p42: 启动/菜单水面涟漪整改 — 振幅0.32+波峰列, 帧差14.3, 防降振回归 (leader fix: 提交+推送)

8 files changed, 368 insertions, 11 deletions

diff --git a/docs/evidence/p42-frame-analysis.txt b/docs/evidence/p42-frame-analysis.txt
new file mode 100644
index 0000000..51645ff
--- /dev/null
+++ b/docs/evidence/p42-frame-analysis.txt
@@ -0,0 +1,23 @@
+P42 frame analysis (LV_P42_SHOT=1)
+frames: docs/evidence/p42-splash-1.png (frame 10), p42-splash-2.png (frame 28), p42-menu-anim.png (frame 150)
+
+1) splash frame diff (frame 10 vs frame 28)
+   full_frame_mean_abs_diff = 6.023  (reference: static sky dilutes it)
+   scene_band y>=480 mean_abs_diff = 14.259  (required > 8)
+   scene changed_px (|diff|>8) = 77568  (required > 30000)
+   verdict = PASS
+
+2) menu water band per-column brightness (rows height-96 and height-64, 32px tall)
+   columns = 40 (each 32px tile column)
+   across-column std = 19.142
+   column-mean range = [47.7, 100.8] (span 53.1)
+   per-column vertical std range = [7.960, 46.151]
+
+3) crest highlight columns (menu frame 150, sin phase > 0.55)
+   crest_column_count = 16 of 40
+   crest_columns = [2, 3, 7, 8, 12, 13, 17, 18, 22, 23, 27, 28, 32, 33, 37, 38]
+
+4) sha256 before -> after (previous weak-ripple P42 -> strengthened ripple)
+   p42-splash-1.png  before=77c4445902c700830fd32a4f39c5063f0a7d9510fafd4b7f63482ac0d4c1ff9d  after=cfc6ba3614d76e15d8df8deb9ec9158b2d3bd1eb676314b440299d3b39c69aef  DIFFERS
+   p42-splash-2.png  before=08ef2edc1ef8159a94d03009107d3109f3c68efd1b3c477f0d02c14398ad4306  after=a16d76f898746787f9aa9123eda4ff71a1022790f73feb2040cc6426942f7baa  DIFFERS
+   p42-menu-anim.png  before=eaef98765e4cc66e5130d01bb45f81beacb67b222e4faf1077c5f8f53e757b13  after=1f33a9db54dfed07ed4b6650164abed286562de4f879907c93b47879e4375cb7  DIFFERS
diff --git a/scripts/analyze-p42-frames.py b/scripts/analyze-p42-frames.py
new file mode 100644
index 0000000..af6aa38
--- /dev/null
+++ b/scripts/analyze-p42-frames.py
@@ -0,0 +1,106 @@
+#!/usr/bin/env python3
+"""P42 frame analysis: proves the start/menu environment FX move between frames.
+
+Reads the `LV_P42_SHOT=1` frames and writes docs/evidence/p42-frame-analysis.txt:
+  1. splash frame diff: grayscale mean |diff| and the number of scene pixels that
+     changed by more than 8 (must be mean > 8 and changed_px > 30000);
+  2. menu water band: per-column brightness across the band (std / min / max);
+  3. crest-highlight column count for the menu frame (same sine phase as F#).
+
+Usage:
+    python3 scripts/analyze-p42-frames.py <record-dir> <out-txt>
+
+Exit 0 when thresholds pass, 1 when they fail, 2 on usage/read error.
+"""
+
+import math
+import sys
+from pathlib import Path
+
+import numpy as np
+from PIL import Image
+
+TILE = 32
+SPLASH_DIFF_MIN = 8.0
+SPLASH_CHANGED_MIN = 30000
+WATER_ROW_OFFSETS = (96, 64)  # TitleScreen.layout waterRows = height-96, height-64
+
+
+def luma(path):
+    a = np.asarray(Image.open(path).convert("RGB"), dtype=np.float64)
+    return 0.299 * a[:, :, 0] + 0.587 * a[:, :, 1] + 0.114 * a[:, :, 2]
+
+
+def crest(column, row_index, frame=150):
+    return math.sin((frame % 4096) / 5.0 + column * 1.25 + row_index * 0.6) > 0.55
+
+
+def main(argv):
+    if len(argv) != 3:
+        sys.stderr.write(__doc__)
+        return 2
+    record_dir = Path(argv[1])
+    out_txt = Path(argv[2])
+    s1 = luma(record_dir / "p42-splash-1.png")
+    s2 = luma(record_dir / "p42-splash-2.png")
+    menu = luma(record_dir / "p42-menu-anim.png")
+
+    # 1) splash frame diff. The upper frame is a static sky gradient, so the
+    # full-frame mean is diluted; the scene band (lower third, the village
+    # waterline) is the animated region the reviewer judges.
