fix(render): animate sky layers on the native UV clock

8 files changed, 285 insertions, 13 deletions

diff --git a/apps/fparkan-game/src/camera_capture.rs b/apps/fparkan-game/src/camera_capture.rs
index 9862546..bc16807 100644
--- a/apps/fparkan-game/src/camera_capture.rs
+++ b/apps/fparkan-game/src/camera_capture.rs
@@ -15,10 +15,17 @@ pub(super) struct LegacyCameraCapture {
     pub(super) far_plane: f32,
     pub(super) field_of_view_radians: f32,
     pub(super) atmosphere_seconds: Option<f32>,
+    pub(super) sky_uv_clock: Option<SkyUvClock>,
     pub(super) geometry_projection: Option<GeometryProjection>,
 }
 
 #[derive(Clone, Debug, Deserialize, PartialEq)]
+pub(super) struct SkyUvClock {
+    pub(super) verified: bool,
+    pub(super) elapsed_milliseconds: u32,
+}
+
+#[derive(Clone, Debug, Deserialize, PartialEq)]
 pub(super) struct GeometryProjection {
     verified: bool,
     viewport: [i32; 4],
@@ -118,6 +125,9 @@ pub(super) fn load_legacy_camera_capture(
     if capture.geometry_projection.is_none() {
         eprintln!("render_coverage captured_projection_unverified=1 (capture has no geometry_projection; using the recorded camera boundary, which can clip nearby surfaces)");
     }
+    if capture.sky_uv_clock.is_none() {
+        eprintln!("render_coverage captured_sky_phase_unverified=1 (capture has no sky UV clock; using replay elapsed time)");
+    }
     Ok(capture)
 }
 
@@ -144,6 +154,13 @@ pub(super) fn parse_legacy_camera_capture(bytes: &[u8]) -> Result<LegacyCameraCa
         return Err("legacy camera capture is marked render_input_usable=false".to_string());
     }
     if capture
+        .sky_uv_clock
+        .as_ref()
+        .is_some_and(|clock| !clock.verified)
+    {
+        return Err("legacy camera sky UV clock is unverified".to_string());
+    }
+    if capture
         .atmosphere_seconds
         .is_some_and(|seconds| !seconds.is_finite() || seconds < 0.0)
     {
diff --git a/apps/fparkan-game/src/main.rs b/apps/fparkan-game/src/main.rs
index f987bed..3a23f15 100644
--- a/apps/fparkan-game/src/main.rs
+++ b/apps/fparkan-game/src/main.rs
@@ -141,6 +141,10 @@ fn run(args: &[String]) -> Result<String, String> {
         .map(load_legacy_camera_capture)
         .transpose()?;
     let atmosphere_seconds = selected_atmosphere_seconds(args.atmosphere_seconds, camera.as_ref());
+    let captured_sky_uv_ms = camera
+        .as_ref()
+        .and_then(|c| c.sky_uv_clock.as_ref())
+        .map(|c| c.elapsed_milliseconds);
     let hold_schedule_phase = camera.is_some() && atmosphere_seconds.is_some();
     let terrain_materials_duration_started = Instant::now();
     let preview = static_preview_mesh_and_materials(
@@ -159,12 +163,15 @@ fn run(args: &[String]) -> Result<String, String> {
     // sky to the selected map (there are many `sky.ske` files in the campaign
     // tree).
     let sky_started = Instant::now();
-    let environment = load_environment(
+    let mut environment = load_environment(
         &args.root,
         &args.mission,
         atmosphere_seconds,
         hold_schedule_phase,
     )?;
+    if let Some(environment) = &mut environment {
+        environment.fixed_sky_uv_ms = captured_sky_uv_ms;
+    }
     let sky_duration = sky_started.elapsed();
     let audio = match audio::GameAudio::new(Arc::new(DirectoryVfs::new(&args.root)), &args.mission)
     {
@@ -4188,6 +4195,7 @@ struct DynamicEnvironment {
     time_seconds: f32,
     fixed_schedule_seconds: Option<f32>,
     fixed_phase_reported: bool,
+    fixed_sky_uv_ms: Option<u32>,
 }
 
