Reintroduce saving / loading

src/EscapeMenuMultiplayer.cs

@@ -141,7 +141,8 @@ public class EscapeMenuMultiplayer : Container
             IntegratedServer = null;
 
             client.Disconnect();
-            this.GetWorld().Clear();
+            this.GetWorld().ClearPlayers();
+            this.GetWorld().ClearBlocks();
         }
 
         if (client.Status == ConnectionStatus.Disconnected) {
@@ -155,8 +156,8 @@ public class EscapeMenuMultiplayer : Container
             }
             client.Connect(address, port);
         } else {
-            client.Disconnect();
-            this.GetWorld().Clear();
+            this.GetWorld().ClearPlayers();
+            this.GetWorld().ClearBlocks();
         }
     }
 }

src/EscapeMenuWorld.cs

@@ -1,10 +1,6 @@
 using System;
 using System.Text;
 using Godot;
-using Path = System.IO.Path;
-using File = System.IO.File;
-using Directory = System.IO.Directory;
-using System.Linq;
 using static Godot.NetworkedMultiplayerPeer;
 
 public class EscapeMenuWorld : CenterContainer
@@ -43,10 +39,9 @@ public class EscapeMenuWorld : CenterContainer
         SaveAsButton.Text = "Save World As...";
         SaveFileDialog.GetOk().Text = "Save";
 
-        var worldsFolder = OS.GetUserDataDir() + "/worlds/";
-        Directory.CreateDirectory(worldsFolder);
-        SaveFileDialog.CurrentPath = worldsFolder;
-        LoadFileDialog.CurrentPath = worldsFolder;
+        new Directory().MakeDirRecursive(WorldSave.WORLDS_DIR);
+        SaveFileDialog.CurrentPath = WorldSave.WORLDS_DIR;
+        LoadFileDialog.CurrentPath = WorldSave.WORLDS_DIR;
 
         this.GetClient().StatusChanged += OnStatusChanged;
     }
@@ -85,17 +80,16 @@ public class EscapeMenuWorld : CenterContainer
 
     private void _on_SaveFileDialog_file_selected(string path)
     {
-        // var server = this.GetClient().GetNode<IntegratedServer>(nameof(IntegratedServer)).Server;
-        // var save   = Save.CreateFromWorld(server, _playtime);
-        // save.WriteToFile(path + ".tmp");
-        // File.Delete(path); // TODO: In later .NET, there is a File.Move(source, dest, overwrite).
-        // File.Move(path + ".tmp", path);
-
-        // _currentWorld = path;
-        // FilenameLabel.Text = Path.GetFileName(path);
-        // LastSavedLabel.Text = save.LastSaved.ToString("yyyy-MM-dd HH:mm");
-        // QuickSaveButton.Visible = true;
-        // SaveAsButton.Text = "Save As...";
+        var server = this.GetClient().GetNode<IntegratedServer>(nameof(IntegratedServer)).Server;
+        var save   = new WorldSave { Playtime = _playtime };
+        save.WriteDataFromWorld(server.GetWorld());
+        save.WriteToFile(path);
+
+        _currentWorld = path;
+        FilenameLabel.Text  = System.IO.Path.GetFileName(path);
+        LastSavedLabel.Text = save.LastSaved.ToString("yyyy-MM-dd HH:mm");
+        QuickSaveButton.Visible = true;
+        SaveAsButton.Text = "Save As...";
     }
 
     private void _on_LoadFrom_pressed()
@@ -106,25 +100,20 @@ public class EscapeMenuWorld : CenterContainer
 
     private void _on_LoadFileDialog_file_selected(string path)
     {
-        // var server = this.GetClient().GetNode<IntegratedServer>(nameof(IntegratedServer)).Server;
-        // var save   = Save.ReadFromFile(path);
-
-        // // Clear out all objects that have a SaveAttribute.
-        // var objectsToRemove = server.Objects.Select(x => x.Item2)
-        //     .Where(x => SaveRegistry.GetOrNull(x.GetType()) != null).ToArray();
-        // foreach (var obj in objectsToRemove) obj.RemoveFromParent();
-
-        // // Reset players' positions.
-        // foreach (var (id, player) in server.Players)
-        //     player.RPC(new []{ id }, player.ResetPosition, Vector2.Zero);
-
-        // save.AddToWorld(server);
-        // _playtime = save.Playtime;
-
-        // _currentWorld = path;
-        // FilenameLabel.Text = Path.GetFileName(path);
-        // LastSavedLabel.Text = save.LastSaved.ToString("yyyy-MM-dd HH:mm");
-        // QuickSaveButton.Visible = true;
-        // SaveAsButton.Text = "Save As...";
+        var server = this.GetClient().GetNode<IntegratedServer>(nameof(IntegratedServer)).Server;
+        var save   = WorldSave.ReadFromFile(path);
+
+        // Reset players' positions.
+        foreach (var player in server.GetWorld().Players)
+            player.RpcId(player.NetworkID, nameof(LocalPlayer.ResetPosition), Vector2.Zero);
+
+        save.ReadDataIntoWorld(server.GetWorld());
+        _playtime = save.Playtime;
+
+        _currentWorld = path;
+        FilenameLabel.Text  = System.IO.Path.GetFileName(path);
+        LastSavedLabel.Text = save.LastSaved.ToString("yyyy-MM-dd HH:mm");
+        QuickSaveButton.Visible = true;
+        SaveAsButton.Text = "Save As...";
     }
 }

