Allow Smellers to smell Scent bearers directly

Content.Client/_Starlight/Scent/ScentSniffBoundUserInterface.cs

@@ -31,6 +31,6 @@ protected override void UpdateState(BoundUserInterfaceState state)
         if (_window == null || state is not ScentSniffBoundUserInterfaceState cast)
             return;
 
-        _window.UpdateEntries(cast.Entries);
+        _window.UpdateEntries(cast.Entries, cast.OwnScentId);
     }
 }

Content.Client/_Starlight/Scent/ScentSniffMenu.xaml.cs

@@ -1,6 +1,9 @@
+using System.Numerics;
+using Content.Client.Administration.UI.CustomControls;
 using Content.Client.Message;
 using Content.Shared._Starlight.Scent;
 using Robust.Client.AutoGenerated;
+using Robust.Client.UserInterface;
 using Robust.Client.UserInterface.Controls;
 using Robust.Client.UserInterface.CustomControls;
 using Robust.Client.UserInterface.XAML;
@@ -19,13 +22,30 @@ public ScentSniffMenu()
         RobustXamlLoader.Load(this);
     }
 
-    public void UpdateEntries(List<ScentTraceEntry> entries)
+    public void UpdateEntries(List<ScentTraceEntry> entries, string? ownScentId)
     {
         Rows.RemoveAllChildren();
 
+        if (ownScentId is { } ownId)
+        {
+            var ownRow = new ContainerButton
+            {
+                ToolTip = Loc.GetString("scent-sniff-window-track-own-tooltip"),
+                HorizontalExpand = true,
+            };
+            ownRow.AddStyleClass(ContainerButton.StyleClassButton);
+            ownRow.AddChild(new Label { Text = Loc.GetString("scent-sniff-window-track-own") });
+            ownRow.OnPressed += _ => OnTrackPressed?.Invoke(ownId);
+            Rows.AddChild(ownRow);
+
+            Rows.AddChild(new HSeparator());
+            Rows.AddChild(new Control { MinSize = new Vector2(0, 10) });
+        }
+
         if (entries.Count == 0)
         {
-            Rows.AddChild(new Label { Text = Loc.GetString("scent-sniff-window-empty") });
+            var emptyKey = ownScentId != null ? "scent-sniff-window-empty-traces" : "scent-sniff-window-empty";
+            Rows.AddChild(new Label { Text = Loc.GetString(emptyKey) });
             return;
         }
 

Content.Server/_Starlight/Scent/Systems/ScentSystem.cs

@@ -101,7 +101,9 @@ private void OnSniffObjectAction(Entity<SmellerComponent> ent, ref SniffObjectAc
         if (trace != null)
             PruneExpiredTraces(trace);
 
-        if (trace == null || trace.Scents.Count == 0)
+        var hasOwnScent = TryComp<ScentComponent>(args.Target, out var targetScent) && targetScent.ScentId != null;
+
+        if ((trace == null || trace.Scents.Count == 0) && !hasOwnScent)
         {
             _popup.PopupEntity(Loc.GetString("scent-sniff-no-scents", ("target", Name(args.Target))), args.Target, ent.Owner);
             args.Handled = true;
@@ -126,23 +128,27 @@ private void OnSniffObjectDoAfter(EntityUid uid, SmellerComponent component, Sni
         if (args.Handled || args.Cancelled || args.Args.Target is not { } target)
             return;
 
-        if (!TryComp<ScentTraceComponent>(target, out var trace))
-            return;
-
-        PruneExpiredTraces(trace);
+        TryComp<ScentTraceComponent>(target, out var trace);
+        if (trace != null)
+            PruneExpiredTraces(trace);
 
         var now = _timing.CurTime;
-        var entries = new List<ScentTraceEntry>(trace.Scents.Count);
-        foreach (var (scentId, info) in trace.Scents)
+        var entries = new List<ScentTraceEntry>(trace?.Scents.Count ?? 0);
+        if (trace != null)
         {
-            var speciesName = Loc.GetString("scent-species-non-humanoid");
-            if (info.Species != null && _prototype.TryIndex<SpeciesPrototype>(info.Species, out var species))
-                speciesName = Loc.GetString(species.Name);
+            foreach (var (scentId, info) in trace.Scents)
+            {
+                var speciesName = Loc.GetString("scent-species-non-humanoid");
+                if (info.Species != null && _prototype.TryIndex<SpeciesPrototype>(info.Species, out var species))
+                    speciesName = Loc.GetString(species.Name);
 