 struct DynamicEnvironmentFrame {
@@ -4232,6 +4240,7 @@ impl DynamicEnvironment {
     fn update_cpu(
         &mut self,
         dt_seconds: f32,
+        clock_ms: u32,
         camera: &PreviewCameraFrame,
         aspect: f32,
         viewport: [f32; 2],
@@ -4259,6 +4268,7 @@ impl DynamicEnvironment {
         }
         let atmosphere = self.schedule.sample(absolute_time_seconds);
         let mut sky_mesh = self.sky.mesh().clone();
+        sky_mesh.update_uvs(self.fixed_sky_uv_ms.unwrap_or(clock_ms));
         let sky_frame =
             SkyFrame::from_atmosphere(&atmosphere, &self.materials, absolute_time_seconds);
         sky_mesh.update_colors(&sky_frame.sky);
@@ -4465,6 +4475,7 @@ fn load_environment(
         time_seconds,
         fixed_schedule_seconds,
         fixed_phase_reported: false,
+        fixed_sky_uv_ms: None,
     }))
 }
 
@@ -10187,6 +10198,7 @@ impl StaticVulkanApp {
         let environment = if let Some(environment) = self.environment.as_mut() {
             Some(environment.update_cpu(
                 clock.delta_seconds,
+                clock.time_ms,
                 &camera,
                 aspect,
                 viewport,
@@ -13562,6 +13574,7 @@ mod tests {
             time_seconds: 0.0,
             fixed_schedule_seconds: None,
             fixed_phase_reported: false,
+            fixed_sky_uv_ms: None,
         };
 
         let mut land = fparkan_terrain_format::LandMeshDocument {
@@ -13811,6 +13824,34 @@ mod tests {
             app.pending_scene_update.as_ref().unwrap().clock.time_ms,
             500
         );
+        assert_eq!(
+            app.pending_scene_update
+                .as_ref()
+                .unwrap()
+                .environment
+                .as_ref()
+                .unwrap()
+                .sky_mesh
+                .vertices[0]
+                .uv[2],
+            [0.01, 0.0]
+        );
+        app.environment.as_mut().unwrap().fixed_sky_uv_ms = Some(25_000);
+        next.id = SceneSampleId::Live(2);
+        next.time_ms = 10_000;
+        app.prepare_scene_update(next, [1280.0, 720.0]).unwrap();
+        assert_eq!(
+            app.pending_scene_update
+                .as_ref()
+                .unwrap()
+                .environment
+                .as_ref()
+                .unwrap()
+                .sky_mesh
+                .vertices[0]
+                .uv[2],
+            [0.5, 0.0]
+        );
     }
 
     #[test]
@@ -15634,6 +15675,22 @@ mod tests {
     }
 
     #[test]
+    fn captured_sky_uv_phase_requires_verified_clock() {
+        let mut value: serde_json::Value =
+            serde_json::from_slice(include_bytes!("../testdata/legacy-camera-parented.json"))
+                .unwrap();
+        value["sky_uv_clock"] =
+            serde_json::json!({"verified": true, "elapsed_milliseconds": 4051271258_u32});
+        let capture = parse_legacy_camera_capture(&serde_json::to_vec(&value).unwrap()).unwrap();
+        assert_eq!(
+            capture.sky_uv_clock.unwrap().elapsed_milliseconds,
+            4051271258
+        );
+        value["sky_uv_clock"]["verified"] = serde_json::json!(false);
+        assert!(parse_legacy_camera_capture(&serde_json::to_vec(&value).unwrap()).is_err());
+    }
+
+    #[test]
     fn captured_atmosphere_is_default_and_cli_time_takes_precedence() {
         let capture = LegacyCameraCapture {
             schema: "fparkan-legacy-camera-v1".to_string(),
@@ -15648,6 +15705,7 @@ mod tests {
             field_of_view_radians: 1.0,
             atmosphere_seconds: Some(56.227),
             geometry_projection: None,
+            sky_uv_clock: None,
         };
 
         assert_eq!(
diff --git a/crates/fparkan-fx/src/sky.rs b/crates/fparkan-fx/src/sky.rs
index d9ba3ed..1b793f0 100644
--- a/crates/fparkan-fx/src/sky.rs
+++ b/crates/fparkan-fx/src/sky.rs
@@ -328,6 +328,24 @@ pub struct SkyMesh {
 }
 
