Physics (#3485)

* Content side new physics structure

* BroadPhase outline done

* But we need to fix WorldAABB

* Fix static pvs AABB

* Fix import

* Rando fixes

* B is for balloon

* Change human mob hitbox to circle

* Decent movement

* Start adding friction to player controller

I think it's the best way to go about it to keep other objects somewhat consistent for physics.

* This baby can fit so many physics bugs in it.

* Slight mob mover optimisations.

* Player mover kinda works okay.

* Beginnings of testbed

* More testbed

* Circlestack bed

* Namespaces

* BB fixes

* Pull WorldAABB

* Joint pulling

* Semi-decent movement I guess.

* Pulling better

* Bullet controller + old movement

* im too dumb for this shit

* Use kinematic mob controller again

It's probably for the best TBH

* Stashed shitcode

* Remove SlipController

* In which movement code is entirely refactored

* Singularity fix

* Fix ApplyLinearImpulse

* MoveRelay fix

* Fix door collisions

* Disable subfloor collisions

Saves on broadphase a fair bit

* Re-implement ClimbController

* Zumzum's pressure

* Laggy item throwing

* Minor atmos change

* Some caching

* Optimise controllers

* Optimise CollideWith to hell and back

* Re-do throwing and tile friction

* Landing too

* Optimise controllers

* Move CCVars and other stuff swept is beautiful

* Cleanup a bunch of controllers

* Fix shooting and high pressure movement controller

* Flashing improvements

* Stuff and things

* Combat collisions

* Combat mode collisions

* Pulling distance joint again

* Cleanup physics interfaces

* More like scuffedularity

* Shit's fucked

* Haha tests go green

* Bigmoneycrab

* Fix dupe pulling

* Zumzum's based fix

* Don't run tile friction for non-predicted bodies

* Experimental pulling improvement

* Everything's a poly now

* Optimise AI region debugging a bit

Could still be better but should improve default performance a LOT

* Mover no updater

* Crazy kinematic body idea

* Good collisions

* KinematicController

* Fix aghost

* Throwing refactor

* Pushing cleanup

* Fix throwing and footstep sounds

* Frametime in ICollideBehavior

* Fix stuff

* Actually fix weightlessness

* Optimise collision behaviors a lot

* Make open lockers still collide with walls

* powwweeerrrrr

* Merge master proper

* AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

* AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

* AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

* Ch ch ch changesss

* SHIP IT

* Fix #if DEBUG

* Fix vaulting and item locker collision

* Fix throwing

* Editing yaml by hand what can go wrong

* on

* Last yaml fixes

* Okay now it's fixed

* Linter

Co-authored-by: Metal Gear Sloth <metalgearsloth@gmail.com>
Co-authored-by: Vera Aguilera Puerto <zddm@outlook.es>

Content.Shared/GameObjects/Components/Movement/IMobMoverComponent.cs

@@ -0,0 +1,17 @@
+using Robust.Shared.GameObjects;
+using Robust.Shared.Map;
+
+
+namespace Content.Shared.GameObjects.Components.Movement
+{
+    public interface IMobMoverComponent : IComponent
+    {
+        EntityCoordinates LastPosition { get; set; }
+
+        public float StepSoundDistance { get; set; }
+
+        float GrabRange { get; set; }
+
+        float PushStrength { get; set; }
+    }
+}

Content.Shared/GameObjects/Components/Movement/IMoverComponent.cs

@@ -19,17 +19,6 @@ namespace Content.Shared.GameObjects.Components.Movement
         /// </summary>
         float CurrentSprintSpeed { get; }
 
-
-        /// <summary>
-        ///     The movement speed (m/s) of the entity when it pushes off of a solid object in zero gravity.
-        /// </summary>
-        float CurrentPushSpeed { get; }
-
-        /// <summary>
-        ///     How far an entity can reach (in meters) to grab hold of a solid object in zero gravity.
-        /// </summary>
-        float GrabRange { get; }
-
         /// <summary>
         ///     Is the entity Sprinting (running)?
         /// </summary>
@@ -40,10 +29,6 @@ namespace Content.Shared.GameObjects.Components.Movement
         /// </summary>
         (Vector2 walking, Vector2 sprinting) VelocityDir { get; }
 
