Add completely custom NetworkAPI

- No more Rpc or Rset calls!
- Custom packet handling and de/serialization
- Lots of useful SendTo* methods!
- Appearance change in multiplayer
  waits for confirmation from server

src/EscapeMenuAppearance.cs

@@ -45,8 +45,9 @@ public class EscapeMenuAppearance : CenterContainer
 
     private void _on_Appearance_visibility_changed()
     {
-        if (IsVisibleInTree()) return;
+        if (!IsVisibleInTree())
-        LocalPlayer.Instance.DisplayName = DisplayName.Text;
+            Player.ChangeAppearance(LocalPlayer.Instance,
-        LocalPlayer.Instance.Color       = ColorPreview.Modulate;
+                DisplayName.Text, ColorPreview.Modulate,
+                Network.IsClient);
     }
 }

src/EscapeMenuMultiplayer.cs

@@ -23,7 +23,7 @@ public class EscapeMenuMultiplayer : Container
         ClientDisConnect = GetNode<Button>(ClientDisConnectPath);
         ClientAddress    = GetNode<LineEdit>(ClientAddressPath);
 
-        Network.Instance.Connect(nameof(Network.StatusChanged), this, nameof(OnNetworkStatusChanged));
+        Network.StatusChanged += OnNetworkStatusChanged;
         ServerPort.PlaceholderText    = Network.DEFAULT_PORT.ToString();
         ClientAddress.PlaceholderText = $"localhost:{Network.DEFAULT_PORT}";
     }

src/Extensions.cs

@@ -12,43 +12,6 @@ public static class Extensions
         (instance as IInitializer)?.Initialize();
         return instance;
     }
-
-
-    public static void RsetProperty(this Node @this, Node propertyOwner, string property, string method, object value)
-    {
-        if (!@this.IsInsideTree()) return;
-        if (Network.IsServer) propertyOwner.RsetExcept(@this as Player, property, value);
-        else if (Network.IsMultiplayerReady) @this.RpcId(1, method, value);
-    }
-
-    public static void RsetPropertyUnreliable(this Node @this, Node propertyOwner, string property, string method, object value)
-    {
-        if (!@this.IsInsideTree()) return;
-        if (Network.IsServer) propertyOwner.RsetUnreliableExcept(@this as Player, property, value);
-        else if (Network.IsMultiplayerReady) @this.RpcUnreliableId(1, method, value);
-    }
-
-
-    public static void RpcExcept(this Node @this, Player except, string method, params object[] args)
-    {
-        foreach (var player in Network.Players)
-            if (player != except)
-                @this.RpcId(player.NetworkId, method, args);
-    }
-
-    public static void RsetExcept(this Node @this, Player except, string property, object value)
-    {
-        foreach (var player in Network.Players)
-            if (player != except)
-                @this.RsetId(player.NetworkId, property, value);
-    }
-
-    public static void RsetUnreliableExcept(this Node @this, Player except, string property, object value)
-    {
-        foreach (var player in Network.Players)
-            if (player != except)
-                @this.RsetUnreliableId(player.NetworkId, property, value);
-    }
 }
 
 public interface IInitializer

src/LocalPlayer.cs

@@ -48,10 +48,4 @@ public class LocalPlayer : Player
             _lastOnFloor = null;
         }
     }
-
-    internal void ResetPositionInternal(Vector2 position)
-        { Position = position; Velocity = Vector2.Zero; }
-    [Puppet]
-    internal void ResetPosition(Vector2 position)
-        => ResetPositionInternal(position);
 }

src/Network.cs

@@ -16,14 +16,24 @@ public class Network : Node
     public const ushort DEFAULT_PORT = 42005;
 
     public static Network Instance { get; private set; }
+    public static NetworkAPI API { get; private set; }
     public static NetworkStatus Status { get; private set; } = NetworkStatus.NoConnection;
 
     public static bool IsMultiplayerReady => (Status == NetworkStatus.ServerRunning) || (Status == NetworkStatus.ConnectedToServer);
     public static bool IsAuthoratative => Status <= NetworkStatus.ServerRunning;
     public static bool IsServer => Status == NetworkStatus.ServerRunning;
-    public static int LocalNetworkId => Instance.GetTree().GetNetworkUniqueId();
+    public static bool IsClient => Status > NetworkStatus.Connecting;
+    public static int LocalNetworkID => Instance.GetTree().GetNetworkUniqueId();
     public static IEnumerable<Player> Players => Instance._playersById.Values;
 
