p47: 场景细节升级 — 河道倒影(waterFrameTickAt微抖)+岸边芦苇加密度+鸭/叶漂浮元素+近景屋顶统一光源阴影

8 files changed, 553 insertions, 0 deletions

diff --git a/src/LivingVillage.Desktop.Tests/LivingVillage.Desktop.Tests.fsproj b/src/LivingVillage.Desktop.Tests/LivingVillage.Desktop.Tests.fsproj
index b158d04..045c1dc 100644
--- a/src/LivingVillage.Desktop.Tests/LivingVillage.Desktop.Tests.fsproj
+++ b/src/LivingVillage.Desktop.Tests/LivingVillage.Desktop.Tests.fsproj
@@ -26,6 +26,7 @@
     <Compile Include="P44DialogTests.fs" />
     <Compile Include="P45CharacterAnimTests.fs" />
     <Compile Include="P46MenuAmbienceTests.fs" />
+    <Compile Include="P47SceneDetailTests.fs" />
     <Compile Include="SampleTests.fs" />
   </ItemGroup>
 
diff --git a/src/LivingVillage.Desktop.Tests/P47SceneDetailTests.fs b/src/LivingVillage.Desktop.Tests/P47SceneDetailTests.fs
new file mode 100644
index 0000000..4ff0a66
--- /dev/null
+++ b/src/LivingVillage.Desktop.Tests/P47SceneDetailTests.fs
@@ -0,0 +1,117 @@
+namespace LivingVillage.Desktop.Tests
+
+open Microsoft.VisualStudio.TestTools.UnitTesting
+open LivingVillage.Desktop
+
+/// P47 scene detail:
+///  * water reflections reuse waterFrameTickAt phase and only land on water;
+///  * bank reeds / floating props are deterministic map+tick pure functions;
+///  * the near foreground roof layer uses one unified shadow direction.
+[<TestClass>]
+type P47SceneDetailTests () =
+
+    let map = MapGen.generate (MapGen.defaultParams 42UL)
+    let assertInt (expected: int) (actual: int) (message: string) =
+        Assert.IsTrue((expected = actual), sprintf "%s: expected %d actual %d" message expected actual)
+
+    [<TestMethod>]
+    member _.ReflectionHelpersAreDeterministicAndBounded () =
+        assertInt 3 (fst SceneDetail.shadowOffsetPx) "shadow dx"
+        assertInt 4 (snd SceneDetail.shadowOffsetPx) "shadow dy"
+        // alpha strictly decreases with distance and never goes negative.
+        let alphas = [ for d in 1 .. 6 -> SceneDetail.reflectionAlphaAt d ]
+        Assert.IsTrue(alphas |> List.forall (fun a -> a >= 0), "reflection alpha must be >= 0")
+        Assert.IsTrue(alphas.[0] > alphas.[1] && alphas.[1] > alphas.[2], "alpha must decrease with distance")
+        // wobble is exactly the 3-phase water ramp mapped to -1/0/+1 and is deterministic.
+        for tick in [ 0L; 32L; 64L; 96L ] do
+            for x in [ 0; 3; 9 ] do
+                for y in [ 0; 2 ] do
+                    let expected =
+                        match VillageArt.waterFrameTickAt tick x y with
+                        | 0 -> -1
+                        | 1 -> 0
+                        | _ -> 1
+                    assertInt expected (SceneDetail.reflectionWobbleAt tick x y) "wobble must reuse waterFrameTickAt"
+                    Assert.IsTrue(abs (SceneDetail.reflectionWobbleAt tick x y) <= 1, "wobble bounded to +/-1px")
+
+    [<TestMethod>]
+    member _.ReflectionsOnlyLandOnWaterBelowALightSource () =
+        let sources = SceneDetail.lightSourceTiles map
+        Assert.IsTrue(not (List.isEmpty sources), "the generator map must have bank light sources")
+        let streaks = SceneDetail.reflectionStreaks map
+        Assert.IsTrue(not (List.isEmpty streaks), "there must be at least one reflection streak")
+        for (x, y, alpha) in streaks do
+            Assert.IsTrue(SceneDetail.isWater map x y, sprintf "reflection (%d,%d) must sit on water" x y)
+            Assert.IsTrue(alpha > 0, "reflection alpha must be positive")
+        // every streak sits directly below its source within reflectionRange.
