diff --git a/OpenRA.Game/Graphics/Viewport.cs b/OpenRA.Game/Graphics/Viewport.cs
index 4538fb1245..c09fc5bb94 100644
--- a/OpenRA.Game/Graphics/Viewport.cs
+++ b/OpenRA.Game/Graphics/Viewport.cs
@@ -163,16 +163,20 @@ namespace OpenRA.Graphics
 					var wtl = worldRenderer.Position(TopLeft);
 					var wbr = worldRenderer.Position(BottomRight);
 
-					// Visible rectangle in map coordinates
-					var ctl = new MPos(wtl.X / 1024, wtl.Y / 1024);
+					// Due to diamond tile staggering, we need to adjust the top-left bounds outwards by half a cell.
+					if (map.TileShape == TileShape.Diamond)
+						wtl -= new WVec(512, 512, 0);
+
+					// Visible rectangle in map coordinates.
 					var dy = map.TileShape == TileShape.Diamond ? 512 : 1024;
-					var cbr = new MPos((wbr.X + 1023) / 1024, (wbr.Y + dy - 1) / dy);
+					var ctl = new MPos(wtl.X / 1024, wtl.Y / dy);
+					var cbr = new MPos(wbr.X / 1024, wbr.Y / dy);
 
-					// Add a 1 cell cordon to prevent holes, then convert back to cell coordinates
-					var tl = map.Clamp(new MPos(ctl.U - 1, ctl.V - 1).ToCPos(map));
+					var tl = map.Clamp(ctl.ToCPos(map));
 
-					// Also need to account for height of cells in rows below the bottom
-					var br = map.Clamp(new MPos(cbr.U + 1, cbr.V + 2 + maxGroundHeight / 2).ToCPos(map));
+					// Also need to account for height of cells in rows below the bottom.
+					var heightPadding = map.TileShape == TileShape.Diamond ? 2 : 0;
+					var br = map.Clamp(new MPos(cbr.U, cbr.V + heightPadding + maxGroundHeight / 2).ToCPos(map));
 
 					cells = new CellRegion(map.TileShape, tl, br);
 					cellsDirty = false;
diff --git a/OpenRA.Mods.Common/Traits/World/ShroudRenderer.cs b/OpenRA.Mods.Common/Traits/World/ShroudRenderer.cs
index 787e1f73d3..7f31a923b8 100644
--- a/OpenRA.Mods.Common/Traits/World/ShroudRenderer.cs
+++ b/OpenRA.Mods.Common/Traits/World/ShroudRenderer.cs
@@ -269,22 +269,26 @@ namespace OpenRA.Mods.Common.Traits
 
 		void Render(CellRegion visibleRegion)
 		{
-			var renderRegion = CellRegion.Expand(visibleRegion, 1).MapCoords;
+			// Due to diamond tile staggering, we need to expand the cordon to get full shroud coverage.
+			if (map.TileShape == TileShape.Diamond)
+				visibleRegion = CellRegion.Expand(visibleRegion, 1);
 
 			if (currentShroud == null)
-			{
-				RenderMapBorderShroud(renderRegion);
-				return;
-			}
-
-			RenderPlayerShroud(visibleRegion, renderRegion);
+				RenderMapBorderShroud(visibleRegion);
+			else
+				RenderPlayerShroud(visibleRegion);
 		}
 
-		void RenderMapBorderShroud(CellRegion.MapCoordsRegion renderRegion)
+		void RenderMapBorderShroud(CellRegion visibleRegion)
 		{
+			// The map border shroud only affects the map border. If none of the visible cells are on the border, then
+			// we don't need to render anything and can bail early for performance.
+			if (CellRegion.Expand(map.Cells, -1).Contains(visibleRegion))
+				return;
+
 			// Render the shroud that just encroaches at the map border. This shroud is always fully cached, so we can
 			// just render straight from the cache.
-			foreach (var uv in renderRegion)
+			foreach (var uv in visibleRegion.MapCoords)
 			{
 				var offset = VertexArrayOffset(uv);
 				RenderCachedTile(shroudSpriteLayer[uv], shroudVertices, offset);
@@ -292,7 +296,7 @@ namespace OpenRA.Mods.Common.Traits
 			}
 		}
 
-		void RenderPlayerShroud(CellRegion visibleRegion, CellRegion.MapCoordsRegion renderRegion)
+		void RenderPlayerShroud(CellRegion visibleRegion)
 		{
 			// Render the shroud by drawing the appropriate tile over each cell that is visible on-screen.
 			// For performance we keep a cache tiles we have drawn previously so we don't have to recalculate the
@@ -303,7 +307,7 @@ namespace OpenRA.Mods.Common.Traits
 			// cached vertices.
 			var visibleUnderShroud = currentShroud.IsExploredTest(visibleRegion);
 			var visibleUnderFog = currentShroud.IsVisibleTest(visibleRegion);
-			foreach (var uv in renderRegion)
+			foreach (var uv in visibleRegion.MapCoords)
 			{
 				var offset = VertexArrayOffset(uv);
 				if (shroudDirty[uv])