Add basic sync for PvP (only allowed with knifes and heatblades for now)

Nitrox.Test/Patcher/Patches/Dynamic/Knife_OnToolUseAnim_PatchTest.cs

@@ -0,0 +1,20 @@
+using System.Collections.Generic;
+using System.Linq;
+using FluentAssertions;
+using HarmonyLib;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using NitroxTest.Patcher;
+
+namespace NitroxPatcher.Patches.Dynamic;
+
+[TestClass]
+public class Knife_OnToolUseAnim_PatchTest
+{
+    [TestMethod]
+    public void Sanity()
+    {
+        IEnumerable<CodeInstruction> originalIl = PatchTestHelper.GetInstructionsFromMethod(Knife_OnToolUseAnim_Patch.TARGET_METHOD);
+        IEnumerable<CodeInstruction> transformedIl = Knife_OnToolUseAnim_Patch.Transpiler(originalIl);
+        transformedIl.Count().Should().Be(originalIl.Count());
+    }
+}

NitroxClient/Communication/Packets/Processors/PvPAttackProcessor.cs

@@ -0,0 +1,15 @@
+using NitroxClient.Communication.Packets.Processors.Abstract;
+using NitroxModel.Packets;
+
+namespace NitroxClient.Communication.Packets.Processors;
+
+public class PvPAttackProcessor : ClientPacketProcessor<PvPAttack>
+{
+    public override void Process(PvPAttack packet)
+    {
+        if (Player.main && Player.main.liveMixin)
+        {
+            Player.main.liveMixin.TakeDamage(packet.Damage);
+        }
+    }
+}

NitroxModel/Packets/PvPAttack.cs

@@ -0,0 +1,24 @@
+using System;
+
+namespace NitroxModel.Packets;
+
+[Serializable]
+public class PvPAttack : Packet
+{
+    public ushort TargetPlayerId { get; }
+    public float Damage { get; set; }
+    public AttackType Type { get; }
+
+    public PvPAttack(ushort targetPlayerId, float damage, AttackType type)
+    {
+        TargetPlayerId = targetPlayerId;
+        Damage = damage;
+        Type = type;
+    }
+
+    public enum AttackType : byte
+    {
+        KnifeHit,
+        HeatbladeHit
+    }
+}

NitroxPatcher/Patches/Dynamic/Knife_OnToolUseAnim_Patch.cs

@@ -0,0 +1,36 @@
+using System.Collections.Generic;
+using System.Reflection;
+using System.Reflection.Emit;
+using HarmonyLib;
+using NitroxModel.Helper;
+
+namespace NitroxPatcher.Patches.Dynamic;
+
+/// <summary>
+/// Registers knife hits's dealer as the main Player object
+/// </summary>
+public sealed partial class Knife_OnToolUseAnim_Patch : NitroxPatch, IDynamicPatch
+{
+    public static readonly MethodInfo TARGET_METHOD = Reflect.Method((Knife t) => t.OnToolUseAnim(default));
+
+    /*
+     * 
+     * bool flag = liveMixin.IsAlive();
+     * REPLACE below line
+     * liveMixin.TakeDamage(this.damage, vector, this.damageType, null);
+     * BY:
+     * liveMixin.TakeDamage(this.damage, vector, this.damageType, Player.mainObject);
+     * this.GiveResourceOnDamage(gameObject, liveMixin.IsAlive(), flag);
+     */
+    public static IEnumerable<CodeInstruction> Transpiler(IEnumerable<CodeInstruction> instructions)
+    {
+        return new CodeMatcher(instructions).MatchEndForward([
+                                                new CodeMatch(OpCodes.Ldloc_0),
+                                                new CodeMatch(OpCodes.Ldarg_0),
+                                                new CodeMatch(OpCodes.Ldfld),
+                                                new CodeMatch(OpCodes.Ldnull)
+                                            ])
+                                            .Set(OpCodes.Ldsfld, Reflect.Field(() => Player.mainObject))
+                                            .InstructionEnumeration();
+    }
+}

NitroxPatcher/Patches/Dynamic/LiveMixin_TakeDamage_Patch.cs

@@ -1,10 +1,13 @@
 using System.Reflection;
+using NitroxClient.Communication.Abstract;
 using NitroxClient.GameLogic;
+using NitroxClient.GameLogic.PlayerLogic;
 using NitroxClient.GameLogic.Spawning.Metadata;
 using NitroxModel.DataStructures;
 using NitroxModel.DataStructures.GameLogic.Entities.Metadata;
 using NitroxModel.DataStructures.Util;
 using NitroxModel.Helper;
+using NitroxModel.Packets;
 using UnityEngine;
 
 namespace NitroxPatcher.Patches.Dynamic;
@@ -26,11 +29,10 @@ public static bool Prefix(out float __state, LiveMixin __instance, GameObject de
         return Resolve<LiveMixinManager>().ShouldApplyNextHealthUpdate(__instance, dealer);
     }
 
