From 0f7da24993a943143879b8669266d214b4385d29 Mon Sep 17 00:00:00 2001
From: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>
Date: Mon, 8 Mar 2021 12:10:04 +1100
Subject: [PATCH] Better throwing collisions (#3568)

Co-authored-by: Metal Gear Sloth <metalgearsloth@gmail.com>
---
 .../Components/Items/Storage/ItemComponent.cs | 26 +------------------
 .../Components/Items/ThrownItemComponent.cs   | 24 ++++++++++++++++-
 2 files changed, 24 insertions(+), 26 deletions(-)

diff --git a/Content.Server/GameObjects/Components/Items/Storage/ItemComponent.cs b/Content.Server/GameObjects/Components/Items/Storage/ItemComponent.cs
index 054e3331f1..6d1c8e76dc 100644
--- a/Content.Server/GameObjects/Components/Items/Storage/ItemComponent.cs
+++ b/Content.Server/GameObjects/Components/Items/Storage/ItemComponent.cs
@@ -7,16 +7,13 @@ using Content.Shared.GameObjects.EntitySystems;
 using Content.Shared.GameObjects.EntitySystems.ActionBlocker;
 using Content.Shared.GameObjects.Verbs;
 using Content.Shared.Interfaces.GameObjects.Components;
-using Content.Shared.Physics;
 using Content.Shared.Utility;
 using Robust.Server.GameObjects;
 using Robust.Shared.Containers;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Localization;
 using Robust.Shared.Players;
-using Robust.Shared.Prototypes;
 using Robust.Shared.Physics;
-using Robust.Shared.Serialization;
 using Robust.Shared.Serialization.Manager.Attributes;
 
 namespace Content.Server.GameObjects.Components.Items.Storage
@@ -25,7 +22,7 @@ namespace Content.Server.GameObjects.Components.Items.Storage
     [ComponentReference(typeof(StorableComponent))]
     [ComponentReference(typeof(SharedStorableComponent))]
     [ComponentReference(typeof(IItemComponent))]
-    public class ItemComponent : StorableComponent, IInteractHand, IExAct, IEquipped, IUnequipped, IItemComponent, IThrown, ILand
+    public class ItemComponent : StorableComponent, IInteractHand, IExAct, IEquipped, IUnequipped, IItemComponent
     {
         public override string Name => "Item";
         public override uint? NetID => ContentNetIDs.ITEM;
@@ -155,26 +152,5 @@ namespace Content.Server.GameObjects.Components.Items.Storage
 
             Owner.TryThrow(dirVec * throwForce);
         }
-
-        // TODO: Predicted
-        void IThrown.Thrown(ThrownEventArgs eventArgs)
-        {
-            if (!Owner.TryGetComponent(out PhysicsComponent physicsComponent)) return;
-
-            foreach (var fixture in physicsComponent.Fixtures)
-            {
-                fixture.CollisionLayer |= (int) CollisionGroup.MobImpassable;
-            }
-        }
-
-        void ILand.Land(LandEventArgs eventArgs)
-        {
-            if (!Owner.TryGetComponent(out PhysicsComponent physicsComponent)) return;
-
-            foreach (var fixture in physicsComponent.Fixtures)
-            {
-                fixture.CollisionLayer &= ~(int) CollisionGroup.MobImpassable;
-            }
-        }
     }
 }
diff --git a/Content.Shared/GameObjects/Components/Items/ThrownItemComponent.cs b/Content.Shared/GameObjects/Components/Items/ThrownItemComponent.cs
index fc53c555fb..727fe326dc 100644
--- a/Content.Shared/GameObjects/Components/Items/ThrownItemComponent.cs
+++ b/Content.Shared/GameObjects/Components/Items/ThrownItemComponent.cs
@@ -1,18 +1,23 @@
 #nullable enable
 using Content.Shared.GameObjects.EntitySystems;
+using Content.Shared.Interfaces.GameObjects.Components;
+using Content.Shared.Physics;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Physics;
 using Robust.Shared.Physics.Collision;
+using Robust.Shared.Physics.Dynamics;
 
 namespace Content.Shared.GameObjects.Components.Items
 {
     [RegisterComponent]
-    public class ThrownItemComponent : Component, IStartCollide, ICollideSpecial
+    public class ThrownItemComponent : Component, IStartCollide, ICollideSpecial, IThrown, ILand
     {
         public override string Name => "ThrownItem";
 
         public IEntity? Thrower { get; set; }
 
+        private Fixture? _fixture;
+
         void IStartCollide.CollideWith(IPhysBody ourBody, IPhysBody otherBody, in Manifold manifold)
         {
             if (otherBody.Entity == Thrower) return;
@@ -23,5 +28,22 @@ namespace Content.Shared.GameObjects.Components.Items
         {
             return collidedwith.Entity == Thrower;
         }
+
+        void IThrown.Thrown(ThrownEventArgs eventArgs)
+        {
+            if (!Owner.TryGetComponent(out PhysicsComponent? physicsComponent) ||
+                physicsComponent.Fixtures.Count != 1) return;
+
+            var shape = physicsComponent.Fixtures[0].Shape;
+            _fixture = new Fixture(physicsComponent, shape) {CollisionLayer = (int) CollisionGroup.ThrownItem, Hard = false};
+            physicsComponent.AddFixture(_fixture);
+        }
+
+        void ILand.Land(LandEventArgs eventArgs)
+        {
+            if (!Owner.TryGetComponent(out PhysicsComponent? physicsComponent) || _fixture == null) return;
+
+            physicsComponent.RemoveFixture(_fixture);
+        }
     }
 }