Fixed the building placement to have the cursor in the centre. Replaced magic numbers with Game.CellSize

Using the building footprint, the placement overlay is offset from the cursor so the cursor is in the approximate middle of the overlay (not precisely due to overlay snapping to tiles). The tile size (24) was used as a magic number in a lot of places, they have been replaced with Game.CellSize.

OpenRa.Game/Actor.cs

@@ -23,7 +23,7 @@ namespace OpenRa.Game
 		{
 			unitInfo = Rules.UnitInfo[ name ];
 			Location = location;
-			CenterLocation = new float2( 12, 12 ) + 24 * (float2)Location;
+			CenterLocation = new float2( 12, 12 ) + Game.CellSize * (float2)Location;
 			Owner = owner;
 
 			switch( name )

OpenRa.Game/Controller.cs

@@ -42,9 +42,9 @@ namespace OpenRa.Game
 				if (!(orderGenerator is PlaceBuilding))
 				{
 					if (dragStart != xy)
-						orderGenerator = new UnitOrderGenerator( game.FindUnits( 24 * dragStart, 24 * xy ) ); /* band-box select */
+						orderGenerator = new UnitOrderGenerator( game.FindUnits( Game.CellSize * dragStart, Game.CellSize * xy ) ); /* band-box select */
 					else
-						orderGenerator = new UnitOrderGenerator( game.FindUnits( 24 * xy, 24 * xy ) );  /* click select */
+						orderGenerator = new UnitOrderGenerator( game.FindUnits( Game.CellSize * xy, Game.CellSize * xy ) );  /* click select */
 				}
 
 				dragStart = dragEnd;
@@ -67,7 +67,7 @@ namespace OpenRa.Game
 			get
 			{
 				if (dragStart == dragEnd) return null;
-				return Pair.New(24 * dragStart, 24 * dragEnd);
+				return Pair.New(Game.CellSize * dragStart, Game.CellSize * dragEnd);
 			}
         }
 	}

OpenRa.Game/Game.cs

@@ -10,7 +10,9 @@ using IjwFramework.Collections;
 namespace OpenRa.Game
 {
 	class Game
-	{
+	{
+		public static readonly int CellSize = 24;
+
 		public readonly World world;
 		public readonly Map map;
 		readonly TreeCache treeCache;

OpenRa.Game/GameRules/Footprint.cs

@@ -41,13 +41,18 @@ namespace OpenRa.Game.GameRules
 			var footprint = Rules.Footprint.GetFootprint(name);
 			var j = 0;
 
+			int maxWidth = 0;
+			foreach (var row in footprint)
+				if (row.Length > maxWidth)
+					maxWidth = row.Length;
+
 			foreach (var row in footprint)
 			{
 				var i = 0;
 				foreach (var c in row)
 				{
 					if (c != '_')
-						yield return position + new int2(i, j);
+						yield return position + new int2(i, j) - new int2(maxWidth / 2, footprint.Length / 2);
 					++i;
 				}
 				++j;

OpenRa.Game/Graphics/OverlayRenderer.cs

@@ -74,7 +74,7 @@ namespace OpenRa.Game.Graphics
 							spriteIndex = 11;
 						else if( overlayIsGems[ map.MapTiles[ x, y ].overlay ] )
 							spriteIndex = 2;
-						spriteRenderer.DrawSprite( sprites[ spriteIndex ], 24 * (float2)( location - map.Offset ), 0 );
+						spriteRenderer.DrawSprite( sprites[ spriteIndex ], Game.CellSize * (float2)( location - map.Offset ), 0 );
 					}
 				}
 			}

OpenRa.Game/Graphics/TerrainRenderer.cs

@@ -30,7 +30,7 @@ namespace OpenRa.Game.Graphics
 
 			tileSet = new TileSet( map.TileSuffix );
 
-            Size tileSize = new Size( 24, 24 );
+            Size tileSize = new Size( Game.CellSize, Game.CellSize );
 
             var tileMapping = new Cache<TileReference, Sprite>(
                 x => SheetBuilder.Add(tileSet.GetBytes(x), tileSize));
@@ -44,7 +44,7 @@ namespace OpenRa.Game.Graphics
                 for (int i = 0; i < map.Width; i++)
                 {
                     Sprite tile = tileMapping[map.MapTiles[i + map.XOffset, j + map.YOffset]];
-                    Util.FastCreateQuad(vertices, indices, 24 * new float2(i, j), tile, 0, nv, ni);
+                    Util.FastCreateQuad(vertices, indices, Game.CellSize * new float2(i, j), tile, 0, nv, ni);
                     nv += 4;
                     ni += 6;
                 }

OpenRa.Game/Graphics/Viewport.cs

@@ -25,7 +25,7 @@ namespace OpenRa.Game.Graphics
 		public Viewport(float2 size, float2 mapSize, Renderer renderer)
 		{
 			this.size = size;
-			this.mapSize = 24 * mapSize - size + new float2(128, 0);
+			this.mapSize = Game.CellSize * mapSize - size + new float2(128, 0);
 			this.renderer = renderer;
 		}
 

