add initial random seed configuration

Author: lucasteles

.nuke/build.schema.json

@@ -36,6 +36,7 @@
         "GenerateBadges",
         "GenerateReport",
         "Lint",
+        "PreCommit",
         "Report",
         "Restore",
         "Test",

_build/Build.cs

@@ -79,6 +79,11 @@ IReadOnlyCollection<Output> BuildProj(AbsolutePath project, Configuration config
             .EnableNoRestore()
             .SetProject(Solution)));
 
+    Target PreCommit => _ => _
+        .Description("Run Format and Tests")
+        .DependsOn(Format)
+        .Triggers(Test);
+
     Target Test => _ => _
         .Description("Run tests with coverage")
         .DependsOn(Build)

samples/ConsoleGame/Game.cs

@@ -19,14 +19,16 @@ public sealed class Game : INetcodeSessionHandler
     readonly View view;
 
     // Actual game state
-    GameState currentState = GameLogic.InitialState();
+    GameState currentState;
 
     public Game(INetcodeSession<GameInput> session, CancellationTokenSource cancellation)
     {
         view = new();
         this.session = session;
         this.cancellation = cancellation;
 
+        currentState = GameLogic.InitialState();
+
         if (session.IsRemote())
         {
             if (!session.TryGetLocalPlayer(out var localPlayer))

samples/ConsoleGame/Program.cs

@@ -50,6 +50,7 @@ static INetcodeSession<GameInput> CreateNetcodeSession(Args args)
         .WithPlayerCount(args.PlayerCount)
         .WithPort(port)
         .WithInputDelayFrames(2)
+        .WithInitialRandomSeed(42)
         .WithLogLevel(LogLevel.Information)
         .UsePlugin<PluginSample>()
         .WithPackageStats()

src/Backdash/Core/RandomNumberGenerator.cs

@@ -4,23 +4,14 @@ namespace Backdash.Core;
 
 interface IRandomNumberGenerator
 {
-    uint SyncNumber();
-    ushort MagicNumber();
+    ushort SyncNumber();
     int NextInt();
     double NextGaussian();
 }
 
 sealed class DefaultRandomNumberGenerator(Random random) : IRandomNumberGenerator
 {
-    public uint SyncNumber()
-    {
-        using var gen = RandomNumberGenerator.Create();
-        Span<byte> buff = stackalloc byte[sizeof(uint)];
-        gen.GetBytes(buff);
-        return BitConverter.ToUInt32(buff);
-    }
-
-    public ushort MagicNumber()
+    public ushort SyncNumber()
     {
         using var gen = RandomNumberGenerator.Create();
         Span<byte> buff = stackalloc byte[sizeof(ushort)];

src/Backdash/Network/Messages/Header.cs

@@ -10,13 +10,13 @@ record struct Header(MessageType Type)
     public const int Size = 6;
 
     public MessageType Type = Type;
-    public ushort Magic = 0;
+    public ushort SyncNumber = 0;
     public ushort SequenceNumber = 0;
 
     public readonly void Serialize(in BinaryRawBufferWriter writer)
     {
         writer.Write((ushort)Type);
-        writer.Write(in Magic);
+        writer.Write(in SyncNumber);
         writer.Write(in SequenceNumber);
     }
 
@@ -25,13 +25,13 @@ public void Deserialize(in BinaryBufferReader reader)
         try
         {
             Type = reader.ReadAsUInt16<MessageType>();
-            Magic = reader.ReadUInt16();
+            SyncNumber = reader.ReadUInt16();
             SequenceNumber = reader.ReadUInt16();
         }
         catch
         {
             Type = MessageType.Unknown;
-            Magic = 0;
+            SyncNumber = 0;
             SequenceNumber = 0;
         }
     }

src/Backdash/Network/Messages/SyncRequest.cs

@@ -7,7 +7,7 @@ namespace Backdash.Network.Messages;
 [Serializable, StructLayout(LayoutKind.Sequential, Pack = 4)]
 record struct SyncRequest : IUtf8SpanFormattable
 {
-    public uint RandomRequest; /* please reply with this random data */
+    public ushort RandomRequest;
     public long Ping;
 
     public readonly void Serialize(in BinaryRawBufferWriter writer)
@@ -18,7 +18,7 @@ public readonly void Serialize(in BinaryRawBufferWriter writer)
 
     public void Deserialize(in BinaryBufferReader reader)
     {
-        RandomRequest = reader.ReadUInt32();
+        RandomRequest = reader.ReadUInt16();
         Ping = reader.ReadInt64();
     }
 

src/Backdash/Network/Protocol/Comm/ProtocolInbox.cs

@@ -58,7 +58,7 @@ public void OnPeerMessage(ref readonly ProtocolMessage message, in SocketAddress
                 return;
             }
 
