Multi-threaded mob movement (#12611)

Content.Client/Physics/Controllers/MoverController.cs

@@ -1,11 +1,14 @@
+using Content.Shared.Inventory;
 using Content.Shared.Movement.Components;
 using Content.Shared.Movement.Systems;
 using Content.Shared.Pulling.Components;
 using Robust.Client.GameObjects;
 using Robust.Client.Player;
+using Robust.Shared.Containers;
 using Robust.Shared.Physics;
 using Robust.Shared.Physics.Components;
 using Robust.Shared.Timing;
+using Robust.Shared.Utility;
 
 namespace Content.Client.Physics.Controllers
 {
@@ -134,8 +137,30 @@ namespace Content.Client.Physics.Controllers
                 }
             }
 
+            var mobQuery = GetEntityQuery<MobMoverComponent>();
+            var inventoryQuery = GetEntityQuery<InventoryComponent>();
+            var containerQuery = GetEntityQuery<ContainerManagerComponent>();
+            var footQuery = GetEntityQuery<FootstepModifierComponent>();
+            DebugTools.Assert(!UsedMobMovement.ContainsKey(mover.Owner));
+
             // Server-side should just be handled on its own so we'll just do this shizznit
-            HandleMobMovement(mover, body, xformMover, frameTime, xformQuery);
+            HandleMobMovement(mover, body, xformMover, frameTime, xformQuery, mobQuery, inventoryQuery, containerQuery, footQuery, out var dirtyMover, out var linearVelocity, out var sound, out var audio);
+
+            MetaDataComponent? metadata = null;
+
+            if (dirtyMover)
+            {
+                Dirty(mover, metadata);
+            }
+
+            if (linearVelocity != null)
+            {
+                PhysicsSystem.SetLinearVelocity(body, linearVelocity.Value, false);
+                PhysicsSystem.SetAngularVelocity(body, 0f, false);
+                Dirty(body, metadata);
+            }
+
+            Audio.PlayPredicted(sound, mover.Owner, mover.Owner, audio);
         }
 
         protected override bool CanSound()

Content.Server/Physics/Controllers/MoverController.cs

@@ -1,20 +1,28 @@
+using System.Buffers;
+using System.Threading.Tasks;
 using Content.Server.Cargo.Components;
 using Content.Server.Shuttles.Components;
 using Content.Server.Shuttles.Systems;
+using Content.Shared.Inventory;
 using Content.Shared.Movement.Components;
 using Content.Shared.Movement.Systems;
 using Content.Shared.Shuttles.Components;
 using Content.Shared.Shuttles.Systems;
 using Robust.Server.GameObjects;
+using Robust.Shared.Audio;
+using Robust.Shared.Containers;
 using Robust.Shared.Map;
 using Robust.Shared.Physics.Components;
 using Robust.Shared.Player;
+using Robust.Shared.Threading;
+using Robust.Shared.Utility;
 
 namespace Content.Server.Physics.Controllers
 {
     public sealed class MoverController : SharedMoverController
     {
         [Dependency] private readonly IMapManager _mapManager = default!;
+        [Dependency] private readonly IParallelManager _parallel = default!;
         [Dependency] private readonly ThrusterSystem _thruster = default!;
 
         private Dictionary<ShuttleComponent, List<(PilotComponent, InputMoverComponent, TransformComponent)>> _shuttlePilots = new();
@@ -64,7 +72,12 @@ namespace Content.Server.Physics.Controllers
             var xformQuery = GetEntityQuery<TransformComponent>();
             var moverQuery = GetEntityQuery<InputMoverComponent>();
 
-            foreach (var mover in EntityQuery<InputMoverComponent>(true))
+            var movers = AllEntityQuery<InputMoverComponent>();
+            var totalCount = EntityManager.Count<InputMoverComponent>();
+            var moveInput = ArrayPool<(InputMoverComponent Mover, TransformComponent Transform, PhysicsComponent Physics)>.Shared.Rent(totalCount);
+            var count = 0;
+
+            while (movers.MoveNext(out var mover))
             {
                 if (relayQuery.TryGetComponent(mover.Owner, out var relayed) && relayed.RelayEntity != null)
                 {
@@ -83,13 +96,11 @@ namespace Content.Server.Physics.Controllers
                     continue;
                 }
 
