Shroud, combine IsVisible and IsExplored into a single function.

OpenRA.Game/Traits/Player/FrozenActorLayer.cs

@@ -155,14 +155,15 @@ namespace OpenRA.Traits
 			// PERF: Avoid LINQ.
 			foreach (var puv in Footprint)
 			{
-				if (shroud.IsVisible(puv))
+				var cv = shroud.GetVisibility(puv);
+				if (cv.HasFlag(Shroud.CellVisibility.Visible))
 				{
 					Visible = false;
 					Shrouded = false;
 					break;
 				}
 
-				if (Shrouded && shroud.IsExplored(puv))
+				if (Shrouded && cv.HasFlag(Shroud.CellVisibility.Explored))
 					Shrouded = false;
 			}
 

OpenRA.Game/Traits/Player/Shroud.cs

@@ -83,6 +83,10 @@ namespace OpenRA.Traits
 			}
 		}
 
+		// Visible is not a super set of Explored. IsExplored may return false even if IsVisible returns true.
+		[Flags]
+		public enum CellVisibility : byte { Hidden = 0x0, Explored = 0x1, Visible = 0x2 }
+
 		readonly Actor self;
 		readonly ShroudInfo info;
 		readonly Map map;
@@ -423,5 +427,53 @@ namespace OpenRA.Traits
 			// about explored here: any of the CellLayers would have been suitable.
 			return explored.Contains(uv);
 		}
+
+		// PERF: Combine IsExplored and IsVisible.
+		public CellVisibility GetVisibility(PPos puv)
+		{
+			var state = CellVisibility.Hidden;
+
+			if (Disabled)
+			{
+				if (FogEnabled)
+				{
+					// Shroud disabled, Fog enabled
+					if (resolvedType.Contains(puv))
+					{
+						state |= CellVisibility.Explored;
+
+						if (resolvedType[puv] == ShroudCellType.Visible)
+							state |= CellVisibility.Visible;
+					}
+				}
+				else if (map.Contains(puv))
+					state |= CellVisibility.Explored | CellVisibility.Visible;
+			}
+			else
+			{
+				if (FogEnabled)
+				{
+					// Shroud and Fog enabled
+					if (resolvedType.Contains(puv))
+					{
+						var rt = resolvedType[puv];
+						if (rt == ShroudCellType.Visible)
+							state |= CellVisibility.Explored | CellVisibility.Visible;
+						else if (rt > ShroudCellType.Shroud)
+							state |= CellVisibility.Explored;
+					}
+				}
+				else if (resolvedType.Contains(puv))
+				{
+					// We do not set Explored since IsExplored may return false.
+					state |= CellVisibility.Visible;
+
+					if (resolvedType[puv] > ShroudCellType.Shroud)
+						state |= CellVisibility.Explored;
+				}
+			}
+
+			return state;
+		}
 	}
 }