Mucin speed boost now only affects Gastropoids

Content.Server/Chemistry/TileReactions/EnsureTileReaction.cs

@@ -0,0 +1,47 @@
+using Content.Server.Fluids.EntitySystems;
+using Content.Shared.Chemistry.Components;
+using Content.Shared.Chemistry.Reaction;
+using Content.Shared.Chemistry.Reagent;
+using Content.Shared.FixedPoint;
+using Content.Shared.Tag;
+using JetBrains.Annotations;
+using Robust.Shared.Map;
+using Robust.Shared.Prototypes;
+
+namespace Content.Server.Chemistry.TileReactions
+{
+    [UsedImplicitly]
+    [DataDefinition]
+    public sealed partial class EnsureTileReaction : ITileReaction
+    {
+        [DataField, ViewVariables]
+        public ComponentRegistry Components = new();
+
+        [DataField, ViewVariables]
+        public HashSet<ProtoId<TagPrototype>> Tags = new();
+
+        [DataField, ViewVariables]
+        public bool Override = false;
+
+        public FixedPoint2 TileReact(TileRef tile,
+            ReagentPrototype reagent,
+            FixedPoint2 reactVolume,
+            IEntityManager entityManager,
+            List<ReagentData>? data)
+        {
+            if (reactVolume < 5)
+                return FixedPoint2.Zero;
+
+            if (entityManager.EntitySysManager.GetEntitySystem<PuddleSystem>()
+                .TrySpillAt(tile, new Solution(reagent.ID, reactVolume, data), out var puddleUid, false, false))
+            {
+                entityManager.AddComponents(puddleUid, Components, Override);
+                entityManager.EntitySysManager.GetEntitySystem<TagSystem>().AddTags(puddleUid, Tags);
+
+                return reactVolume;
+            }
+
+            return FixedPoint2.Zero;
+        }
+    }
+}

Content.Shared/Fluids/Components/PropulsedByComponent.cs

@@ -0,0 +1,11 @@
+using Robust.Shared.GameStates;
+
+namespace Content.Shared.Fluids.Components
+{
+    [RegisterComponent, NetworkedComponent]
+    public sealed partial class PropulsedByComponent : Component
+    {
+        [ViewVariables(VVAccess.ReadOnly)]
+        public HashSet<Entity<PropulsionComponent>> Sources = new();
+    }
+}

Content.Shared/Fluids/Components/PropulsionComponent.cs

@@ -0,0 +1,35 @@
+using Content.Shared.Whitelist;
+using Robust.Shared.GameStates;
+
+namespace Content.Shared.Fluids.Components
+{
+    /// <summary>
+    /// This object will speed up the movement speed of entities
+    /// when collided with
+    /// 
+    /// Used for mucin
+    /// 
+    /// This partially replicates SpeedModifierContactsComponent because that
+    /// component is already heavily coupled with existing puddle code.
+    /// </summary>
+    [RegisterComponent, NetworkedComponent]
+    [AutoGenerateComponentState]
+    public sealed partial class PropulsionComponent : Component
+    {
+        [DataField, ViewVariables]
+        [AutoNetworkedField]
+        public float WalkSpeedModifier = 1.0f;
+
+        [AutoNetworkedField]
+        [DataField, ViewVariables]
+        public float SprintSpeedModifier = 1.0f;
+
+        /// <summary>
+        /// If an entity passes this, apply the speed modifier.
+        /// Passes all entities if not defined.
+        /// </summary>
+        [AutoNetworkedField]
+        [DataField, ViewVariables]
+        public EntityWhitelist? Whitelist;
+    }
+}

Content.Shared/Fluids/EntitySystems/PropulsionSystem.cs

@@ -0,0 +1,62 @@
+using System.Linq;
+using Content.Shared.Fluids.Components;
+using Content.Shared.Movement.Components;
+using Content.Shared.Movement.Systems;
+using Content.Shared.Whitelist;
+using Robust.Shared.Physics.Events;
+
+namespace Content.Shared.Fluids.EntitySystems;
+
+public sealed class PropulsionSystem : EntitySystem
+{
+    [Dependency] private readonly SpeedModifierContactsSystem _speedModifier = default!;
+    [Dependency] private readonly EntityWhitelistSystem _whitelistSystem = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        SubscribeLocalEvent<PropulsionComponent, ComponentInit>(OnComponentInit);
+        SubscribeLocalEvent<PropulsionComponent, StartCollideEvent>(OnStartCollide);
+        SubscribeLocalEvent<PropulsionComponent, EndCollideEvent>(OnEndCollide);
+        SubscribeLocalEvent<PropulsedByComponent, RefreshMovementSpeedModifiersEvent>(OnRefreshSpeed);
+    }
+
+    public void OnComponentInit(Entity<PropulsionComponent> ent, ref ComponentInit args)
+    {
+        EnsureComp<SpeedModifierContactsComponent>(ent);
+    }
+
+    public void OnStartCollide(Entity<PropulsionComponent> ent, ref StartCollideEvent args)
+    {
+        if (!HasComp<MovementSpeedModifierComponent>(args.OtherEntity))
+            return;
+
+        if (_whitelistSystem.IsWhitelistFail(ent.Comp.Whitelist, args.OtherEntity))
+            return;
+
+        _speedModifier.AddModifiedEntity(args.OtherEntity);
+
+        var propulse = EnsureComp<PropulsedByComponent>(args.OtherEntity);
+        propulse.Sources.Add(ent);
+    }
+
+    public void OnEndCollide(Entity<PropulsionComponent> ent, ref EndCollideEvent args)
+    {
+        if (TryComp<PropulsedByComponent>(args.OtherEntity, out var propulse))
+        {
+            propulse.Sources.Remove(ent);
+        }
+    }
+
+    public static void OnRefreshSpeed(Entity<PropulsedByComponent> ent, ref RefreshMovementSpeedModifiersEvent args)
+    {
+        ent.Comp.Sources.RemoveWhere((ent) => !ent.Owner.IsValid() || ent.Comp.Deleted);
+
+        if (ent.Comp.Sources.Count == 0)
+            return;
+
+        var modifier = ent.Comp.Sources.First();
+        args.ModifySpeed(modifier.Comp.WalkSpeedModifier, modifier.Comp.SprintSpeedModifier);
+    }
+}

Resources/Prototypes/Entities/Effects/puddle.yml

@@ -76,16 +76,19 @@
   parent: PuddleTemporary
   suffix: Mucin
   components:
-  - type: TimedDespawn
-    lifetime: 5
-  - type: EvaporationSparkle
   - type: SolutionContainerManager
     solutions:
       puddle:
         maxVol: 1000
         reagents:
         - ReagentId: Mucin
           Quantity: 20
+  - type: Propulsion
+    walkSpeedModifier: 2.0
+    sprintSpeedModifier: 2.0
+    whitelist:
+      components:
+        - SnailSpeed
 
 - type: entity
   id: PuddleFlour

Resources/Prototypes/Reagents/biological.yml

@@ -92,7 +92,7 @@
   recognizable: true
   physicalDesc: reagent-physical-desc-viscous
   slippery: false
-  viscosity: -0.5
+  viscosity: 0.1
   metabolisms:
     Food:
       effects:
@@ -103,7 +103,14 @@
     params:
       volume: 6
   tileReactions:
-    - !type:SpillTileReaction
+    - !type:EnsureTileReaction
+      components:
+        - type: Propulsion
+          walkSpeedModifier: 2.0
+          sprintSpeedModifier: 2.0
+          whitelist:
+            components:
+              - SnailSpeed
 
 - type: reagent
   id: Sap