moved helper functions out of Game, into WorldUtils

OpenRa.Game/Actor.cs

@@ -89,7 +89,7 @@ namespace OpenRa
 				return null;
 			
 			var loc = mi.Location + Game.viewport.Location;
-			var underCursor = Game.FindUnits(loc, loc).FirstOrDefault();
+			var underCursor = Game.world.FindUnits(loc, loc).FirstOrDefault();
 
 			if (underCursor != null && !underCursor.traits.Contains<Selectable>())
 				underCursor = null;

OpenRa.Game/Combat.cs

@@ -15,8 +15,8 @@ namespace OpenRa
 		{
 			var targetTile = ((1f / Game.CellSize) * loc.ToFloat2()).ToInt2();
 
-			var isWater = Game.IsWater(targetTile);
+			var isWater = Game.world.IsWater(targetTile);
-			var hitWater = Game.IsCellBuildable(targetTile, UnitMovementType.Float);
+			var hitWater = Game.world.IsCellBuildable(targetTile, UnitMovementType.Float);
 
 			if (warhead.Explosion != 0)
 				Game.world.AddFrameEndTask(
@@ -31,7 +31,7 @@ namespace OpenRa
 			if (warhead.Ore) Ore.Destroy(targetTile.X, targetTile.Y);
 
 			var maxSpread = GetMaximumSpread(weapon, warhead);
-			var hitActors = Game.FindUnitsInCircle(loc, maxSpread);
+			var hitActors = Game.world.FindUnitsInCircle(loc, maxSpread);
 			
 			foreach (var victim in hitActors)
 				victim.InflictDamage(firedBy, (int)GetDamageToInflict(victim, loc, weapon, warhead), warhead);

OpenRa.Game/Controller.cs

@@ -95,7 +95,7 @@ namespace OpenRa
 			{
 				if (orderGenerator is UnitOrderGenerator)
 				{
-					var newSelection = Game.SelectActorsInBox(Game.CellSize * dragStart, Game.CellSize * xy);
+					var newSelection = Game.world.SelectActorsInBox(Game.CellSize * dragStart, Game.CellSize * xy);
 					CombineSelection(newSelection, mi.Modifiers.HasModifier(Modifiers.Shift), dragStart == xy);
 				}
 

OpenRa.Game/Game.cs

@@ -208,130 +208,9 @@ namespace OpenRa
 			renderer.PaletteTexture = palette.Texture;
 		}
 
