Basic drug shader (#9033)

Content.Client/Drugs/DrugOverlaySystem.cs

@@ -0,0 +1,58 @@
+using Content.Shared.Drugs;
+using Robust.Client.GameObjects;
+using Robust.Client.Graphics;
+using Robust.Client.Player;
+
+namespace Content.Client.Drugs;
+
+/// <summary>
+///     System to handle drug related overlays.
+/// </summary>
+public sealed class DrugOverlaySystem : EntitySystem
+{
+    [Dependency] private readonly IPlayerManager _player = default!;
+    [Dependency] private readonly IOverlayManager _overlayMan = default!;
+
+    private RainbowOverlay _overlay = default!;
+
+    public static string RainbowKey = "SeeingRainbows";
+
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        SubscribeLocalEvent<SeeingRainbowsComponent, ComponentInit>(OnInit);
+        SubscribeLocalEvent<SeeingRainbowsComponent, ComponentShutdown>(OnShutdown);
+
+        SubscribeLocalEvent<SeeingRainbowsComponent, PlayerAttachedEvent>(OnPlayerAttached);
+        SubscribeLocalEvent<SeeingRainbowsComponent, PlayerDetachedEvent>(OnPlayerDetached);
+
+        _overlay = new();
+    }
+
+    private void OnPlayerAttached(EntityUid uid, SeeingRainbowsComponent component, PlayerAttachedEvent args)
+    {
+        _overlayMan.AddOverlay(_overlay);
+    }
+
+    private void OnPlayerDetached(EntityUid uid, SeeingRainbowsComponent component, PlayerDetachedEvent args)
+    {
+        _overlay.Intoxication = 0;
+        _overlayMan.RemoveOverlay(_overlay);
+    }
+
+    private void OnInit(EntityUid uid, SeeingRainbowsComponent component, ComponentInit args)
+    {
+        if (_player.LocalPlayer?.ControlledEntity == uid)
+            _overlayMan.AddOverlay(_overlay);
+    }
+
+    private void OnShutdown(EntityUid uid, SeeingRainbowsComponent component, ComponentShutdown args)
+    {
+        if (_player.LocalPlayer?.ControlledEntity == uid)
+        {
+            _overlay.Intoxication = 0;
+            _overlayMan.RemoveOverlay(_overlay);
+        }
+    }
+}