✨ Usable multiplayer

Scripts/Logic/PlayerInput.cs

@@ -0,0 +1,33 @@
+using Godot;
+
+namespace CodingLand.Scripts.Logic;
+
+public partial class PlayerInput : MultiplayerSynchronizer
+{
+    [Export] public bool IsDashing;
+
+    [Export] public Vector2 MovementDirection;
+
+    public override void _Ready()
+    {
+        if (GetMultiplayerAuthority() != Multiplayer.GetUniqueId())
+        {
+            SetProcess(false);
+            SetPhysicsProcess(false);
+        }
+    }
+
+    [Rpc(CallLocal = true)]
+    private void Dash()
+    {
+        IsDashing = true;
+    }
+
+    public override void _Process(double delta)
+    {
+        MovementDirection = Input.GetVector("move_left", "move_right", "move_up", "move_down");
+
+        if (Input.IsActionJustPressed("move_dash"))
+            Rpc(nameof(Dash));
+    }
+}

Scripts/Logic/World.cs

@@ -0,0 +1,68 @@
+using System.Numerics;
+using Godot;
+using Vector2 = Godot.Vector2;
+
+namespace CodingLand.Scripts.Logic;
+
+public partial class World : Node2D
+{
+    [Export] public PackedScene PlayerScene;
+
+    public void StartGame()
+    {
+        if (!Multiplayer.IsServer())
+            return;
+
+        // Handling player connect / disconnect after this client connected
+        Multiplayer.PeerDisconnected += RemovePlayer_Adaptor;
+        Multiplayer.PeerConnected += AddPlayer_Adaptor;
+
+        // Handling player connected before this client
+        foreach (var id in Multiplayer.GetPeers())
+            AddPlayer(id);
+
+        // Add this client as a player if client isn't a dedicated server
+        if (!OS.HasFeature("dedicated_server"))
+            AddPlayer(1);
+    }
+
+    public override void _ExitTree()
+    {
+        if (!Multiplayer.IsServer())
+            return;
+
+        Multiplayer.PeerDisconnected -= RemovePlayer_Adaptor;
+        Multiplayer.PeerConnected -= AddPlayer_Adaptor;
+    }
+
+    private string BuildPlayerName(int id)
+    {
+        return $"Player#{id}";
+    }
+
+    private void AddPlayer_Adaptor(long id)
+        => AddPlayer((int)id);
+
+    private void RemovePlayer_Adaptor(long id)
+        => RemovePlayer((int)id);
+
+    private void AddPlayer(int id)
+    {
+        var player = PlayerScene.Instantiate<Player>();
+        player.SetPlayerId(id);
+        var position = Vector2.FromAngle(GD.Randf() * 2 * Mathf.Pi);
+        player.Position = new Vector2(position.X * 5f * GD.Randf(), position.Y * 5f * GD.Randf());
+        player.Name = BuildPlayerName(id);
+
+        AddChild(player, true);
+    }
+
+    private void RemovePlayer(int id)
+    {
+        var name = BuildPlayerName(id);
+        if (!HasNode(name))
+            return;
+
+        GetNode(name).QueueFree();
+    }
+}

Scripts/Multiplayer.cs

@@ -1,23 +1,22 @@
-using System;
+using CodingLand.Scripts.Logic;
 using Godot;
 
 namespace CodingLand.Scripts;
 
 public partial class Multiplayer : Node
 {
-	[Export] public Node2D Playground;
+	[Export] public World World;
 	
 	private void GameFreeze()
 	{
-		Playground.Hide();
 		GetTree().Paused = true;
+		World.Hide();
 	}
 
 	private void GameUnfreeze()
 	{
-		Playground.Show();
-		Playground.GetNode<Camera2D>("Camera2D").Enabled = true;
 		GetTree().Paused = false;
+		World.Show();
 	}
 	
 	public override void _Ready()
@@ -41,9 +40,12 @@ public partial class Multiplayer : Node
 			OS.Alert("Failed to start multiplayer server...");
 			return false;
 		}
+		
+		GD.Print("Running game as server...");
 
