Adds InRangeUnobstructed method to InteractionSystem (#698)

* You cannot pickup items across walls, or pickup items when dead/in crit.

* Adds InRangeUnobstructed method to InteractionSystem.
Changes HandsSystem and ItemComponent to use it.

Content.Server/GameObjects/Components/Items/Storage/ItemComponent.cs

@@ -2,11 +2,14 @@
 using Content.Server.Interfaces.GameObjects;
 using Content.Shared.GameObjects;
 using Content.Shared.GameObjects.Components.Items;
+using Content.Shared.Physics;
 using Robust.Server.GameObjects;
 using Robust.Server.Interfaces.GameObjects;
 using Robust.Shared.Containers;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Map;
+using Robust.Shared.Interfaces.Physics;
 using Robust.Shared.Interfaces.Random;
 using Robust.Shared.IoC;
 using Robust.Shared.Maths;
@@ -24,6 +27,9 @@ namespace Content.Server.GameObjects
 
         #pragma warning disable 649
         [Dependency] private readonly IRobustRandom _robustRandom;
+        [Dependency] private readonly IPhysicsManager _physicsManager;
+        [Dependency] private readonly IMapManager _mapManager;
+        [Dependency] private readonly IEntitySystemManager _entitySystemManager;
         #pragma warning restore 649
 
         private string _equippedPrefix;
@@ -64,8 +70,19 @@ namespace Content.Server.GameObjects
             serializer.DataField(ref _equippedPrefix, "HeldPrefix", null);
         }
 
+        public bool CanPickup(IEntity user)
+        {
+            var coords = Owner.Transform.GridPosition;
+
+            if (!ActionBlockerSystem.CanPickup(user)) return false;
+            return _entitySystemManager.GetEntitySystem<InteractionSystem>()
+                .InRangeUnobstructed(coords, user.Transform.GridPosition, ignoredEnt:Owner);
+        }
+
         public bool AttackHand(AttackHandEventArgs eventArgs)
         {
+            if (!CanPickup(eventArgs.User)) return false;
+
             var hands = eventArgs.User.GetComponent<IHandsComponent>();
             hands.PutInHand(this, hands.ActiveIndex, fallback: false);
             return true;
@@ -85,7 +102,7 @@ namespace Content.Server.GameObjects
 
             protected override VerbVisibility GetVisibility(IEntity user, ItemComponent component)
             {
-                if (ContainerHelpers.IsInContainer(component.Owner))
+                if (ContainerHelpers.IsInContainer(component.Owner) || !component.CanPickup(user))
                 {
                     return VerbVisibility.Invisible;
                 }

Content.Server/GameObjects/Components/Mobs/DamageStates.cs

@@ -62,7 +62,12 @@ namespace Content.Server.GameObjects
         {
             return true;
         }
-        
+
+        bool IActionBlocker.CanPickup()
+        {
+            return true;
+        }
+
         bool IActionBlocker.CanEmote()
         {
             return true;
@@ -113,7 +118,12 @@ namespace Content.Server.GameObjects
         {
             return false;
         }
-        
+
+        bool IActionBlocker.CanPickup()
+        {
+            return false;
+        }
+
         bool IActionBlocker.CanEmote()
         {
             return false;
@@ -184,7 +194,12 @@ namespace Content.Server.GameObjects
         {
             return false;
         }
-        
+
+        bool IActionBlocker.CanPickup()
+        {
+            return false;
+        }
+
         bool IActionBlocker.CanEmote()
         {
             return false;

Content.Server/GameObjects/Components/Mobs/SpeciesComponent.cs

@@ -107,6 +107,11 @@ namespace Content.Server.GameObjects
             return CurrentDamageState.CanDrop();
         }
 
+        bool IActionBlocker.CanPickup()
+        {
+            return CurrentDamageState.CanPickup();
+        }
+
         bool IActionBlocker.CanEmote()
         {
             return CurrentDamageState.CanEmote();

Content.Server/GameObjects/EntitySystems/ActionBlockerSystem.cs

@@ -17,6 +17,8 @@ namespace Content.Server.GameObjects.EntitySystems
 
         bool CanDrop();
 
+        bool CanPickup();
+
         bool CanEmote();
     }
 
@@ -81,7 +83,17 @@ namespace Content.Server.GameObjects.EntitySystems
             }
             return candrop;
 		}
-            
+
+        public static bool CanPickup(IEntity entity)
+        {
+            bool canpickup = true;
+            foreach (var actionblockercomponents in entity.GetAllComponents<IActionBlocker>())
+            {
+                canpickup &= actionblockercomponents.CanPickup();
+            }
+            return canpickup;
+        }
+
         public static bool CanEmote(IEntity entity)
         {
             bool canemote = true;

