diff --git a/OpenRA.Mods.RA/ShroudRenderer.cs b/OpenRA.Mods.RA/ShroudRenderer.cs
index 302d466984..0d5b45ff12 100644
--- a/OpenRA.Mods.RA/ShroudRenderer.cs
+++ b/OpenRA.Mods.RA/ShroudRenderer.cs
@@ -177,19 +177,19 @@ namespace OpenRA.Mods.RA
 			return useExtendedIndex ? u ^ uside : u & 0x0F;
 		}
 
-		static int ObserverShroudedEdges(CPos p, Rectangle bounds, bool useExtendedIndex)
+		static int ObserverShroudedEdges(Map map, CPos p, bool useExtendedIndex)
 		{
 			var u = 0;
-			if (p.Y == bounds.Top) u |= 0x13;
-			if (p.X == bounds.Right - 1) u |= 0x26;
-			if (p.Y == bounds.Bottom - 1) u |= 0x4C;
-			if (p.X == bounds.Left)	u |= 0x89;
+			if (!map.Contains(p + new CVec(0, -1))) u |= 0x13;
+			if (!map.Contains(p + new CVec(1, 0))) u |= 0x26;
+			if (!map.Contains(p + new CVec(0, 1))) u |= 0x4C;
+			if (!map.Contains(p + new CVec(-1, 0))) u |= 0x89;
 
 			var uside = u & 0x0F;
-			if (p.X == bounds.Left && p.Y == bounds.Top) u |= 0x01;
-			if (p.X == bounds.Right - 1 && p.Y == bounds.Top) u |= 0x02;
-			if (p.X == bounds.Right - 1 && p.Y == bounds.Bottom - 1) u |= 0x04;
-			if (p.X == bounds.Left && p.Y == bounds.Bottom - 1) u |= 0x08;
+			if (!map.Contains(p + new CVec(-1, -1))) u |= 0x01;
+			if (!map.Contains(p + new CVec(1, -1))) u |= 0x02;
+			if (!map.Contains(p + new CVec(1, 1))) u |= 0x04;
+			if (!map.Contains(p + new CVec(-1, 1))) u |= 0x08;
 
 			return useExtendedIndex ? u ^ uside : u & 0x0F;
 		}
@@ -229,7 +229,7 @@ namespace OpenRA.Mods.RA
 				foreach (var cell in map.Cells)
 				{
 					var t = tiles[cell];
-					var shrouded = ObserverShroudedEdges(t.Position, map.Bounds, info.UseExtendedIndex);
+					var shrouded = ObserverShroudedEdges(map, t.Position, info.UseExtendedIndex);
 
 					t.Shroud = shrouded != 0 ? shroudSprites[t.Variant * variantStride + spriteMap[shrouded]] : null;
 					t.Fog = shrouded != 0 ? fogSprites[t.Variant * variantStride + spriteMap[shrouded]] : null;