Calculate building placement offsets in screen space.

OpenRA.Mods.Common/EditorBrushes/EditorActorBrush.cs

@@ -26,8 +26,7 @@ namespace OpenRA.Mods.Common.Widgets
 		readonly EditorActorLayer editorLayer;
 		readonly EditorViewportControllerWidget editorWidget;
 		readonly ActorPreviewWidget preview;
-		readonly CVec locationOffset;
+		readonly WVec centerOffset;
-		readonly WVec previewOffset;
 		readonly PlayerReference owner;
 		readonly CVec[] footprint;
 
@@ -49,10 +48,7 @@ namespace OpenRA.Mods.Common.Widgets
 
 			var buildingInfo = actor.TraitInfoOrDefault<BuildingInfo>();
 			if (buildingInfo != null)
-			{
+				centerOffset = buildingInfo.CenterOffset(world);
-				locationOffset = -buildingInfo.LocationOffset();
-				previewOffset = buildingInfo.CenterOffset(world);
-			}
 
 			var td = new TypeDictionary();
 			td.Add(new FacingInit(facing));
@@ -91,17 +87,16 @@ namespace OpenRA.Mods.Common.Widgets
 				return false;
 			}
 
-			var cell = worldRenderer.Viewport.ViewToWorld(mi.Location);
+			var cell = worldRenderer.Viewport.ViewToWorld(mi.Location - worldRenderer.ScreenPxOffset(centerOffset));
 			if (mi.Button == MouseButton.Left && mi.Event == MouseInputEvent.Down)
 			{
 				// Check the actor is inside the map
-				if (!footprint.All(c => world.Map.Tiles.Contains(cell + locationOffset + c)))
+				if (!footprint.All(c => world.Map.Tiles.Contains(cell + c)))
 					return true;
 
 				var newActorReference = new ActorReference(Actor.Name);
 				newActorReference.Add(new OwnerInit(owner.Name));
 
-				cell += locationOffset;
 				newActorReference.Add(new LocationInit(cell));
 
 				var ios = Actor.TraitInfoOrDefault<IOccupySpaceInfo>();
@@ -128,8 +123,8 @@ namespace OpenRA.Mods.Common.Widgets
 
 		public void Tick()
 		{
-			var cell = worldRenderer.Viewport.ViewToWorld(Viewport.LastMousePos);
+			var cell = worldRenderer.Viewport.ViewToWorld(Viewport.LastMousePos - worldRenderer.ScreenPxOffset(centerOffset));
-			var pos = world.Map.CenterOfCell(cell + locationOffset) + previewOffset;
+			var pos = world.Map.CenterOfCell(cell) + centerOffset;
 
 			var origin = worldRenderer.Viewport.WorldToViewPx(worldRenderer.ScreenPxPosition(pos));
 

OpenRA.Mods.Common/Orders/PlaceBuildingOrderGenerator.cs

@@ -33,14 +33,18 @@ namespace OpenRA.Mods.Common.Orders
 		readonly string faction;
 		readonly Sprite buildOk;
 		readonly Sprite buildBlocked;
+		readonly Viewport viewport;
+		readonly WVec centerOffset;
+		readonly int2 topLeftScreenOffset;
 		IActorPreview[] preview;
 
 		bool initialized;
 
-		public PlaceBuildingOrderGenerator(ProductionQueue queue, string name)
+		public PlaceBuildingOrderGenerator(ProductionQueue queue, string name, WorldRenderer worldRenderer)
 		{
 			var world = queue.Actor.World;
 			this.queue = queue;
+			viewport = worldRenderer.Viewport;
 			placeBuildingInfo = queue.Actor.Owner.PlayerActor.Info.TraitInfo<PlaceBuildingInfo>();
 			building = name;
 
@@ -53,6 +57,8 @@ namespace OpenRA.Mods.Common.Orders
 
 			var info = map.Rules.Actors[building];
 			buildingInfo = info.TraitInfo<BuildingInfo>();
+			centerOffset = buildingInfo.CenterOffset(world);
+			topLeftScreenOffset = -worldRenderer.ScreenPxOffset(centerOffset);
 
 			var buildableInfo = info.TraitInfo<BuildableInfo>();
 			var mostLikelyProducer = queue.MostLikelyProducer();
@@ -99,7 +105,7 @@ namespace OpenRA.Mods.Common.Orders
 			if (mi.Button == MouseButton.Left)
 			{
 				var orderType = "PlaceBuilding";
-				var topLeft = cell - buildingInfo.LocationOffset();
+				var topLeft = viewport.ViewToWorld(Viewport.LastMousePos + topLeftScreenOffset);
 
 				var plugInfo = world.Map.Rules.Actors[building].TraitInfoOrDefault<PlugInfo>();
 				if (plugInfo != null)
@@ -162,14 +168,13 @@ namespace OpenRA.Mods.Common.Orders
 		public IEnumerable<IRenderable> Render(WorldRenderer wr, World world) { yield break; }
 		public IEnumerable<IRenderable> RenderAboveShroud(WorldRenderer wr, World world)
 		{
-			var xy = wr.Viewport.ViewToWorld(Viewport.LastMousePos);
+			var topLeft = viewport.ViewToWorld(Viewport.LastMousePos + topLeftScreenOffset);
-			var topLeft = xy - buildingInfo.LocationOffset();
+			var centerPosition = world.Map.CenterOfCell(topLeft) + centerOffset;
-			var offset = world.Map.CenterOfCell(topLeft) + buildingInfo.CenterOffset(world);
 			var rules = world.Map.Rules;
 
 			var actorInfo = rules.Actors[building];
 			foreach (var dec in actorInfo.TraitInfos<IPlaceBuildingDecorationInfo>())
-				foreach (var r in dec.Render(wr, world, actorInfo, offset))
+				foreach (var r in dec.Render(wr, world, actorInfo, centerPosition))
 					yield return r;
 
 			var cells = new Dictionary<CPos, CellType>();
@@ -219,7 +224,7 @@ namespace OpenRA.Mods.Common.Orders
 				}
 
 				var previewRenderables = preview
-					.SelectMany(p => p.Render(wr, offset))
+					.SelectMany(p => p.Render(wr, centerPosition))
 					.OrderBy(WorldRenderer.RenderableScreenZPositionComparisonKey);
 
 				foreach (var r in previewRenderables)

OpenRA.Mods.Common/Traits/Buildings/Building.cs

@@ -144,11 +144,6 @@ namespace OpenRA.Mods.Common.Traits
 				yield return t;
 		}
 
-		public CVec LocationOffset()
-		{
-			return new CVec(Dimensions.X / 2, Dimensions.Y > 1 ? (Dimensions.Y + 1) / 2 : 0);
-		}
-
 		public WVec CenterOffset(World w)
 		{
 			var off = (w.Map.CenterOfCell(new CPos(Dimensions.X, Dimensions.Y)) - w.Map.CenterOfCell(new CPos(1, 1))) / 2;

OpenRA.Mods.Common/Widgets/ProductionPaletteWidget.cs

@@ -200,7 +200,7 @@ namespace OpenRA.Mods.Common.Widgets
 
 			if (item != null && item.Done && actor.HasTraitInfo<BuildingInfo>())
 			{
-				World.OrderGenerator = new PlaceBuildingOrderGenerator(CurrentQueue, icon.Name);
+				World.OrderGenerator = new PlaceBuildingOrderGenerator(CurrentQueue, icon.Name, worldRenderer);
 				return true;
 			}