROTHER 0`

## Internals

If you are interested in network programming yourself, you may want to read the network subsystem documentation.

This document was created by Manuel Moos

Last modification: 2026-04-17

First Start | Installation | Network Play | Configuration | FAQ | Redistribution