Implement elevated bridge placeholders.

OpenRA.Mods.Common/OpenRA.Mods.Common.csproj

@@ -798,6 +798,8 @@
     <Compile Include="Traits\World\TerrainTunnel.cs" />
     <Compile Include="Traits\World\SubterraneanActorLayer.cs" />
     <Compile Include="Traits\World\JumpjetActorLayer.cs" />
+    <Compile Include="Traits\World\ElevatedBridgeLayer.cs" />
+    <Compile Include="Traits\World\ElevatedBridgePlaceholder.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <Target Name="AfterBuild">

OpenRA.Mods.Common/Traits/Mobile.cs

@@ -44,6 +44,7 @@ namespace OpenRA.Mods.Common.Traits
 		public const byte Tunnel = 1;
 		public const byte Subterranean = 2;
 		public const byte Jumpjet = 3;
+		public const byte ElevatedBridge = 4;
 	}
 
 	[Desc("Unit is able to move.")]

OpenRA.Mods.Common/Traits/World/ElevatedBridgeLayer.cs

@@ -0,0 +1,95 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2017 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System.Collections.Generic;
+using OpenRA.Graphics;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.Common.Traits
+{
+	public class ElevatedBridgeLayerInfo : ITraitInfo, Requires<DomainIndexInfo>, ILobbyCustomRulesIgnore
+	{
+		[Desc("Terrain type used by cells outside any elevated bridge footprint.")]
+		public readonly string ImpassableTerrainType = "Impassable";
+
+		public object Create(ActorInitializer init) { return new ElevatedBridgeLayer(init.Self, this); }
+	}
+
+	// For now this is mostly copies TerrainTunnelLayer. This will change once bridge destruction is implemented
+	public class ElevatedBridgeLayer : ICustomMovementLayer, IWorldLoaded
+	{
+		readonly Map map;
+		readonly CellLayer<WPos> cellCenters;
+		readonly CellLayer<byte> terrainIndices;
+		readonly HashSet<CPos> ends = new HashSet<CPos>();
+		bool enabled;
+
+		public ElevatedBridgeLayer(Actor self, ElevatedBridgeLayerInfo info)
+		{
+			map = self.World.Map;
+			cellCenters = new CellLayer<WPos>(map);
+			terrainIndices = new CellLayer<byte>(map);
+			terrainIndices.Clear(map.Rules.TileSet.GetTerrainIndex(info.ImpassableTerrainType));
+		}
+
+		public void WorldLoaded(World world, WorldRenderer wr)
+		{
+			var domainIndex = world.WorldActor.Trait<DomainIndex>();
+			foreach (var tti in world.WorldActor.Info.TraitInfos<ElevatedBridgePlaceholderInfo>())
+			{
+				enabled = true;
+
+				var terrain = map.Rules.TileSet.GetTerrainIndex(tti.TerrainType);
+				foreach (var c in tti.BridgeCells())
+				{
+					var uv = c.ToMPos(map);
+					terrainIndices[uv] = terrain;
+
+					var pos = map.CenterOfCell(c);
+					cellCenters[uv] = pos - new WVec(0, 0, pos.Z - 512 * tti.Height);
+				}
+
+				var end = tti.EndCells();
+				domainIndex.AddFixedConnection(end);
+				foreach (var c in end)
+				{
+					// Need to explicitly set both default and tunnel layers, otherwise the .Contains check will fail
+					ends.Add(new CPos(c.X, c.Y, 0));
+					ends.Add(new CPos(c.X, c.Y, CustomMovementLayerType.ElevatedBridge));
+				}
+			}
+		}
+
+		bool ICustomMovementLayer.EnabledForActor(ActorInfo a, MobileInfo mi) { return enabled; }
+		byte ICustomMovementLayer.Index { get { return CustomMovementLayerType.ElevatedBridge; } }
+		bool ICustomMovementLayer.InteractsWithDefaultLayer { get { return true; } }
+
+		WPos ICustomMovementLayer.CenterOfCell(CPos cell)
+		{
+			return cellCenters[cell];
+		}
+
+		int ICustomMovementLayer.EntryMovementCost(ActorInfo a, MobileInfo mi, CPos cell)
+		{
+			return ends.Contains(cell) ? 0 : int.MaxValue;
+		}
+
+		int ICustomMovementLayer.ExitMovementCost(ActorInfo a, MobileInfo mi, CPos cell)
+		{
+			return ends.Contains(cell) ? 0 : int.MaxValue;
+		}
+
+		byte ICustomMovementLayer.GetTerrainIndex(CPos cell)
+		{
+			return terrainIndices[cell];
+		}
+	}
+}

OpenRA.Mods.Common/Traits/World/ElevatedBridgePlaceholder.cs

@@ -0,0 +1,75 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2017 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System.Collections.Generic;
+using System.Linq;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.Common.Traits
+{
+	public enum ElevatedBridgePlaceholderOrientation { X, Y }
+
+	[Desc("Placeholder to make static elevated bridges work.",
+		"Define individual trait instances for each elevated bridge footprint in the map.")]
+	public class ElevatedBridgePlaceholderInfo : TraitInfo<ElevatedBridgePlaceholder>, Requires<ElevatedBridgeLayerInfo>, ILobbyCustomRulesIgnore
+	{
+		[FieldLoader.Require]
+		[Desc("Location of the bridge")]
+		public readonly CPos Location = CPos.Zero;
+
+		[FieldLoader.Require]
+		[Desc("Orientation of the bridge.")]
+		public readonly ElevatedBridgePlaceholderOrientation Orientation;
+
+		[FieldLoader.Require]
+		[Desc("Length of the bridge")]
+		public readonly int Length = 0;
+
+		[FieldLoader.Require]
+		[Desc("Height of the bridge in map height steps.")]
+		public readonly byte Height = 0;
+
+		[Desc("Terrain type of the bridge.")]
+		public readonly string TerrainType = "Road";
+
+		public IEnumerable<CPos> BridgeCells()
+		{
+			var dimensions = Orientation == ElevatedBridgePlaceholderOrientation.X ?
+				new CVec(Length + 1, 3) : new CVec(3, Length + 1);
+
+			for (var y = 0; y < dimensions.Y; y++)
+				for (var x = 0; x < dimensions.X; x++)
+					yield return Location + new CVec(x, y);
+		}
+
+		public IEnumerable<CPos> EndCells()
+		{
+			if (Orientation == ElevatedBridgePlaceholderOrientation.X)
+			{
+				for (var y = 0; y < 3; y++)
+				{
+					yield return Location + new CVec(0, y);
+					yield return Location + new CVec(Length, y);
+				}
+			}
+			else
+			{
+				for (var x = 0; x < 3; x++)
+				{
+					yield return Location + new CVec(x, 0);
+					yield return Location + new CVec(x, Length);
+				}
+			}
+		}
+	}
+
+	public class ElevatedBridgePlaceholder { }
+}