Portals & hand teleporter (#13266)

* basic system with portals & linked ents * hand tele sprites, no impl * hand tele and teleportation works * fancy it up * oog * special case projectiles * predict portal-to-portal teleportation * this stuff * check nullspace * sloth * give to rd instead * i guess this can probably happen * docs
2023-01-02 19:58:25 -06:00
parent a21a4711b6
commit c821ca71aa
23 changed files with 592 additions and 3 deletions
--- a/Content.Shared/Teleportation/Systems/LinkedEntitySystem.cs
+++ b/Content.Shared/Teleportation/Systems/LinkedEntitySystem.cs
@@ -0,0 +1,115 @@
+using System.Linq;
+using Content.Shared.Teleportation.Components;
+using Robust.Shared.GameStates;
+
+namespace Content.Shared.Teleportation.Systems;
+
+/// <summary>
+///     Handles symmetrically linking two entities together, and removing links properly.
+///     This does not do anything on its own (outside of deleting entities that have 0 links, if that option is true)
+///     Systems can do whatever they please with the linked entities, such as <see cref="PortalSystem"/>.
+/// </summary>
+public sealed class LinkedEntitySystem : EntitySystem
+{
+    [Dependency] private readonly SharedAppearanceSystem _appearance = default!;
+
+    /// <inheritdoc/>
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        SubscribeLocalEvent<LinkedEntityComponent, ComponentShutdown>(OnLinkShutdown);
+
+        SubscribeLocalEvent<LinkedEntityComponent, ComponentGetState>(OnGetState);
+        SubscribeLocalEvent<LinkedEntityComponent, ComponentHandleState>(OnHandleState);
+    }
+
+    private void OnGetState(EntityUid uid, LinkedEntityComponent component, ref ComponentGetState args)
+    {
+        args.State = new LinkedEntityComponentState(component.LinkedEntities);
+    }
+
+    private void OnHandleState(EntityUid uid, LinkedEntityComponent component, ref ComponentHandleState args)
+    {
+        if (args.Current is LinkedEntityComponentState state)
+            component.LinkedEntities = state.LinkedEntities;
+    }
+
+    private void OnLinkShutdown(EntityUid uid, LinkedEntityComponent component, ComponentShutdown args)
+    {
+        // Remove any links to this entity when deleted.
+        foreach (var ent in component.LinkedEntities.ToArray())
+        {
+            if (LifeStage(ent) < EntityLifeStage.Terminating && TryComp<LinkedEntityComponent>(ent, out var link))
+            {
+                TryUnlink(uid, ent, component, link);
+            }
+        }
+    }
+
+    #region Public API
+
+    /// <summary>
+    ///     Links two entities together. Does not require the existence of <see cref="LinkedEntityComponent"/> on either
+    ///     already. Linking is symmetrical, so order doesn't matter.
+    /// </summary>
+    /// <param name="first">The first entity to link</param>
+    /// <param name="second">The second entity to link</param>
+    /// <param name="deleteOnEmptyLinks">Whether both entities should now delete once their links are removed</param>
+    /// <returns>Whether linking was successful (e.g. they weren't already linked)</returns>
+    public bool TryLink(EntityUid first, EntityUid second, bool deleteOnEmptyLinks=false)
+    {
+        var firstLink = EnsureComp<LinkedEntityComponent>(first);
+        var secondLink = EnsureComp<LinkedEntityComponent>(second);
+
+        firstLink.DeleteOnEmptyLinks = deleteOnEmptyLinks;
+        secondLink.DeleteOnEmptyLinks = deleteOnEmptyLinks;
+
+        _appearance.SetData(first, LinkedEntityVisuals.HasAnyLinks, true);
+        _appearance.SetData(second, LinkedEntityVisuals.HasAnyLinks, true);
+
+        Dirty(firstLink);
+        Dirty(secondLink);
+
+        return firstLink.LinkedEntities.Add(second)
+            && secondLink.LinkedEntities.Add(first);
+    }
+
+    /// <summary>
+    ///     Unlinks two entities. Deletes either entity if <see cref="LinkedEntityComponent.DeleteOnEmptyLinks"/>
+    ///     was true and its links are now empty. Symmetrical, so order doesn't matter.
+    /// </summary>
+    /// <param name="first">The first entity to unlink</param>
+    /// <param name="second">The second entity to unlink</param>
+    /// <param name="firstLink">Resolve comp</param>
+    /// <param name="secondLink">Resolve comp</param>
+    /// <returns>Whether unlinking was successful (e.g. they both were actually linked to one another)</returns>
+    public bool TryUnlink(EntityUid first, EntityUid second,
+        LinkedEntityComponent? firstLink=null, LinkedEntityComponent? secondLink=null)
+    {
+        if (!Resolve(first, ref firstLink))
+            return false;
+
+        if (!Resolve(second, ref secondLink))
+            return false;
+
+        var success = firstLink.LinkedEntities.Remove(second)
+                      && secondLink.LinkedEntities.Remove(first);
+
+        _appearance.SetData(first, LinkedEntityVisuals.HasAnyLinks, firstLink.LinkedEntities.Any());
+        _appearance.SetData(second, LinkedEntityVisuals.HasAnyLinks, secondLink.LinkedEntities.Any());
+
+        Dirty(firstLink);
+        Dirty(secondLink);
+
+        if (firstLink.LinkedEntities.Count == 0 && firstLink.DeleteOnEmptyLinks)
+            QueueDel(first);
+
+        if (secondLink.LinkedEntities.Count == 0 && secondLink.DeleteOnEmptyLinks)
+            QueueDel(second);
+
+        return success;
+    }
+
+    #endregion
+}