-		public static bool IsCellBuildable(int2 a, UnitMovementType umt)
-		{
-			return IsCellBuildable(a, umt, null);
-		}
-
-		public static bool IsCellBuildable(int2 a, UnitMovementType umt, Actor toIgnore)
-		{
-			if (Game.world.BuildingInfluence.GetBuildingAt(a) != null) return false;
-			if (Game.world.UnitInfluence.GetUnitsAt(a).Any(b => b != toIgnore)) return false;
-
-			return Game.world.Map.IsInMap(a.X, a.Y) &&
-				TerrainCosts.Cost(umt,
-					Game.world.TileSet.GetWalkability(Game.world.Map.MapTiles[a.X, a.Y])) < double.PositiveInfinity;
-		}
-
-		public static bool IsActorCrushableByActor(Actor a, Actor b)
-		{
-			return IsActorCrushableByMovementType(a, b.traits.GetOrDefault<IMovement>().GetMovementType());
-		}
-		
-		public static bool IsActorPathableToCrush(Actor a, UnitMovementType umt)
-		{
-			return a != null &&
-					a.traits.WithInterface<ICrushable>()
-					.Any(c => c.IsPathableCrush(umt, a.Owner));
-		}
-		
-		public static bool IsActorCrushableByMovementType(Actor a, UnitMovementType umt)
-		{
-			return a != null &&
-				a.traits.WithInterface<ICrushable>()
-				.Any(c => c.IsCrushableBy(umt, a.Owner));
-		}
-		
-		public static bool IsWater(int2 a)
-		{
-			return Game.world.Map.IsInMap(a.X, a.Y) &&
-				TerrainCosts.Cost(UnitMovementType.Float,
-					Game.world.TileSet.GetWalkability(Game.world.Map.MapTiles[a.X, a.Y])) < double.PositiveInfinity;
-		}
-
-		public static IEnumerable<Actor> FindUnits(float2 a, float2 b)
-		{
-			var min = float2.Min(a, b);
-			var max = float2.Max(a, b);
-
-			var rect = new RectangleF(min.X, min.Y, max.X - min.X, max.Y - min.Y);
-
-			return world.Actors
-				.Where(x => x.GetBounds(true).IntersectsWith(rect));
-		}
-
-		public static IEnumerable<Actor> FindUnitsInCircle(float2 a, float r)
-		{
-			var min = a - new float2(r, r);
-			var max = a + new float2(r, r);
-
-			var rect = new RectangleF(min.X, min.Y, max.X - min.X, max.Y - min.Y);
-
-			var inBox = world.Actors.Where(x => x.GetBounds(false).IntersectsWith(rect));
-
-			return inBox.Where(x => (x.CenterLocation - a).LengthSquared < r * r);
-		}
-
-		public static IEnumerable<int2> FindTilesInCircle(int2 a, int r)
-		{
-			var min = a - new int2(r, r);
-			var max = a + new int2(r, r);
-			if (min.X < 0) min.X = 0;
-			if (min.Y < 0) min.Y = 0;
-			if (max.X > 127) max.X = 127;
-			if (max.Y > 127) max.Y = 127;
-
-			for (var j = min.Y; j <= max.Y; j++)
-				for (var i = min.X; i <= max.X; i++)
-					if (r * r >= (new int2(i, j) - a).LengthSquared)
-						yield return new int2(i, j);
-		}
-
-		public static IEnumerable<Actor> SelectActorsInBox(float2 a, float2 b)
-		{
-			return FindUnits(a, b)
-				.Where( x => x.traits.Contains<Selectable>() )
-				.GroupBy(x => (x.Owner == LocalPlayer) ? x.Info.Traits.Get<SelectableInfo>().Priority : 0)
-				.OrderByDescending(g => g.Key)
-				.Select( g => g.AsEnumerable() )
-				.DefaultIfEmpty( new Actor[] {} )
-				.FirstOrDefault();
-		}
-
 		public static Random SharedRandom = new Random(0);		/* for things that require sync */
 		public static Random CosmeticRandom = new Random();		/* for things that are just fluff */
 
-		public static bool CanPlaceBuilding(string name, BuildingInfo building, int2 xy, Actor toIgnore, bool adjust)
-		{
-			return !Footprint.Tiles(name, building, xy, adjust).Any(
-				t => !Game.world.Map.IsInMap(t.X, t.Y) || Game.world.Map.ContainsResource(t) || !Game.IsCellBuildable(t,
-					building.WaterBound ? UnitMovementType.Float : UnitMovementType.Wheel,
-					toIgnore));
-		}
-
-		public static bool IsCloseEnoughToBase(Player p, string buildingName, BuildingInfo bi, int2 position)
-		{
-			var maxDistance = bi.Adjacent + 1;
-
-			var search = new PathSearch()
-			{
-				heuristic = loc =>
-				{
-					var b = Game.world.BuildingInfluence.GetBuildingAt(loc);
-					if (b != null && b.Owner == p && b.Info.Traits.Get<BuildingInfo>().BaseNormal) return 0;
-					if ((loc - position).Length > maxDistance)
-						return float.PositiveInfinity;	/* not quite right */
-					return 1;
-				},
-				checkForBlocked = false,
-				ignoreTerrain = true,
-			};
-
-			foreach (var t in Footprint.Tiles(buildingName, bi, position)) search.AddInitialCell(t);
-
-			return Game.world.PathFinder.FindPath(search).Count != 0;
-		}
-
 		public static void SyncLobbyInfo(string data)
 		{
 			var session = new Session();

OpenRa.Game/Graphics/WorldRenderer.cs

@@ -102,7 +102,7 @@ namespace OpenRa.Graphics
 			lineRenderer.DrawLine(a + b + c, a + c, Color.White, Color.White);
 			lineRenderer.DrawLine(a, a + c, Color.White, Color.White);
 
-			foreach (var u in Game.SelectActorsInBox(selbox.Value.First, selbox.Value.Second))
+			foreach (var u in Game.world.SelectActorsInBox(selbox.Value.First, selbox.Value.Second))
 				DrawSelectionBox(u, Color.Yellow, false);
 		}
 