-    public static void Postfix(float __state, LiveMixin __instance, bool __runOriginal)
+    public static void Postfix(float __state, LiveMixin __instance, float originalDamage, GameObject dealer, bool __runOriginal)
     {
-        // Did we realize a change in health?
-        if (!__runOriginal || __state == __instance.health || Resolve<LiveMixinManager>().IsRemoteHealthChanging ||
-            __instance.GetComponent<BaseCell>())
+        bool healthChanged = __state != __instance.health;
+        if (!__runOriginal || !ShouldBroadcastDamage(__instance, dealer, originalDamage, healthChanged))
         {
             return;
         }
@@ -46,4 +48,43 @@ public static void Postfix(float __state, LiveMixin __instance, bool __runOrigin
             }
         }
     }
+
+    private static bool ShouldBroadcastDamage(LiveMixin victim, GameObject dealer, float damage, bool healthChanged)
+    {
+        if (Resolve<LiveMixinManager>().IsRemoteHealthChanging || victim.GetComponent<BaseCell>())
+        {
+            return false;
+        }
+
+        if (victim.TryGetComponent(out RemotePlayerIdentifier remotePlayerIdentifier))
+        {
+            // Handle it internally
+            HandlePvP(remotePlayerIdentifier.RemotePlayer, dealer, damage);
+            return false;
+        }
+
+        // The health change check must happen after the PvP one
+        return healthChanged;
+    }
+
+    private static void HandlePvP(RemotePlayer remotePlayer, GameObject dealer, float damage)
+    {
+        if (dealer == Player.mainObject && Inventory.main.GetHeldObject())
+        {
+            PvPAttack.AttackType attackType;
+            switch (Inventory.main.GetHeldTool())
+            {
+                case HeatBlade:
+                    attackType = PvPAttack.AttackType.HeatbladeHit;
+                    break;
+                case Knife:
+                    attackType = PvPAttack.AttackType.KnifeHit;
+                    break;
+                default:
+                    // We don't want to send non-registered attacks
+                    return;
+            }
+            Resolve<IPacketSender>().Send(new PvPAttack(remotePlayer.PlayerId, damage, attackType));
+        }
+    }
 }

NitroxServer/Communication/Packets/Processors/PvPAttackProcessor.cs

@@ -0,0 +1,37 @@
+using System.Collections.Generic;
+using NitroxModel.Packets;
+using NitroxServer.Communication.Packets.Processors.Abstract;
+using NitroxServer.GameLogic;
+using NitroxServer.Serialization;
+
+namespace NitroxServer.Communication.Packets.Processors;
+
+public class PvPAttackProcessor : AuthenticatedPacketProcessor<PvPAttack>
+{
+    private readonly ServerConfig serverConfig;
+    private readonly PlayerManager playerManager;
+
+    // TODO: In the future, do a whole config for damage sources
+    private static readonly Dictionary<PvPAttack.AttackType, float> damageMultiplierByType = new()
+    {
+        { PvPAttack.AttackType.KnifeHit, 0.5f },
+        { PvPAttack.AttackType.HeatbladeHit, 1f }
+    };
+
+    public PvPAttackProcessor(ServerConfig serverConfig, PlayerManager playerManager)
+    {
+        this.serverConfig = serverConfig;
+        this.playerManager = playerManager;
+    }
+
+    public override void Process(PvPAttack packet, Player player)
+    {
+        if (serverConfig.PvPEnabled &&
+            playerManager.TryGetPlayerById(packet.TargetPlayerId, out Player targetPlayer) &&
+            damageMultiplierByType.TryGetValue(packet.Type, out float multiplier))
+        {
+            packet.Damage *= multiplier;
+            targetPlayer.SendPacket(packet);
+        }
+    }
+}

NitroxServer/GameLogic/PlayerManager.cs

@@ -20,6 +20,7 @@ namespace NitroxServer.GameLogic
     public class PlayerManager
     {
         private readonly ThreadSafeDictionary<string, Player> allPlayersByName;
+        private readonly ThreadSafeDictionary<ushort, Player> connectedPlayersById = [];
         private readonly ThreadSafeDictionary<INitroxConnection, ConnectionAssets> assetsByConnection = new();
         private readonly ThreadSafeDictionary<string, PlayerContext> reservations = new();
         private readonly ThreadSafeSet<string> reservedPlayerNames = new("Player"); // "Player" is often used to identify the local player and should not be used by any user
@@ -215,6 +216,8 @@ public Player PlayerConnected(INitroxConnection connection, string reservationKe
                 allPlayersByName[playerContext.PlayerName] = player;
             }
 
+            connectedPlayersById.Add(playerContext.PlayerId, player);
+
             // TODO: make a ConnectedPlayer wrapper so this is not stateful
             player.PlayerContext = playerContext;
             player.Connection = connection;
@@ -248,6 +251,7 @@ public void PlayerDisconnected(INitroxConnection connection)
             {
                 Player player = assetPackage.Player;
                 reservedPlayerNames.Remove(player.Name);
+                connectedPlayersById.Remove(player.Id);
             }
 
             assetsByConnection.Remove(connection);
@@ -301,6 +305,11 @@ public bool TryGetPlayerByName(string playerName, out Player foundPlayer)
             return false;
         }
 
+        public bool TryGetPlayerById(ushort playerId, out Player player)
+        {
+            return connectedPlayersById.TryGetValue(playerId, out player);
+        }
+
         public Player GetPlayer(INitroxConnection connection)
         {
             if (!assetsByConnection.TryGetValue(connection, out ConnectionAssets assetPackage))

NitroxServer/Serialization/ServerConfig.cs

@@ -117,5 +117,8 @@ public string SaveName
 
         [PropertyDescription("When true, will reject any build actions detected as desynced")]
         public bool SafeBuilding { get; set; } = true;
+
+        [PropertyDescription("Activates/Deactivates Player versus Player damage/interactions")]
+        public bool PvPEnabled { get; set; } = true;
     }
 }