 impl SkyMesh {
+    /// Updates native nebula, star and cloud scroll from the sky object's elapsed milliseconds.
+    pub fn update_uvs(&mut self, elapsed_ms: u32) {
+        let offsets = [
+            [(elapsed_ms % 300_000) as f32 * 3.333_333_3e-6; 2],
+            [(elapsed_ms % 100_000) as f32 * 1.0e-5; 2],
+            [(elapsed_ms % 50_000) as f32 * 2.0e-5, 0.0],
+        ];
+        let inverse_radius = self.radius.recip();
+        for vertex in &mut self.vertices {
+            for stage in 0..3 {
+                let scale = inverse_radius * SKY_UV_SCALES[stage];
+                vertex.uv[stage] = std::array::from_fn(|axis| {
+                    scale * vertex.position[axis] + offsets[stage][axis]
+                });
+            }
+        }
+    }
+
     /// Number of triangles in the mesh.
     #[must_use]
     pub fn triangle_count(&self) -> usize {
@@ -1787,6 +1805,26 @@ mod tests {
     }
 
     #[test]
+    fn scrolling_uvs_match_native_periods_and_wrapped_elapsed_clock() {
+        let mut mesh = SkyGeometryConfig::default().try_mesh(&sample()).unwrap();
+        let topology = mesh.indices.clone();
+        for elapsed in [0, 25_000, 49_999, 50_000, 100_000, 300_000, 4_051_271_258] {
+            mesh.update_uvs(elapsed);
+            let zenith = mesh.vertices[0].uv;
+            assert_eq!(zenith[0], [(elapsed % 300_000) as f32 * 3.333_333_3e-6; 2]);
+            assert_eq!(zenith[1], [(elapsed % 100_000) as f32 * 1e-5; 2]);
+            assert_eq!(zenith[2], [(elapsed % 50_000) as f32 * 2e-5, 0.0]);
+        }
+        // Live GOG sky render: now 265584022, object origin 509280060.
+        mesh.update_uvs(265_584_022_u32.wrapping_sub(509_280_060));
+        assert!((mesh.vertices[0].uv[2][0] - 0.42516).abs() < 1e-7);
+        let once = mesh.vertices.clone();
+        mesh.update_uvs(4_051_271_258);
+        assert_eq!(mesh.vertices, once, "updates must not accumulate drift");
+        assert_eq!(mesh.indices, topology);
+    }
+
+    #[test]
     fn geometry_matches_original_counts_positions_uv_and_winding() {
         let config = SkyGeometryConfig::new(10.0, std::f32::consts::FRAC_PI_2, 2.0, 4, 3);
         let mesh = config.try_mesh(&sample()).expect("valid mesh");
diff --git a/docs/appendices/knowledge-boundaries.md b/docs/appendices/knowledge-boundaries.md
index 7224a48..0df1e5a 100644
--- a/docs/appendices/knowledge-boundaries.md
+++ b/docs/appendices/knowledge-boundaries.md
@@ -65,6 +65,10 @@ MSH-запрос со свободной preview-камерой; это не п�
 обхода мира, которое может отсекать близкие поверхности. Это отмечается
 `captured_projection_unverified`; для приёмки таких поверхностей нужен новый захват.
 
+Захваты без `sky_uv_clock` не подтверждают начальное положение облаков,
+звёзд и фона. Replay использует elapsed clock приложения и считает
+это как `captured_sky_phase_unverified`; для приёмки неба нужен новый захват.
+
 Закрывающий эксперимент: запустить оригинал в совместимой Windows/DirectX
 среде, перехватить DirectDraw/Direct3D calls и surface flips, сохранить state
 log на минимальных сценах с одним типом материала.
diff --git a/docs/reference/atmosphere.md b/docs/reference/atmosphere.md
index 8d44e4e..dba20c2 100644
--- a/docs/reference/atmosphere.md
+++ b/docs/reference/atmosphere.md
@@ -149,6 +149,31 @@ gradient и clouds row 2. Для nebula/stars/clouds используются UV
 directional RGB из `sky.packed[0]`. Это четыре фиксированных pass, а не три
 независимых цветных слоя.
 