-                PhysicsComponent? body = null;
+                PhysicsComponent? body;
-                TransformComponent? xformMover = xform;
-
                 if (mover.ToParent && relayQuery.HasComponent(xform.ParentUid))
                 {
                     if (!bodyQuery.TryGetComponent(xform.ParentUid, out body) ||
-                        !TryComp(xform.ParentUid, out xformMover))
+                        !xformQuery.HasComponent(xform.ParentUid))
                     {
                         continue;
                     }
@@ -99,9 +110,64 @@ namespace Content.Server.Physics.Controllers
                     continue;
                 }
 
-                HandleMobMovement(mover, body, xformMover, frameTime, xformQuery);
+                DebugTools.Assert(!UsedMobMovement.ContainsKey(mover.Owner));
+
+                // To avoid threading issues on adding dictionary entries later.
+                UsedMobMovement[mover.Owner] = false;
+                moveInput[count++] = (mover, xform, body);
             }
 
+            var moveResults = ArrayPool<(bool DirtyMover, Vector2? LinearVelocity, SoundSpecifier? sound, AudioParams audio)>.Shared.Rent(count);
+            var mobQuery = GetEntityQuery<MobMoverComponent>();
+            var inventoryQuery = GetEntityQuery<InventoryComponent>();
+            var containerQuery = GetEntityQuery<ContainerManagerComponent>();
+            var footQuery = GetEntityQuery<FootstepModifierComponent>();
+
+            var options = new ParallelOptions()
+            {
+                MaxDegreeOfParallelism = _parallel.ParallelProcessCount,
+            };
+
+            Parallel.For(0, count, options, i =>
+            {
+                var (mover, xform, body) = moveInput[i];
+                HandleMobMovement(mover, body, xform, frameTime, xformQuery, mobQuery, inventoryQuery, containerQuery, footQuery, out var dirtyMover, out var linearVelocity, out var sound, out var audio);
+                moveResults[i] = (dirtyMover, linearVelocity, sound, audio);
+            });
+
+            var metaQuery = GetEntityQuery<MetaDataComponent>();
+
+            for (var i = 0; i < count; i++)
+            {
+                var results = moveResults[i];
+                var input = moveInput[i];
+                MetaDataComponent? metadata = null;
+
+                // Calling dirty isn't thread-safe sadly.
+                if (results.DirtyMover)
+                {
+                    metadata ??= metaQuery.GetComponent(input.Mover.Owner);
+                    Dirty(input.Mover, metadata);
+                }
+
+                if (results.LinearVelocity != null)
+                {
+                    metadata ??= metaQuery.GetComponent(input.Physics.Owner);
+                    PhysicsSystem.SetLinearVelocity(input.Physics, results.LinearVelocity.Value, false);
+                    PhysicsSystem.SetAngularVelocity(input.Physics, 0f, false);
+                    Dirty(input.Physics, metadata);
+                }
+
+                if (results.sound != null)
+                {
+                    Audio.PlayPredicted(results.sound, input.Mover.Owner, input.Mover.Owner, results.audio);
+                }
+
+                moveInput[i] = default;
+            }
+
+            ArrayPool<(bool DirtyMover, Vector2? LinearVelocity, SoundSpecifier? Sound, AudioParams Audio)>.Shared.Return(moveResults);
+            ArrayPool<(InputMoverComponent, TransformComponent, PhysicsComponent)>.Shared.Return(moveInput);
             HandleShuttleMovement(frameTime);
         }
 

Content.Shared/Movement/Components/InputMoverComponent.cs

@@ -1,5 +1,6 @@
 using Content.Shared.Movement.Systems;
 using Robust.Shared.GameStates;
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom;
 using Robust.Shared.Timing;
 
 namespace Content.Shared.Movement.Components
@@ -61,8 +62,8 @@ namespace Content.Shared.Movement.Components
         /// <summary>
         /// If we traverse on / off a grid then set a timer to update our relative inputs.
         /// </summary>
-        [ViewVariables(VVAccess.ReadWrite)]
+        [ViewVariables(VVAccess.ReadWrite), DataField("lerpTarget", customTypeSerializer: typeof(TimeOffsetSerializer))]
-        public float LerpAccumulator;
+        public TimeSpan LerpTarget;
 
         public const float LerpTime = 1.0f;
 