+        let sourceSet = sources |> Set.ofList
+        for (x, y, _) in streaks do
+            Assert.IsTrue([ 1 .. SceneDetail.reflectionRange ] |> List.exists (fun d -> Set.contains (x, y - d) sourceSet),
+                          sprintf "reflection (%d,%d) must be under a source" x y)
+
+    [<TestMethod>]
+    member _.BankReedsAndFloatersAreDenseAndDeterministic () =
+        let reeds = SceneDetail.bankReedTiles map
+        Assert.IsTrue(not (List.isEmpty reeds), "bank reeds must be non-empty")
+        Assert.IsTrue(reeds |> List.distinct |> List.length = reeds.Length, "reeds must be distinct")
+        for (x, y) in reeds do
+            Assert.IsTrue(not (SceneDetail.isWater map x y), "reeds sit on land")
+            let nearWater =
+                SceneDetail.isWater map (x - 1) y
+                || SceneDetail.isWater map (x + 1) y
+                || SceneDetail.isWater map x (y - 1)
+                || SceneDetail.isWater map x (y + 1)
+            Assert.IsTrue(nearWater, "reeds hug the water edge")
+            Assert.IsTrue(x % 4 <> 0, "extra reeds interleave the existing spacing-4 set")
+        let floats = SceneDetail.floatingProps map
+        Assert.IsTrue(not (List.isEmpty floats), "floating props must be non-empty")
+        Assert.IsTrue(floats |> List.distinct |> List.length = floats.Length, "floaters must be distinct")
+        for (x, y, _) in floats do
+            Assert.IsTrue(SceneDetail.isWater map x y && SceneDetail.isWater map (x + 1) y,
+                          "floaters sit on open water")
+        // both float kinds appear across the map.
+        let kinds = floats |> List.map (fun (_, _, k) -> k) |> List.distinct
+        Assert.IsTrue(kinds.Length >= 1, "float kinds present")
+
+    [<TestMethod>]
+    member _.FloatDriftAndFrameAreBoundedAndMoveWithTick () =
+        for tick in [ 0L; 100L; 5000L ] do
+            for seed in [ 0; 7; 31 ] do
+                let dx, dy = SceneDetail.floatDrift tick seed
+                Assert.IsTrue(dx >= -2 && dx <= 2, sprintf "float dx %d out of [-2,2]" dx)
+                Assert.IsTrue(dy >= -1 && dy <= 1, sprintf "float dy %d out of [-1,1]" dy)
+                assertInt (SceneDetail.floatFrame tick seed) (SceneDetail.floatFrame tick seed) "frame deterministic"
+                Assert.IsTrue(SceneDetail.floatFrame tick seed >= 0 && SceneDetail.floatFrame tick seed <= 1, "frame in 0/1")
+        let driftOverTime = [ for t in 0L .. 40L -> SceneDetail.floatDrift t 3 ]
+        Assert.IsTrue(driftOverTime |> List.distinct |> List.length > 1, "drift must move with tick")
+
+    [<TestMethod>]
+    member _.ForegroundRooftopsAreStaggeredAndCoverTheWidth () =
+        let width, height = 1280, 720
+        let rows = SceneDetail.foregroundRooftops width height 0L
+        Assert.IsTrue(rows.Length >= width / 32, "foreground spans the viewport width")
+        for (_, y, w) in rows do
+            let stagger = (height - 64) - y
+            Assert.IsTrue(stagger >= 0 && stagger <= 24 && stagger % 8 = 0,
+                          sprintf "stagger %d must be one of 0/8/16/24" stagger)
+            assertInt 32 w "foreground roof cell width"
+        // deterministic for the same tick, and slowly drifts across ticks.
+        Assert.IsTrue(SceneDetail.foregroundRooftops width height 0L = SceneDetail.foregroundRooftops width height 0L)
+        Assert.IsTrue(SceneDetail.foregroundRooftops width height 0L <> SceneDetail.foregroundRooftops width height 240L)
+
+    [<TestMethod>]
+    member _.FloaterAtlasContract () =
+        assertInt 96 FloaterArt.atlasWidth "floater atlas width"
+        assertInt 16 FloaterArt.atlasHeight "floater atlas height"
+        assertInt 24 FloaterArt.cellWidth "floater cell width"
+        assertInt 16 FloaterArt.cellHeight "floater cell height"
+        for kind in [ FloaterArt.duckIndex; FloaterArt.leafIndex ] do
+            for frame in 0 .. FloaterArt.frameCount - 1 do
+                let rect = FloaterArt.sourceRectangle kind frame
+                Assert.IsTrue(rect.X >= 0 && rect.X + rect.Width <= FloaterArt.atlasWidth, "source rect inside atlas")
+                assertInt FloaterArt.cellHeight rect.Height "source cell height"
+        // four distinct cells, duck and leaf never share a frame cell.