OpenRa.Game/OpenRa.Game.csproj

@@ -7,7 +7,7 @@
     <ProjectGuid>{0DFB103F-2962-400F-8C6D-E2C28CCBA633}</ProjectGuid>
     <OutputType>WinExe</OutputType>
     <AppDesignerFolder>Properties</AppDesignerFolder>
-    <RootNamespace>OpenRa.Game</RootNamespace>
+    <RootNamespace>OpenRa</RootNamespace>
     <AssemblyName>OpenRa.Game</AssemblyName>
     <FileUpgradeFlags>
     </FileUpgradeFlags>
@@ -274,6 +274,7 @@
     <Compile Include="UnitInfluenceMap.cs" />
     <Compile Include="Orders\UnitOrderGenerator.cs" />
     <Compile Include="World.cs" />
+    <Compile Include="WorldUtils.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\OpenRa.FileFormats\OpenRa.FileFormats.csproj">

OpenRa.Game/Orders/ChronosphereSelectOrderGenerator.cs

@@ -28,7 +28,7 @@ namespace OpenRa.Orders
 			if (mi.Button == MouseButton.Left)
 			{
 				var loc = mi.Location + Game.viewport.Location;
-				var underCursor = Game.FindUnits(loc, loc)
+				var underCursor = Game.world.FindUnits(loc, loc)
 					.Where(a => a.Owner == Game.LocalPlayer
 						&& a.traits.Contains<Chronoshiftable>()
 						&& a.traits.Contains<Selectable>()).FirstOrDefault();

OpenRa.Game/Orders/IronCurtainOrderGenerator.cs

@@ -28,7 +28,7 @@ namespace OpenRa.Orders
 			if (mi.Button == MouseButton.Left)
 			{
 				var loc = mi.Location + Game.viewport.Location;
-				var underCursor = Game.FindUnits(loc, loc)
+				var underCursor = Game.world.FindUnits(loc, loc)
 					.Where(a => a.Owner == Game.LocalPlayer
 						&& a.traits.Contains<IronCurtainable>()
 						&& a.traits.Contains<Selectable>()).FirstOrDefault();

OpenRa.Game/Orders/PlaceBuildingOrderGenerator.cs

@@ -28,8 +28,8 @@ namespace OpenRa.Orders
 		{
 			if (mi.Button == MouseButton.Left)
 			{
-				if (!Game.CanPlaceBuilding( Building, BuildingInfo, xy, null, true)
+				if (!Game.world.CanPlaceBuilding( Building, BuildingInfo, xy, null, true)
-					|| !Game.IsCloseEnoughToBase(Producer.Owner, Building, BuildingInfo, xy))
+					|| !Game.world.IsCloseEnoughToBase(Producer.Owner, Building, BuildingInfo, xy))
 				{
 					Sound.Play("nodeply1.aud");
 					yield break;

OpenRa.Game/Orders/PowerDownOrderGenerator.cs

@@ -22,7 +22,7 @@ namespace OpenRa.Orders
 			if (mi.Button == MouseButton.Left)
 			{
 				var loc = mi.Location + Game.viewport.Location;
-				var underCursor = Game.FindUnits(loc, loc)
+				var underCursor = Game.world.FindUnits(loc, loc)
 					.Where(a => a.Owner == Game.LocalPlayer
 						&& a.traits.Contains<Building>()
 						&& a.traits.Contains<Selectable>()).FirstOrDefault();

OpenRa.Game/Orders/RepairOrderGenerator.cs

@@ -22,7 +22,7 @@ namespace OpenRa.Orders
 			if (mi.Button == MouseButton.Left)
 			{
 				var loc = mi.Location + Game.viewport.Location;
-				var underCursor = Game.FindUnits(loc, loc)
+				var underCursor = Game.world.FindUnits(loc, loc)
 					.Where(a => a.Owner == Game.LocalPlayer
 						&& a.traits.Contains<Building>()
 						&& a.traits.Contains<Selectable>()).FirstOrDefault();

OpenRa.Game/Orders/SellOrderGenerator.cs

@@ -22,7 +22,7 @@ namespace OpenRa.Orders
 			if (mi.Button == MouseButton.Left)
 			{
 				var loc = mi.Location + Game.viewport.Location;
-				var underCursor = Game.FindUnits(loc, loc)
+				var underCursor = Game.world.FindUnits(loc, loc)
 					.Where(a => a.Owner == Game.LocalPlayer
 						&& a.traits.Contains<Building>()
 						&& a.traits.Contains<Selectable>()).FirstOrDefault();

