Linebuild walls

OpenRA.Game/UiOverlay.cs

@@ -72,7 +72,46 @@ namespace OpenRA
 				spriteRenderer.DrawSprite( ( isCloseEnough && world.IsCellBuildable( t, bi.WaterBound
 					? UnitMovementType.Float : UnitMovementType.Wheel ) && !world.Map.ContainsResource( t ) )
 					? buildOk : buildBlocked, Game.CellSize * t, "terrain" );
+			
+			// Linebuild for walls.
+			// Assumes a 1x1 footprint; weird things will happen for other footprints
+			if (Rules.Info[ name ].Traits.Contains<LineBuildInfo>())
+			{
+				int range = Rules.Info[ name ].Traits.Get<LineBuildInfo>().Range;
+				
+				// Start at place location, search outwards
+				// TODO: First make it work, then make it nice
+				int[] dirs = {0,0,0,0};
+				for (int d = 0; d < 4; d++)
+				{
+					for (int i = 1; i < range; i++)
+					{
+						if (dirs[d] != 0)
+							continue;
+						
+						int2 cell = world.OffsetCell(topLeft,i,d);
+						
+						if (world.IsCellBuildable(cell, bi.WaterBound ? UnitMovementType.Float : UnitMovementType.Wheel,null))
+							continue; // Cell is empty; continue search
 
+						// Cell contains an actor. Is it the type we want?
+						if (Game.world.Queries.WithTrait<LineBuild>().Any(a => (a.Actor.Info.Name == name && a.Actor.Location.X == cell.X && a.Actor.Location.Y == cell.Y)))
+							dirs[d] = i; // Cell contains actor of correct type
+						else
+							dirs[d] = -1; // Cell is blocked by another actor type
+					}
+					
+					// Place intermediate-line sections
+					if (dirs[d] > 0)
+					{
+						for (int i = 1; i < dirs[d]; i++)
+						{
+							int2 cell = world.OffsetCell(topLeft,i,d);
+							spriteRenderer.DrawSprite( world.IsCloseEnoughToBase(world.LocalPlayer, name, bi, cell) ? buildOk : buildBlocked, Game.CellSize * cell, "terrain" );
+						}
+					}
+				}
+			}
 			spriteRenderer.Flush();
 		}
 	}