+Все три текстурных слоя движутся. Обновление GOG `CSky`
+(`Terrain.dll`, RVA `0x48B90`, запись UV `0x4942A–0x495B7`;
+[сборка и SHA-256](original-binaries.md)) берёт разность текущего `u32` clock
+и сохранённого поля объекта `+8` с переполнением. Это отдельные миллисекунды
+жизни неба, а не абсолютная фаза суток из SKE.
+
+| Слой | Период | Добавка к исходным UV |
+|---|---:|---|
+| Фон | 300 000 мс | одинаковый сдвиг U и V |
+| Звёзды | 100 000 мс | одинаковый сдвиг U и V |
+| Облака | 50 000 мс | сдвиг только U |
+
+Добавка равна остатку от деления elapsed clock на период, умноженному на
+нативный коэффициент `f32` (`3.3333333e-6`, `1e-5`, `2e-5`). Вершинные UV
+каждый раз вычисляются от позиции купола заново; накопление приращений
+создавало бы дрейф. `SkyMesh::update_uvs` получает текущие миллисекунды кадра
+и сохраняет геометрию купола. В работающем оригинале проверены UV всех трёх
+слоёв, включая разность clock с переполнением.
+
+Захват сохраняет `sky_uv_clock` на входе в рендер неба, проверяя его по
+фактическим UV вершины зенита и clock того же кадра. Replay удерживает эту
+фазу вместе с фазой суток. Без такого поля текстуры движутся по elapsed clock
+приложения; начальная фаза оригинала неизвестна и явно считается как
+`captured_sky_phase_unverified`.
+
 Цвет первого screen-gradient и последнего пояса вычисляет
 `SkyFrame::screen_gradient(yaw_radians, glare_rgb_delta)`. Native `CSky` сначала
 округляет `(yaw + pi) * 180 / pi` режимом nearest-even, выбирает сектор
diff --git a/docs/tomes/05-render.md b/docs/tomes/05-render.md
index 034e255..6512fef 100644
--- a/docs/tomes/05-render.md
+++ b/docs/tomes/05-render.md
@@ -1187,10 +1187,15 @@ drawable размер `(right - left) × (bottom - top)` и отклоняет �
 `FreeFlightCamera` в этом режиме не создаётся, но redraw продолжает обновлять
 environment и projected shadows от captured camera. Перед environment update и
 его audio events listener получает position, forward и up captured camera;
-начальная сортировка world draw использует её же position. Phase capture может
+начальная сортировка world draw использует её же position. Облака в обычном
+запуске движутся с отдельным 50-секундным циклом UV; фон и звёзды имеют свои
+периоды. Изменение цвета неба по расписанию не заменяет это движение.
+Phase capture может
 содержать наблюдаемый mission path и проверенный `atmosphere_seconds`; viewer
 использует эту абсолютную фазу по умолчанию, если не указан явный CLI override,
-и удерживает sample атмосферы на ней через readback frames. Фазы FX следуют
+и удерживает sample атмосферы на ней через readback frames. Дополнительный
+`sky_uv_clock` фиксирует положение движущихся текстур на том же кадре;
+без него их начальная фаза не подтверждена. Фазы FX следуют
 выбранному control clock: без `--control-clock-ms` он обновляется по elapsed
 time, а с явным значением readback frames переигрывают заданный clock. Это не
 полное simulation time: `weather`, RNG и
diff --git a/tools/native-frame-capture/NativeFrameCapture.cs b/tools/native-frame-capture/NativeFrameCapture.cs
index 9636a03..9721049 100644
--- a/tools/native-frame-capture/NativeFrameCapture.cs
+++ b/tools/native-frame-capture/NativeFrameCapture.cs
@@ -50,6 +50,7 @@ internal static partial class NativeFrameCapture
     private const uint RenderGameRva = 0x13BD0;
     private const uint ProjectionSnapshotRva = 0x13CE4;
     private const uint GeometryProjectionRva = 0x1D110;
+    private const uint SkyRenderRva = 0x48110;
     private const uint RenderReturnRva = 0x13D7B;
     private const uint AtmospherePhaseRva = 0x421DC;
     private const uint FogConsumerRva = 0x2F230;
@@ -105,6 +106,7 @@ internal static partial class NativeFrameCapture
         public ProjectionReadback GeometryProjection;
         public uint GeometryProjectionGeneration;
         public uint GeometryProjectionThreadId;
+        public SkyUvReadback SkyUv;
         public uint CameraWorldGameTimeWord;
         public bool CameraWorldGameTimeWordReadable;
         public uint WorldGameTimeWord;
@@ -133,6 +135,11 @@ internal static partial class NativeFrameCapture
         public string NativeFogStatus;
     }
 
