Add simple miss chances for NPCs (#12978)

Doesn't consider juking potential but okay for now.

Content.Server/NPC/Components/NPCMeleeCombatComponent.cs

@@ -11,6 +11,12 @@ public sealed class NPCMeleeCombatComponent : Component
     /// </summary>
     [ViewVariables] public EntityUid Weapon;
 
+    /// <summary>
+    /// If the target is moving what is the chance for this NPC to miss.
+    /// </summary>
+    [ViewVariables(VVAccess.ReadWrite)]
+    public float MissChance;
+
     [ViewVariables]
     public EntityUid Target;
 

Content.Server/NPC/HTN/PrimitiveTasks/Operators/Melee/MeleeOperator.cs

@@ -31,6 +31,7 @@ public sealed class MeleeOperator : HTNOperator
     {
         base.Startup(blackboard);
         var melee = _entManager.EnsureComponent<NPCMeleeCombatComponent>(blackboard.GetValue<EntityUid>(NPCBlackboard.Owner));
+        melee.MissChance = blackboard.GetValueOrDefault<float>(NPCBlackboard.MeleeMissChance, _entManager);
         melee.Target = blackboard.GetValue<EntityUid>(TargetKey);
     }
 

Content.Server/NPC/NPCBlackboard.cs

@@ -20,6 +20,7 @@ public sealed class NPCBlackboard : IEnumerable<KeyValuePair<string, object>>
         {"IdleRange", 7f},
         {"MaximumIdleTime", 7f},
         {MedibotInjectRange, 4f},
+        {MeleeMissChance, 0.3f},
         {"MeleeRange", 1f},
         {"MinimumIdleTime", 2f},
         {"MovementRange", 1.5f},
@@ -190,6 +191,9 @@ public sealed class NPCBlackboard : IEnumerable<KeyValuePair<string, object>>
     public const string CanMove = "CanMove";
     public const string FollowTarget = "FollowTarget";
     public const string MedibotInjectRange = "MedibotInjectRange";
+
+    public const string MeleeMissChance = "MeleeMissChance";
+
     public const string Owner = "Owner";
     public const string OwnerCoordinates = "OwnerCoordinates";
     public const string MovementTarget = "MovementTarget";
@@ -216,7 +220,6 @@ public sealed class NPCBlackboard : IEnumerable<KeyValuePair<string, object>>
 
     public const string RotateSpeed = "RotateSpeed";
     public const string VisionRadius = "VisionRadius";
-    public const float MeleeRange = 1f;
 
     public IEnumerator<KeyValuePair<string, object>> GetEnumerator()
     {

Content.Server/NPC/Systems/NPCCombatSystem.Melee.cs

@@ -4,6 +4,8 @@ using Content.Shared.MobState;
 using Content.Shared.MobState.Components;
 using Content.Shared.Weapons.Melee;
 using Robust.Shared.Map;
+using Robust.Shared.Physics.Components;
+using Robust.Shared.Random;
 
 namespace Content.Server.NPC.Systems;
 
@@ -42,6 +44,8 @@ public sealed partial class NPCCombatSystem
     {
         var combatQuery = GetEntityQuery<CombatModeComponent>();
         var xformQuery = GetEntityQuery<TransformComponent>();
+        var physicsQuery = GetEntityQuery<PhysicsComponent>();
+        var curTime = _timing.CurTime;
 
         foreach (var (comp, _) in EntityQuery<NPCMeleeCombatComponent, ActiveNPCComponent>())
         {
@@ -51,17 +55,14 @@ public sealed partial class NPCCombatSystem
                 continue;
             }
 
-            Attack(comp, xformQuery);
+            Attack(comp, curTime, physicsQuery, xformQuery);
         }
     }
 
-    private void Attack(NPCMeleeCombatComponent component, EntityQuery<TransformComponent> xformQuery)
+    private void Attack(NPCMeleeCombatComponent component, TimeSpan curTime, EntityQuery<PhysicsComponent> physicsQuery, EntityQuery<TransformComponent> xformQuery)
     {
         component.Status = CombatStatus.Normal;
 
-        // TODO:
-        // Also need some blackboard data for stuff like juke frequency, assigning target slots (to surround targets), etc.
-        // miss %
         if (!TryComp<MeleeWeaponComponent>(component.Weapon, out var weapon))
         {
             component.Status = CombatStatus.NoWeapon;
@@ -105,6 +106,19 @@ public sealed partial class NPCCombatSystem
 
         // Gets unregistered on component shutdown.
         _steering.TryRegister(component.Owner, new EntityCoordinates(component.Target, Vector2.Zero), steering);
+
+        if (weapon.NextAttack > curTime)
+            return;
+
+        if (_random.Prob(component.MissChance) &&
+            physicsQuery.TryGetComponent(component.Target, out var targetPhysics) &&
+            targetPhysics.LinearVelocity.LengthSquared != 0f)
+        {
+            _melee.AttemptLightAttackMiss(component.Owner, weapon, targetXform.Coordinates.Offset(_random.NextVector2(0.5f)));
+        }
+        else
+        {
             _melee.AttemptLightAttack(component.Owner, weapon, component.Target);
         }
     }
+}

Content.Server/NPC/Systems/NPCCombatSystem.cs

@@ -1,9 +1,8 @@
 using Content.Server.Interaction;
 using Content.Server.Weapons.Ranged.Systems;
-using Content.Shared.CombatMode;
-using Content.Shared.Interaction;
 using Content.Shared.Weapons.Melee;
 using Robust.Shared.Map;
+using Robust.Shared.Random;
 using Robust.Shared.Timing;
 
 namespace Content.Server.NPC.Systems;
@@ -13,7 +12,9 @@ namespace Content.Server.NPC.Systems;
 /// </summary>
 public sealed partial class NPCCombatSystem : EntitySystem
 {
+    [Dependency] private readonly IGameTiming _timing = default!;
     [Dependency] private readonly IMapManager _mapManager = default!;
+    [Dependency] private readonly IRobustRandom _random = default!;
     [Dependency] private readonly GunSystem _gun = default!;
     [Dependency] private readonly InteractionSystem _interaction = default!;
     [Dependency] private readonly SharedAudioSystem _audio = default!;

Content.Shared/Weapons/Melee/SharedMeleeWeaponSystem.cs

@@ -261,6 +261,11 @@ public abstract class SharedMeleeWeaponSystem : EntitySystem
         return null;
     }
 
+    public void AttemptLightAttackMiss(EntityUid user, MeleeWeaponComponent weapon, EntityCoordinates coordinates)
+    {
+        AttemptAttack(user, weapon, new LightAttackEvent(null, weapon.Owner, coordinates), null);
+    }
+
     public void AttemptLightAttack(EntityUid user, MeleeWeaponComponent weapon, EntityUid target)
     {
         if (!TryComp<TransformComponent>(target, out var targetXform))