OpenRa.Game/Orders/UnitOrderGenerator.cs

@@ -50,7 +50,7 @@ namespace OpenRa.Orders
 				.FirstOrDefault(a => a != null);
 
 			return c ??
-				(Game.SelectActorsInBox(Game.CellSize * p, 
+				(Game.world.SelectActorsInBox(Game.CellSize * p, 
 				Game.CellSize * p).Any()
 					? Cursor.Select : Cursor.Default);
 		}
@@ -70,7 +70,7 @@ namespace OpenRa.Orders
 						return Cursor.MoveBlocked;
 				case "DeployMcv":
 					var factBuildingInfo = Rules.ActorInfo["fact"].Traits.Get<BuildingInfo>();
-					if (Game.CanPlaceBuilding("fact", factBuildingInfo, a.Location - new int2(1, 1), a, false))
+					if (Game.world.CanPlaceBuilding("fact", factBuildingInfo, a.Location - new int2(1, 1), a, false))
 						return Cursor.Deploy;
 					else
 						return Cursor.DeployBlocked;

OpenRa.Game/PathFinder.cs

@@ -40,8 +40,8 @@ namespace OpenRa
 		{
 			using( new PerfSample( "find_unit_path_multiple_src" ) )
 			{
-				var tilesInRange = Game.FindTilesInCircle(target, range)
+				var tilesInRange = Game.world.FindTilesInCircle(target, range)
-					.Where( t => Game.IsCellBuildable( t, umt ) );
+					.Where( t => Game.world.IsCellBuildable( t, umt ) );
 
 				var path = FindPath( PathSearch.FromPoints( tilesInRange, src, umt, false ).WithCustomBlocker(AvoidUnitsNear(src, 4)));
 				path.Reverse();

OpenRa.Game/PathSearch.cs

@@ -64,7 +64,7 @@ namespace OpenRa
 				}
 				
 				// Replicate real-ra behavior of not being able to enter a cell if there is a mixture of crushable and uncrushable units
-				if (checkForBlocked && (Game.world.UnitInfluence.GetUnitsAt(newHere).Any(a => !Game.IsActorPathableToCrush(a, umt))))
+				if (checkForBlocked && (Game.world.UnitInfluence.GetUnitsAt(newHere).Any(a => !Game.world.IsActorPathableToCrush(a, umt))))
 					continue;
 				
 				if (customBlock != null && customBlock(newHere))

OpenRa.Game/Shroud.cs

@@ -81,7 +81,7 @@ namespace OpenRa
 		
 		public void Explore(Actor a)
 		{
-			foreach (var t in Game.FindTilesInCircle(
+			foreach (var t in Game.world.FindTilesInCircle(
 				(1f / Game.CellSize * a.CenterLocation).ToInt2(), 
 				a.Info.Traits.Get<OwnedActorInfo>().Sight))
 			{

OpenRa.Game/Traits/Activities/HeliLand.cs

@@ -16,7 +16,7 @@ namespace OpenRa.Traits.Activities
 			if (unit.Altitude == 0)
 				return NextActivity;
 
-			if (requireSpace && !Game.IsCellBuildable(self.Location, UnitMovementType.Foot))
+			if (requireSpace && !Game.world.IsCellBuildable(self.Location, UnitMovementType.Foot))
 				return this;	// fail to land if no space
 
 			--unit.Altitude;

OpenRa.Game/Traits/Activities/Move.cs

@@ -63,7 +63,7 @@ namespace OpenRa.Traits.Activities
 			
 			// Cannot enter a cell if any unit inside is uncrushable
 			// This will need to be updated for multiple-infantry-in-a-cell
-			return (!Game.world.UnitInfluence.GetUnitsAt(c).Any(a => a != self && !Game.IsActorCrushableByActor(a, self)));
+			return (!Game.world.UnitInfluence.GetUnitsAt(c).Any(a => a != self && !Game.world.IsActorCrushableByActor(a, self)));
 		}
 
 		public IActivity Tick( Actor self )

OpenRa.Game/Traits/Activities/Rearm.cs

@@ -20,7 +20,7 @@ namespace OpenRa.Traits.Activities
 			{
 				if (!limitedAmmo.GiveAmmo()) return NextActivity;
 
