Grid physics 2: gun pushback

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

@@ -3,6 +3,8 @@
 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;
@@ -11,6 +13,7 @@
 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;
@@ -29,12 +32,21 @@ 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()
     {
         base.Initialize();
 
         SubscribeLocalEvent<SprayComponent, AfterInteractEvent>(OnAfterInteract);
+        Subs.CVar(_cfg, CCVars.GridImpulseMultiplier, UpdateGridMassMultiplier, true);
+    }
+
+    private void UpdateGridMassMultiplier(float value)
+    {
+        _gridImpulseMultiplier = value;
     }
 
     private void OnAfterInteract(Entity<SprayComponent> entity, ref AfterInteractEvent args)
@@ -66,7 +78,7 @@ private void OnAfterInteract(Entity<SprayComponent> entity, ref AfterInteractEve
         var userXform = xformQuery.GetComponent(args.User);
 
         var userMapPos = _transform.GetMapCoordinates(userXform);
-        var clickMapPos = args.ClickLocation.ToMap(EntityManager, _transform);
+        var clickMapPos = _transform.ToMapCoordinates(args.ClickLocation);
 
         var diffPos = clickMapPos.Position - userMapPos.Position;
         if (diffPos == Vector2.Zero || diffPos == Vector2Helpers.NaN)
@@ -138,7 +150,21 @@ private void OnAfterInteract(Entity<SprayComponent> entity, ref AfterInteractEve
             if (TryComp<PhysicsComponent>(args.User, out var body))
             {
                 if (_gravity.IsWeightless(args.User, body))
-                    _physics.ApplyLinearImpulse(args.User, -impulseDirection.Normalized() * entity.Comp.PushbackAmount, body: body);
+                {
+                    // push back the player
+                    _physics.ApplyLinearImpulse(args.User, -impulseDirection * entity.Comp.PushbackAmount, body: body);
+                }
+                else
+                {
+                    // push back the grid the player is standing on
+                    var userTransform = Transform(args.User);
+                    if (userTransform.GridUid != null)
+                    {
+                        // 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.cs

@@ -1504,6 +1504,18 @@ public static readonly CVarDef<int>
         public static readonly CVarDef<int> HideSplitGridsUnder =
             CVarDef.Create("shuttle.hide_split_grids_under", 30, CVar.SERVERONLY);
 
+        /// <summary>
+        /// Impulse multiplier for player interactions that move grids (other than shuttle thrusters, gyroscopes and grid collisons).
+        /// At the moment this affects the pushback in SpraySystem and from shooting guns.
+        /// 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.REPLICATED | CVar.SERVER);
+
         /// <summary>
         /// Whether to automatically spawn escape shuttles.
         /// </summary>

Content.Shared/Weapons/Ranged/Components/GunComponent.cs

@@ -232,6 +232,13 @@ public sealed partial class GunComponent : Component
     /// </summary>
     [DataField]
     public bool ClumsyProof = false;
+
+    /// <summary>
+    /// Pushback impulse applied to the gun's holder or the grid they are standing on when fired.
+    /// In kg*m/s
+    /// </summary>
+    [DataField]
+    public float ImpulseStrength = 25f;
 }
 
 [Flags]

Content.Shared/Weapons/Ranged/Systems/SharedGunSystem.cs

@@ -4,6 +4,7 @@
 using Content.Shared.Actions;
 using Content.Shared.Administration.Logs;
 using Content.Shared.Audio;
+using Content.Shared.CCVar;
 using Content.Shared.CombatMode;
 using Content.Shared.Containers.ItemSlots;
 using Content.Shared.Damage;
@@ -24,6 +25,7 @@
 using Content.Shared.Whitelist;
 using Robust.Shared.Audio;
 using Robust.Shared.Audio.Systems;
+using Robust.Shared.Configuration;
 using Robust.Shared.Containers;
 using Robust.Shared.Map;
 using Robust.Shared.Network;
@@ -65,7 +67,9 @@ public abstract partial class SharedGunSystem : EntitySystem
     [Dependency] protected readonly ThrowingSystem ThrowingSystem = default!;
     [Dependency] private   readonly UseDelaySystem _useDelay = default!;
     [Dependency] private readonly EntityWhitelistSystem _whitelistSystem = default!;
+    [Dependency] private readonly IConfigurationManager _cfg = default!;
 
+    private float _gridImpulseMultiplier;
     private const float InteractNextFire = 0.3f;
     private const double SafetyNextFire = 0.5;
     private const float EjectOffset = 0.4f;
@@ -97,6 +101,12 @@ public override void Initialize()
         SubscribeLocalEvent<GunComponent, CycleModeEvent>(OnCycleMode);
         SubscribeLocalEvent<GunComponent, HandSelectedEvent>(OnGunSelected);
         SubscribeLocalEvent<GunComponent, MapInitEvent>(OnMapInit);
+        Subs.CVar(_cfg, CCVars.GridImpulseMultiplier, UpdateGridMassMultiplier, true);
+    }
+
+    private void UpdateGridMassMultiplier(float value)
+    {
+        _gridImpulseMultiplier = value;
     }
 
     private void OnMapInit(Entity<GunComponent> gun, ref MapInitEvent args)
@@ -354,8 +364,7 @@ private void AttemptShoot(EntityUid user, EntityUid gunUid, GunComponent gun)
 
         if (userImpulse && TryComp<PhysicsComponent>(user, out var userPhysics))
         {
-            if (_gravity.IsWeightless(user, userPhysics))
-                CauseImpulse(fromCoordinates, toCoordinates.Value, user, userPhysics);
+            CauseImpulse(gun.ImpulseStrength, fromCoordinates, toCoordinates.Value, user, userPhysics);
         }
 
         Dirty(gunUid, gun);
@@ -479,15 +488,29 @@ protected void MuzzleFlash(EntityUid gun, AmmoComponent component, Angle worldAn
         CreateEffect(gun, ev, gun);
     }
 
-    public void CauseImpulse(EntityCoordinates fromCoordinates, EntityCoordinates toCoordinates, EntityUid user, PhysicsComponent userPhysics)
+    public void CauseImpulse(float impulseStrength, EntityCoordinates fromCoordinates, EntityCoordinates toCoordinates, EntityUid user, PhysicsComponent userPhysics)
     {
         var fromMap = fromCoordinates.ToMapPos(EntityManager, TransformSystem);
         var toMap = toCoordinates.ToMapPos(EntityManager, TransformSystem);
         var shotDirection = (toMap - fromMap).Normalized();
 
-        const float impulseStrength = 25.0f;
-        var impulseVector =  shotDirection * impulseStrength;
-        Physics.ApplyLinearImpulse(user, -impulseVector, body: userPhysics);
+        var impulseVector = shotDirection * impulseStrength;
+        if (_gravity.IsWeightless(user, userPhysics))
+        {
+            // push back the player
+            Physics.ApplyLinearImpulse(user, -impulseVector, body: userPhysics);
+        }
+        else
+        {
+            // push back the grid the player is standing on
+            var userTransform = Transform(user);
+            if (userTransform.GridUid != null)
+            {
+                // 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, -impulseVector * _gridImpulseMultiplier, userTransform.LocalPosition);
+            }
+        }
     }
 
     public void RefreshModifiers(Entity<GunComponent?> gun)