-        EntityCoordinates LastPosition { get; set; }
-
-        float StepSoundDistance { get; set; }
-
         /// <summary>
         ///     Toggles one of the four cardinal directions. Each of the four directions are
         ///     composed into a single direction vector, <see cref="SharedPlayerInputMoverComponent.VelocityDir"/>. Enabling
@@ -55,6 +40,5 @@ namespace Content.Shared.GameObjects.Components.Movement
         void SetVelocityDirection(Direction direction, ushort subTick, bool enabled);
 
         void SetSprinting(ushort subTick, bool walking);
-
     }
 }

Content.Shared/GameObjects/Components/Movement/SharedClimbingComponent.cs

@@ -5,62 +5,107 @@ using Content.Shared.Physics;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Physics;
 using Robust.Shared.Serialization;
+using Robust.Shared.ViewVariables;
 
 namespace Content.Shared.GameObjects.Components.Movement
 {
-    public abstract class SharedClimbingComponent : Component, IActionBlocker, ICollideSpecial
+    public abstract class SharedClimbingComponent : Component, IActionBlocker
     {
         public sealed override string Name => "Climbing";
         public sealed override uint? NetID => ContentNetIDs.CLIMBING;
 
-        protected IPhysicsComponent? Body;
-        protected bool IsOnClimbableThisFrame;
-
-        protected bool OwnerIsTransitioning
+        protected bool IsOnClimbableThisFrame
         {
             get
             {
-                if (Body != null && Body.TryGetController<ClimbController>(out var controller))
+                if (Body == null) return false;
+
+                foreach (var entity in Body.GetBodiesIntersecting())
                 {
-                    return controller.IsActive;
+                    if ((entity.CollisionLayer & (int) CollisionGroup.VaultImpassable) != 0) return true;
                 }
 
                 return false;
             }
         }
 
-        public abstract bool IsClimbing { get; set; }
-
         bool IActionBlocker.CanMove() => !OwnerIsTransitioning;
-        bool IActionBlocker.CanChangeDirection() => !OwnerIsTransitioning;
 
-        bool ICollideSpecial.PreventCollide(IPhysBody collided)
+        [ViewVariables]
+        protected virtual bool OwnerIsTransitioning
         {
-            if (((CollisionGroup)collided.CollisionLayer).HasFlag(CollisionGroup.VaultImpassable) && collided.Entity.HasComponent<IClimbable>())
+            get => _ownerIsTransitioning;
+            set
             {
-                IsOnClimbableThisFrame = true;
-                return IsClimbing;
+                if (_ownerIsTransitioning == value) return;
+                _ownerIsTransitioning = value;
+                if (Body == null) return;
+                if (value)
+                {
+                    Body.BodyType = BodyType.Dynamic;
+                }
+                else
+                {
+                    Body.BodyType = BodyType.KinematicController;
+                }
             }
-
-            return false;
         }
 
-        public override void Initialize()
-        {
-            base.Initialize();
+        private bool _ownerIsTransitioning = false;
 
-            Owner.TryGetComponent(out Body);
+        [ComponentDependency] protected PhysicsComponent? Body;
+
+        protected TimeSpan StartClimbTime = TimeSpan.Zero;
+
+        /// <summary>
+        ///     We'll launch the mob onto the table and give them at least this amount of time to be on it.
+        /// </summary>
+        protected const float BufferTime = 0.3f;
+
+        public virtual bool IsClimbing
+        {
+            get => _isClimbing;
+            set
+            {
+                if (_isClimbing == value) return;
+                _isClimbing = value;
+
+                ToggleVaultPassable(value);
+            }
+        }
+
+        protected bool _isClimbing;
+
+        // TODO: Layers need a re-work
+        private void ToggleVaultPassable(bool value)
+        {
+            // Hope the mob has one fixture
+            if (Body == null || Body.Deleted) return;
+
+            foreach (var fixture in Body.Fixtures)
+            {
+                if (value)
+                {
+                    fixture.CollisionMask &= ~(int) CollisionGroup.VaultImpassable;
+                }
+                else
+                {
+                    fixture.CollisionMask |= (int) CollisionGroup.VaultImpassable;
+                }
+            }
         }
 