 		Multiplayer.MultiplayerPeer = peer;
 		GameUnfreeze();
+		World.StartGame();
 
 		return true;
 	}
@@ -62,8 +64,11 @@ public partial class Multiplayer : Node
 			return false;
 		}
 
+		GD.Print("Running game as client...");
+		
 		Multiplayer.MultiplayerPeer = peer;
 		GameUnfreeze();
+		World.StartGame();
 		
 		return true;
 	}

Scripts/Player.cs

@@ -1,39 +1,54 @@
-using System;
+using CodingLand.Scripts.Logic;
 using Godot;
 
 namespace CodingLand.Scripts;
 
 public partial class Player : CharacterBody2D
 {
+	private int _currentPlayerId = 1;
+	
 	[Export] public float MaxSpeed = 400f;
 	[Export] public float Acceleration = 500f;
 	[Export] public float Deceleration = 500f;
 	[Export] public float RotationSpeed = 5f;
 
-	[Export] public float CameraSmoothness = 0.05f;
-	
 	[Export] public Camera2D PlayerCamera;
-	
+
+	[Export] public PlayerInput PlayerInput;
+
 	[Export] public Timer PlayerDashCountdown;
 	[Export] public float PlayerDashAcceleration = 2f;
 
+	[Export] public int PlayerId
+	{
+		get => _currentPlayerId;
+		set
+		{
+			_currentPlayerId = value;
+			PlayerInput.SetMultiplayerAuthority(value);
+		}
+	}
+
+	public void SetPlayerId(int id)
+	{
+		PlayerId = id;
+		PlayerInput.SetMultiplayerAuthority(id);
+	}
+
+	public override void _Ready()
+	{
+		if (PlayerId == Multiplayer.GetUniqueId())
+			PlayerCamera.Enabled = true;
+	}
+
 	public override void _PhysicsProcess(double delta)
 	{
-		var input = Vector2.Zero;
+		var input = PlayerInput.MovementDirection;
 
-		if (Input.IsActionPressed("move_right"))
-			input.X += 1;
-		if (Input.IsActionPressed("move_left"))
-			input.X -= 1;
-		if (Input.IsActionPressed("move_down"))
-			input.Y += 1;
-		if (Input.IsActionPressed("move_up"))
-			input.Y -= 1;
-
-		input = input.Normalized();
 
 		if (input != Vector2.Zero)
 		{
+			input = input.Normalized();
 			Velocity = Velocity.MoveToward(input * MaxSpeed, Acceleration * (float)delta);
 
 			var finalRotation = input.Angle() + Mathf.Pi / 2;
@@ -44,18 +59,14 @@ public partial class Player : CharacterBody2D
 			Velocity = Velocity.MoveToward(Vector2.Zero, Deceleration * (float)delta);
 		}
 
-		if (Input.IsActionJustPressed("move_dash") && PlayerDashCountdown.IsStopped())
+		if (PlayerInput.IsDashing && PlayerDashCountdown.IsStopped())
 		{
+			PlayerInput.IsDashing = false;
 			Velocity *= PlayerDashAcceleration;
 			PlayerDashCountdown.Start();
 		}
-		
+
 		Position += Velocity * (float)delta;
 		MoveAndSlide();
-		
-		if (PlayerCamera != null)
-		{
-			PlayerCamera.Position = GlobalPosition;
-		}
 	}
 }

Scripts/UI/MultiplayerUi.cs

@@ -55,7 +55,7 @@ public partial class MultiplayerUi : Control
 			if (result)
 				Hide();
 		};
-		StartAsServerButton.Pressed += () =>
+		StartAsClientButton.Pressed += () =>
 		{
 			if (!DoValidation())
 			{