From a2af79ff98f0918e1b3ecd86bb8634ad3d1224be Mon Sep 17 00:00:00 2001
From: Paul Chote <pchote@users.noreply.github.com>
Date: Sat, 4 Apr 2015 01:00:45 +0100
Subject: [PATCH] Add support for wall preview neighbours.

---
 .../Traits/Render/RenderBuildingWall.cs       | 47 ++++++++++++++++++-
 1 file changed, 45 insertions(+), 2 deletions(-)

diff --git a/OpenRA.Mods.Common/Traits/Render/RenderBuildingWall.cs b/OpenRA.Mods.Common/Traits/Render/RenderBuildingWall.cs
index b4fdc0ae6d..7ed6d8868d 100644
--- a/OpenRA.Mods.Common/Traits/Render/RenderBuildingWall.cs
+++ b/OpenRA.Mods.Common/Traits/Render/RenderBuildingWall.cs
@@ -24,9 +24,44 @@ namespace OpenRA.Mods.Common.Traits
 
 		public override IEnumerable<IActorPreview> RenderPreviewSprites(ActorPreviewInitializer init, RenderSpritesInfo rs, string image, int facings, PaletteReference p)
 		{
-			// Show a static frame instead of animating all of the wall states
+			var adjacent = 0;
+
+			if (init.Contains<RuntimeNeighbourInit>())
+			{
+				var location = CPos.Zero;
+				if (init.Contains<LocationInit>())
+					location = init.Get<LocationInit, CPos>();
+
+				var neighbours = init.Get<RuntimeNeighbourInit, Dictionary<CPos, string[]>>();
+				foreach (var kv in neighbours)
+				{
+					var haveNeighbour = false;
+					foreach (var n in kv.Value)
+					{
+						var rb = init.World.Map.Rules.Actors[n].Traits.GetOrDefault<RenderBuildingWallInfo>();
+						if (rb != null && rb.Type == Type)
+						{
+							haveNeighbour = true;
+							break;
+						}
+					}
+
+					if (!haveNeighbour)
+						continue;
+
+					if (kv.Key == location + new CVec(0, -1))
+						adjacent |= 1;
+					else if (kv.Key == location + new CVec(+1, 0))
+						adjacent |= 2;
+					else if (kv.Key == location + new CVec(0, +1))
+						adjacent |= 4;
+					else if (kv.Key == location + new CVec(-1, 0))
+						adjacent |= 8;
+				}
+			}
+
 			var anim = new Animation(init.World, image, () => 0);
-			anim.PlayFetchIndex(RenderSprites.NormalizeSequence(anim, init.GetDamageState(), Sequence), () => 0);
+			anim.PlayFetchIndex(RenderSprites.NormalizeSequence(anim, init.GetDamageState(), Sequence), () => adjacent);
 
 			yield return new SpriteActorPreview(anim, WVec.Zero, 0, p, rs.Scale);
 		}
@@ -110,4 +145,12 @@ namespace OpenRA.Mods.Common.Traits
 			UpdateNeighbours(self);
 		}
 	}
+
+	public class RuntimeNeighbourInit : IActorInit<Dictionary<CPos, string[]>>
+	{
+		[FieldFromYamlKey] readonly Dictionary<CPos, string[]> value = null;
+		public RuntimeNeighbourInit() { }
+		public RuntimeNeighbourInit(Dictionary<CPos, string[]> init) { value = init; }
+		public Dictionary<CPos, string[]> Value(World world) { return value; }
+	}
 }