+    public static event Action<NetworkStatus> StatusChanged;
+
+    public static Player GetPlayer(int id)
+        => Instance._playersById.TryGetValue(id, out var value) ? value : null;
+    public static Player GetPlayerOrThrow(int id)
+        => GetPlayer(id) ?? throw new ArgumentException(
+            $"No player instance found for ID {id}", nameof(id));
+
 
     private readonly Dictionary<int, Player> _playersById = new Dictionary<int, Player>();
 
@@ -32,10 +42,11 @@ public class Network : Node
 
     public Node PlayerContainer { get; private set; }
 
-    [Signal] public delegate void StatusChanged(NetworkStatus status);
 
-
+    public Network()
-    public Network() => Instance = this;
+    {
+        Instance = this;
+    }
 
     public override void _Ready()
     {
@@ -47,27 +58,35 @@ public class Network : Node
 
         GetTree().Connect("network_peer_connected", this, nameof(OnPeerConnected));
         GetTree().Connect("network_peer_disconnected", this, nameof(OnPeerDisconnected));
+
+        var multiplayerApi = GetTree().Multiplayer;
+        API = new NetworkAPI(multiplayerApi);
+        multiplayerApi.Connect("network_peer_packet", this, nameof(OnPacketReceived));
+
+        API.RegisterC2SPacket<ClientAuthPacket>(OnClientAuthPacket);
+        API.RegisterS2CPacket<SpawnPlayerPacket>(OnSpawnPlayerPacket);
+        Player.RegisterPackets();
     }
 
+    // Let NetworkAPI handle receiving of custom packages.
+    private void OnPacketReceived(int id, byte[] bytes)
+        => API.OnPacketReceived(id, bytes);
 
-    public Player GetPlayer(int id)
-        => _playersById.TryGetValue(id, out var value) ? value : null;
 
     public void ClearPlayers()
     {
-        LocalPlayer.Instance.NetworkId = -1;
+        LocalPlayer.Instance.NetworkID = -1;
         foreach (var player in _playersById.Values)
             if (!player.IsLocal)
                 player.RemoveFromParent();
         _playersById.Clear();
     }
 
-
     private void ChangeStatus(NetworkStatus status)
     {
         if (Status == status) return;
         Status = status;
-        EmitSignal(nameof(StatusChanged), status);
+        StatusChanged?.Invoke(status);
 
         PlayerContainer.PauseMode = IsMultiplayerReady
             ? PauseModeEnum.Process : PauseModeEnum.Stop;
@@ -83,7 +102,7 @@ public class Network : Node
         if (error != Error.Ok) return error;
         GetTree().NetworkPeer = peer;
 
-        LocalPlayer.Instance.NetworkId = 1;
+        LocalPlayer.Instance.NetworkID = 1;
         _playersById.Add(1, LocalPlayer.Instance);
 
         ChangeStatus(NetworkStatus.ServerRunning);
@@ -101,6 +120,7 @@ public class Network : Node
         ChangeStatus(NetworkStatus.NoConnection);
     }
 
+
     public Error ConnectToServer(string address, ushort port)
     {
         if (GetTree().NetworkPeer != null) throw new InvalidOperationException();
@@ -114,6 +134,20 @@ public class Network : Node
         return Error.Ok;
     }
 
+    private void OnClientConnected()
+    {
+        ChangeStatus(NetworkStatus.Authenticating);
+
+        var id = GetTree().GetNetworkUniqueId();
+        LocalPlayer.Instance.NetworkID = id;
+        _playersById.Add(id, LocalPlayer.Instance);
+
+        API.SendToServer(new ClientAuthPacket {
+            DisplayName = LocalPlayer.Instance.DisplayName,
+            Color       = LocalPlayer.Instance.Color
+        });
+    }
+
     public void DisconnectFromServer()
     {
         if ((GetTree().NetworkPeer == null) || GetTree().IsNetworkServer()) throw new InvalidOperationException();
@@ -126,64 +160,61 @@ public class Network : Node
     }
 
