Add PlaceCentered bool to PlaceableSurfaceComponent (#2771)

* Added bool _placeCentered to check if an entity must be placed at mouse position or center of the PlaceableSurface (+ offset) when dropped.

* private variables formatted to camel case

* Use EqualsApprox in the setter for PositionOffset

* -Changed client-side SurfaceComponent to camelCase
-Added placeCentered and positionOffset to PlaceableSurfaceComponentState
-Getter and setters for placeCentered and positionOffset client-side

* Update Content.Client/GameObjects/Components/PlaceableSurfaceComponent.cs

Co-authored-by: Vera Aguilera Puerto <6766154+Zumorica@users.noreply.github.com>

* Add "_" to private vars name

* Made YAML properties camelCase

* Add "_" to private vars name

* Call Dirty() when IsPlaceable,PlaceCentered and PositionOffset are changed.

* Removed Dirty() from client.

Co-authored-by: Vera Aguilera Puerto <6766154+Zumorica@users.noreply.github.com>

Content.Server/GameObjects/Components/PlaceableSurfaceComponent.cs

@@ -1,8 +1,9 @@
-using System.Threading.Tasks;
+using System.Threading.Tasks;
 using Content.Server.GameObjects.Components.GUI;
 using Content.Shared.GameObjects.Components;
 using Content.Shared.Interfaces.GameObjects.Components;
 using Robust.Shared.GameObjects;
+using Robust.Shared.Maths;
 using Robust.Shared.Serialization;
 using Robust.Shared.ViewVariables;
 
@@ -13,6 +14,8 @@ namespace Content.Server.GameObjects.Components
     public class PlaceableSurfaceComponent : SharedPlaceableSurfaceComponent, IInteractUsing
     {
         private bool _isPlaceable;
+        private bool _placeCentered;
+        private Vector2 _positionOffset;
 
         [ViewVariables(VVAccess.ReadWrite)]
         public override bool IsPlaceable
@@ -31,6 +34,42 @@ namespace Content.Server.GameObjects.Components
             }
         }
 
+        [ViewVariables(VVAccess.ReadWrite)]
+        public override bool PlaceCentered
+        {
+            get => _placeCentered;
+            set
+            {
+                if (_placeCentered == value)
+                {
+                    return;
+                }
+
+                _placeCentered = value;
+
+                Dirty();
+
+            }
+        }
+
+        [ViewVariables(VVAccess.ReadWrite)]
+        public override Vector2 PositionOffset
+        {
+            get => _positionOffset;
+            set
+            {
+                if (_positionOffset.EqualsApprox(value))
+                {
+                    return;
+                }
+
+                _positionOffset = value;
+
+                Dirty();
+
+            }
+        }
+
         [ViewVariables]
         int IInteractUsing.Priority => -10;
 
@@ -39,11 +78,13 @@ namespace Content.Server.GameObjects.Components
             base.ExposeData(serializer);
 
             serializer.DataField(ref _isPlaceable, "IsPlaceable", true);
+            serializer.DataField(ref _placeCentered, "placeCentered", false);
+            serializer.DataField(ref _positionOffset, "positionOffset", Vector2.Zero);
         }
 
         public override ComponentState GetComponentState()
         {
-            return new PlaceableSurfaceComponentState(_isPlaceable);
+            return new PlaceableSurfaceComponentState(_isPlaceable,_placeCentered,_positionOffset);
         }
 
         public async Task<bool> InteractUsing(InteractUsingEventArgs eventArgs)
@@ -56,7 +97,10 @@ namespace Content.Server.GameObjects.Components
                 return false;
             }
             handComponent.Drop(eventArgs.Using);
-            eventArgs.Using.Transform.WorldPosition = eventArgs.ClickLocation.Position;
+            if (_placeCentered)
+                eventArgs.Using.Transform.WorldPosition = eventArgs.Target.Transform.WorldPosition + _positionOffset;
+            else
+                eventArgs.Using.Transform.WorldPosition = eventArgs.ClickLocation.Position;
             return true;
         }
     }