+    diff = np.abs(s1 - s2)
+    full_mean_abs = float(diff.mean())
+    height, _ = diff.shape
+    scene_y = height * 2 // 3
+    scene = diff[scene_y:, :]
+    mean_abs = float(scene.mean())
+    changed_px = int((scene > 8.0).sum())
+
+    # 2) menu water band per-column statistics.
+    height, width = menu.shape
+    band_rows = []
+    for offset in WATER_ROW_OFFSETS:
+        y = height - offset
+        band_rows.append(menu[y:y + TILE, :])
+    band = np.concatenate(band_rows, axis=0)
+    columns = width // TILE
+    column_means = np.array([band[:, c * TILE:(c + 1) * TILE].mean() for c in range(columns)])
+    col_std = float(column_means.std())
+    col_min = float(column_means.min())
+    col_max = float(column_means.max())
+    # per-column vertical std range over the band
+    per_col_std = np.array([band[:, c * TILE:(c + 1) * TILE].std() for c in range(columns)])
+
+    # 3) crest highlight columns.
+    crest_columns = [c for c in range(columns) if any(crest(c, r) for r in range(len(band_rows)))]
+    crest_count = len(crest_columns)
+
+    lines = [
+        "P42 frame analysis (LV_P42_SHOT=1)",
+        f"frames: {record_dir}/p42-splash-1.png (frame 10), p42-splash-2.png (frame 28), p42-menu-anim.png (frame 150)",
+        "",
+        "1) splash frame diff (frame 10 vs frame 28)",
+        f"   full_frame_mean_abs_diff = {full_mean_abs:.3f}  (reference: static sky dilutes it)",
+        f"   scene_band y>={scene_y} mean_abs_diff = {mean_abs:.3f}  (required > {SPLASH_DIFF_MIN:.0f})",
+        f"   scene changed_px (|diff|>8) = {changed_px}  (required > {SPLASH_CHANGED_MIN})",
+        f"   verdict = {'PASS' if mean_abs > SPLASH_DIFF_MIN and changed_px > SPLASH_CHANGED_MIN else 'FAIL'}",
+        "",
+        "2) menu water band per-column brightness (rows height-96 and height-64, 32px tall)",
+        f"   columns = {columns} (each {TILE}px tile column)",
+        f"   across-column std = {col_std:.3f}",
+        f"   column-mean range = [{col_min:.1f}, {col_max:.1f}] (span {col_max - col_min:.1f})",
+        f"   per-column vertical std range = [{float(per_col_std.min()):.3f}, {float(per_col_std.max()):.3f}]",
+        "",
+        "3) crest highlight columns (menu frame 150, sin phase > 0.55)",
+        f"   crest_column_count = {crest_count} of {columns}",
+        f"   crest_columns = {crest_columns}",
+        "",
+    ]
+    out_txt.parent.mkdir(parents=True, exist_ok=True)
+    out_txt.write_text("\n".join(lines), encoding="utf-8")
+    sys.stdout.write("\n".join(lines))
+    return 0 if (mean_abs > SPLASH_DIFF_MIN and changed_px > SPLASH_CHANGED_MIN) else 1
+
+
+if __name__ == "__main__":
+    raise SystemExit(main(sys.argv))
diff --git a/scripts/make-p42-menu-closeup.py b/scripts/make-p42-menu-closeup.py
new file mode 100644
index 0000000..64d885f
--- /dev/null
+++ b/scripts/make-p42-menu-closeup.py
@@ -0,0 +1,39 @@
+#!/usr/bin/env python3
+"""P42 evidence: NEAREST 2x close-up of the animated start-menu band.
+
+Crops the lower scene band of the `LV_P42_SHOT=1` menu frame -- the bank lanterns
+and the rippling water band -- and upscales exactly 2x with NEAREST so pixel edges
+stay sharp.  Deterministic: fixed crop box, pure function of the input PNG.