OpenRa.Game/Sidebar.cs

@@ -214,7 +214,15 @@ namespace OpenRa.Game
 				game.world.AddFrameEndTask(_ =>
 				{
 					Log.Write("Player \"{0}\" builds {1}", building.Owner.PlayerName, building.Name);
-					game.world.Add(new Actor(building.Name, xy, building.Owner));
+
+					//Adjust placement for cursor to be in middle
+					var footprint = Rules.Footprint.GetFootprint(building.Name);
+					int maxWidth = 0;
+					foreach (var row in footprint)
+						if (row.Length > maxWidth)
+							maxWidth = row.Length;
+
+					game.world.Add(new Actor(building.Name, xy - new int2(maxWidth / 2, footprint.Length / 2), building.Owner));
 
 					game.controller.orderGenerator = null;
 					game.worldRenderer.uiOverlay.KillOverlay();

OpenRa.Game/Traits/Building.cs

@@ -17,7 +17,7 @@ namespace OpenRa.Game.Traits
 			if (first && self.Owner == game.LocalPlayer)
 			{
 				self.Owner.TechTree.Build(self.unitInfo.Name, true);
-				self.CenterLocation = 24 * (float2)self.Location + 0.5f * self.SelectedSize;
+				self.CenterLocation = Game.CellSize * (float2)self.Location + 0.5f * self.SelectedSize;
 			}
 			first = false;
 		}

OpenRa.Game/Traits/Mobile.cs

@@ -59,7 +59,7 @@ namespace OpenRa.Game.Traits
 		void UpdateCenterLocation()
 		{
 			float fraction = (moveFraction > 0) ? (float)moveFraction / moveFractionTotal : 0f;
-			self.CenterLocation = new float2(12, 12) + 24 * float2.Lerp(fromCell, toCell, fraction);
+			self.CenterLocation = new float2(12, 12) + Game.CellSize * float2.Lerp(fromCell, toCell, fraction);
 		}
 
 		public void Tick(Actor self, Game game, int dt)

OpenRa.Game/Traits/RenderUnit.cs

@@ -25,7 +25,7 @@ namespace OpenRa.Game.Traits
 		{
 			var mobile = self.traits.Get<Mobile>();
 			float fraction = (mobile.moveFraction > 0) ? (float)mobile.moveFraction / mobile.moveFractionTotal : 0f;
-			var centerLocation = new float2(12, 12) + 24 * float2.Lerp(mobile.fromCell, mobile.toCell, fraction);
+			var centerLocation = new float2(12, 12) + Game.CellSize * float2.Lerp(mobile.fromCell, mobile.toCell, fraction);
 			yield return Centered(anim.Image, centerLocation);
 		}
 	}

OpenRa.Game/Traits/Tree.cs

@@ -18,7 +18,7 @@ namespace OpenRa.Game.Traits
 
 		public IEnumerable<Pair<Sprite, float2>> Render(Actor self)
 		{
-			yield return Pair.New(Image, 24 * (float2)self.Location);
+			yield return Pair.New(Image, Game.CellSize * (float2)self.Location);
 		}
 	}
 }

OpenRa.Game/Traits/Turreted.cs

@@ -7,7 +7,7 @@ namespace OpenRa.Game.Traits
 {
 	class Turreted : ITick // temporary.
 	{
-		public int turretFacing = 24;
+		public int turretFacing = Game.CellSize;
 
 		public Turreted(Actor self)
 		{

OpenRa.Game/UiOverlay.cs

@@ -23,13 +23,13 @@ namespace OpenRa.Game
 
 		static Sprite SynthesizeTile(byte paletteIndex)
 		{
-			byte[] data = new byte[24 * 24];
+			byte[] data = new byte[Game.CellSize * Game.CellSize];
 
-			for (int i = 0; i < 24; i++)
+			for (int i = 0; i < Game.CellSize; i++)
-				for (int j = 0; j < 24; j++)
+				for (int j = 0; j < Game.CellSize; j++)
-					data[i * 24 + j] = ((i + j) % 4 < 2) ? (byte)0 : paletteIndex;
+					data[i * Game.CellSize + j] = ((i + j) % 4 < 2) ? (byte)0 : paletteIndex;
 
-			return SheetBuilder.Add( data, new Size(24,24) );
+			return SheetBuilder.Add( data, new Size(Game.CellSize,Game.CellSize) );
 		}
 
 		public void Draw()
@@ -38,7 +38,7 @@ namespace OpenRa.Game
 				return;
 
 			foreach (var t in Footprint.Tiles(name,position))
-				spriteRenderer.DrawSprite(game.IsCellBuildable(t) ? buildOk : buildBlocked, 24 * t, 0);
+				spriteRenderer.DrawSprite(game.IsCellBuildable(t) ? buildOk : buildBlocked, Game.CellSize * t, 0);
 
 			spriteRenderer.Flush();
 		}