 
-    private void OnClientConnected()
+    private Player SpawnOtherPlayer(int networkID, Vector2 position, string displayName, Color color)
     {
-        ChangeStatus(NetworkStatus.Authenticating);
+        var player = OtherPlayerScene.Init<Player>();
+        player.NetworkID   = networkID;
+        // TODO: We need to find a way to sync these property automatically.
+        player.Position    = position;
+        player.DisplayName = displayName;
+        player.Color       = color;
+        _playersById.Add(networkID, player);
+        PlayerContainer.AddChild(player);
+        return player;
+    }
 
-        var id = GetTree().GetNetworkUniqueId();
-        LocalPlayer.Instance.NetworkId = id;
-        _playersById.Add(id, LocalPlayer.Instance);
 
-        Rpc(nameof(OnClientAuthenticate), LocalPlayer.Instance.DisplayName, LocalPlayer.Instance.Color);
+    private class ClientAuthPacket
+    {
+        public string DisplayName { get; set; }
+        public Color Color { get; set; }
     }
-
+    private void OnClientAuthPacket(int networkID, ClientAuthPacket packet)
-    [Master]
-    private void OnClientAuthenticate(string displayName, Color color)
     {
-        var id = GetTree().GetRpcSenderId();
-
         // Authentication message is only sent once, so once the Player object exists, ignore this message.
-        if (GetPlayer(id) != null) return;
+        if (GetPlayer(networkID) != null) return;
-
-        var newPlayer = SpawnOtherPlayerInternal(id, Vector2.Zero, displayName, color);
-        RpcId(id, nameof(SpawnLocalPlayer), newPlayer.Position);
 
-        foreach (var player in _playersById.Values) {
+        foreach (var player in _playersById.Values)
-            if (player == newPlayer) continue;
+            API.SendTo(networkID, new SpawnPlayerPacket(player));
-
+        var newPlayer = SpawnOtherPlayer(networkID, Vector2.Zero, packet.DisplayName, packet.Color);
-            // Spawn existing players for the new player.
+        API.SendToEveryone(new SpawnPlayerPacket(newPlayer));
-            RpcId(id, nameof(SpawnOtherPlayer), player.NetworkId, player.Position, player.DisplayName, player.Color);
-
-            // Spawn new player for existing players.
-            if (!player.IsLocal) // Don't spawn the player for the host, it already called SpawnOtherPlayer itself.
-                RpcId(player.NetworkId, nameof(SpawnOtherPlayer), newPlayer.NetworkId, newPlayer.Position, newPlayer.DisplayName, newPlayer.Color);
-        }
     }
 
-    [Puppet]
-    private void SpawnLocalPlayer(Vector2 position)
-    {
-        LocalPlayer.Instance.Position = position;
-        LocalPlayer.Instance.Velocity = Vector2.Zero;
 
-        ChangeStatus(NetworkStatus.ConnectedToServer);
+    private class SpawnPlayerPacket
+    {
+        public int NetworkID { get; set; }
+        public Vector2 Position { get; set; }
+        public string DisplayName { get; set; }
+        public Color Color { get; set; }
+
+        public SpawnPlayerPacket(Player player)
+        {
+            NetworkID   = player.NetworkID;
+            Position    = player.Position;
+            DisplayName = player.DisplayName;
+            Color       = player.Color;
+        }
     }
-
+    private void OnSpawnPlayerPacket(SpawnPlayerPacket packet)
-    private Player SpawnOtherPlayerInternal(int id, Vector2 position, string displayName, Color color)
     {
-        var player = OtherPlayerScene.Init<Player>();
+        if (packet.NetworkID == LocalNetworkID) {
-        player.NetworkId = id;
+            var player = LocalPlayer.Instance;
-        // TODO: We need to find a way to sync these property automatically.
+            player.Position = packet.Position;
-        player.Position    = position;
+            player.Velocity = Vector2.Zero;
-        player.DisplayName = displayName;
+            ChangeStatus(NetworkStatus.ConnectedToServer);
-        player.Color       = color;
+        } else SpawnOtherPlayer(packet.NetworkID, packet.Position, packet.DisplayName, packet.Color);
-        _playersById.Add(id, player);
-        PlayerContainer.AddChild(player);
-        return player;
     }
-    [Puppet]
-    private void SpawnOtherPlayer(int id, Vector2 position, string displayName, Color color)
-        => SpawnOtherPlayerInternal(id, position, displayName, color);
 