-				var hostBuilding = Game.FindUnits(self.CenterLocation, self.CenterLocation)
+				var hostBuilding = Game.world.FindUnits(self.CenterLocation, self.CenterLocation)
 					.FirstOrDefault(a => a.traits.Contains<RenderBuilding>());
 
 				if (hostBuilding != null)

OpenRa.Game/Traits/Activities/Repair.cs

@@ -32,7 +32,7 @@ namespace OpenRa.Traits.Activities
 				if (self.Health == hp)
 					return NextActivity;
 
-				var hostBuilding = Game.FindUnits(self.CenterLocation, self.CenterLocation)
+				var hostBuilding = Game.world.FindUnits(self.CenterLocation, self.CenterLocation)
 					.FirstOrDefault(a => a.traits.Contains<RenderBuilding>());
 
 				if (hostBuilding != null)

OpenRa.Game/Traits/Activities/UnloadCargo.cs

@@ -19,7 +19,7 @@ namespace OpenRa.Traits.Activities
 			for (var i = -1; i < 2; i++)
 				for (var j = -1; j < 2; j++)
 					if ((i != 0 || j != 0) && 
-						Game.IsCellBuildable(self.Location + new int2(i, j), 
+						Game.world.IsCellBuildable(self.Location + new int2(i, j), 
 							UnitMovementType.Foot))
 						return self.Location + new int2(i, j);
 

OpenRa.Game/Traits/AutoHeal.cs

@@ -43,7 +43,7 @@ namespace OpenRa.Traits
 
 		Actor ChooseTarget(Actor self, float range)
 		{
-			var inRange = Game.FindUnitsInCircle(self.CenterLocation, Game.CellSize * range);
+			var inRange = Game.world.FindUnitsInCircle(self.CenterLocation, Game.CellSize * range);
 
 			return inRange
 				.Where(a => a.Owner == self.Owner && a != self)	/* todo: one day deal with friendly players */

OpenRa.Game/Traits/AutoTarget.cs

@@ -27,7 +27,7 @@ namespace OpenRa.Traits
 
 		Actor ChooseTarget(Actor self, float range)
 		{
-			var inRange = Game.FindUnitsInCircle(self.CenterLocation, Game.CellSize * range);
+			var inRange = Game.world.FindUnitsInCircle(self.CenterLocation, Game.CellSize * range);
 
 			return inRange
 				.Where(a => a.Owner != null && a.Owner != self.Owner)	/* todo: one day deal with friendly players */

OpenRa.Game/Traits/ConstructionYard.cs

@@ -27,7 +27,7 @@ namespace OpenRa.Traits
 			{
 				// force-move
 				if (!mi.Modifiers.HasModifier(Modifiers.Alt)) return null;
-				if (!Game.IsActorCrushableByActor(underCursor, self)) return null;
+				if (!Game.world.IsActorCrushableByActor(underCursor, self)) return null;
 			}
 
 			return new Order("Move", self, null, xy, null);
@@ -57,7 +57,7 @@ namespace OpenRa.Traits
 			{
 				if (actor == self) continue;
 				
-				if (!Game.IsActorCrushableByActor(actor, self))
+				if (!Game.world.IsActorCrushableByActor(actor, self))
 				{
 					crushable = false;
 					break;

OpenRa.Game/Traits/GeneratesGap.cs

@@ -28,7 +28,7 @@ namespace OpenRa.Traits
 			// Gap Generator building; powered down
 			return (self.traits.Contains<Building>() && self.traits.Get<Building>().Disabled) 
 				? new int2[] {} 
-				: Game.FindTilesInCircle(self.Location, range);
+				: Game.world.FindTilesInCircle(self.Location, range);
 		}
 	}
 }

OpenRa.Game/Traits/McvDeploy.cs

@@ -25,7 +25,7 @@ namespace OpenRa.Traits
 			if( order.OrderString == "DeployMcv" )
 			{
 				var factBuildingInfo = Rules.ActorInfo[ "fact" ].Traits.Get<BuildingInfo>();
-				if( Game.CanPlaceBuilding( "fact", factBuildingInfo, self.Location - new int2( 1, 1 ), self, false ) )
+				if( Game.world.CanPlaceBuilding( "fact", factBuildingInfo, self.Location - new int2( 1, 1 ), self, false ) )
 				{
 					self.CancelActivity();
 					self.QueueActivity( new Turn( 96 ) );