src/Network/WorldSave.cs

@@ -0,0 +1,82 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Collections.Generic;
+using Godot;
+using File = System.IO.File;
+
+public class WorldSave
+{
+    public const string FILE_EXT    = ".yf5";
+    public const int MAGIC_NUMBER   = 0x59463573; // "YF5s"
+    public const int LATEST_VERSION = 0;
+
+    public static readonly string WORLDS_DIR = OS.GetUserDataDir() + "/worlds/";
+
+
+    public DateTime LastSaved { get; private set; }
+    public int Version { get; private set; } = LATEST_VERSION;
+    public TimeSpan Playtime { get; set; } = TimeSpan.Zero;
+
+    public List<(BlockPos, Color, bool)> Blocks { get; private set; }
+
+
+    public static WorldSave ReadFromFile(string path)
+    {
+        var save = new WorldSave { LastSaved = File.GetLastAccessTime(path) };
+        using (var stream = File.OpenRead(path)) {
+            using (var reader = new BinaryReader(stream)) {
+                var magic = reader.ReadInt32();
+                if (magic != MAGIC_NUMBER) throw new IOException(
+                    $"Magic number does not match ({magic:X8} != {MAGIC_NUMBER:X8})");
+
+                // TODO: See how to support multiple versions.
+                save.Version = reader.ReadUInt16();
+                if (save.Version != LATEST_VERSION) throw new IOException(
+                    $"Version does not match ({save.Version} != {LATEST_VERSION})");
+
+                save.Playtime = TimeSpan.FromSeconds(reader.ReadUInt32());
+
+                var numBlocks = reader.ReadInt32();
+                save.Blocks   = new List<(BlockPos, Color, bool)>();
+                for (var i = 0; i < numBlocks; i++)
+                    save.Blocks.Add((new BlockPos(reader.ReadInt32(), reader.ReadInt32()),
+                                     new Color(reader.ReadInt32()),
+                                     reader.ReadBoolean()));
+            }
+        }
+        return save;
+    }
+
+    public void WriteToFile(string path)
+    {
+        using (var stream = File.OpenWrite(path + ".tmp")) {
+            using (var writer = new BinaryWriter(stream)) {
+                writer.Write(MAGIC_NUMBER);
+                writer.Write((ushort)LATEST_VERSION);
+                writer.Write((uint)Playtime.TotalSeconds);
+
+                writer.Write(Blocks.Count);
+                foreach (var (position, color, unbreakable) in Blocks) {
+                    writer.Write(position.X);
+                    writer.Write(position.Y);
+                    writer.Write(color.ToRgba32());
+                    writer.Write(unbreakable);
+                }
+            }
+        }
+        new Godot.Directory().Rename(path + ".tmp", path);
+        LastSaved = File.GetLastWriteTime(path);
+    }
+
+
+    public void WriteDataFromWorld(World world)
+        => Blocks = world.Blocks.Select(block => (block.Position, block.Color, block.Unbreakable)).ToList();
+
+    public void ReadDataIntoWorld(World world)
+    {
+        world.Rpc(nameof(World.ClearBlocks));
+        foreach (var (position, color, unbreakable) in Blocks)
+            world.Rpc(nameof(World.SpawnBlock), position.X, position.Y, color, unbreakable);
+    }
+}

src/Utility/Extensions.cs

@@ -18,6 +18,12 @@ public static class Extensions
         => node.GetGame() as Server;
     public static World GetWorld(this Node node)
         => node.GetGame().GetNode<World>("World");
+
+    public static void RemoveFromParent(this Node node)
+    {
+        node.GetParent().RemoveChild(node);
+        node.QueueFree();
+    }
 }
 
 public interface IInitializable

src/World.cs

@@ -28,22 +28,15 @@ public class World : Node
         => PlayerContainer.GetChildren().Cast<Player>();
     public Player GetPlayer(int networkID)
         => PlayerContainer.GetNode<Player>(networkID.ToString());
+    public void ClearPlayers()
+        { foreach (var player in Players) player.RemoveFromParent(); }
 
+    public IEnumerable<Block> Blocks
+        => BlockContainer.GetChildren().Cast<Block>();
     public Block GetBlockAt(BlockPos position)
         => BlockContainer.GetNodeOrNull<Block>(position.ToString());
-
-
-    public void Clear()
-    {
-        foreach (var player in Players) {
-            BlockContainer.RemoveChild(player);
-            player.QueueFree();
-        }
-        foreach (var node in BlockContainer.GetChildren().Cast<Node>()) {
-            BlockContainer.RemoveChild(node);
-            node.QueueFree();
-        }
-    }
+    [PuppetSync] public void ClearBlocks()
+        { foreach (var block in Blocks) block.RemoveFromParent(); }
 
 
     [PuppetSync]