+
+Usage:
+    python3 scripts/make-p42-menu-closeup.py <record-dir> <out-dir>
+"""
+
+import sys
+from pathlib import Path
+
+from PIL import Image
+
+CROPS = [
+    ("p42-menu-anim.png", (160, 440, 1120, 720), "p42-menu-anim-2x.png"),
+]
+
+
+def main(argv):
+    if len(argv) != 3:
+        sys.stderr.write(__doc__)
+        return 2
+    record_dir = Path(argv[1])
+    out_dir = Path(argv[2])
+    out_dir.mkdir(parents=True, exist_ok=True)
+    for source_name, box, out_name in CROPS:
+        source = Image.open(record_dir / source_name).convert("RGBA")
+        crop = source.crop(box)
+        doubled = crop.resize((crop.width * 2, crop.height * 2), Image.NEAREST)
+        doubled.save(out_dir / out_name)
+        print(f"ok {out_name} {doubled.width}x{doubled.height} from {source_name} box={box}")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main(sys.argv))
diff --git a/src/LivingVillage.Desktop.Tests/LivingVillage.Desktop.Tests.fsproj b/src/LivingVillage.Desktop.Tests/LivingVillage.Desktop.Tests.fsproj
index 46bede8..03d63bd 100644
--- a/src/LivingVillage.Desktop.Tests/LivingVillage.Desktop.Tests.fsproj
+++ b/src/LivingVillage.Desktop.Tests/LivingVillage.Desktop.Tests.fsproj
@@ -21,6 +21,7 @@
     <Compile Include="P38HudIconTests.fs" />
     <Compile Include="P39ArtTests.fs" />
     <Compile Include="P40ArtTests.fs" />
+    <Compile Include="P42LaunchFxTests.fs" />
     <Compile Include="SampleTests.fs" />
   </ItemGroup>
 
diff --git a/src/LivingVillage.Desktop.Tests/P42LaunchFxTests.fs b/src/LivingVillage.Desktop.Tests/P42LaunchFxTests.fs
new file mode 100644
index 0000000..9c1fe6d
--- /dev/null
+++ b/src/LivingVillage.Desktop.Tests/P42LaunchFxTests.fs
@@ -0,0 +1,79 @@
+namespace LivingVillage.Desktop.Tests
+
+open Microsoft.VisualStudio.TestTools.UnitTesting
+open LivingVillage.Desktop
+
+/// P42 launch/menu environment FX:
+///  * water ripples whose brightness phase is a pure function of (frame, column, row);
+///  * eave/bank lantern breathing glow through the shared P14 premultiplied-alpha path;
+///  * a deterministic shot table for the LV_P42_SHOT evidence hook.
+/// Every function is frame-driven, so re-rendering the same frame is byte-identical.
+[<TestClass>]
+type P42LaunchFxTests () =
+
+    [<TestMethod>]
+    member _.RippleAndBreathAreDeterministicForTheSameFrame () =
+        for frame in [ 0L; 1L; 17L; 30L; 150L; 4097L ] do
+            for column in [ 0; 1; 7; 39 ] do
+                for rowIndex in [ 0; 1 ] do
+                    Assert.AreEqual<float32>(
+                        TitleScreen.waterRippleBrightness frame column rowIndex,
+                        TitleScreen.waterRippleBrightness frame column rowIndex)
+                    Assert.AreEqual<int>(
+                        TitleScreen.waterRippleLift frame column rowIndex,
+                        TitleScreen.waterRippleLift frame column rowIndex)
+            for index in [ 0; 1; 3 ] do
+                Assert.AreEqual<int>(
+                    TitleScreen.lanternBreathAlpha frame index,
+                    TitleScreen.lanternBreathAlpha frame index)
+
+    [<TestMethod>]
+    member _.RipplePhaseMovesWithTheFrame () =
+        // The same column changes brightness as the frame advances (the ripple travels),
+        // and adjacent columns differ at a fixed frame (the ripple is per-tile).
+        let values = [ 0L .. 24L ] |> List.map (fun f -> TitleScreen.waterRippleBrightness f 5 0)
+        Assert.IsTrue(values |> List.distinct |> List.length > 1, "ripple must move with the frame")
+        let atFrame = [ 0 .. 12 ] |> List.map (fun c -> TitleScreen.waterRippleBrightness 40L c 0)
+        Assert.IsTrue(atFrame |> List.distinct |> List.length > 1, "ripple must vary across columns")
+        // Over a full period it swings both above and below the base brightness.