Content.Shared/Movement/Systems/SharedMoverController.Input.cs

@@ -80,7 +80,7 @@ namespace Content.Shared.Movement.Systems
             component.RelativeRotation = state.RelativeRotation;
             component.TargetRelativeRotation = state.TargetRelativeRotation;
             component.RelativeEntity = state.RelativeEntity;
-            component.LerpAccumulator = state.LerpAccumulator;
+            component.LerpTarget = state.LerpTarget;
         }
 
         private void OnInputGetState(EntityUid uid, InputMoverComponent component, ref ComponentGetState args)
@@ -91,7 +91,7 @@ namespace Content.Shared.Movement.Systems
                 component.RelativeRotation,
                 component.TargetRelativeRotation,
                 component.RelativeEntity,
-                component.LerpAccumulator);
+                component.LerpTarget);
         }
 
         private void ShutdownInput()
@@ -118,13 +118,73 @@ namespace Content.Shared.Movement.Systems
 
         public void ResetCamera(EntityUid uid)
         {
-            if (CameraRotationLocked || !TryComp<InputMoverComponent>(uid, out var mover) || mover.TargetRelativeRotation.Equals(Angle.Zero))
+            if (CameraRotationLocked ||
+                !TryComp<InputMoverComponent>(uid, out var mover))
+            {
+                return;
+            }
+
+            // If we updated parent then cancel the accumulator and force it now.
+            var xformQuery = GetEntityQuery<TransformComponent>();
+
+            if (!TryUpdateRelative(mover, xformQuery.GetComponent(uid), xformQuery) && mover.TargetRelativeRotation.Equals(Angle.Zero))
                 return;
 
+            mover.LerpTarget = TimeSpan.Zero;
             mover.TargetRelativeRotation = Angle.Zero;
             Dirty(mover);
         }
 
+        private bool TryUpdateRelative(InputMoverComponent mover, TransformComponent xform, EntityQuery<TransformComponent> xformQuery)
+        {
+            var relative = xform.GridUid;
+            relative ??= xform.MapUid;
+
+            // So essentially what we want:
+            // 1. If we go from grid to map then preserve our rotation and continue as usual
+            // 2. If we go from grid -> grid then (after lerp time) snap to nearest cardinal (probably imperceptible)
+            // 3. If we go from map -> grid then (after lerp time) snap to nearest cardinal
+
+            if (mover.RelativeEntity.Equals(relative))
+                return false;
+
+            // Okay need to get our old relative rotation with respect to our new relative rotation
+            // e.g. if we were right side up on our current grid need to get what that is on our new grid.
+            var currentRotation = Angle.Zero;
+            var targetRotation = Angle.Zero;
+
+            // Get our current relative rotation
+            if (xformQuery.TryGetComponent(mover.RelativeEntity, out var oldRelativeXform))
+            {
+                currentRotation = _transform.GetWorldRotation(oldRelativeXform, xformQuery) + mover.RelativeRotation;
+            }
+
+            if (xformQuery.TryGetComponent(relative, out var relativeXform))
+            {
+                // This is our current rotation relative to our new parent.
+                mover.RelativeRotation = (currentRotation - _transform.GetWorldRotation(relativeXform, xformQuery)).FlipPositive();
+            }
+
+            // If we went from grid -> map we'll preserve our worldrotation
+            if (relative != null && _mapManager.IsMap(relative.Value))
+            {
+                targetRotation = currentRotation.FlipPositive().Reduced();
+            }
+            // If we went from grid -> grid OR grid -> map then snap the target to cardinal and lerp there.
+            // OR just rotate to zero (depending on cvar)
+            else if (relative != null && _mapManager.IsGrid(relative.Value))
+            {
+                if (CameraRotationLocked)
+                    targetRotation = Angle.Zero;
+                else
+                    targetRotation = mover.RelativeRotation.GetCardinalDir().ToAngle().Reduced();
+            }
+
+            mover.RelativeEntity = relative;
+            mover.TargetRelativeRotation = targetRotation;
+            return true;
+        }
+
         public Angle GetParentGridAngle(InputMoverComponent mover, EntityQuery<TransformComponent> xformQuery)
         {
             var rotation = mover.RelativeRotation;
@@ -161,16 +221,16 @@ namespace Content.Shared.Movement.Systems
             // If we go on a grid and back off then just reset the accumulator.
             if (relative == component.RelativeEntity)
             {
-                if (component.LerpAccumulator != 0f)
+                if (component.LerpTarget >= Timing.CurTime)
                 {
-                    component.LerpAccumulator = 0f;
+                    component.LerpTarget = TimeSpan.Zero;
                     Dirty(component);
                 }
 
                 return;
             }
 
-            component.LerpAccumulator = InputMoverComponent.LerpTime;
+            component.LerpTarget = TimeSpan.FromSeconds(InputMoverComponent.LerpTime) + Timing.CurTime;
             Dirty(component);
         }
 