 
     private void OnPeerConnected(int id)

src/NetworkAPI.cs

@@ -0,0 +1,273 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using System.Runtime.Serialization;
+using Godot;
+
+[Flags]
+public enum PacketDirection
+{
+    ServerToClient = 0b01,
+    ClientToServer = 0b10,
+    Both = ServerToClient | ClientToServer,
+}
+
+public enum TransferMode
+{
+    Unreliable        = NetworkedMultiplayerPeer.TransferModeEnum.Unreliable,
+    UnreliableOrdered = NetworkedMultiplayerPeer.TransferModeEnum.UnreliableOrdered,
+    Reliable          = NetworkedMultiplayerPeer.TransferModeEnum.Reliable,
+}
+
+// TODO: Improve performance and type safety of de/serialization.
+// TODO: Support easily spawning and syncronizing objects and their properties.
+public class NetworkAPI
+{
+    private readonly MultiplayerAPI _multiplayerAPI;
+    private readonly List<PacketInfo> _packetsById = new List<PacketInfo>();
+    private readonly Dictionary<Type, PacketInfo> _packetsByType = new Dictionary<Type, PacketInfo>();
+    private readonly Dictionary<Type, INetworkDeSerializer> _deSerializers = new Dictionary<Type, INetworkDeSerializer>();
+    // private readonly List<INetworkDeSerializerMulti> _multiDeSerializers = new List<INetworkDeSerializerMulti>();
+
+    private class PacketInfo
+    {
+        public int ID { get; }
+        public Type Type { get; }
+        public PacketDirection Direction { get; }
+        public TransferMode DefaultTransformMode { get; }
+        public INetworkDeSerializer DeSerializer { get; }
+        public Action<int, object> OnPacketReceived { get; }
+
+        public PacketInfo(int id, Type type, PacketDirection direction,
+            TransferMode defaultTransferMode, INetworkDeSerializer deSerializer,
+            Action<int, object> onPacketReceived)
+        {
+            ID = id;
+            Type = type;
+            Direction = direction;
+            DefaultTransformMode = defaultTransferMode;
+            DeSerializer = deSerializer;
+            OnPacketReceived = onPacketReceived;
+        }
+    }
+
+    public NetworkAPI(MultiplayerAPI multiplayerAPI)
+    {
+        _multiplayerAPI = multiplayerAPI;
+
+        RegisterDeSerializer((writer, value) => writer.Write(value), reader => reader.ReadBoolean());
+        RegisterDeSerializer((writer, value) => writer.Write(value), reader => reader.ReadByte());
+        RegisterDeSerializer((writer, value) => writer.Write(value), reader => reader.ReadSByte());
+        RegisterDeSerializer((writer, value) => writer.Write(value), reader => reader.ReadInt16());
+        RegisterDeSerializer((writer, value) => writer.Write(value), reader => reader.ReadUInt16());
+        RegisterDeSerializer((writer, value) => writer.Write(value), reader => reader.ReadInt32());
+        RegisterDeSerializer((writer, value) => writer.Write(value), reader => reader.ReadUInt32());
+        RegisterDeSerializer((writer, value) => writer.Write(value), reader => reader.ReadInt64());
+        RegisterDeSerializer((writer, value) => writer.Write(value), reader => reader.ReadUInt64());
+        RegisterDeSerializer((writer, value) => writer.Write(value), reader => reader.ReadSingle());
+        RegisterDeSerializer((writer, value) => writer.Write(value), reader => reader.ReadDouble());
+        RegisterDeSerializer((writer, value) => writer.Write(value), reader => reader.ReadString());
+
+        // byte[]
+        RegisterDeSerializer((writer, value) => { writer.Write(value.Length); writer.Write(value); },
+                             reader => reader.ReadBytes(reader.ReadInt32()));
+        // Vector2
+        RegisterDeSerializer((writer, value) => { writer.Write(value.x); writer.Write(value.y); },
+                             reader => new Vector2(reader.ReadSingle(), reader.ReadSingle()));
+        // Color
+        RegisterDeSerializer((writer, value) => writer.Write(value.ToRgba32()),
+                             reader => new Color(reader.ReadInt32()));
+
+        // TODO: Add handling for Array, List and Dictionary.
+    }
+
+    public void RegisterDeSerializer<T>(Action<BinaryWriter, T> serialize, Func<BinaryReader, T> deserialize)
+        => _deSerializers.Add(typeof(T), new SimpleNetworkDeSerializer<T>(serialize, deserialize));
+    public void RegisterDeSerializer<T>(INetworkDeSerializer deSerializer)
+        => _deSerializers.Add(typeof(T), deSerializer);