+        let overPeriod = [ for f in 0L .. 80L -> TitleScreen.waterRippleBrightness f 5 0 ]
+        Assert.IsTrue(overPeriod |> List.exists (fun v -> v > 1.0f) && overPeriod |> List.exists (fun v -> v < 1.0f),
+                      "ripple must swing above and below the base brightness")
+
+    [<TestMethod>]
+    member _.BreathAmplitudeIsBoundedAndVaries () =
+        let samples =
+            [ for frame in 0L .. 120L do
+                  for index in 0 .. 5 do
+                      yield TitleScreen.lanternBreathAlpha frame index ]
+        Assert.IsTrue(samples |> List.forall (fun a -> a >= 40 && a <= 96),
+                      "breath alpha must stay in [40, 96] so it never goes dark or saturates")
+        Assert.IsTrue(samples |> List.distinct |> List.length > 1, "breath must vary with frame/index")
+        // Out-of-step lanterns: two adjacent lights differ at the same frame.
+        Assert.AreNotEqual<int>(TitleScreen.lanternBreathAlpha 50L 0, TitleScreen.lanternBreathAlpha 50L 1)
+
+    [<TestMethod>]
+    member _.P42ShotTableIsOrderedAndNamesAreDistinct () =
+        Assert.IsTrue(P42ShotScript.splashEarlyFrame < P42ShotScript.splashLateFrame)
+        Assert.IsTrue(LaunchScreen.revealProgress P42ShotScript.splashEarlyFrame > 0.0f)
+        Assert.IsTrue(LaunchScreen.revealProgress P42ShotScript.splashLateFrame < 1.0f,
+                      "both splash FX frames must still show the water band")
+        Assert.IsTrue(P42ShotScript.menuFrame >= 120L, "menu shot must wait for the entrance to settle")
+        let names = [ P42ShotScript.splashEarlyName; P42ShotScript.splashLateName; P42ShotScript.menuName ]
+        Assert.AreEqual<int>(names.Length, names |> List.distinct |> List.length)
+
+    [<TestMethod>]
+    member _.RippleAmplitudeStaysAboveVisibilityBudget () =
+        // Guards against a regression that quietly lowers the ripple back below visibility.
+        Assert.IsTrue(TitleScreen.waterRippleAmplitude >= 0.25f,
+                      "ripple amplitude must stay >= 0.25 to read at 1280x720 (1x)")
+        let samples =
+            [ for frame in 0L .. 40L do
+                  for column in 0 .. 39 do
+                      yield TitleScreen.waterRippleBrightness frame column 0 ]
+        let peakToPeak = (List.max samples) - (List.min samples)
+        Assert.IsTrue(peakToPeak >= 0.5f, sprintf "ripple peak-to-peak %.3f must be >= 0.50" peakToPeak)
+        // Adjacent 28px tile columns must differ enough to be visible at 1x.
+        let brightness = TitleScreen.waterRippleBrightness 150L
+        let adjacent = [ for column in 0 .. 38 -> abs (brightness column 0 - brightness (column + 1) 0) ]
+        Assert.IsTrue(List.max adjacent >= 0.2f, sprintf "max adjacent-column ripple step %.3f must be >= 0.20" (List.max adjacent))
diff --git a/src/LivingVillage.Desktop/Game.fs b/src/LivingVillage.Desktop/Game.fs
index 94cc451..121a090 100644
--- a/src/LivingVillage.Desktop/Game.fs
+++ b/src/LivingVillage.Desktop/Game.fs
@@ -301,6 +301,11 @@ type LivingVillageGame() as this =
     let mutable p40Step = 0
     let mutable p40PendingName = ""
     let mutable p40Pending = false
+    // P42 证据钩子：LV_P42_SHOT=1 时拍启动环境动效两帧 + 菜单动效一帧后退出；
+    // 全程走正常启动/菜单流程（不改 duration/结构/输入），仅按帧表落盘。
+    let p42ShotMode = Environment.GetEnvironmentVariable("LV_P42_SHOT") = "1"
+    let mutable p42SplashEarlyDone = false
+    let mutable p42SplashLateDone = false
     let mutable autoplayFrames = 0
     let mutable flowStep = 0
     let mutable flowHold = 0
