Lunar

What is Lunar?

Lunar is a library for developing multiplayer games with LibGDX. In it's current state its more appropriate for small scale multiplayer games or prototypes.

Headline features

• Ashley and Box2d support
• Fully customizable entity system
• Networked players and entities with interpolation
• A-lot of boilerplate written for you
• Expandable protocol

Beyond the headline features

• Support for texture/sprite entities
• Expandable networked worlds
• Multiple entity types for players, network players, etc
• A comprehensive server library
• • more

A quick peek inside

provided without any context of course, but you get the idea.

final MyPlayer player = ...;
world.spawnPlayerInWorld(player, 0.0f, 0.0f);

final PlayerConnectionHandler connection = clientServer.getConnection();
connection.registerPacket(MyCustomPacket.ID, MyCustomPacket::new, packet -> handleMyPacket(packet));

// override default behaviour
connection.registerHandlerSync(S2CPacketJoinWorld.PACKET_ID, packet -> world.handleWorldJoin((S2CPacketJoinWorld) packet));

// an example of a basic player with many customizable configuration options
public final class DemoPlayer extends LunarPlayer {

    public DemoPlayer(boolean initializeComponents, TextureRegion playerTexture) {
        super(initializeComponents);

        setMoveSpeed(6.0f);
        disablePlayerCollision(true);
        setNetworkSendRateInMs(10, 10);
        // default player texture
        addRegion("player", playerTexture);
        // default player configuration
        setSize(16, 16, (1 / 16.0f));
    }
}

// Create a networked world for others to join us.
// By default the world will handle physics, player updates and network updates!
world = new MultiplayerGameWorld(player, new World(Vector2.Zero, true), myGameInstance);
// add default world systems
world.addWorldSystems();
// ignore player collisions
world.addDefaultPlayerCollisionListener();
// Spawn our player in the world.
player.spawnEntityInWorld(world, mySpawnX, mySpawnY);

// connect to remote server.
final LunarClientServer server = new LunarClientServer(myProtocol, "localhost", 6969);
server.connect();

// get our connection
final PlayerConnection connection = (PlayerConnection) server.getConnection();
// join a remote server world
connection.joinWorld("MyWorld", player.getName());

// provide our own implementation for player connections
server.setConnectionProvider(channel -> new MyPlayerConnectionHandler(channel, protocol));

Documentation and Examples

The wiki includes most things you will need to get started. Not all methods are described, I encourage to explore the source of a few key components like AbstractLunarEntity and AbstractGameWorld as this is where most fundamentals reside.

Future Plans

things that should have been implemented forever ago

• Instances: basically just interiors and other things within a world you enter, like a dungeon for example.
• Encryption and better authentication
• And in general, expanding upon this library

Using Lunar

Lunar uses Java 21.

You can find releases in the releases section. Both client and server rely on the Protocol dependency.

A netty dependency is also required:

// or whatever version
implementation group: 'io.netty', name: 'netty-all', version: '4.1.100.Final'