don't leak information about actors under fog etc

OpenRA.Game/Traits/Modifiers/HiddenUnderFog.cs

@@ -20,7 +20,7 @@
 
 using System.Collections.Generic;
 
-namespace OpenRA.Traits.Render
+namespace OpenRA.Traits
 {
 	class HiddenUnderFogInfo : ITraitInfo
 	{
@@ -36,13 +36,17 @@ namespace OpenRA.Traits.Render
 			shroud = self.World.WorldActor.traits.Get<Shroud>();
 		}
 
+		public bool IsVisible(Actor self)
+		{
+			return self.World.LocalPlayer == null
+				|| self.Owner == self.World.LocalPlayer
+				|| shroud.visibleCells[self.Location.X, self.Location.Y] > 0;
+		}
+
 		static Renderable[] Nothing = { };
 		public IEnumerable<Renderable> ModifyRender(Actor self, IEnumerable<Renderable> r)
 		{
-			if (self.World.LocalPlayer == null || self.Owner == self.World.LocalPlayer || shroud.visibleCells[self.Location.X, self.Location.Y] > 0)
+			return IsVisible(self) ? r : Nothing;
-				return r;
-			else
-				return Nothing;
 		}
 	}
 }

OpenRA.Game/WorldUtils.cs

@@ -81,7 +81,7 @@ namespace OpenRA
 		public static IEnumerable<Actor> FindUnitsAtMouse(this World world, int2 mouseLocation)
 		{
 			var loc = mouseLocation + Game.viewport.Location;
-			return FindUnits(world, loc, loc);
+			return FindUnits(world, loc, loc).Where(a => a.IsVisible());
 		}
 
 		public static IEnumerable<Actor> FindUnits(this World world, float2 a, float2 b)
@@ -147,15 +147,18 @@ namespace OpenRA
 		public static bool IsVisible(this Actor a)
 		{
 			var shroud = a.World.WorldActor.traits.Get<Shroud>();
-			return a.traits.Contains<Unit>()
+			if (!Shroud.GetVisOrigins(a).Any(o => shroud.exploredCells[o.X, o.Y]))		// covered by shroud
-				? Shroud.GetVisOrigins(a).Any(o => shroud.visibleCells[o.X, o.Y] > 0)
+				return false;
-				: Shroud.GetVisOrigins(a).Any(o => shroud.exploredCells[o.X, o.Y]);
+
+			var huf = a.traits.GetOrDefault<HiddenUnderFog>();							// hidden under fog
+			if (huf != null && !huf.IsVisible(a))
+				return false;
+
+			return true;
 		}
 
 		public static bool IsCloseEnoughToBase(this World world, Player p, string buildingName, BuildingInfo bi, int2 topLeft)
 		{
-			
-			
 			var buildingMaxBounds = bi.Dimensions;
 			if( Rules.Info[ buildingName ].Traits.Contains<BibInfo>() )
 				buildingMaxBounds.Y += 1;