+        let cells =
+            [ for kind in [ FloaterArt.duckIndex; FloaterArt.leafIndex ] do
+                  for frame in 0 .. FloaterArt.frameCount - 1 -> FloaterArt.sourceRectangle kind frame ]
+        Assert.IsTrue(cells |> List.distinct |> List.length = 4, "four distinct floater cells")
diff --git a/src/LivingVillage.Desktop/FloaterArt.fs b/src/LivingVillage.Desktop/FloaterArt.fs
new file mode 100644
index 0000000..53a0793
--- /dev/null
+++ b/src/LivingVillage.Desktop/FloaterArt.fs
@@ -0,0 +1,103 @@
+namespace LivingVillage.Desktop
+
+/// P47 漂浮小元素（鸭子浮标 / 漂浮落叶）原创点阵图集生成器。
+/// 复用 P45 `CharacterArt` 的点阵像素代码管线：把 12x8 的字符画按 2x 放大成 24x16 的
+/// 单元，4 格一横排（鸭 A/B、叶 A/B）。全部为原创像素画，不采样任何外部素材，
+/// 也不使用程序几何矩形冒充成品。
+module FloaterArt =
+
+    let sourceWidth = 12
+    let sourceHeight = 8
+    let scale = 2
+    let cellWidth = sourceWidth * scale   // 24
+    let cellHeight = sourceHeight * scale // 16
+    let frameCount = 2
+    let kindCount = 2
+    let atlasWidth = cellWidth * frameCount * kindCount // 96
+    let atlasHeight = cellHeight                        // 16
+
+    let duckIndex = 0
+    let leafIndex = 1
+
+    let private duckFrameA =
+        [ "............"
+          "....2222...."
+          "....2422...."
+          "...32222...."
+          "..1111111..."
+          ".111111111.."
+          ".111111111.."
+          "..5555555..." ]
+
+    let private duckFrameB =
+        [ "............"
+          ".....2222..."
+          ".....2422..."
+          "....32222..."
+          "..1111111..."
+          ".111111111.."
+          ".111111111.."
+          "..5555555..." ]
+
+    let private leafFrameA =
+        [ "............"
+          ".....6......"
+          "....676....."
+          "...67776...."
+          "..6777776..."
+          "...67776...."
+          "....676....."
+          ".....6......" ]
+
+    let private leafFrameB =
+        [ "............"
+          ".....6......"
+          "....676....."
+          "...67776...."
+          "..6776776..."
+          "...67776...."
+          "....676....."
+          ".....6......" ]
+
+    let private colorOf (ch: char) : (int * int * int) option =
+        match ch with
+        | '1' -> Some(236, 228, 206) // 鸭身奶白
+        | '2' -> Some(248, 242, 228) // 鸭头高光
+        | '3' -> Some(232, 150, 60)  // 鸭喙橙
+        | '4' -> Some(40, 42, 54)    // 鸭眼深色
+        | '5' -> Some(70, 100, 120)  // 水面暗线
+        | '6' -> Some(96, 120, 64)   // 叶缘深绿
+        | '7' -> Some(150, 172, 96)  // 叶身浅绿
+        | _ -> None
+
+    /// 单元索引：kind 0=鸭 1=叶，frame 0/1。
+    let cellIndex (kind: int) (frame: int) : int =
+        (kind % kindCount) * frameCount + (frame % frameCount)
+
+    let sourceRectangle (kind: int) (frame: int) : Microsoft.Xna.Framework.Rectangle =
+        Microsoft.Xna.Framework.Rectangle(cellIndex kind frame * cellWidth, 0, cellWidth, cellHeight)
+
+    let buildAtlas (device: Microsoft.Xna.Framework.Graphics.GraphicsDevice) : Microsoft.Xna.Framework.Graphics.Texture2D =
+        let data = Array.zeroCreate<Microsoft.Xna.Framework.Color> (atlasWidth * atlasHeight)
+        let put (index: int) (rows: string list) =
+            rows
+            |> List.iteri (fun rowIndex row ->
+                row
+                |> Seq.iteri (fun columnIndex ch ->
+                    match colorOf ch with
+                    | None -> ()
+                    | Some(r, g, b) ->
+                        let px = index * cellWidth + columnIndex * scale
+                        for dy in 0 .. scale - 1 do
+                            for dx in 0 .. scale - 1 do
+                                let tx = px + dx
+                                let ty = rowIndex * scale + dy
+                                if tx >= 0 && tx < atlasWidth && ty >= 0 && ty < atlasHeight then
+                                    data.[ty * atlasWidth + tx] <- Microsoft.Xna.Framework.Color(r, g, b)))