+    // public void RegisterDeSerializer(INetworkDeSerializerMulti deSerializer)
+    //     => _multiDeSerializers.Add(deSerializer);
+
+    public void RegisterS2CPacket<T>(Action<T> action, TransferMode defaultTransferMode = TransferMode.Reliable)
+        => RegisterPacket((int _id, T packet) => action(packet), defaultTransferMode, PacketDirection.ServerToClient);
+
+    public void RegisterC2SPacket<T>(Action<int, T> action, TransferMode defaultTransferMode = TransferMode.Reliable)
+        => RegisterPacket(action, defaultTransferMode, PacketDirection.ClientToServer);
+    public void RegisterC2SPacket<T>(Action<Player, T> action, TransferMode defaultTransferMode = TransferMode.Reliable)
+        => RegisterPacket(action, defaultTransferMode, PacketDirection.ClientToServer);
+
+    public void RegisterPacket<T>(Action<Player, T> action,
+                                  TransferMode defaultTransferMode = TransferMode.Reliable,
+                                  PacketDirection direction = PacketDirection.Both)
+        => RegisterPacket((int id, T packet) => action(Network.GetPlayerOrThrow(id), packet), defaultTransferMode, direction);
+    public void RegisterPacket<T>(Action<int, T> action,
+        TransferMode defaultTransferMode = TransferMode.Reliable,
+        PacketDirection direction = PacketDirection.Both)
+    {
+        var deSerializer = GetDeSerializer(typeof(T), true);
+        var info = new PacketInfo(_packetsById.Count, typeof(T),
+            direction, defaultTransferMode, deSerializer,
+            (id, packet) => action(id, (T)packet));
+        _packetsByType.Add(typeof(T), info);
+        _packetsById.Add(info);
+    }
+
+    public void SendToServer<T>(T packet, TransferMode? transferMode = null)
+        => SendTo(1, packet, transferMode);
+
+    public void SendTo<T>(Player player, T packet, TransferMode? transferMode = null)
+        => SendTo(player.NetworkID, packet, transferMode);
+    public void SendTo<T>(int id, T packet, TransferMode? transferMode = null)
+        => SendTo(new []{ id }, packet, transferMode);
+
+    public void SendToEveryone<T>(T packet, TransferMode? transferMode = null)
+        => SendTo(_multiplayerAPI.GetNetworkConnectedPeers(), packet, transferMode);
+    public void SendToEveryoneExcept<T>(Player except, T packet, TransferMode? transferMode = null)
+        => SendToEveryoneExcept(except?.NetworkID ?? 0, packet, transferMode);
+    public void SendToEveryoneExcept<T>(int except, T packet, TransferMode? transferMode = null)
+        => SendTo(_multiplayerAPI.GetNetworkConnectedPeers().Where(id => id != except), packet, transferMode);
+
+    public void SendTo<T>(IEnumerable<Player> players, T packet, TransferMode? transferMode = null)
+        => SendTo(players.Select(p => p.NetworkID), packet, transferMode);
+    public void SendTo<T>(IEnumerable<int> ids, T packet, TransferMode? transferMode = null)
+    {
+        var info = GetPacketInfoAndVerifyDirection<T>();
+        var mode = ToPeerTransferMode(info, transferMode);
+        byte[] bytes = null;
+        foreach (var id in ids) {
+            // Only serialize the packet if sending to at least 1 player.
+            bytes = bytes ?? PacketToBytes(info, packet);
+            _multiplayerAPI.SendBytes(bytes, id, mode);
+        }
+    }
+
+    private PacketInfo GetPacketInfoAndVerifyDirection<T>()
+    {
+        if (!_packetsByType.TryGetValue(typeof(T), out var info))
+            throw new InvalidOperationException($"No packet of type {typeof(T)} has been registered");
+
+        var direction = Network.IsServer ? PacketDirection.ServerToClient : PacketDirection.ClientToServer;
+        if ((direction & info.Direction) == 0) throw new InvalidOperationException(
+            $"Attempting to send packet {typeof(T)} in invalid direction {direction}");
+
+        return info;
+    }
+    private byte[] PacketToBytes(PacketInfo info, object packet)
+    {
+        using (var stream = new MemoryStream()) {
+            using (var writer = new BinaryWriter(stream)) {
+                writer.Write((ushort)info.ID);
+                info.DeSerializer.Serialize(writer, packet);
+            }
+            return stream.ToArray();
+        }
+    }
+    private NetworkedMultiplayerPeer.TransferModeEnum ToPeerTransferMode(PacketInfo info, TransferMode? transferMode)
+        => (NetworkedMultiplayerPeer.TransferModeEnum)(transferMode ?? info.DefaultTransformMode);