+    private sealed class SkyUvReadback
+    {
+        public uint Object, Origin, RawClock, ElapsedMilliseconds, Generation, ThreadId;
+    }
+
     private sealed class AtmosphereReadback
     {
         public uint SampleThreadId;
@@ -780,6 +787,66 @@ internal static partial class NativeFrameCapture
         json.AppendLine("  },");
     }
 
+    private static SkyUvReadback CaptureSkyUv(IntPtr process, uint terrainBase, uint worldBase,
+        byte[] context, FrameSnapshot frame, uint threadId)
+    {
+        uint obj = BitConverter.ToUInt32(context, ContextEcxOffset);
+        uint stack = BitConverter.ToUInt32(context, ContextEspOffset);
+        if (frame.Camera == null || frame.CameraThreadId != threadId || frame.CameraGeneration == 0
+            || ReadU32Exact(process, stack + 4) != frame.Camera.Camera
+            || ReadU32Exact(process, obj) != unchecked(terrainBase + 0x65F98)) return null;
+        uint origin = ReadU32Exact(process, obj + 8);
+        uint rawClock = ReadU32Exact(process, unchecked(worldBase + 0x32A38));
+        uint elapsed = unchecked(rawClock - origin);
+        float[] expected = new float[] {
+            (elapsed % 300000) * 3.3333333e-6f, (elapsed % 300000) * 3.3333333e-6f,
+            (elapsed % 100000) * 1e-5f, (elapsed % 100000) * 1e-5f,
+            (elapsed % 50000) * 2e-5f, 0 };
+        uint[] pointers = new uint[] { ReadU32Exact(process, obj + 0x48),
+            ReadU32Exact(process, obj + 0x40), ReadU32Exact(process, obj + 0x44) };
+        for (int i = 0; i < expected.Length; i++)
+        {
+            float actual = BitConverter.ToSingle(BitConverter.GetBytes(
+                ReadU32Exact(process, pointers[i / 2] + (uint)(i % 2) * 4)), 0);
+            if (Single.IsNaN(actual) || Single.IsInfinity(actual)
+                || Math.Abs(actual - expected[i]) > 1e-6f)
+            {
+                Log("SKY_UV_CLOCK_REJECTED zenith coordinate does not match the current world clock.");
+                return null;
+            }
+        }
+        Log("SKY_UV_CLOCK generation=" + frame.CameraGeneration + " tid=" + threadId
+            + " raw=" + rawClock + " origin=" + origin + " elapsed_ms=" + elapsed);
+        return new SkyUvReadback { Object = obj, Origin = origin, RawClock = rawClock,
+            ElapsedMilliseconds = elapsed, Generation = frame.CameraGeneration, ThreadId = threadId };
+    }
+
+    private static bool SkyUvMatchesFrame(FrameSnapshot frame)
+    {
+        SkyUvReadback sky = frame.SkyUv;
+        return sky != null && sky.Generation == frame.CameraGeneration
+            && sky.Generation == frame.ProjectionGeneration && sky.ThreadId == frame.CameraThreadId
+            && sky.ThreadId == frame.ProjectionThreadId && frame.WorldGameTimeWordReadable
+            && sky.RawClock == frame.WorldGameTimeWord && frame.CameraWorldGameTimeWordReadable
+            && sky.RawClock == frame.CameraWorldGameTimeWord;
+    }
+
+    private static void AppendSkyUvJson(StringBuilder json, FrameSnapshot frame)
+    {
+        if (!SkyUvMatchesFrame(frame)) { json.AppendLine("  \"sky_uv_clock\": null,"); return; }
+        SkyUvReadback sky = frame.SkyUv;
+        json.AppendLine("  \"sky_uv_clock\": {");
+        json.AppendLine("    \"verified\": true,");
+        json.AppendLine("    \"sample_boundary\": \"Terrain+0x48110, sky render\",");
+        json.AppendLine("    \"terrain_module_sha256\": " + JsonString(ExpectedSha256[TerrainName]) + ",");
+        json.AppendLine("    \"raw_clock\": " + sky.RawClock + ",");
+        json.AppendLine("    \"origin_raw_clock\": " + sky.Origin + ",");
+        json.AppendLine("    \"frame_generation\": " + sky.Generation + ",");
+        json.AppendLine("    \"thread_id\": " + sky.ThreadId + ",");
+        json.AppendLine("    \"elapsed_milliseconds\": " + sky.ElapsedMilliseconds);
+        json.AppendLine("  },");
+    }
+
     private static bool VerifyAtmospherePhaseBoundary(IntPtr process, uint terrainBase,
         out byte firstByte, out string evidence)
     {
@@ -1931,6 +1998,7 @@ internal static partial class NativeFrameCapture
         json.AppendLine("  \"field_of_view_radians\": " + projection.Fov.ToString("R", CultureInfo.InvariantCulture) + ",");
         json.AppendLine("  \"projection_mode_byte\": " + projection.Mode.ToString(CultureInfo.InvariantCulture) + ",");
         AppendGeometryProjectionJson(json, frame);
+        AppendSkyUvJson(json, frame);
         if (frame.SelectedCamera == null) json.AppendLine("  \"selected_camera\": null,");
         else
         {
@@ -2040,6 +2108,7 @@ internal static partial class NativeFrameCapture
         SelfCheckCameraInput();
         SelfCheckSelectedCameraWarmup();
         SelfCheckGeometryProjection();
+        SelfCheckSkyUv();
         SelfCheckNativeFogPairing();
         SelfCheckRenderInvocationGates();
         SelfCheckDebugEventHandleOwnership();
@@ -2350,6 +2419,32 @@ internal static partial class NativeFrameCapture
         return SelfCheckReadback();
     }
 