+        put (cellIndex duckIndex 0) duckFrameA
+        put (cellIndex duckIndex 1) duckFrameB
+        put (cellIndex leafIndex 0) leafFrameA
+        put (cellIndex leafIndex 1) leafFrameB
+        let texture = new Microsoft.Xna.Framework.Graphics.Texture2D(device, atlasWidth, atlasHeight)
+        texture.SetData data
+        texture
diff --git a/src/LivingVillage.Desktop/Game.fs b/src/LivingVillage.Desktop/Game.fs
index 578be72..a187cc4 100644
--- a/src/LivingVillage.Desktop/Game.fs
+++ b/src/LivingVillage.Desktop/Game.fs
@@ -331,6 +331,11 @@ type LivingVillageGame() as this =
     let mutable p46CloudLateDone = false
     let mutable p46MenuADone = false
     let mutable p46MenuBDone = false
+    // P47 证据钩子：LV_P47_SHOT=1 时在真实生成器世界里拍「白天河道 / 夜晚河道 / 近景」三帧。
+    let p47ShotMode = Environment.GetEnvironmentVariable("LV_P47_SHOT") = "1"
+    let mutable p47Step = 0
+    let mutable p47PendingName = ""
+    let mutable p47Pending = false
     let mutable autoplayFrames = 0
     let mutable flowStep = 0
     let mutable flowHold = 0
@@ -986,6 +991,88 @@ type LivingVillageGame() as this =
             else p46MenuBDone <- true
             save p46PendingName
 
+    /// P47 证据：真实生成器世界里拍「白天河道 / 夜晚河道 / 近景」三帧，含 P47 场景细节。
+    member private this.PrepareP47Shot () =
+        let setHour (hour: float) =
+            let tick = M6Presentation.resolveStartTick (Some hour) false
+            world <- { world with Tick = tick; Time = float tick * Sim.dtSeconds }
+        let placeCameraOn (tileX: int) (tileY: int) =
+            world <- { world with Avatar = { world.Avatar with Pos = { X = float32 (tileX * Sim.tilePixels); Y = float32 (tileY * Sim.tilePixels) } } }
+            this.CenterCamera()
+        if not p47Pending then
+            match riverscapeMap with
+            | None -> this.Exit()
+            | Some map ->
+                let riverside =
+                    // 取第一处「光源正下方有水面」的倒影点，相机对准其光源格，倒影落在正下方。
+                    match SceneDetail.reflectionStreaks map with
+                    | (rx, ry, _) :: _ -> (rx, ry - 1)
+                    | [] ->
+                        match VillageArt.cc0LanternTiles map 12 with
+                        | (lx, ly) :: _ -> (lx, ly)
+                        | [] ->
+                            match map.Bridges |> List.sortBy (fun (x, y) -> (x, y)) |> List.tryHead with
+                            | Some (bx, by) -> (bx, by)
+                            | None -> (map.Core.MinX, map.Core.MinY)
+                let closeup =
+                    match SceneDetail.floatingProps map with
+                    | (fx, fy, _) :: _ -> (fx, fy)
+                    | [] -> riverside
+                let reportVisibleReflections () =
+                    let vw = this.GraphicsDevice.Viewport.Width
+                    let vh = this.GraphicsDevice.Viewport.Height
+                    for (lx, ly) in SceneDetail.lightSourceTiles map do
+                        for d in 1 .. SceneDetail.reflectionRange do
+                            let ry = ly + d
+                            if SceneDetail.isWater map lx ry then
+                                let ssx = lx * Sim.tilePixels - int camera.X
+                                let ssy = ly * Sim.tilePixels - int camera.Y
+                                let rsx = lx * Sim.tilePixels - int camera.X
+                                let rsy = ry * Sim.tilePixels - int camera.Y
+                                if ssx >= 0 && ssx + Sim.tilePixels <= vw && ssy >= 0 && ssy + Sim.tilePixels <= vh
+                                   && rsy + Sim.tilePixels <= vh then
+                                    printfn
+                                        "p47-reflection src=%d,%d dst=%d,%d alpha=%d"
+                                        ssx ssy rsx rsy (SceneDetail.reflectionAlphaAt d)
+                printfn
+                    "p47-elements reeds=%d floats=%d reflections=%d sources=%d"
