Allow fire extinguishers and sprays to push grids you are standing on (#31754)

* allow fire extinguishers and sprays to push grids

* add cvar and reduce pushback

* EmoGarbage Review - Resolve Conflicts

* Ensure grid parenting

---------

Co-authored-by: EmoGarbage404 <retron404@gmail.com>

Content.Server/Fluids/Components/SprayComponent.cs

@@ -32,10 +32,10 @@ public sealed partial class SprayComponent : Component
     /// <summary>
     /// How much the player is pushed back for each spray.
     /// </summary>
-    [ViewVariables(VVAccess.ReadWrite), DataField]
-    public float PushbackAmount = 2f;
+    [DataField]
+    public float PushbackAmount = 5f;
 
-    [ViewVariables(VVAccess.ReadWrite), DataField(required: true)]
+    [DataField(required: true)]
     [Access(typeof(SpraySystem), Other = AccessPermissions.ReadExecute)] // FIXME Friends
     public SoundSpecifier SpraySound { get; private set; } = default!;
 }

Content.Server/Fluids/EntitySystems/SpraySystem.cs

@@ -3,14 +3,16 @@ using Content.Server.Chemistry.EntitySystems;
 using Content.Server.Fluids.Components;
 using Content.Server.Gravity;
 using Content.Server.Popups;
+using Content.Shared.CCVar;
+using Content.Shared.Chemistry.EntitySystems;
 using Content.Shared.FixedPoint;
 using Content.Shared.Fluids;
 using Content.Shared.Interaction;
 using Content.Shared.Timing;
 using Content.Shared.Vapor;
-using Content.Shared.Chemistry.EntitySystems;
 using Robust.Server.GameObjects;
 using Robust.Shared.Audio.Systems;
+using Robust.Shared.Configuration;
 using Robust.Shared.Physics.Components;
 using Robust.Shared.Prototypes;
 using System.Numerics;
@@ -30,6 +32,9 @@ public sealed class SpraySystem : EntitySystem
     [Dependency] private readonly VaporSystem _vapor = default!;
     [Dependency] private readonly SharedAppearanceSystem _appearance = default!;
     [Dependency] private readonly SharedTransformSystem _transform = default!;
+    [Dependency] private readonly IConfigurationManager _cfg = default!;
+
+    private float _gridImpulseMultiplier;
 
     public override void Initialize()
     {
@@ -37,6 +42,7 @@ public sealed class SpraySystem : EntitySystem
 
         SubscribeLocalEvent<SprayComponent, AfterInteractEvent>(OnAfterInteract);
         SubscribeLocalEvent<SprayComponent, UserActivateInWorldEvent>(OnActivateInWorld);
+        Subs.CVar(_cfg, CCVars.GridImpulseMultiplier, UpdateGridMassMultiplier, true);
     }
 
     private void OnActivateInWorld(Entity<SprayComponent> entity, ref UserActivateInWorldEvent args)
@@ -51,6 +57,11 @@ public sealed class SpraySystem : EntitySystem
         Spray(entity, args.User, targetMapPos);
     }
 
+    private void UpdateGridMassMultiplier(float value)
+    {
+        _gridImpulseMultiplier = value;
+    }
+
     private void OnAfterInteract(Entity<SprayComponent> entity, ref AfterInteractEvent args)
     {
         if (args.Handled)
@@ -156,7 +167,21 @@ public sealed class SpraySystem : EntitySystem
             if (TryComp<PhysicsComponent>(user, out var body))
             {
                 if (_gravity.IsWeightless(user, body))
-                    _physics.ApplyLinearImpulse(user, -impulseDirection.Normalized() * entity.Comp.PushbackAmount, body: body);
+                {
+                    // push back the player
+                    _physics.ApplyLinearImpulse(user, -impulseDirection * entity.Comp.PushbackAmount, body: body);
+                }
+                else
+                {
+                    // push back the grid the player is standing on
+                    var userTransform = Transform(user);
+                    if (userTransform.GridUid == userTransform.ParentUid)
+                    {
+                        // apply both linear and angular momentum depending on the player position
+                        // multiply by a cvar because grid mass is currently extremely small compared to all other masses
+                        _physics.ApplyLinearImpulse(userTransform.GridUid.Value, -impulseDirection * _gridImpulseMultiplier * entity.Comp.PushbackAmount, userTransform.LocalPosition);
+                    }
+                }
             }
         }
 

Content.Shared/CCVar/CCVars.Shuttle.cs

@@ -182,4 +182,16 @@ public sealed partial class CCVars
     /// </summary>
     public static readonly CVarDef<int> EmergencyShuttleAutoCallExtensionTime =
         CVarDef.Create("shuttle.auto_call_extension_time", 45, CVar.SERVERONLY);
+
+    /// <summary>
+    ///     Impulse multiplier for player interactions that move grids (other than shuttle thrusters, gyroscopes and grid collisons).
+    ///     At the moment this only affects the pushback in SpraySystem.
+    ///     A higher value means grids have a lower effective mass and therefore will get pushed stronger.
+    ///     A value of 0 will disable pushback.
+    ///     The default has been chosen such that a one tile grid roughly equals 2/3 Urist masses.
+    ///     TODO: Make grid mass a sane number so we can get rid of this.
+    ///         At the moment they have a very low mass of roughly 0.48 kg per tile independent of any walls or anchored objects on them.
+    /// </summary>
+    public static readonly CVarDef<float> GridImpulseMultiplier =
+        CVarDef.Create("shuttle.grid_impulse_multiplier", 0.01f, CVar.SERVERONLY);
 }