+
+
+    internal void OnPacketReceived(int id, byte[] bytes)
+    {
+        if (!Network.IsServer && (id != 1))
+            throw new Exception($"Received packet from other player (ID {id})");
+
+
+        using (var stream = new MemoryStream(bytes)) {
+            using (var reader = new BinaryReader(stream)) {
+                var packetId = reader.ReadUInt16();
+                if (packetId >= _packetsById.Count) throw new Exception(
+                    $"Received packet with invalid ID {packetId}");
+                var info = _packetsById[packetId];
+
+                var direction = Network.IsServer ? PacketDirection.ClientToServer : PacketDirection.ServerToClient;
+                if ((direction & info.Direction) == 0) throw new Exception(
+                    $"Received packet {info.Type} on invalid side {(_multiplayerAPI.IsNetworkServer() ? "server" : "client")}");
+
+                var packet = info.DeSerializer.Deserialize(reader);
+                var playerID = Network.IsServer ? id : Network.LocalNetworkID;
+                info.OnPacketReceived(id, packet);
+            }
+        }
+    }
+
+
+    private INetworkDeSerializer GetDeSerializer(Type type, bool createIfMissing)
+    {
+        if (!_deSerializers.TryGetValue(type, out var value)) {
+            if (!createIfMissing) throw new InvalidOperationException(
+                $"No DeSerializer for type {type} found");
+
+            value = new ComplexNetworkDeSerializer(type);
+            _deSerializers.Add(type, value);
+        }
+        return value;
+    }
+
+    private class SimpleNetworkDeSerializer<T>
+        : INetworkDeSerializer
+    {
+        private readonly Action<BinaryWriter, T> _serialize;
+        private readonly Func<BinaryReader, T> _deserialize;
+        public SimpleNetworkDeSerializer(Action<BinaryWriter, T> serialize, Func<BinaryReader, T> deserialize)
+            { _serialize = serialize; _deserialize = deserialize; }
+        public void Serialize(BinaryWriter writer, object value) => _serialize(writer, (T)value);
+        public object Deserialize(BinaryReader reader) => _deserialize(reader);
+    }
+
+    // private class ArrayNetworkDeSerializer
+    //     : INetworkDeSerializerMulti
+    // {
+    //     public bool Handles(Type type) => type.IsArray;
+
+    //     public void Serialize(BinaryWriter writer, object value)
+    //     {
+    //         var array = (Array)value;
+    //         writer.Write(array.Length);
+    //         var deSerializer = Network.API.GetOrCreateDeserializer(array.GetType().GetElementType());
+    //         foreach (var element in array) deSerializer.Serialize(writer, element);
+    //     }
+
+    //     public object Deserialize(BinaryReader reader)
+    //     {
+    // TODO: This doesn't work. We need the type to initialize the array.
+    //       We may want to generate a new INetworkDeSerializer for each array type..?
+    //     }
+    // }
+
+    private class ComplexNetworkDeSerializer
+        : INetworkDeSerializer
+    {
+        private readonly Type _type;
+        private event Action<BinaryWriter, object> OnSerialize;
+        private event Action<BinaryReader, object> OnDeserialize;
+
+        public ComplexNetworkDeSerializer(Type type)
+        {
+            _type = type;
+            foreach (var field in type.GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)) {
+                var deSerializer = Network.API.GetDeSerializer(field.FieldType, false);
+                OnSerialize += (writer, value) => deSerializer.Serialize(writer, field.GetValue(value));
+                OnDeserialize += (reader, instance) => field.SetValue(instance, deSerializer.Deserialize(reader));
+            }
+            if (OnSerialize == null) throw new InvalidOperationException(
+                $"Unable to create serializer for type {type}");
+        }
+
+        public void Serialize(BinaryWriter writer, object value)
+            => OnSerialize(writer, value);
+        public object Deserialize(BinaryReader reader)
+        {
+            var instance = FormatterServices.GetUninitializedObject(_type);
+            OnDeserialize(reader, instance);
+            return instance;
+        }
+    }
+}
+
+public interface INetworkDeSerializer
+{
+    void Serialize(BinaryWriter writer, object value);
+    object Deserialize(BinaryReader reader);
+}

