feat(desktop): P26 民居立面第二变体（挑檐/木格栅窗/院门）沿河沿路交替

1 files changed, 22 insertions, 4 deletions

diff --git a/src/LivingVillage.Desktop.Tests/PrototypeTests.fs b/src/LivingVillage.Desktop.Tests/PrototypeTests.fs
index e58139c..a38228f 100644
--- a/src/LivingVillage.Desktop.Tests/PrototypeTests.fs
+++ b/src/LivingVillage.Desktop.Tests/PrototypeTests.fs
@@ -1104,6 +1104,23 @@ type PrototypeTests () =
         // 953775FA 硬对齐由 --performance-baseline 于 finalWorld 支线证据。
 
     [<TestMethod>]
+    member _.HouseFacadeVariantsAlternateAlongTheVillage () =
+        // P26：512 大图上两种民居立面都要出现，且按位置确定性交替（纯函数）。
+        let map = MapGen.generateWithSize 512 384 (uint64 4242)
+        let variants = map.Buildings |> List.map VillageArt.houseFacadeVariant
+        Assert.IsTrue(Set.ofList variants |> Set.contains 0, "variant A must appear")
+        Assert.IsTrue(Set.ofList variants |> Set.contains 1, "variant B must appear")
+        let repeated = MapGen.generateWithSize 512 384 (uint64 4242)
+        Assert.AreEqual<(int list)>(variants, repeated.Buildings |> List.map VillageArt.houseFacadeVariant)
+        // Neighbouring buildings along the same river bank must flip variant, i.e. not one solid run.
+        let flipped =
+            variants
+            |> List.pairwise
+            |> List.filter (fun (a, b) -> a <> b)
+            |> List.length
+        Assert.IsTrue(flipped > 0, "facades must alternate, not stay one variant")
+
+    [<TestMethod>]
     member _.JiangnanArtAssetsArePackagedAsRealPngFiles () =
         let requiredAssets =
             [ "Assets/jiangnan-world.png"
@@ -1116,9 +1133,10 @@ type PrototypeTests () =
 
         Assert.AreEqual<string list>([], missing, sprintf "Missing Jiangnan PNG assets: %s" (String.concat ", " missing))
 
-        // The baked world atlas must match the 28-slot layout the renderer indexes into
-        // (P17 added 石灯笼/水缸/摊贩摊位 as slots 25..27).
-        Assert.AreEqual<int>(28, VillageArt.worldTileCount)
+        // The baked world atlas must match the 31-slot layout the renderer indexes into
+        // (P17 added 石灯笼/水缸/摊贩摊位 as slots 25..27; P26 added the variant-B house
+        // parts 屋檐挑出/木格栅窗/院门 as slots 28..30).
+        Assert.AreEqual<int>(31, VillageArt.worldTileCount)
         let worldPath = Path.Combine(AppContext.BaseDirectory, "Assets/jiangnan-world.png")
         let header = File.ReadAllBytes worldPath
         let be32 offset =
@@ -1128,7 +1146,7 @@ type PrototypeTests () =
             ||| int header.[offset + 3]
         let atlasWidth : int = be32 16
         let atlasHeight : int = be32 20
-        Assert.IsTrue((atlasWidth = VillageArt.worldAtlasWidth), "world atlas width must match 28 x 32px slots")
+        Assert.IsTrue((atlasWidth = VillageArt.worldAtlasWidth), "world atlas width must match 31 x 32px slots")
         Assert.IsTrue((atlasHeight = VillageArt.worldAtlasHeight), "world atlas height must stay 32px")
 
     [<TestMethod>]