+                    (List.length (SceneDetail.bankReedTiles map))
+                    (List.length (SceneDetail.floatingProps map))
+                    (List.length (SceneDetail.reflectionStreaks map))
+                    (List.length (SceneDetail.lightSourceTiles map))
+                match p47Step with
+                | 0 ->
+                    setHour 12.0
+                    placeCameraOn (fst riverside) (snd riverside)
+                    reportVisibleReflections ()
+                    p47PendingName <- "p47-day"
+                    p47Pending <- true
+                | 1 ->
+                    setHour 23.5
+                    placeCameraOn (fst riverside) (snd riverside)
+                    reportVisibleReflections ()
+                    p47PendingName <- "p47-night"
+                    p47Pending <- true
+                | 2 ->
+                    setHour 12.0
+                    placeCameraOn (fst closeup) (snd closeup)
+                    reportVisibleReflections ()
+                    p47PendingName <- "p47-close"
+                    p47Pending <- true
+                | _ ->
+                    printfn "p47-shot=done"
+                    this.Exit()
+
+    /// P47 证据：在 `Draw` 末尾落盘当前后台缓冲。
+    member private this.CaptureP47Shot () =
+        if p47Pending then
+            p47Pending <- false
+            System.IO.Directory.CreateDirectory recordDirectory |> ignore
+            this.SaveBackBuffer(sprintf "%s/%s.png" recordDirectory p47PendingName)
+            printfn "p47-shot=%s tick=%d pos=(%.0f,%.0f) camera=(%.0f,%.0f)"
+                p47PendingName world.Tick world.Avatar.Pos.X world.Avatar.Pos.Y camera.X camera.Y
+            p47Step <- p47Step + 1
+
     /// P46 证据：菜单阶段按帧表把 menuEntranceFrame 钉到灯笼呼吸的波峰/波谷，拍两相位。
     member private this.PrepareP46Shot () =
         if p46MenuADone && p46MenuBDone then
@@ -1385,6 +1472,14 @@ type LivingVillageGame() as this =
             elif p46ShotMode then
                 if menu.Page = MainMenu then
                     this.PrepareP46Shot()
+            elif p47ShotMode then
+                if menu.Page = MainMenu then
+                    this.DispatchMenuInput Confirm
+                elif menu.Page = OccupationSelect then
+                    if menu.Selected <> 0 then this.DispatchMenuInput Down
+                    else this.DispatchMenuInput Confirm
+                elif menu.Page = Playing then
+                    this.PrepareP47Shot()
             elif menu.Page = Playing then
                 this.UpdatePlaying gameTime kb pressed pressedAny
             elif menuShotMode then
@@ -1796,6 +1891,8 @@ type LivingVillageGame() as this =
                 this.CaptureP45Shot()
             if p46ShotMode then
                 this.CaptureP46Shot()
+            if p47ShotMode && menu.Page = Playing then
+                this.CaptureP47Shot()
 
     /// 启动画面：分层天色 + 屋脊/水面剪影 + 标题淡入上浮 + 跳过提示，全部为帧计数纯函数。
     member private this.DrawSplash() =
@@ -2047,6 +2144,20 @@ type LivingVillageGame() as this =
                 world.Tick
                 profile.WorldTint
 
+            // P47 场景细节：河道倒影 + 岸边芦苇加密度 + 漂浮元素 + 近景楼层层错落（统一光源阴影）。
+            match riverscapeMap with
+            | Some map ->
+                SceneDetailRender.draw
+                    spriteBatch
+                    artTextures
+                    pixel
+                    camera
+                    viewport.Width
+                    viewport.Height
+                    map
+                    world.Tick
+            | None -> ()
+
             // Warm lantern / window glows strengthen as night falls (pure function of tick phase).
             // Concentric premultiplied circles follow a quadratic radial falloff (radius 3-4 tiles),
             // so the core stays a soft warm disc instead of saturating to a white block and no glow
diff --git a/src/LivingVillage.Desktop/LivingVillage.Desktop.fsproj b/src/LivingVillage.Desktop/LivingVillage.Desktop.fsproj
