Power cell culling (#8814)

Content.Client/PowerCell/PowerCellSystem.cs

@@ -1,7 +1,38 @@
 using Content.Shared.PowerCell;
 using JetBrains.Annotations;
+using Robust.Client.GameObjects;
 
 namespace Content.Client.PowerCell;
 
 [UsedImplicitly]
-public sealed class PowerCellSystem : SharedPowerCellSystem { }
+public sealed class PowerCellSystem : SharedPowerCellSystem
+{
+    public override void Initialize()
+    {
+        base.Initialize();
+        SubscribeLocalEvent<PowerCellVisualsComponent, AppearanceChangeEvent>(OnPowerCellVisualsChange);
+    }
+
+    private void OnPowerCellVisualsChange(EntityUid uid, PowerCellVisualsComponent component, ref AppearanceChangeEvent args)
+    {
+        if (args.Sprite == null) return;
+
+        if (args.Component.TryGetData(PowerCellVisuals.ChargeLevel, out byte level))
+        {
+            if (level == 0)
+            {
+                args.Sprite.LayerSetVisible(PowerCellVisualLayers.Unshaded, false);
+                return;
+            }
+
+            args.Sprite.LayerSetVisible(PowerCellVisualLayers.Unshaded, true);
+            args.Sprite.LayerSetState(PowerCellVisualLayers.Unshaded, $"o{level}");
+        }
+    }
+
+    private enum PowerCellVisualLayers : byte
+    {
+        Base,
+        Unshaded,
+    }
+}