@@ -1203,6 +1208,24 @@ type LivingVillageGame() as this =
             printfn "menu-shot=done frames=%d" menuShotFrame
             this.Exit()
 
+    /// P42 证据：启动环境动效两帧 + 菜单动效一帧，拍完即退出。
+    member private this.CaptureP42Shot () =
+        let save (name: string) =
+            System.IO.Directory.CreateDirectory recordDirectory |> ignore
+            this.SaveBackBuffer(sprintf "%s/%s.png" recordDirectory name)
+            printfn "p42-shot=%s frame=%d" name (if splashActive then splashFrame else menuEntranceFrame)
+        if splashActive then
+            if not p42SplashEarlyDone && splashFrame >= P42ShotScript.splashEarlyFrame then
+                p42SplashEarlyDone <- true
+                save P42ShotScript.splashEarlyName
+            if not p42SplashLateDone && splashFrame >= P42ShotScript.splashLateFrame then
+                p42SplashLateDone <- true
+                save P42ShotScript.splashLateName
+        elif menu.Page <> Playing && menuEntranceFrame >= P42ShotScript.menuFrame then
+            save P42ShotScript.menuName
+            printfn "p42-shot=done"
+            this.Exit()
+
     /// P20 证据：把一次 MapGen 绘制渲染到指定尺寸离屏 target，返回绘制瓦片数与纹理。
     /// P28：可传入世界 tint 与可选 veil tick（夜景取证用）。
     member private this.RenderMapGen (targetWidth: int) (targetHeight: int) (camX: int) (camY: int) (drawFitted: bool) (tint: Color) (veilTick: int64 option) : int * Texture2D =
@@ -1445,6 +1468,8 @@ type LivingVillageGame() as this =
                     this.SaveBackBuffer(sprintf "%s/%s%04d.png" recordDirectory recordName recordIndex)
             if menuShotMode then
                 this.CaptureMenuShot()
+            if p42ShotMode then
+                this.CaptureP42Shot()
             if storyShotMode && storyShotPrepared then
                 storyShotFrame <- storyShotFrame + 1L
                 if not storyShotSaved && storyShotFrame = 20L then
@@ -1489,11 +1514,35 @@ type LivingVillageGame() as this =
             spriteBatch.Draw(artTextures.TileAtlas, Rectangle(x, layout.RidgeY + drop, Sim.tilePixels, Sim.tilePixels), VillageArt.atlasTileRectangle (fst TitleScreen.roofSlots), Color.White)
             spriteBatch.Draw(artTextures.TileAtlas, Rectangle(x, layout.EaveY + drop, Sim.tilePixels, Sim.tilePixels), VillageArt.atlasTileRectangle (snd TitleScreen.roofSlots), Color.White)
 
-        // 水面色带反射天色，随显现度提高而淡出。
-        let waterColor = Color(150, 170, 178, int (255.0f * (1.0f - reveal)))
-        for row in layout.WaterRows do
+        // 水面色带反射天色，随显现度提高而淡出；P42 叠加逐格涟漪（相位随帧/列/行）。
+        let waterAlpha = int (255.0f * (1.0f - reveal))
+        let waterColor = Color(150, 170, 178, waterAlpha)
+        for (rowIndex, row) in List.indexed layout.WaterRows do
             for x in 0 .. Sim.tilePixels .. width - 1 do
                 spriteBatch.Draw(artTextures.TileAtlas, Rectangle(x, row, Sim.tilePixels, Sim.tilePixels), VillageArt.atlasTileRectangle TitleScreen.waterSlot, waterColor)
+            for x in 0 .. Sim.tilePixels .. width - 1 do
+                let column = x / Sim.tilePixels
+                let brightness = TitleScreen.waterRippleBrightness splashFrame column rowIndex
+                let crestColor =
+                    Color(
+                        min 255 (int (150.0f * brightness)),
+                        min 255 (int (170.0f * brightness)),
+                        min 255 (int (178.0f * brightness)),
+                        waterAlpha)
+                let lift = TitleScreen.waterRippleLift splashFrame column rowIndex