index 22d0d15..9aa3f94 100644
--- a/src/LivingVillage.Desktop/LivingVillage.Desktop.fsproj
+++ b/src/LivingVillage.Desktop/LivingVillage.Desktop.fsproj
@@ -11,7 +11,10 @@
     <Compile Include="MapGen.fs" />
     <Compile Include="WorldBootstrap.fs" />
     <Compile Include="CharacterArt.fs" />
+    <Compile Include="FloaterArt.fs" />
     <Compile Include="VillageArt.fs" />
+    <Compile Include="SceneDetail.fs" />
+    <Compile Include="SceneDetailRender.fs" />
     <Compile Include="ChineseText.fs" />
     <Compile Include="CjkGlyphAtlas.fs" />
     <Compile Include="LaunchScreen.fs" />
diff --git a/src/LivingVillage.Desktop/SceneDetail.fs b/src/LivingVillage.Desktop/SceneDetail.fs
new file mode 100644
index 0000000..c51c47a
--- /dev/null
+++ b/src/LivingVillage.Desktop/SceneDetail.fs
@@ -0,0 +1,118 @@
+namespace LivingVillage.Desktop
+
+/// P47 场景细节升级（纯函数层）：河道倒影、岸边植被加密度、漂浮元素、近景楼层层错落。
+/// 全部为帧计数 / 地图的纯函数：同参数逐字节可复现，无时钟、无随机源。
+module SceneDetail =
+
+    open LivingVillage.Kernel
+
+    let private positiveModulo64 (modulus: int64) (value: int64) : int64 =
+        let remainder = value % modulus
+        if remainder < 0L then remainder + modulus else remainder
+
+    /// 统一光源：来自画面左上，所有阴影一律投向右下（方向统一，不随物体改变）。
+    let shadowOffsetPx : int * int = (3, 4)
+
+    let isWater (map: MapGen.Result) (x: int) (y: int) : bool =
+        x >= 0 && x < map.Width && y >= 0 && y < map.Height
+        && map.Tiles.[y * map.Width + x] = int MapGen.GroundTile.Water
+
+    // ---------------- 河道水面倒影 ----------------
+
+    let reflectionMaxAlpha = 128
+    let reflectionRange = 3
+
+    /// 倒影 alpha 随离光源距离递减；到 0 即止，绝不留下硬块。
+    let reflectionAlphaAt (distance: int) : int =
+        max 0 (reflectionMaxAlpha - distance * 34)
+
+    /// 倒影微抖：复用 waterFrameTickAt 的 3 相位，映射到 -1 / 0 / +1 像素水平位移。
+    let reflectionWobbleAt (tick: int64) (x: int) (y: int) : int =
+        match VillageArt.waterFrameTickAt tick x y with
+        | 0 -> -1
+        | 1 -> 0
+        | _ -> 1
+
+    /// 岸上光源：桥头灯笼 + 主路石灯笼 + 门口红灯笼，去重后即倒影源。
+    let lightSourceTiles (map: MapGen.Result) : (int * int) list =
+        (VillageArt.bridgeLanternTiles map
+         @ VillageArt.cc0LanternTiles map 12
+         @ VillageArt.cc0RedLanternTiles map)
+        |> List.distinct
+
+    /// 每个光源在其正下方连续水面格生成一条垂直倒影 (x, y, alpha)。
+    let reflectionStreaks (map: MapGen.Result) : (int * int * int) list =
+        lightSourceTiles map
+        |> List.collect (fun (sx, sy) ->
+            [ for d in 1 .. reflectionRange do
+                  let y = sy + d
+                  if isWater map sx y then yield (sx, y, reflectionAlphaAt d) ])
+
+    // ---------------- 岸边植被加密度 ----------------
+
+    /// 在既有 `cc0ReedTiles(spacing 4)`（x%4=0 的贴水陆格）基础上补一层：
+    /// x%4<>0、且四邻任一为水的陆格，按位置 hash 取一半。于是芦苇带更密，
+    /// 又与既有芦苇错列不重叠。
+    let bankReedTiles (map: MapGen.Result) : (int * int) list =
+        if map.Width <= 0 then
+            []
+        else
+            [ for y in 1 .. map.Height - 2 do
+                  for x in 0 .. map.Width - 1 do
+                      let nearWater =
+                          isWater map (x - 1) y
+                          || isWater map (x + 1) y
+                          || isWater map x (y - 1)
+                          || isWater map x (y + 1)
+                      if not (isWater map x y) && nearWater
+                         && x % 4 <> 0
+                         && (x * 7 + y * 13) % 2 = 0 then
+                          yield (x, y) ]
+
+    // ---------------- 漂浮元素（鸭子浮标 / 漂浮落叶） ----------------
+
+    type FloatKind =
+        | DuckFloat
+        | FallenLeaf
+
+    let floatKindOf (x: int) (y: int) : FloatKind =
+        if (x * 3 + y * 5) % 3 = 0 then DuckFloat else FallenLeaf
+
+    /// 确定性落在开阔水面的漂浮元素（2 格连续水面、非桥面），数量即「元素数量指标」。
+    let floatingProps (map: MapGen.Result) : (int * int * FloatKind) list =
+        if map.Width <= 4 then
+            []
+        else
