add rollovers for health/production

OpenRA.Game/Graphics/WorldRenderer.cs

@@ -145,6 +145,13 @@ namespace OpenRA.Graphics
 			Game.Renderer.LineRenderer.DrawLine(XY, XY + new float2(0, -4), c, c);
 		}
 
+		public void DrawRollover(Actor unit)
+		{
+			var selectable = unit.TraitOrDefault<Selectable>();
+			if (selectable != null)
+				selectable.DrawRollover(this, unit);
+		}
+
 		public void DrawLocus(Color c, int2[] cells)
 		{
 			var dict = cells.ToDictionary(a => a, a => 0);

OpenRA.Game/Traits/Selectable.cs

@@ -50,7 +50,24 @@ namespace OpenRA.Traits
 			DrawPips(wr, self, xY);
 			DrawTags(wr, self, new float2(.5f * (bounds.Left + bounds.Right), bounds.Top));
 			DrawUnitPath(self);
+			DrawExtraBars(self, xy, Xy);
+		}
 
+		public void DrawRollover(WorldRenderer wr, Actor self)
+		{
+			var bounds = self.GetBounds(false);
+			
+			var xy = new float2(bounds.Left, bounds.Top);
+			var Xy = new float2(bounds.Right, bounds.Top);
+			var xY = new float2(bounds.Left, bounds.Bottom);
+			var XY = new float2(bounds.Right, bounds.Bottom);
+
+			DrawHealthBar(self, xy, Xy);
+			DrawExtraBars(self, xy, Xy);
+		}
+
+		void DrawExtraBars(Actor self, float2 xy, float2 Xy)
+		{
 			foreach (var extraBar in self.TraitsImplementing<ISelectionBar>())
 			{
 				var value = extraBar.GetValue();

OpenRA.Game/Widgets/WorldInteractionControllerWidget.cs

@@ -31,6 +31,9 @@ namespace OpenRA.Widgets
 		
 		public override void DrawInner()
 		{
+			foreach( var u in SelectActorsInBox(world, Game.CellSize * dragStart, Game.CellSize * dragStart ))
+				worldRenderer.DrawRollover( u );
+
 			var selbox = SelectionBox;
 			if (selbox == null) return;