src/Player.cs

@@ -7,33 +7,23 @@ public class Player : KinematicBody2D, IInitializer
 
     public Label DisplayNameLabel { get; private set; }
     public Sprite Sprite { get; private set; }
-    public Network Network { get; private set; }
 
     public bool IsLocal => this is LocalPlayer;
 
     private int _networkId = -1;
-    public int NetworkId {
+    public int NetworkID {
         get => _networkId;
-        set {
+        set { Name = ((_networkId = value) > 0) ? value.ToString() : "LocalPlayer"; }
-            _networkId = value;
-            Name = (_networkId > 0) ? value.ToString() : "LocalPlayer";
-        }
     }
 
     public Color Color {
         get => Sprite.Modulate;
-        set {
+        set { Sprite.Modulate = value; }
-            Sprite.Modulate = value;
-            this.RsetProperty(Sprite, "modulate", nameof(OnColorChanged), value);
-        }
     }
 
     public string DisplayName {
         get => DisplayNameLabel.Text;
-        set {
+        set { DisplayNameLabel.Text = value; }
-            DisplayNameLabel.Text = value;
-            this.RsetProperty(DisplayNameLabel, "text", nameof(OnDisplayNameChanged), value);
-        }
     }
 
 
@@ -46,33 +36,92 @@ public class Player : KinematicBody2D, IInitializer
     public override void _Ready()
     {
         Initialize();
-        Network = GetNode<Network>("/root/Game/Network");
-
-        RsetConfig("position", MultiplayerAPI.RPCMode.Puppetsync);
-        Sprite.RsetConfig("modulate", MultiplayerAPI.RPCMode.Puppetsync);
-        DisplayNameLabel.RsetConfig("text", MultiplayerAPI.RPCMode.Puppetsync);
     }
 
     public override void _Process(float delta)
     {
-        this.RsetPropertyUnreliable(this, "position", nameof(OnPositionChanged), Position);
+        if (Network.IsMultiplayerReady) {
+            if (Network.IsServer) Network.API.SendToEveryoneExcept(this, new PositionChangedPacket(this));
+            else if (IsLocal) Network.API.SendToServer(new MovePacket(Position));
+        }
 
