Add slipping moving you forward a few tiles (#1520)

* Add slipping moving you forward

* Check for weightless and change decay to a multiplier

* Pragma moment

Content.Shared/GameObjects/Components/Movement/SharedSlipperyComponent.cs

@@ -74,6 +74,12 @@ namespace Content.Shared.GameObjects.Components.Movement
                 return false;
             }
 
+            if (entity.TryGetComponent(out ICollidableComponent collidable))
+            {
+                var controller = collidable.EnsureController<SlipController>();
+                controller.LinearVelocity = collidable.LinearVelocity;
+            }
+
             stun.Paralyze(5);
             _slipped.Add(entity.Uid);
 

Content.Shared/Physics/SlipController.cs

@@ -0,0 +1,40 @@
+using Robust.Shared.Interfaces.Physics;
+using Robust.Shared.IoC;
+using Robust.Shared.Physics;
+
+namespace Content.Shared.Physics
+{
+    public class SlipController : VirtualController
+    {
+#pragma warning disable 649
+        [Dependency] private readonly IPhysicsManager _physicsManager;
+#pragma warning restore 649
+
+        public SlipController()
+        {
+            IoCManager.InjectDependencies(this);
+        }
+
+        private float Decay { get; set; } = 0.95f;
+
+        public override void UpdateAfterProcessing()
+        {
+            if (ControlledComponent == null)
+            {
+                return;
+            }
+
+            if (_physicsManager.IsWeightless(ControlledComponent.Owner.Transform.GridPosition))
+            {
+                return;
+            }
+
+            LinearVelocity *= Decay;
+
+            if (LinearVelocity.Length < 0.001)
+            {
+                Stop();
+            }
+        }
+    }
+}