use the disabled palette to render husks

closes #4631

OpenRA.Mods.RA/Modifiers/DisabledOverlay.cs

@@ -0,0 +1,36 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2014 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using System.Collections.Generic;
+using OpenRA.FileFormats;
+using OpenRA.Graphics;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.RA
+{
+	[Desc("Use together with CanPowerDown/RequiresPower on buildings or Husk for vehicles.")]
+	public class DisabledOverlayInfo : TraitInfo<DisabledOverlay> { }
+
+	public class DisabledOverlay : IRenderModifier
+	{
+		public IEnumerable<IRenderable> ModifyRender(Actor self, WorldRenderer wr, IEnumerable<IRenderable> r)
+		{
+			var disabled = self.IsDisabled();
+			foreach (var a in r)
+			{
+				yield return a;
+				if (disabled && !a.IsDecoration)
+					yield return a.WithPalette(wr.Palette("disabled"))
+						.WithZOffset(a.ZOffset + 1)
+						.AsDecoration();
+			}
+		}
+	}
+}