         [Serializable, NetSerializable]
         protected sealed class ClimbModeComponentState : ComponentState
         {
-            public ClimbModeComponentState(bool climbing) : base(ContentNetIDs.CLIMBING)
+            public ClimbModeComponentState(bool climbing, bool isTransitioning) : base(ContentNetIDs.CLIMBING)
             {
                 Climbing = climbing;
+                IsTransitioning = isTransitioning;
             }
 
             public bool Climbing { get; }
+            public bool IsTransitioning { get; }
         }
     }
 }

Content.Shared/GameObjects/Components/Movement/SharedDummyInputMoverComponent.cs

@@ -10,14 +10,12 @@ namespace Content.Shared.GameObjects.Components.Movement
     public class SharedDummyInputMoverComponent : Component, IMoverComponent
     {
         public override string Name => "DummyInputMover";
+        public bool IgnorePaused => false;
         public float CurrentWalkSpeed => 0f;
         public float CurrentSprintSpeed => 0f;
-        public float CurrentPushSpeed => 0f;
-        public float GrabRange => 0f;
+
         public bool Sprinting => false;
         public (Vector2 walking, Vector2 sprinting) VelocityDir => (Vector2.Zero, Vector2.Zero);
-        public EntityCoordinates LastPosition { get; set; }
-        public float StepSoundDistance { get; set; }
 
         public void SetVelocityDirection(Direction direction, ushort subTick, bool enabled)
         {

Content.Shared/GameObjects/Components/Movement/SharedPlayerInputMoverComponent.cs

@@ -5,7 +5,6 @@ using Robust.Shared.Configuration;
 using Robust.Shared.GameObjects;
 using Robust.Shared.IoC;
 using Robust.Shared.Log;
-using Robust.Shared.Map;
 using Robust.Shared.Maths;
 using Robust.Shared.Physics;
 using Robust.Shared.Players;
@@ -15,7 +14,9 @@ using Robust.Shared.ViewVariables;
 
 namespace Content.Shared.GameObjects.Components.Movement
 {
-    public abstract class SharedPlayerInputMoverComponent : Component, IMoverComponent, ICollideSpecial
+    [RegisterComponent]
+    [ComponentReference(typeof(IMoverComponent))]
+    public class SharedPlayerInputMoverComponent : Component, IMoverComponent
     {
         // This class has to be able to handle server TPS being lower than client FPS.
         // While still having perfectly responsive movement client side.
@@ -39,8 +40,10 @@ namespace Content.Shared.GameObjects.Components.Movement
         [Dependency] private readonly IConfigurationManager _configurationManager = default!;
         [Dependency] private readonly IGameTiming _gameTiming = default!;
 
-        public sealed override string Name => "PlayerInputMover";
-        public sealed override uint? NetID => ContentNetIDs.PLAYER_INPUT_MOVER;
+        [ComponentDependency] private readonly MovementSpeedModifierComponent? _movementSpeed = default!;
+
+        public override string Name => "PlayerInputMover";
+        public override uint? NetID => ContentNetIDs.PLAYER_INPUT_MOVER;
 
         private GameTick _lastInputTick;
         private ushort _lastInputSubTick;
@@ -49,36 +52,10 @@ namespace Content.Shared.GameObjects.Components.Movement
 
         private MoveButtons _heldMoveButtons = MoveButtons.None;
 
-        public float CurrentWalkSpeed
-        {
-            get
-            {
-                if (Owner.TryGetComponent(out MovementSpeedModifierComponent? component))
-                {
-                    return component.CurrentWalkSpeed;
-                }
+        public float CurrentWalkSpeed => _movementSpeed?.CurrentWalkSpeed ?? MovementSpeedModifierComponent.DefaultBaseWalkSpeed;
 
-                return MovementSpeedModifierComponent.DefaultBaseWalkSpeed;
-            }
-        }
+        public float CurrentSprintSpeed => _movementSpeed?.CurrentSprintSpeed ?? MovementSpeedModifierComponent.DefaultBaseSprintSpeed;
 
-        public float CurrentSprintSpeed
-        {
-            get
-            {
-                if (Owner.TryGetComponent(out MovementSpeedModifierComponent? component))
-                {
-                    return component.CurrentSprintSpeed;
-                }
-
-                return MovementSpeedModifierComponent.DefaultBaseSprintSpeed;
-            }
-        }
-
-        [ViewVariables(VVAccess.ReadWrite)]
-        public float CurrentPushSpeed => 5;
-        [ViewVariables(VVAccess.ReadWrite)]
-        public float GrabRange => 0.2f;
         public bool Sprinting => !HasFlag(_heldMoveButtons, MoveButtons.Walk);
 