-            if (message.Header.Magic != state.RemoteMagicNumber)
+            if (message.Header.SyncNumber != state.RemoteSyncNumber)
             {
                 logger.Write(LogLevel.Debug, $"recv rejecting: {message} on {state.Player}");
                 return;
@@ -228,7 +228,7 @@ bool OnSyncReply(ref readonly ProtocolMessage msg, ref ProtocolMessage replyMsg)
         if (state.CurrentStatus is not ProtocolStatus.Syncing)
         {
             logger.Write(LogLevel.Trace, "Ignoring SyncReply while not syncing");
-            return msg.Header.Magic == state.RemoteMagicNumber;
+            return msg.Header.SyncNumber == state.RemoteSyncNumber;
         }
 
         if (msg.SyncReply.RandomReply != state.Sync.CurrentRandom)
@@ -257,7 +257,7 @@ bool OnSyncReply(ref readonly ProtocolMessage msg, ref ProtocolMessage replyMsg)
             state.CurrentStatus = ProtocolStatus.Running;
             state.Stats.RoundTripTime = ping;
             lastReceivedInput.ResetFrame();
-            state.RemoteMagicNumber = msg.Header.Magic;
+            state.RemoteSyncNumber = msg.Header.SyncNumber;
             networkEvents.OnNetworkEvent(new(ProtocolEvent.Synchronized, state.Player)
             {
                 Synchronized = new(ping),
@@ -282,11 +282,11 @@ bool OnSyncReply(ref readonly ProtocolMessage msg, ref ProtocolMessage replyMsg)
 
     public bool OnSyncRequest(ref readonly ProtocolMessage msg, ref ProtocolMessage replyMsg)
     {
-        var remoteMagicNumber = state.RemoteMagicNumber;
-        if (remoteMagicNumber is not 0 && msg.Header.Magic != remoteMagicNumber)
+        var remoteMagicNumber = state.RemoteSyncNumber;
+        if (remoteMagicNumber is not 0 && msg.Header.SyncNumber != remoteMagicNumber)
         {
             logger.Write(LogLevel.Warning,
-                $"Ignoring sync request from unknown endpoint ({msg.Header.Magic} != {remoteMagicNumber})");
+                $"Ignoring sync request from unknown endpoint ({msg.Header.SyncNumber} != {remoteMagicNumber})");
             return false;
         }
 

src/Backdash/Network/Protocol/Comm/ProtocolOutbox.cs

@@ -18,7 +18,7 @@ Logger logger
 
     public void BeforeSendMessage(ref ProtocolMessage message)
     {
-        message.Header.Magic = state.SyncNumber;
+        message.Header.SyncNumber = state.SyncNumber;
         message.Header.SequenceNumber = (ushort)nextSendSeq;
         nextSendSeq++;
 

src/Backdash/Network/Protocol/ProtocolState.cs

@@ -24,7 +24,7 @@ ushort syncNumber
     public readonly ConnectionsState LocalConnectStatuses = localConnectStatuses;
     public readonly ConnectionsState PeerConnectStatuses = new(Max.NumberOfPlayers, Frame.Null);
     public readonly ushort SyncNumber = syncNumber;
-    public ushort RemoteMagicNumber;
+    public ushort RemoteSyncNumber;
     public ProtocolStatus CurrentStatus;
 
     public sealed class ConnectionState
@@ -91,10 +91,10 @@ public sealed class SyncState
     {
         public readonly object Locker = new();
         int remainingRoundTrips;
-        uint currentRandom;
+        ushort currentRandom;
         TimeSpan totalRoundTripsPing;
 
-        public uint CurrentRandom
+        public ushort CurrentRandom
         {
             get
             {