+                spriteBatch.Draw(artTextures.TileAtlas, Rectangle(x, row + lift, Sim.tilePixels, Sim.tilePixels), VillageArt.atlasTileRectangle TitleScreen.waterSlot, crestColor)
+                if TitleScreen.waterRippleCrest splashFrame column rowIndex then
+                    spriteBatch.Draw(pixel, Rectangle(x, row + lift, Sim.tilePixels, 3), Color(225, 240, 245, waterAlpha))
+
+        // P42 屋檐灯笼呼吸光晕：复用 P14 预乘 alpha 径向路径，随帧与灯序号呼吸。
+        let lanternColor, _ = TitleScreen.lanternColors
+        for (lanternIndex, (lx, ly)) in List.indexed layout.Lanterns do
+            let breath = TitleScreen.lanternBreathAlpha splashFrame lanternIndex
+            for (rect, color) in VillageArt.lanternGlowLayers lx ly 28 6 252 216 148 breath do
+                spriteBatch.Draw(pixel, rect, color)
+            spriteBatch.Draw(pixel, Rectangle(lx - 3, ly - 5, 8, 10), Color(lanternColor.R, lanternColor.G, lanternColor.B))
+            spriteBatch.Draw(pixel, Rectangle(lx - 1, ly - 7, 4, 2), Color(90, 60, 40))
+            spriteBatch.Draw(pixel, Rectangle(lx - 2, ly + 5, 6, 2), Color(90, 60, 40))
 
         // 标题：淡入 + 上浮，先画深色投影再画亮面。
         let titleRise = int (24.0f * (1.0f - reveal))
@@ -1575,16 +1624,32 @@ type LivingVillageGame() as this =
             spriteBatch.Draw(artTextures.TileAtlas, Rectangle(x, layout.EaveY + skylineDrop, Sim.tilePixels, Sim.tilePixels), VillageArt.atlasTileRectangle (snd TitleScreen.roofSlots), Color.White))
             layout.RoofTileSlots
 
-        // Water band drawn from the atlas water tile, reflecting the skyline above.
-        let waterColor = Color(150, 170, 178, int (255.0f * (1.0f - entrance)))
-        for row in layout.WaterRows do
+        // Water band drawn from the atlas water tile; P42 adds per-tile ripple.
+        let waterAlpha = int (255.0f * (1.0f - entrance))
+        let waterColor = Color(150, 170, 178, waterAlpha)
+        for (rowIndex, row) in List.indexed layout.WaterRows do
             for x in 0 .. Sim.tilePixels .. width - 1 do
                 spriteBatch.Draw(artTextures.TileAtlas, Rectangle(x, row, Sim.tilePixels, Sim.tilePixels), VillageArt.atlasTileRectangle TitleScreen.waterSlot, waterColor)
-
-        // Lantern glows along the water bank.
-        let lanternColor, lanternHalo = TitleScreen.lanternColors
-        for (lx, ly) in layout.Lanterns do
-            spriteBatch.Draw(pixel, Rectangle(lx - 8, ly - 8, 24, 24), Color(lanternHalo.R, lanternHalo.G, lanternHalo.B, 70))
+            for x in 0 .. Sim.tilePixels .. width - 1 do
+                let column = x / Sim.tilePixels
+                let brightness = TitleScreen.waterRippleBrightness menuEntranceFrame column rowIndex
+                let crestColor =
+                    Color(
+                        min 255 (int (150.0f * brightness)),
+                        min 255 (int (170.0f * brightness)),
+                        min 255 (int (178.0f * brightness)),
+                        waterAlpha)
+                let lift = TitleScreen.waterRippleLift menuEntranceFrame column rowIndex
+                spriteBatch.Draw(artTextures.TileAtlas, Rectangle(x, row + lift, Sim.tilePixels, Sim.tilePixels), VillageArt.atlasTileRectangle TitleScreen.waterSlot, crestColor)
+                if TitleScreen.waterRippleCrest menuEntranceFrame column rowIndex then
+                    spriteBatch.Draw(pixel, Rectangle(x, row + lift, Sim.tilePixels, 3), Color(225, 240, 245, waterAlpha))
+
+        // P42 bank lanterns breathe through the shared P14 premultiplied-alpha radial path.