         /// <summary>
@@ -131,9 +108,6 @@ namespace Content.Shared.GameObjects.Components.Movement
             }
         }
 
-        public abstract EntityCoordinates LastPosition { get; set; }
-        public abstract float StepSoundDistance { get; set; }
-
         /// <summary>
         ///     Whether or not the player can move diagonally.
         /// </summary>
@@ -141,18 +115,12 @@ namespace Content.Shared.GameObjects.Components.Movement
         public bool DiagonalMovementEnabled => _configurationManager.GetCVar<bool>(CCVars.GameDiagonalMovement);
 
         /// <inheritdoc />
-        public override void OnAdd()
+        public override void Initialize()
         {
-            // This component requires that the entity has a IPhysicsComponent.
-            if (!Owner.HasComponent<IPhysicsComponent>())
-                Logger.Error(
-                    $"[ECS] {Owner.Prototype?.Name} - {nameof(SharedPlayerInputMoverComponent)} requires" +
-                    $" {nameof(IPhysicsComponent)}. ");
-
-            base.OnAdd();
+            base.Initialize();
+            Owner.EnsureComponentWarn<PhysicsComponent>();
         }
 
-
         /// <summary>
         ///     Toggles one of the four cardinal directions. Each of the four directions are
         ///     composed into a single direction vector, <see cref="VelocityDir"/>. Enabling
@@ -266,12 +234,6 @@ namespace Content.Shared.GameObjects.Components.Movement
             return vec;
         }
 
-        bool ICollideSpecial.PreventCollide(IPhysBody collidedWith)
-        {
-            // Don't collide with other mobs
-            return collidedWith.Entity.HasComponent<IBody>();
-        }
-
         [Serializable, NetSerializable]
         private sealed class MoverComponentState : ComponentState
         {