@@ -499,16 +559,16 @@ namespace Content.Shared.Movement.Systems
             /// </summary>
             public Angle TargetRelativeRotation;
             public EntityUid? RelativeEntity;
-            public float LerpAccumulator = 0f;
+            public TimeSpan LerpTarget;
 
-            public InputMoverComponentState(MoveButtons buttons, bool canMove, Angle relativeRotation, Angle targetRelativeRotation, EntityUid? relativeEntity, float lerpAccumulator)
+            public InputMoverComponentState(MoveButtons buttons, bool canMove, Angle relativeRotation, Angle targetRelativeRotation, EntityUid? relativeEntity, TimeSpan lerpTarget)
             {
                 Buttons = buttons;
                 CanMove = canMove;
                 RelativeRotation = relativeRotation;
                 TargetRelativeRotation = targetRelativeRotation;
                 RelativeEntity = relativeEntity;
-                LerpAccumulator = lerpAccumulator;
+                LerpTarget = lerpTarget;
             }
         }
 

Content.Shared/Movement/Systems/SharedMoverController.cs

@@ -36,7 +36,7 @@ namespace Content.Shared.Movement.Systems
         [Dependency] private   readonly SharedContainerSystem _container = default!;
         [Dependency] private   readonly SharedGravitySystem _gravity = default!;
         [Dependency] private   readonly SharedMobStateSystem _mobState = default!;
-        [Dependency] private readonly SharedAudioSystem _audio = default!;
+        [Dependency] protected readonly SharedAudioSystem Audio = default!;
         [Dependency] private   readonly SharedTransformSystem _transform = default!;
         [Dependency] private   readonly TagSystem _tags = default!;
 
@@ -96,69 +96,35 @@ namespace Content.Shared.Movement.Systems
         /// <summary>
         ///     Movement while considering actionblockers, weightlessness, etc.
         /// </summary>
+        /// <remarks>
+        /// Yes this signature is massive but this is also called a lot.
+        /// </remarks>
         protected void HandleMobMovement(
             InputMoverComponent mover,
             PhysicsComponent physicsComponent,
             TransformComponent xform,
             float frameTime,
-            EntityQuery<TransformComponent> xformQuery)
+            EntityQuery<TransformComponent> xformQuery,
+            EntityQuery<MobMoverComponent> mobQuery,
+            EntityQuery<InventoryComponent> inventoryQuery,
+            EntityQuery<ContainerManagerComponent> containerQuery,
+            EntityQuery<FootstepModifierComponent> footQuery,
+            out bool dirtyMover,
+            out Vector2? linearVelocity,
+            out SoundSpecifier? sound,
+            out AudioParams audio)
         {
-            DebugTools.Assert(!UsedMobMovement.ContainsKey(mover.Owner));
+            dirtyMover = false;
+            linearVelocity = Vector2.Zero;
+            sound = null;
+            audio = default;
 