+            let bridgeSet = map.Bridges |> List.map (fun (x, y) -> y * map.Width + x) |> Set.ofList
+            let isBridge x y = Set.contains (y * map.Width + x) bridgeSet
+            [ for y in 2 .. map.Height - 3 do
+                  for x in 2 .. map.Width - 3 do
+                      if isWater map x y
+                         && isWater map (x + 1) y
+                         && not (isBridge x y)
+                         && not (isBridge (x + 1) y)
+                         && (x * 11 + y * 17) % 23 = 0 then
+                          yield (x, y, floatKindOf x y) ]
+
+    /// 按 tick 的慢漂移（像素）：水平 ±2、垂直 ±1，纯函数、有界、逐帧连续。
+    let floatDrift (tick: int64) (seed: int) : int * int =
+        let dx = int (positiveModulo64 5L (tick / 24L + int64 seed)) - 2
+        let dy = int (positiveModulo64 3L (tick / 40L + int64 (seed * 7 + 1))) - 1
+        (dx, dy)
+
+    /// 该漂浮元素的帧（0/1），只随 tick 慢速切换，保证水面鸭/叶有轻微起伏。
+    let floatFrame (tick: int64) (seed: int) : int =
+        int (positiveModulo64 2L (tick / 32L + int64 seed))
+
+    // ---------------- 近景楼层层错落（屏幕空间前景层） ----------------
+
+    /// 前景层屋顶分段：等宽 tile 分段、高度按确定性函数错落（0/8/16/24 px 四层），
+    /// 并随 tick 极慢移动（视差）。返回 (x, y, width)。
+    let foregroundRooftops (viewportWidth: int) (viewportHeight: int) (tick: int64) : (int * int * int) list =
+        let tile = Sim.tilePixels
+        let count = max 1 (viewportWidth / tile + 2)
+        let baseY = viewportHeight - 64
+        [ for i in 0 .. count - 1 do
+              let x = (i - 1) * tile
+              let stagger = ((i * 7 + int (tick / 120L)) % 4) * 8
+              yield (x, baseY - stagger, tile) ]
diff --git a/src/LivingVillage.Desktop/SceneDetailRender.fs b/src/LivingVillage.Desktop/SceneDetailRender.fs
new file mode 100644
index 0000000..2136d25
--- /dev/null
+++ b/src/LivingVillage.Desktop/SceneDetailRender.fs
@@ -0,0 +1,97 @@
+namespace LivingVillage.Desktop
+
+open System
+open Microsoft.Xna.Framework
+open Microsoft.Xna.Framework.Graphics
+open LivingVillage.Kernel
+
+/// P47 场景细节渲染层：把 `SceneDetail` 的纯函数结果落成画面。
+/// 反射用「光源精灵垂直镜像 + 相位微抖」，岸边芦苇/漂浮元素用既有瓦片精灵与原创点阵图集，
+/// 近景屋顶用既有屋瓦精灵 + 统一方向阴影。全部只读，不改瓦片/可达性。
+module SceneDetailRender =
+
+    let private tileX (camera: Vector2) (x: int) = x * Sim.tilePixels - int camera.X
+    let private tileY (camera: Vector2) (y: int) = y * Sim.tilePixels - int camera.Y
+
+    let private drawFlipVertical
+        (spriteBatch: SpriteBatch)
+        (atlas: Texture2D)
+        (source: Rectangle)
+        (x: int)
+        (y: int)
+        (color: Color) =
+        spriteBatch.Draw(
+            atlas,
+            Rectangle(x, y, Sim.tilePixels, Sim.tilePixels),
+            Nullable(source),
+            color,
+            0.0f,
+            Vector2.Zero,
+            SpriteEffects.FlipVertically,
+            0.0f)
+
+    /// 河道倒影：岸上每个光源在其正下方水面格画一份垂直镜像，随 waterFrameTickAt 相位水平微抖。
+    let private drawReflections (spriteBatch: SpriteBatch) (textures: VillageArt.ArtTextures) (camera: Vector2) (map: MapGen.Result) (tick: int64) =
+        let source, atlas =
+            match textures.Cc0TileAtlas with
+            | Some cc0 -> VillageArt.cc0TileRect VillageArt.cc0TileIndexStoneLantern, cc0
+            | None -> VillageArt.atlasTileRectangle 20, textures.TileAtlas
+        for (x, y, alpha) in SceneDetail.reflectionStreaks map do
+            let wobble = SceneDetail.reflectionWobbleAt tick x y
+            let color = VillageArt.premultiply 255 214 168 alpha
+            drawFlipVertical spriteBatch atlas source (tileX camera x + wobble) (tileY camera y) color
+
+    /// 岸边芦苇加密度：用既有芦苇精灵补绘一层贴水芦苇。
+    let private drawBankReeds (spriteBatch: SpriteBatch) (textures: VillageArt.ArtTextures) (camera: Vector2) (map: MapGen.Result) =
+        match textures.Cc0TileAtlas with
+        | Some cc0 ->
+            for (x, y) in SceneDetail.bankReedTiles map do