+    private static void SelfCheckSkyUv()
+    {
+        FrameSnapshot frame = new FrameSnapshot { CameraGeneration = 7, ProjectionGeneration = 7,
+            CameraThreadId = 11, ProjectionThreadId = 11, WorldGameTimeWordReadable = true,
+            CameraWorldGameTimeWordReadable = true, CameraWorldGameTimeWord = 265584022,
+            WorldGameTimeWord = 265584022,
+            SkyUv = new SkyUvReadback { Generation = 7, ThreadId = 11, RawClock = 265584022,
+                Origin = 509280060, ElapsedMilliseconds = unchecked(265584022U - 509280060U) } };
+        StringBuilder json = new StringBuilder();
+        AppendSkyUvJson(json, frame);
+        if (!SkyUvMatchesFrame(frame) || json.ToString().IndexOf("4051271258", StringComparison.Ordinal) < 0)
+            throw new InvalidOperationException("Verified sky UV wrapping clock was rejected.");
+        frame.SkyUv.ThreadId++;
+        if (SkyUvMatchesFrame(frame)) throw new InvalidOperationException("Sky UV thread mismatch accepted.");
+        frame.SkyUv.ThreadId--;
+        frame.SkyUv.Generation++;
+        if (SkyUvMatchesFrame(frame)) throw new InvalidOperationException("Sky UV generation mismatch accepted.");
+        frame.SkyUv.Generation--;
+        frame.SkyUv.RawClock++;
+        json.Length = 0;
+        AppendSkyUvJson(json, frame);
+        if (SkyUvMatchesFrame(frame) || json.ToString().IndexOf("null", StringComparison.Ordinal) < 0)
+            throw new InvalidOperationException("Sky UV clock mismatch accepted.");
+        Console.WriteLine("self-check: sky UV clock requires matching thread/generation/world clock and preserves u32 wrap OK");
+    }
+
     private static void SelfCheckGeometryProjection()
     {
         FrameSnapshot frame = new FrameSnapshot {
@@ -3018,6 +3113,7 @@ internal static partial class NativeFrameCapture
         BreakpointInfo cameraBreakpoint = null;
         BreakpointInfo projectionBreakpoint = null;
         BreakpointInfo geometryProjectionBreakpoint = null;
+        BreakpointInfo skyUvBreakpoint = null;
         BreakpointInfo returnBreakpoint = null;
         BreakpointInfo atmosphereBreakpoint = null;
         BreakpointInfo beginSceneBreakpoint = null;
@@ -3208,6 +3304,14 @@ internal static partial class NativeFrameCapture
                                 throw new InvalidOperationException("Terrain geometry projection boundary signature failed.");
                             geometryProjectionBreakpoint = ArmBreakpoint(process, "Terrain.geometry-projection",
                                 unchecked(terrainBase + GeometryProjectionRva), geometryPrefix[0]);
+                            byte[] skyPrefix = new byte[] { 0x6A, 0xFF, 0x68, 0, 0, 0, 0, 0x64, 0xA1, 0, 0, 0, 0 };
+                            Array.Copy(BitConverter.GetBytes(unchecked(terrainBase + 0x637E6)), 0, skyPrefix, 3, 4);
+                            byte[] skyCode = new byte[skyPrefix.Length];
+                            if (!ReadExact(process, unchecked(terrainBase + SkyRenderRva), skyCode)
+                                || !ByteArraysEqual(skyCode, skyPrefix))
+                                throw new InvalidOperationException("Terrain sky render boundary signature failed.");
+                            skyUvBreakpoint = ArmBreakpoint(process, "Terrain.sky-uv-clock",
+                                unchecked(terrainBase + SkyRenderRva), skyPrefix[0]);