             // Update relative movement
-            if (mover.LerpAccumulator > 0f)
+            if (mover.LerpTarget < Timing.CurTime)
             {
-                Dirty(mover);
+                if (TryUpdateRelative(mover, xform, xformQuery))
-                mover.LerpAccumulator -= frameTime;
-
-                if (mover.LerpAccumulator <= 0f)
                 {
-                    mover.LerpAccumulator = 0f;
+                    dirtyMover = true;
-                    var relative = xform.GridUid;
-                    relative ??= xform.MapUid;
-
-                    // So essentially what we want:
-                    // 1. If we go from grid to map then preserve our rotation and continue as usual
-                    // 2. If we go from grid -> grid then (after lerp time) snap to nearest cardinal (probably imperceptible)
-                    // 3. If we go from map -> grid then (after lerp time) snap to nearest cardinal
-
-                    if (!mover.RelativeEntity.Equals(relative))
-                    {
-                        // Okay need to get our old relative rotation with respect to our new relative rotation
-                        // e.g. if we were right side up on our current grid need to get what that is on our new grid.
-                        var currentRotation = Angle.Zero;
-                        var targetRotation = Angle.Zero;
-
-                        // Get our current relative rotation
-                        if (xformQuery.TryGetComponent(mover.RelativeEntity, out var oldRelativeXform))
-                        {
-                            currentRotation = oldRelativeXform.WorldRotation + mover.RelativeRotation;
-                        }
-
-                        if (xformQuery.TryGetComponent(relative, out var relativeXform))
-                        {
-                            // This is our current rotation relative to our new parent.
-                            mover.RelativeRotation = (currentRotation - relativeXform.WorldRotation).FlipPositive();
-                        }
-
-                        // If we went from grid -> map we'll preserve our worldrotation
-                        if (relative != null && _mapManager.IsMap(relative.Value))
-                        {
-                            targetRotation = currentRotation.FlipPositive().Reduced();
-                        }
-                        // If we went from grid -> grid OR grid -> map then snap the target to cardinal and lerp there.
-                        // OR just rotate to zero (depending on cvar)
-                        else if (relative != null && _mapManager.IsGrid(relative.Value))
-                        {
-                            if (CameraRotationLocked)
-                                targetRotation = Angle.Zero;
-                            else
-                                targetRotation = mover.RelativeRotation.GetCardinalDir().ToAngle().Reduced();
-                        }
-
-                        mover.RelativeEntity = relative;
-                        mover.TargetRelativeRotation = targetRotation;
-                    }
                 }
             }
 
@@ -183,13 +149,13 @@ namespace Content.Shared.Movement.Systems
 
                 mover.RelativeRotation += adjustment;
                 mover.RelativeRotation.FlipPositive();
-                Dirty(mover);
+                dirtyMover = true;
             }
             else if (!angleDiff.Equals(Angle.Zero))
             {
                 mover.TargetRelativeRotation.FlipPositive();
                 mover.RelativeRotation = mover.TargetRelativeRotation;
-                Dirty(mover);
+                dirtyMover = true;
             }
 
             if (!UseMobMovement(mover, physicsComponent))
@@ -217,7 +183,7 @@ namespace Content.Shared.Movement.Systems
                     // No gravity: is our entity touching anything?
                     touching = ev.CanMove;
 
-                    if (!touching && TryComp<MobMoverComponent>(xform.Owner, out var mobMover))
+                    if (!touching && mobQuery.TryGetComponent(xform.Owner, out var mobMover))
                         touching |= IsAroundCollider(PhysicsSystem, xform, mobMover, physicsComponent);
                 }
             }
@@ -274,19 +240,20 @@ namespace Content.Shared.Movement.Systems
             {
                 // This should have its event run during island solver soooo
                 xform.DeferUpdates = true;
-                xform.WorldRotation = worldTotal.ToWorldAngle();
+                _transform.SetWorldRotation(xform, worldTotal.ToWorldAngle(), xformQuery);
                 xform.DeferUpdates = false;
 
                 if (!weightless && TryComp<MobMoverComponent>(mover.Owner, out var mobMover) &&
-                    TryGetSound(weightless, mover, mobMover, xform, out var sound))
+                    TryGetSound(weightless, mover, mobMover, xform, inventoryQuery, containerQuery, footQuery, out var soundSpec))
                 {
                     var soundModifier = mover.Sprinting ? 1.0f : FootstepWalkingAddedVolumeMultiplier;
 
-                    var audioParams = sound.Params
+                    var audioParams = soundSpec.Params
                         .WithVolume(FootstepVolume * soundModifier)
-                        .WithVariation(sound.Params.Variation ?? FootstepVariation);
+                        .WithVariation(soundSpec.Params.Variation ?? FootstepVariation);
 
-                    _audio.PlayPredicted(sound, mover.Owner, mover.Owner, audioParams);
+                    sound = soundSpec;
+                    audio = audioParams;
                 }
             }
 
@@ -295,10 +262,13 @@ namespace Content.Shared.Movement.Systems
             if (!weightless || touching)
                 Accelerate(ref velocity, in worldTotal, accel, frameTime);
 
-            PhysicsSystem.SetLinearVelocity(physicsComponent, velocity);
+            if (physicsComponent.LinearVelocity.EqualsApprox(velocity, 0.0001f) &&
+                MathHelper.CloseTo(physicsComponent.AngularVelocity, 0f))
+            {
+                return;
+            }
 
