Add InfiltrateForDecoration trait.

OpenRA.Mods.RA/OpenRA.Mods.RA.csproj

@@ -116,6 +116,7 @@
     <Compile Include="Scripting\Properties\ParatroopersProperties.cs" />
     <Compile Include="Traits\Render\WithDisguisingInfantryBody.cs" />
     <Compile Include="ImportRedAlertLegacyMapCommand.cs" />
+    <Compile Include="Traits\Infiltration\InfiltrateForDecoration.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\OpenRA.Game\OpenRA.Game.csproj">

OpenRA.Mods.RA/Traits/Infiltration/InfiltrateForDecoration.cs

@@ -0,0 +1,43 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2016 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, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System.Collections.Generic;
+using System.Linq;
+using OpenRA.Mods.Common.Traits.Render;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.RA.Traits
+{
+	[Desc("Reveals a decoration sprite to the indicated players when infiltrated.")]
+	class InfiltrateForDecorationInfo : WithDecorationInfo
+	{
+		public override object Create(ActorInitializer init) { return new InfiltrateForDecoration(init.Self, this); }
+	}
+
+	class InfiltrateForDecoration : WithDecoration, INotifyInfiltrated
+	{
+		readonly HashSet<Player> infiltrators = new HashSet<Player>();
+
+		public InfiltrateForDecoration(Actor self, InfiltrateForDecorationInfo info)
+			: base(self, info) { }
+
+		public void Infiltrated(Actor self, Actor infiltrator)
+		{
+			infiltrators.Add(infiltrator.Owner);
+		}
+
+		protected override bool ShouldRender(Actor self)
+		{
+			return self.World.RenderPlayer == null || infiltrators.Any(i =>
+				Info.ValidStances.HasStance(i.Stances[self.World.RenderPlayer]));
+		}
+	}
+}