         if (Network.IsAuthoratative && (Position.y > 9000)) {
-            if (this is LocalPlayer localPlayer) localPlayer.ResetPositionInternal(Vector2.Zero);
+            if (this is LocalPlayer localPlayer) {
-            else RpcId(NetworkId, nameof(LocalPlayer.ResetPosition), Vector2.Zero);
+                localPlayer.Position = Vector2.Zero;
+                localPlayer.Velocity = Vector2.Zero;
+            } else Network.API.SendTo(this, new PositionChangedPacket(this));
         }
     }
 
 
-    [Master]
+    public static void RegisterPackets()
-    private void OnPositionChanged(Vector2 value)
+    {
-        { if (GetTree().GetRpcSenderId() == NetworkId) Position = value.Floor(); }
+        Network.API.RegisterS2CPacket<PositionChangedPacket>(packet => {
+            var player = Network.GetPlayerOrThrow(packet.ID);
+            player.Position = packet.Position;
+            if (player is LocalPlayer localPlayer)
+                localPlayer.Velocity = Vector2.Zero;
+        }, TransferMode.UnreliableOrdered);
+
+        Network.API.RegisterS2CPacket<ColorChangedPacket>(packet =>
+            Network.GetPlayerOrThrow(packet.ID).Color = packet.Color);
+        Network.API.RegisterS2CPacket<DisplayNameChangedPacket>(packet =>
+            Network.GetPlayerOrThrow(packet.ID).DisplayName = packet.DisplayName);
+
+        Network.API.RegisterC2SPacket<MovePacket>((player, packet) => {
+            // TODO: Somewhat verify the movement of players.
+            player.Position = packet.Position;
+        }, TransferMode.UnreliableOrdered);
+
+        Network.API.RegisterC2SPacket<ChangeAppearancePacket>((player, packet) =>
+            ChangeAppearance(player, packet.DisplayName, packet.Color, false));
+    }
+
+    public static void ChangeAppearance(Player player,
+        string displayName, Color color, bool sendPacket)
+    {
+        if (!sendPacket) {
+            player.DisplayName = displayName;
+            player.Color       = color;
+            if (Network.IsServer) {
+                Network.API.SendToEveryone(new DisplayNameChangedPacket(player));
+                Network.API.SendToEveryone(new ColorChangedPacket(player));
+            }
+        } else Network.API.SendToServer(new ChangeAppearancePacket(displayName, color));
+    }
 
-    [Master]
+    private class PositionChangedPacket
-    private void OnColorChanged(Color value)
+    {
-        { if (GetTree().GetRpcSenderId() == NetworkId) Color = value; }
+        public int ID { get; set; }
+        public Vector2 Position { get; set; }
+        public PositionChangedPacket(Player player)
+            { ID = player.NetworkID; Position = player.Position; }
+    }
+    private class DisplayNameChangedPacket
+    {
+        public int ID { get; set; }
+        public string DisplayName { get; set; }
+        public DisplayNameChangedPacket(Player player)
+            { ID = player.NetworkID; DisplayName = player.DisplayName; }
+    }
+    private class ColorChangedPacket
+    {
+        public int ID { get; set; }
+        public Color Color { get; set; }
+        public ColorChangedPacket(Player player)
+            { ID = player.NetworkID; Color = player.Color; }
+    }
 
-    [Master]
+    private class MovePacket
-    private void OnDisplayNameChanged(string value)
+    {
-        { if (GetTree().GetRpcSenderId() == NetworkId) DisplayName = value; }
+        public Vector2 Position { get; set; }
+        public MovePacket(Vector2 position) => Position = position;
+    }
+    private class ChangeAppearancePacket
+    {
+        public string DisplayName { get; set; }
+        public Color Color { get; set; }
+        public ChangeAppearancePacket(string displayName, Color color)
+            { DisplayName = displayName; Color = color; }
+    }
 }