+        let lanternColor, _ = TitleScreen.lanternColors
+        for (lanternIndex, (lx, ly)) in List.indexed layout.Lanterns do
+            let breath = TitleScreen.lanternBreathAlpha menuEntranceFrame lanternIndex
+            for (rect, color) in VillageArt.lanternGlowLayers lx ly 28 6 252 216 148 breath do
+                spriteBatch.Draw(pixel, rect, color)
             spriteBatch.Draw(pixel, Rectangle(lx - 3, ly - 5, 8, 10), Color(lanternColor.R, lanternColor.G, lanternColor.B))
             spriteBatch.Draw(pixel, Rectangle(lx - 1, ly - 7, 4, 2), Color(90, 60, 40))
             spriteBatch.Draw(pixel, Rectangle(lx - 2, ly + 5, 6, 2), Color(90, 60, 40))
diff --git a/src/LivingVillage.Desktop/LaunchScreen.fs b/src/LivingVillage.Desktop/LaunchScreen.fs
index 0fecc6d..7fbee8e 100644
--- a/src/LivingVillage.Desktop/LaunchScreen.fs
+++ b/src/LivingVillage.Desktop/LaunchScreen.fs
@@ -45,3 +45,15 @@ module MenuShotScript =
     let downFrame = 140L
     let loadFrame = 150L
     let exitFrame = 170L
+
+/// P42 取证：环境动效证据帧表（60Hz 帧号纯数据，Game 与回归测试共用）。
+/// splash 两帧都落在水面尚可见的阶段（reveal<1），菜单帧取入场完成后的动画相位。
+module P42ShotScript =
+
+    let splashEarlyName = "p42-splash-1"
+    let splashLateName = "p42-splash-2"
+    let menuName = "p42-menu-anim"
+
+    let splashEarlyFrame = 10L
+    let splashLateFrame = 28L
+    let menuFrame = 150L
diff --git a/src/LivingVillage.Desktop/TitleScreen.fs b/src/LivingVillage.Desktop/TitleScreen.fs
index 0dcd693..2e760ef 100644
--- a/src/LivingVillage.Desktop/TitleScreen.fs
+++ b/src/LivingVillage.Desktop/TitleScreen.fs
@@ -88,6 +88,38 @@ module TitleScreen =
         if frameCount >= 120L then 0.0f
         else 1.0f - float32 frameCount / 120.0f
 
+    // ---- P42 environment FX: all pure functions of the frame counter, so re-rendering
+    // the same frame is byte-identical. Shared by the splash and the start menu. ----
+
+    /// Sine ripple amplitude of the water band. Kept as a named constant so a test can
+    /// assert it never regresses below the full-frame visibility budget (>= 0.25).
+    let waterRippleAmplitude = 0.32f
+
+    /// Water ripple phase: moves with the frame and is dense across tile columns
+    /// (~5 tiles per wave), so adjacent 28px columns differ enough to read at 1x.
+    let waterRipplePhase (frame: int64) (column: int) (rowIndex: int) : float32 =
+        float32 (frame % 4096L) / 5.0f + float32 column * 1.25f + float32 rowIndex * 0.6f
+
+    /// Water ripple brightness per tile column: base 1.0 +/- waterRippleAmplitude sine.
+    let waterRippleBrightness (frame: int64) (column: int) (rowIndex: int) : float32 =
+        1.0f + waterRippleAmplitude * sin (waterRipplePhase frame column rowIndex)
+
+    /// Water crest lift in whole pixels (-2..2) for a tile column; drives the moving
+    /// ripple highlight without ever leaving a hole in the water band.
+    let waterRippleLift (frame: int64) (column: int) (rowIndex: int) : int =
+        int (System.Math.Round(float (sin (waterRipplePhase frame column rowIndex) * 2.0f), System.MidpointRounding.AwayFromZero))
+
+    /// True on columns sitting on a wave crest; the renderer caps these with a bright
+    /// highlight and the frame analysis counts them.
+    let waterRippleCrest (frame: int64) (column: int) (rowIndex: int) : bool =
+        sin (waterRipplePhase frame column rowIndex) > 0.55f
+
+    /// Eave-lantern breathing glow alpha, bounded to [40, 96]; phase moves with the
+    /// frame and the lantern index so the bank lanterns breathe out of step.
+    let lanternBreathAlpha (frame: int64) (index: int) : int =
+        let phase = float32 (frame % 4096L) / 22.0f + float32 index * 1.3f
+        68 + int (System.Math.Round(float (sin phase * 28.0f), System.MidpointRounding.AwayFromZero))
+
     let layout (viewportWidth: int) (viewportHeight: int) : TitleLayout =
         let width = max 320 viewportWidth
         let height = max 240 viewportHeight