Content.Shared/GameObjects/Components/Movement/SharedPlayerMobMoverComponent.cs

@@ -0,0 +1,123 @@
+#nullable enable
+using System;
+using Content.Shared.GameObjects.Components.Body;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Log;
+using Robust.Shared.Map;
+using Robust.Shared.Maths;
+using Robust.Shared.Physics;
+using Robust.Shared.Players;
+using Robust.Shared.Serialization;
+using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.ViewVariables;
+
+namespace Content.Shared.GameObjects.Components.Movement
+{
+    /// <summary>
+    ///     The basic player mover with footsteps and grabbing
+    /// </summary>
+    [RegisterComponent]
+    [ComponentReference(typeof(IMobMoverComponent))]
+    public class SharedPlayerMobMoverComponent : Component, IMobMoverComponent, ICollideSpecial
+    {
+        public override string Name => "PlayerMobMover";
+        public override uint? NetID => ContentNetIDs.PLAYER_MOB_MOVER;
+
+        private float _stepSoundDistance;
+        [DataField("grabRange")]
+        private float _grabRange = 0.2f;
+        [DataField("pushStrength")]
+        private float _pushStrength = 600.0f;
+
+        [ViewVariables(VVAccess.ReadWrite)]
+        public EntityCoordinates LastPosition { get; set; }
+
+        /// <summary>
+        ///     Used to keep track of how far we have moved before playing a step sound
+        /// </summary>
+        [ViewVariables(VVAccess.ReadWrite)]
+        public float StepSoundDistance
+        {
+            get => _stepSoundDistance;
+            set
+            {
+                if (MathHelper.CloseTo(_stepSoundDistance, value)) return;
+                _stepSoundDistance = value;
+            }
+        }
+
+        [ViewVariables(VVAccess.ReadWrite)]
+        public float GrabRange
+        {
+            get => _grabRange;
+            set
+            {
+                if (MathHelper.CloseTo(_grabRange, value)) return;
+                _grabRange = value;
+                Dirty();
+            }
+        }
+
+        [ViewVariables(VVAccess.ReadWrite)]
+        public float PushStrength
+        {
+            get => _pushStrength;
+            set
+            {
+                if (MathHelper.CloseTo(_pushStrength, value)) return;
+                _pushStrength = value;
+                Dirty();
+            }
+        }
+
+        public override void Initialize()
+        {
+            base.Initialize();
+            if (!Owner.HasComponent<IMoverComponent>())
+            {
+                Owner.EnsureComponentWarn<SharedPlayerInputMoverComponent>();
+            }
+
+            if (Owner.TryGetComponent(out IPhysBody? body) && body.BodyType != BodyType.KinematicController)
+            {
+                Logger.WarningS("mover", $"Attached {nameof(SharedPlayerMobMoverComponent)} to a mob that's BodyType is not KinematicController!'");
+            }
+        }
+
+        public override ComponentState GetComponentState(ICommonSession session)
+        {
+            return new PlayerMobMoverComponentState(_grabRange, _pushStrength);
+        }
+
+        public override void HandleComponentState(ComponentState? curState, ComponentState? nextState)
+        {
+            base.HandleComponentState(curState, nextState);
+            if (curState is not PlayerMobMoverComponentState playerMoverState) return;
+            GrabRange = playerMoverState.GrabRange;
+            PushStrength = playerMoverState.PushStrength;
+        }
+
+        bool ICollideSpecial.PreventCollide(IPhysBody collidedWith)
+        {
+            // Don't collide with other mobs
+            // unless they have combat mode on
+            return collidedWith.Entity.HasComponent<IBody>();  /* &&
+                (!Owner.TryGetComponent(out SharedCombatModeComponent? ownerCombat) || !ownerCombat.IsInCombatMode) &&
+                (!collidedWith.Entity.TryGetComponent(out SharedCombatModeComponent? otherCombat) || !otherCombat.IsInCombatMode);
+                */
+        }
+
+        [Serializable, NetSerializable]
+        private sealed class PlayerMobMoverComponentState : ComponentState
+        {
+            public float GrabRange;
+            public float PushStrength;
+
+            public PlayerMobMoverComponentState(float grabRange, float pushStrength) : base(ContentNetIDs.PLAYER_MOB_MOVER)
+            {
+                GrabRange = grabRange;
+                PushStrength = pushStrength;
+            }
+        }
+    }
+}

Content.Shared/GameObjects/Components/Movement/SharedSlipperyComponent.cs

@@ -7,13 +7,15 @@ using Content.Shared.GameObjects.EntitySystems.EffectBlocker;
 using Content.Shared.Physics;
 using Robust.Shared.Containers;
 using Robust.Shared.GameObjects;
+using Robust.Shared.Physics;
+using Robust.Shared.Physics.Collision;
 using Robust.Shared.Serialization;
 using Robust.Shared.Serialization.Manager.Attributes;
 using Robust.Shared.ViewVariables;
 
 namespace Content.Shared.GameObjects.Components.Movement
 {
-    public abstract class SharedSlipperyComponent : Component, ICollideBehavior
+    public abstract class SharedSlipperyComponent : Component, IStartCollide
     {
         public sealed override string Name => "Slippery";
 
@@ -58,14 +60,12 @@ namespace Content.Shared.GameObjects.Components.Movement
         [DataField("slippery")]
         public virtual bool Slippery { get; set; } = true;
 
-        private bool TrySlip(IEntity entity)
+        private bool TrySlip(IPhysBody ourBody, IPhysBody otherBody)
         {
             if (!Slippery
                 || Owner.IsInContainer()
-                ||  _slipped.Contains(entity.Uid)
-                ||  !entity.TryGetComponent(out SharedStunnableComponent? stun)
-                ||  !entity.TryGetComponent(out IPhysicsComponent? otherBody)
-                ||  !Owner.TryGetComponent(out IPhysicsComponent? body))
+                ||  _slipped.Contains(otherBody.Entity.Uid)
+                ||  !otherBody.Entity.TryGetComponent(out SharedStunnableComponent? stun))
             {
                 return false;
             }
@@ -75,26 +75,22 @@ namespace Content.Shared.GameObjects.Components.Movement
                 return false;
             }
 
-            var percentage = otherBody.WorldAABB.IntersectPercentage(body.WorldAABB);
+            var percentage = otherBody.GetWorldAABB().IntersectPercentage(ourBody.GetWorldAABB());
 
             if (percentage < IntersectPercentage)
             {
                 return false;
             }
 