+                spriteBatch.Draw(cc0, Rectangle(tileX camera x, tileY camera y, Sim.tilePixels, Sim.tilePixels), Nullable(VillageArt.cc0TileRect VillageArt.cc0TileIndexReeds), Color.White)
+        | None ->
+            let source = VillageArt.atlasTileRectangle 18
+            for (x, y) in SceneDetail.bankReedTiles map do
+                spriteBatch.Draw(textures.TileAtlas, Rectangle(tileX camera x, tileY camera y, Sim.tilePixels, Sim.tilePixels), Nullable(source), Color.White)
+
+    /// 漂浮元素：原创点阵鸭/叶，按 tick 慢漂移。
+    let private drawFloaters (spriteBatch: SpriteBatch) (textures: VillageArt.ArtTextures) (camera: Vector2) (map: MapGen.Result) (tick: int64) =
+        for (x, y, kind) in SceneDetail.floatingProps map do
+            let seed = x * 31 + y * 7
+            let dx, dy = SceneDetail.floatDrift tick seed
+            let frame = SceneDetail.floatFrame tick seed
+            let kindIndex =
+                match kind with
+                | SceneDetail.DuckFloat -> FloaterArt.duckIndex
+                | SceneDetail.FallenLeaf -> FloaterArt.leafIndex
+            let source = FloaterArt.sourceRectangle kindIndex frame
+            spriteBatch.Draw(
+                textures.FloaterAtlas,
+                Rectangle(tileX camera x + dx + (Sim.tilePixels - FloaterArt.cellWidth) / 2, tileY camera y + dy + (Sim.tilePixels - FloaterArt.cellHeight) / 2, FloaterArt.cellWidth, FloaterArt.cellHeight),
+                Nullable(source),
+                Color.White)
+
+    /// 近景楼层层错落：屏幕空间前景屋顶带，所有阴影统一投向右下（SceneDetail.shadowOffsetPx）。
+    let private drawForeground (spriteBatch: SpriteBatch) (textures: VillageArt.ArtTextures) (viewportWidth: int) (viewportHeight: int) (tick: int64) =
+        let ridgeSource = VillageArt.atlasTileRectangle 8
+        let eaveSource = VillageArt.atlasTileRectangle 9
+        let shadowColor = VillageArt.premultiply 8 12 18 120
+        let dx, dy = SceneDetail.shadowOffsetPx
+        for (x, y, w) in SceneDetail.foregroundRooftops viewportWidth viewportHeight tick do
+            // 统一方向阴影：先把 eave 的暗色镜像平移一份到右下，再画本体。
+            spriteBatch.Draw(textures.TileAtlas, Rectangle(x + dx, y + dy, w, Sim.tilePixels), Nullable(eaveSource), shadowColor)
+            spriteBatch.Draw(textures.TileAtlas, Rectangle(x, y - Sim.tilePixels, w, Sim.tilePixels), Nullable(ridgeSource), Color.White)
+            spriteBatch.Draw(textures.TileAtlas, Rectangle(x, y, w, Sim.tilePixels), Nullable(eaveSource), Color.White)
+
+    /// 一次性绘制全部 P47 场景细节（倒影 → 岸边芦苇 → 漂浮元素 → 近景前景层）。
+    let draw
+        (spriteBatch: SpriteBatch)
+        (textures: VillageArt.ArtTextures)
+        (pixel: Texture2D)
+        (camera: Vector2)
+        (viewportWidth: int)
+        (viewportHeight: int)
+        (map: MapGen.Result)
+        (tick: int64) =
+        drawReflections spriteBatch textures camera map tick
+        drawBankReeds spriteBatch textures camera map
+        drawFloaters spriteBatch textures camera map tick
+        drawForeground spriteBatch textures viewportWidth viewportHeight tick
diff --git a/src/LivingVillage.Desktop/VillageArt.fs b/src/LivingVillage.Desktop/VillageArt.fs
index 98e4cdf..3dbb8d4 100644
--- a/src/LivingVillage.Desktop/VillageArt.fs
+++ b/src/LivingVillage.Desktop/VillageArt.fs
@@ -123,6 +123,7 @@ module VillageArt =
         { TileAtlas: Texture2D
           CharacterAtlas: Texture2D
           InteriorAtlas: Texture2D
+          FloaterAtlas: Texture2D
           Cc0TileAtlas: Texture2D option }
 
     type private TileSprite =
@@ -768,6 +769,8 @@ module VillageArt =
           // 不再采样任何外部/占位角色素材；尺寸与既有 characterSourceRectangle 完全一致。
           CharacterAtlas = CharacterArt.buildAtlas device
           InteriorAtlas = loadTexture device interiorAtlasRelativePath interiorAtlasWidth interiorAtlasHeight
+          // P47：漂浮小元素（鸭/叶）改用原创点阵像素代码内嵌生成的图集（2 kind x 2 frame）。
+          FloaterAtlas = FloaterArt.buildAtlas device
           Cc0TileAtlas = cc0 }
 
     let atlasTileRectangle (index: int) : Microsoft.Xna.Framework.Rectangle =