Partial kudzu fix (#10854)

Content.Shared/Movement/Systems/SlowContactsSystem.cs

@@ -1,4 +1,5 @@
 using Content.Shared.Movement.Components;
+using Robust.Shared.GameStates;
 using Robust.Shared.Physics.Dynamics;
 
 namespace Content.Shared.Movement.Systems;
@@ -8,65 +9,96 @@ public sealed class SlowContactsSystem : EntitySystem
     [Dependency] private readonly SharedPhysicsSystem _physics = default!;
     [Dependency] private readonly MovementSpeedModifierSystem _speedModifierSystem = default!;
 
-    private readonly Dictionary<EntityUid, int> _statusCapableInContact = new();
+    private HashSet<EntityUid> _toUpdate = new();
+    private HashSet<EntityUid> _toRemove = new();
 
     public override void Initialize()
     {
         base.Initialize();
         SubscribeLocalEvent<SlowContactsComponent, StartCollideEvent>(OnEntityEnter);
         SubscribeLocalEvent<SlowContactsComponent, EndCollideEvent>(OnEntityExit);
-        SubscribeLocalEvent<SlowsOnContactComponent, RefreshMovementSpeedModifiersEvent>(MovementSpeedCheck);
+        SubscribeLocalEvent<SlowedByContactComponent, RefreshMovementSpeedModifiersEvent>(MovementSpeedCheck);
+
+        SubscribeLocalEvent<SlowContactsComponent, ComponentHandleState>(OnHandleState);
+        SubscribeLocalEvent<SlowContactsComponent, ComponentGetState>(OnGetState);
+
+        UpdatesAfter.Add(typeof(SharedPhysicsSystem));
     }
 
-    private void MovementSpeedCheck(EntityUid uid, SlowsOnContactComponent component, RefreshMovementSpeedModifiersEvent args)
+    public override void Update(float frameTime)
     {
-        if (!_statusCapableInContact.ContainsKey(uid) || _statusCapableInContact[uid] <= 0)
+        base.Update(frameTime);
+
+        _toRemove.Clear();
+
+        foreach (var ent in _toUpdate)
+        {
+            _speedModifierSystem.RefreshMovementSpeedModifiers(ent);
+        }
+
+        foreach (var ent in _toRemove)
+        {
+            RemComp<SlowedByContactComponent>(ent);
+        }
+
+        _toUpdate.Clear();
+    }
+
+    private void OnGetState(EntityUid uid, SlowContactsComponent component, ref ComponentGetState args)
+    {
+        args.State = new SlowContactsComponentState(component.WalkSpeedModifier, component.SprintSpeedModifier);
+    }
+
+    private void OnHandleState(EntityUid uid, SlowContactsComponent component, ref ComponentHandleState args)
+    {
+        if (args.Current is not SlowContactsComponentState state)
             return;
 
+        component.WalkSpeedModifier = state.WalkSpeedModifier;
+        component.SprintSpeedModifier = state.SprintSpeedModifier;
+    }
+
+    private void MovementSpeedCheck(EntityUid uid, SlowedByContactComponent component, RefreshMovementSpeedModifiersEvent args)
+    {
         if (!EntityManager.TryGetComponent<PhysicsComponent>(uid, out var physicsComponent))
             return;
 
         var walkSpeed = 1.0f;
         var sprintSpeed = 1.0f;
 
-        foreach (var colliding in _physics.GetCollidingEntities(physicsComponent))
+        bool remove = true;
+        foreach (var colliding in _physics.GetContactingEntities(physicsComponent))
         {
             var ent = colliding.Owner;
-            if (!EntityManager.TryGetComponent<SlowContactsComponent>(ent, out var slowContactsComponent))
+            if (!TryComp<SlowContactsComponent>(ent, out var slowContactsComponent))
                 continue;
 
             walkSpeed = Math.Min(walkSpeed, slowContactsComponent.WalkSpeedModifier);
             sprintSpeed = Math.Min(sprintSpeed, slowContactsComponent.SprintSpeedModifier);
+            remove = false;
         }
 
         args.ModifySpeed(walkSpeed, sprintSpeed);
+
+        // no longer colliding with anything
+        if (remove)
+            _toRemove.Add(uid);
     }
 
     private void OnEntityExit(EntityUid uid, SlowContactsComponent component, EndCollideEvent args)
     {
         var otherUid = args.OtherFixture.Body.Owner;
-        if (!EntityManager.HasComponent<MovementSpeedModifierComponent>(otherUid)
-            || !EntityManager.HasComponent<SlowsOnContactComponent>(otherUid))
-            return;
-        if (!_statusCapableInContact.ContainsKey(otherUid))
-            Logger.ErrorS("slowscontacts", $"The entity {otherUid} left a body ({uid}) it was never in.");
-        _statusCapableInContact[otherUid]--;
-        if (_statusCapableInContact[otherUid] == 0)
-            EntityManager.RemoveComponentDeferred<SlowsOnContactComponent>(otherUid);
-        _speedModifierSystem.RefreshMovementSpeedModifiers(otherUid);
-
+        if (HasComp<MovementSpeedModifierComponent>(otherUid))
+            _toUpdate.Add(otherUid);
     }
 
     private void OnEntityEnter(EntityUid uid, SlowContactsComponent component, StartCollideEvent args)
     {
         var otherUid = args.OtherFixture.Body.Owner;
-        if (!EntityManager.HasComponent<MovementSpeedModifierComponent>(otherUid))
+        if (!HasComp<MovementSpeedModifierComponent>(otherUid))
             return;
-        if (!_statusCapableInContact.ContainsKey(otherUid))
-            _statusCapableInContact[otherUid] = 0;
-        _statusCapableInContact[otherUid]++;
 
-        EnsureComp<SlowsOnContactComponent>(otherUid);
-        _speedModifierSystem.RefreshMovementSpeedModifiers(otherUid);
+        EnsureComp<SlowedByContactComponent>(otherUid);
+        _toUpdate.Add(otherUid);
     }
 }