OpenRa.Game/Traits/Mobile.cs

@@ -59,7 +59,7 @@ namespace OpenRa.Traits
 			{
 				// force-move
 				if (!mi.Modifiers.HasModifier(Modifiers.Alt)) return null;
-				if (!Game.IsActorCrushableByActor(underCursor, self)) return null;
+				if (!Game.world.IsActorCrushableByActor(underCursor, self)) return null;
 			}
 
 			if (Util.GetEffectiveSpeed(self) == 0) return null;		/* allow disabling move orders from modifiers */
@@ -97,7 +97,7 @@ namespace OpenRa.Traits
 			{
 				if (actor == self) continue;
 				
-				if (!Game.IsActorCrushableByActor(actor, self))
+				if (!Game.world.IsActorCrushableByActor(actor, self))
 				{
 					crushable = false;
 					break;

OpenRa.Game/Traits/ProductionSurround.cs

@@ -20,7 +20,7 @@ namespace OpenRa.Traits
 
 			for (var j = min.Y; j <= max.Y; j++)
 				for (var i = min.X; i <= max.X; i++)
-					if (Game.IsCellBuildable(new int2(i, j), umt))
+					if (Game.world.IsCellBuildable(new int2(i, j), umt))
 						return new int2(i, j);
 
 			return null;

OpenRa.Game/UiOverlay.cs

@@ -46,10 +46,10 @@ namespace OpenRa
 		public void DrawBuildingGrid( string name, BuildingInfo bi )
 		{
 			var position = Game.controller.MousePosition.ToInt2();
-			var isCloseEnough = Game.IsCloseEnoughToBase(Game.LocalPlayer, name, bi, position);
+			var isCloseEnough = Game.world.IsCloseEnoughToBase(Game.LocalPlayer, name, bi, position);
 
 			foreach( var t in Footprint.Tiles( name, bi, position ) )
-				spriteRenderer.DrawSprite( ( isCloseEnough && Game.IsCellBuildable( t, bi.WaterBound
+				spriteRenderer.DrawSprite( ( isCloseEnough && Game.world.IsCellBuildable( t, bi.WaterBound
 					? UnitMovementType.Float : UnitMovementType.Wheel ) && !Game.world.Map.ContainsResource( t ) )
 					? buildOk : buildBlocked, Game.CellSize * t, 0 );
 

OpenRa.Game/UnitInfluenceMap.cs

@@ -33,7 +33,7 @@ namespace OpenRa
 					{
 						// There should only be one (counterexample: An infantry and a tank try to pick up a crate at the same time.)
 						// If there is more than one, do action on the first crusher
-						var crusher = GetUnitsAt(cell).Where(b => a != b && Game.IsActorCrushableByActor(a, b)).FirstOrDefault();
+						var crusher = GetUnitsAt(cell).Where(b => a != b && Game.world.IsActorCrushableByActor(a, b)).FirstOrDefault();
 						if (crusher != null)
 						{
 							Log.Write("{0} crushes {1}", crusher.Info.Name, a.Info.Name);