-            if (!EffectBlockerSystem.CanSlip(entity))
+            if (!EffectBlockerSystem.CanSlip(otherBody.Entity))
             {
                 return false;
             }
 
-            if (entity.TryGetComponent(out IPhysicsComponent? physics))
-            {
-                var controller = physics.EnsureController<SlipController>();
-                controller.LinearVelocity = physics.LinearVelocity * LaunchForwardsMultiplier;
-            }
+            otherBody.LinearVelocity *= LaunchForwardsMultiplier;
 
             stun.Paralyze(5);
-            _slipped.Add(entity.Uid);
+            _slipped.Add(otherBody.Entity.Uid);
 
             OnSlip();
 
@@ -103,9 +99,9 @@ namespace Content.Shared.GameObjects.Components.Movement
 
         protected virtual void OnSlip() { }
 
-        public void CollideWith(IEntity collidedWith)
+        void IStartCollide.CollideWith(IPhysBody ourBody, IPhysBody otherBody, in Manifold manifold)
         {
-            TrySlip(collidedWith);
+            TrySlip(ourBody, otherBody);
         }
 
         public void Update()
@@ -119,10 +115,10 @@ namespace Content.Shared.GameObjects.Components.Movement
                 }
 
                 var entity = Owner.EntityManager.GetEntity(uid);
-                var physics = Owner.GetComponent<IPhysicsComponent>();
-                var otherPhysics = entity.GetComponent<IPhysicsComponent>();
+                var physics = Owner.GetComponent<IPhysBody>();
+                var otherPhysics = entity.GetComponent<IPhysBody>();
 
-                if (!physics.WorldAABB.Intersects(otherPhysics.WorldAABB))
+                if (!physics.GetWorldAABB().Intersects(otherPhysics.GetWorldAABB()))
                 {
                     _slipped.Remove(uid);
                 }
@@ -137,12 +133,12 @@ namespace Content.Shared.GameObjects.Components.Movement
 
             physics.Hard = false;
 
-            var shape = physics.PhysicsShapes.FirstOrDefault();
+            var fixtures = physics.Fixtures.FirstOrDefault();
 
-            if (shape != null)
+            if (fixtures != null)
             {
-                shape.CollisionLayer |= (int) CollisionGroup.SmallImpassable;
-                shape.CollisionMask = (int) CollisionGroup.None;
+                fixtures.CollisionLayer |= (int) CollisionGroup.SmallImpassable;
+                fixtures.CollisionMask = (int) CollisionGroup.None;
             }
         }
     }

Content.Shared/GameObjects/Components/Movement/TileFrictionModifier.cs

@@ -0,0 +1,58 @@
+#nullable enable
+using System;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Maths;
+using Robust.Shared.Players;
+using Robust.Shared.Serialization;
+using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.ViewVariables;
+
+namespace Content.Shared.GameObjects.Components.Movement
+{
+    [RegisterComponent]
+    public class SharedTileFrictionModifier : Component
+    {
+        public override string Name => "TileFrictionModifier";
+
+        /// <summary>
+        ///     Multiply the tilefriction cvar by this to get the body's actual tilefriction.
+        /// </summary>
+        [ViewVariables(VVAccess.ReadWrite)]
+        public float Modifier
+        {
+            get => _modifier;
+            set
+            {
+                if (MathHelper.CloseTo(_modifier, value)) return;
+
+                _modifier = value;
+            }
+        }
+
+        [DataField("modifier")]
+        private float _modifier = 1.0f;
+
+        public override ComponentState GetComponentState(ICommonSession session)
+        {
+            return new TileFrictionComponentState(_modifier);
+        }
+
+        public override void HandleComponentState(ComponentState? curState, ComponentState? nextState)
+        {
+            base.HandleComponentState(curState, nextState);
+            if (curState is not TileFrictionComponentState tileState) return;
+            _modifier = tileState.Modifier;
+        }
+
+        [NetSerializable, Serializable]
+        protected class TileFrictionComponentState : ComponentState
+        {
+            public float Modifier;
+
+            public TileFrictionComponentState(float modifier) : base(ContentNetIDs.TILE_FRICTION)
+            {
+                Modifier = modifier;
+            }
+        }
+    }
+}