Content.Server/GameObjects/EntitySystems/Click/InteractionSystem.cs

@@ -4,6 +4,7 @@ using Content.Server.GameObjects.Components.Mobs;
 using Content.Server.GameObjects.Components.Timing;
 using Content.Server.Interfaces.GameObjects;
 using Content.Shared.Input;
+using Content.Shared.Physics;
 using JetBrains.Annotations;
 using Robust.Server.GameObjects.EntitySystems;
 using Robust.Server.Interfaces.Player;
@@ -14,6 +15,7 @@ using Robust.Shared.Input;
 using Robust.Shared.Interfaces.GameObjects;
 using Robust.Shared.Interfaces.GameObjects.Components;
 using Robust.Shared.Interfaces.Map;
+using Robust.Shared.Interfaces.Physics;
 using Robust.Shared.IoC;
 using Robust.Shared.Log;
 using Robust.Shared.Map;
@@ -248,6 +250,7 @@ namespace Content.Server.GameObjects.EntitySystems
     {
 #pragma warning disable 649
         [Dependency] private readonly IMapManager _mapManager;
+        [Dependency] private readonly IPhysicsManager _physicsManager;
 #pragma warning restore 649
 
         public const float InteractionRange = 2;
@@ -264,6 +267,34 @@ namespace Content.Server.GameObjects.EntitySystems
                 new PointerInputCmdHandler(HandleActivateItemInWorld));
         }
 
+        /// <summary>
+        ///     Checks that these coordinates are within a certain distance without any
+        ///     entity that matches the collision mask obstructing them.
+        ///     If the <paramref name="range"/> is zero or negative,
+        ///     this method will only check if nothing obstructs the two sets of coordinates..
+        /// </summary>
+        /// <param name="mapManager">Map manager containing the two GridIds.</param>
+        /// <param name="coords">Set of coordinates to use.</param>
+        /// <param name="otherCoords">Other set of coordinates to use.</param>
+        /// <param name="range">maximum distance between the two sets of coordinates.</param>
+        /// <param name="collisionMask">the mask to check for collisions</param>
+        /// <param name="ignoredEnt">the entity to be ignored when checking for collisions.</param>
+        /// <returns>True if the two points are within a given range without being obstructed.</returns>
+        public bool InRangeUnobstructed(GridCoordinates coords, GridCoordinates otherCoords, float range = InteractionRange, int collisionMask = (int)CollisionGroup.Impassable, IEntity ignoredEnt = null)
+        {
+            if (range > 0f && !coords.InRange(_mapManager, otherCoords, range))
+            {
+                return false;
+            }
+
+            var dir = (otherCoords.Position - coords.Position);
+            if (!(dir.Length > 0f)) return true;
+            var ray = new CollisionRay(coords.Position, dir.Normalized, collisionMask);
+            var rayResults = _physicsManager.IntersectRay(_mapManager.GetGrid(coords.GridID).ParentMapId, ray, dir.Length, ignoredEnt);
+
+            return !rayResults.DidHitObject;
+        }
+
         private bool HandleActivateItemInWorld(ICommonSession session, GridCoordinates coords, EntityUid uid)
         {
             if (!EntityManager.TryGetEntity(uid, out var used))

Content.Server/GameObjects/EntitySystems/HandsSystem.cs

@@ -31,6 +31,7 @@ namespace Content.Server.GameObjects.EntitySystems
     {
 #pragma warning disable 649
         [Dependency] private readonly IMapManager _mapManager;
+        [Dependency] private readonly IEntitySystemManager _entitySystemManager;
 #pragma warning restore 649
 
         private const float ThrowForce = 1.5f; // Throwing force of mobs in Newtons
@@ -126,11 +127,9 @@ namespace Content.Server.GameObjects.EntitySystems
             if (handsComp.GetActiveHand == null)
                 return false;
 
-            var dir = (coords.Position - ent.Transform.GridPosition.Position);
+            var interactionSystem = _entitySystemManager.GetEntitySystem<InteractionSystem>();
-            var ray = new CollisionRay(ent.Transform.GridPosition.Position, dir.Normalized, (int) CollisionGroup.Impassable);
-            var rayResults = IoCManager.Resolve<IPhysicsManager>().IntersectRay(ent.Transform.MapID, ray, dir.Length, ent);
 
-            if(!rayResults.DidHitObject)
+            if(interactionSystem.InRangeUnobstructed(coords, ent.Transform.GridPosition, 0f, ignoredEnt:ent))
                 if (coords.InRange(_mapManager, ent.Transform.GridPosition, InteractionSystem.InteractionRange))
                 {
                     handsComp.Drop(handsComp.ActiveIndex, coords);