OpenRa.Game/WorldUtils.cs

@@ -0,0 +1,133 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using OpenRa.Traits;
+using System.Drawing;
+using OpenRa.GameRules;
+
+namespace OpenRa
+{
+	static class WorldUtils
+	{
+		public static bool IsCellBuildable(this World world, int2 a, UnitMovementType umt)
+		{
+			return world.IsCellBuildable(a, umt, null);
+		}
+
+		public static bool IsCellBuildable(this World world, int2 a, UnitMovementType umt, Actor toIgnore)
+		{
+			if (world.BuildingInfluence.GetBuildingAt(a) != null) return false;
+			if (world.UnitInfluence.GetUnitsAt(a).Any(b => b != toIgnore)) return false;
+
+			return world.Map.IsInMap(a.X, a.Y) &&
+				TerrainCosts.Cost(umt,
+					world.TileSet.GetWalkability(world.Map.MapTiles[a.X, a.Y])) < double.PositiveInfinity;
+		}
+
+		public static bool IsActorCrushableByActor(this World world, Actor a, Actor b)
+		{
+			return world.IsActorCrushableByMovementType(a, b.traits.GetOrDefault<IMovement>().GetMovementType());
+		}
+		
+		public static bool IsActorPathableToCrush(this World world, Actor a, UnitMovementType umt)
+		{
+			return a != null &&
+					a.traits.WithInterface<ICrushable>()
+					.Any(c => c.IsPathableCrush(umt, a.Owner));
+		}
+		
+		public static bool IsActorCrushableByMovementType(this World world, Actor a, UnitMovementType umt)
+		{
+			return a != null &&
+				a.traits.WithInterface<ICrushable>()
+				.Any(c => c.IsCrushableBy(umt, a.Owner));
+		}
+		
+		public static bool IsWater(this World world, int2 a)
+		{
+			return world.Map.IsInMap(a.X, a.Y) &&
+				TerrainCosts.Cost(UnitMovementType.Float,
+					world.TileSet.GetWalkability(world.Map.MapTiles[a.X, a.Y])) < double.PositiveInfinity;
+		}
+
+		public static IEnumerable<Actor> FindUnits(this World world, float2 a, float2 b)
+		{
+			var min = float2.Min(a, b);
+			var max = float2.Max(a, b);
+
+			var rect = new RectangleF(min.X, min.Y, max.X - min.X, max.Y - min.Y);
+
+			return world.Actors
+				.Where(x => x.GetBounds(true).IntersectsWith(rect));
+		}
+
+		public static IEnumerable<Actor> FindUnitsInCircle(this World world, float2 a, float r)
+		{
+			var min = a - new float2(r, r);
+			var max = a + new float2(r, r);
+
+			var rect = new RectangleF(min.X, min.Y, max.X - min.X, max.Y - min.Y);
+
+			var inBox = world.Actors.Where(x => x.GetBounds(false).IntersectsWith(rect));
+
+			return inBox.Where(x => (x.CenterLocation - a).LengthSquared < r * r);
+		}
+
+		public static IEnumerable<int2> FindTilesInCircle(this World world, int2 a, int r)
+		{
+			var min = a - new int2(r, r);
+			var max = a + new int2(r, r);
+			if (min.X < 0) min.X = 0;
+			if (min.Y < 0) min.Y = 0;
+			if (max.X > 127) max.X = 127;
+			if (max.Y > 127) max.Y = 127;
+
+			for (var j = min.Y; j <= max.Y; j++)
+				for (var i = min.X; i <= max.X; i++)
+					if (r * r >= (new int2(i, j) - a).LengthSquared)
+						yield return new int2(i, j);
+		}
+
+		public static IEnumerable<Actor> SelectActorsInBox(this World world, float2 a, float2 b)
+		{
+			return world.FindUnits(a, b)
+				.Where( x => x.traits.Contains<Selectable>() )
+				.GroupBy(x => (x.Owner == Game.LocalPlayer) ? x.Info.Traits.Get<SelectableInfo>().Priority : 0)
+				.OrderByDescending(g => g.Key)
+				.Select( g => g.AsEnumerable() )
+				.DefaultIfEmpty( new Actor[] {} )
+				.FirstOrDefault();
+		}
+
+		public static bool CanPlaceBuilding(this World world, string name, BuildingInfo building, int2 xy, Actor toIgnore, bool adjust)
+		{
+			return !Footprint.Tiles(name, building, xy, adjust).Any(
+				t => !world.Map.IsInMap(t.X, t.Y) || world.Map.ContainsResource(t) || !world.IsCellBuildable(t,
+					building.WaterBound ? UnitMovementType.Float : UnitMovementType.Wheel,
+					toIgnore));
+		}
+
+		public static bool IsCloseEnoughToBase(this World world, Player p, string buildingName, BuildingInfo bi, int2 position)
+		{
+			var maxDistance = bi.Adjacent + 1;
+
+			var search = new PathSearch()
+			{
+				heuristic = loc =>
+				{
+					var b = world.BuildingInfluence.GetBuildingAt(loc);
+					if (b != null && b.Owner == p && b.Info.Traits.Get<BuildingInfo>().BaseNormal) return 0;
+					if ((loc - position).Length > maxDistance)
+						return float.PositiveInfinity;	/* not quite right */
+					return 1;
+				},
+				checkForBlocked = false,
+				ignoreTerrain = true,
+			};
+
+			foreach (var t in Footprint.Tiles(buildingName, bi, position)) search.AddInitialCell(t);
+
+			return world.PathFinder.FindPath(search).Count != 0;
+		}
+	}
+}