-            // Ensures that players do not spiiiiiiin
+            linearVelocity = velocity;
-            PhysicsSystem.SetAngularVelocity(physicsComponent, 0);
         }
 
         private void Friction(float minimumFrictionSpeed, float frameTime, float friction, ref Vector2 velocity)
@@ -379,7 +349,16 @@ namespace Content.Shared.Movement.Systems
 
         protected abstract bool CanSound();
 
-        private bool TryGetSound(bool weightless, InputMoverComponent mover, MobMoverComponent mobMover, TransformComponent xform, [NotNullWhen(true)] out SoundSpecifier? sound)
+        private bool TryGetSound(
+            bool weightless,
+            InputMoverComponent mover,
+            MobMoverComponent mobMover,
+            TransformComponent xform,
+            EntityQuery<InventoryComponent> inventoryQuery,
+            EntityQuery<ContainerManagerComponent> containerQuery,
+            EntityQuery<FootstepModifierComponent> footQuery,
+
+        [NotNullWhen(true)] out SoundSpecifier? sound)
         {
             sound = null;
 
@@ -413,18 +392,21 @@ namespace Content.Shared.Movement.Systems
             if (mobMover.StepSoundDistance < distanceNeeded) return false;
 
             mobMover.StepSoundDistance -= distanceNeeded;
+            EntityUid? shoes = null;
 
-            if (_inventory.TryGetSlotEntity(mover.Owner, "shoes", out var shoes) &&
+            if (inventoryQuery.TryGetComponent(mover.Owner, out var inventory) &&
-                EntityManager.TryGetComponent<FootstepModifierComponent>(shoes, out var modifier))
+                containerQuery.TryGetComponent(mover.Owner, out var containerManager) &&
+                _inventory.TryGetSlotEntity(mover.Owner, "shoes", out shoes, inventory, containerManager) &&
+                footQuery.TryGetComponent(shoes, out var modifier))
             {
                 sound = modifier.Sound;
                 return true;
             }
 
-            return TryGetFootstepSound(coordinates, shoes != null, out sound);
+            return TryGetFootstepSound(coordinates, shoes != null, footQuery, out sound);
         }
 
-        private bool TryGetFootstepSound(EntityCoordinates coordinates, bool haveShoes, [NotNullWhen(true)] out SoundSpecifier? sound)
+        private bool TryGetFootstepSound(EntityCoordinates coordinates, bool haveShoes, EntityQuery<FootstepModifierComponent> footQuery, [NotNullWhen(true)] out SoundSpecifier? sound)
         {
             sound = null;
             var gridUid = coordinates.GetGridUid(EntityManager);
@@ -432,7 +414,7 @@ namespace Content.Shared.Movement.Systems
             // Fallback to the map
             if (gridUid == null)
             {
-                if (TryComp<FootstepModifierComponent>(coordinates.GetMapUid(EntityManager), out var modifier))
+                if (footQuery.TryGetComponent(coordinates.GetMapUid(EntityManager), out var modifier))
                 {
                     sound = modifier.Sound;
                     return true;
@@ -444,18 +426,21 @@ namespace Content.Shared.Movement.Systems
             var grid = _mapManager.GetGrid(gridUid.Value);
             var tile = grid.GetTileRef(coordinates);
 
-            if (tile.IsSpace(_tileDefinitionManager)) return false;
+            if (tile.IsSpace(_tileDefinitionManager))
+                return false;
 
             // If the coordinates have a FootstepModifier component
             // i.e. component that emit sound on footsteps emit that sound
-            foreach (var maybeFootstep in grid.GetAnchoredEntities(tile.GridIndices))
+            var anchoredEnumerator = grid.GetAnchoredEntitiesEnumerator(tile.GridIndices);
-            {
+
-                if (EntityManager.TryGetComponent(maybeFootstep, out FootstepModifierComponent? footstep))
+            while (anchoredEnumerator.MoveNext(out var maybeFootstep))
             {
+                if (!footQuery.TryGetComponent(maybeFootstep, out var footstep))
+                    continue;
+
                 sound = footstep.Sound;
                 return true;
             }
-            }
 
             // Walking on a tile.
             var def = (ContentTileDefinition) _tileDefinitionManager[tile.Tile.TypeId];