-            var age = (float)(now - info.LastTouched).TotalSeconds;
-            entries.Add(new ScentTraceEntry(scentId, GetFreshness(age, trace.TraceLifetime), speciesName));
+                var age = (float)(now - info.LastTouched).TotalSeconds;
+                entries.Add(new ScentTraceEntry(scentId, GetFreshness(age, trace.TraceLifetime), speciesName));
+            }
         }
 
+        var ownScentId = TryComp<ScentComponent>(target, out var targetScent) ? targetScent.ScentId : null;
+
         if (!_ui.TryOpenUi(uid, ScentSniffUiKey.Key, uid))
         {
             Log.Warning($"{ToPrettyString(uid)} has SmellerComponent but couldn't open ScentSniffUiKey - " +
@@ -151,7 +157,7 @@ private void OnSniffObjectDoAfter(EntityUid uid, SmellerComponent component, Sni
         }
 
         component.SniffTarget = target;
-        _ui.SetUiState(uid, ScentSniffUiKey.Key, new ScentSniffBoundUserInterfaceState(entries));
+        _ui.SetUiState(uid, ScentSniffUiKey.Key, new ScentSniffBoundUserInterfaceState(entries, ownScentId));
 
         args.Handled = true;
     }
@@ -191,7 +197,10 @@ private void OnTrackMessage(EntityUid uid, SmellerComponent component, ScentSnif
         if (!_transform.InRange(xform.Coordinates, targetXform.Coordinates, component.SniffRange))
             return;
 
-        if (!TryComp<ScentTraceComponent>(target, out var trace) || !trace.Scents.ContainsKey(args.ScentId))
+        var isOwnScent = TryComp<ScentComponent>(target, out var targetScent) && targetScent.ScentId == args.ScentId;
+        var isTracedScent = TryComp<ScentTraceComponent>(target, out var trace) && trace.Scents.ContainsKey(args.ScentId);
+
+        if (!isOwnScent && !isTracedScent)
             return;
 
         SetTrackedScent((uid, component), args.ScentId, target);

Content.Shared/_Starlight/Scent/ScentSniffUi.cs

@@ -45,9 +45,14 @@ public sealed class ScentSniffBoundUserInterfaceState : BoundUserInterfaceState
 {
     public readonly List<ScentTraceEntry> Entries;
 
-    public ScentSniffBoundUserInterfaceState(List<ScentTraceEntry> entries)
+    // The target's own current scent, if it has ScentComponent. Always offered as a pinned
+    // option above the trace list, separately from whatever traces were found on it.
+    public readonly string? OwnScentId;
+
+    public ScentSniffBoundUserInterfaceState(List<ScentTraceEntry> entries, string? ownScentId)
     {
         Entries = entries;
+        OwnScentId = ownScentId;
     }
 }
 

Resources/Locale/en-US/_Starlight/scent/scent.ftl

@@ -1,9 +1,12 @@
 scent-sniff-window-title = Scent Trace
 scent-sniff-window-empty = No scents detected.
+scent-sniff-window-empty-traces = No other scent traces detected.
 scent-sniff-window-entry-id = [color={$color}]Scent ({$id}...)[/color]
 scent-sniff-window-entry-detail = [color={$color}]{$species} - {$freshness}[/color]
 scent-sniff-window-track-tooltip = Click to track this scent
 scent-sniff-window-tracking-popup = You start tracking this scent.
+scent-sniff-window-track-own = Track this creature's scent directly
+scent-sniff-window-track-own-tooltip = Track this individual's scent directly.
 
 scent-species-non-humanoid = Non-Humanoid