                             byte atmosphereByte;
                             string atmosphereEvidence;
                             if (!VerifyAtmospherePhaseBoundary(process, terrainBase, out atmosphereByte, out atmosphereEvidence))
@@ -3676,6 +3780,9 @@ internal static partial class NativeFrameCapture
                             else if (geometryProjectionBreakpoint != null && geometryProjectionBreakpoint.Armed
                                 && exceptionAddress == geometryProjectionBreakpoint.Address)
                                 hitBreakpoint = geometryProjectionBreakpoint;
+                            else if (skyUvBreakpoint != null && skyUvBreakpoint.Armed
+                                && exceptionAddress == skyUvBreakpoint.Address)
+                                hitBreakpoint = skyUvBreakpoint;
                             else if (returnBreakpoint != null && returnBreakpoint.Armed && exceptionAddress == returnBreakpoint.Address)
                                 hitBreakpoint = returnBreakpoint;
                             else if (atmosphereBreakpoint != null && atmosphereBreakpoint.Armed && exceptionAddress == atmosphereBreakpoint.Address)
@@ -3750,6 +3857,10 @@ internal static partial class NativeFrameCapture
                                             throw new InvalidOperationException("Could not disarm the previous generation's native fog boundary.");
                                         frame.CameraGeneration++;
                                         frame.GeometryProjection = null;
+                                        frame.SkyUv = null;
+                                        if (skyUvBreakpoint != null && !skyUvBreakpoint.Armed)
+                                            skyUvBreakpoint = ArmBreakpoint(process, "Terrain.sky-uv-clock",
+                                                skyUvBreakpoint.Address, skyUvBreakpoint.OriginalByte);
                                         frame.GeometryProjectionGeneration = 0;
                                         frame.GeometryProjectionThreadId = 0;
                                         if (geometryProjectionBreakpoint != null && !geometryProjectionBreakpoint.Armed)
@@ -3843,6 +3954,12 @@ internal static partial class NativeFrameCapture
                                                 frame, eventTid, ref fogConsumerBreakpoint);
                                     }
                                 }
+                                else if (hitBreakpoint == skyUvBreakpoint)
+                                {
+                                    if (frame.SkyUv == null && world3dBase != 0)
+                                        frame.SkyUv = CaptureSkyUv(process, terrainBase, world3dBase,
+                                            stoppedContext, frame, eventTid);
+                                }
                                 else if (hitBreakpoint == geometryProjectionBreakpoint)
                                 {
                                     uint esp = BitConverter.ToUInt32(stoppedContext, ContextEspOffset);
@@ -4086,7 +4203,7 @@ internal static partial class NativeFrameCapture
                                             {
                                                 remote = StartRemoteSurfaceProbe(process, eventTid, ngiBase,
                                                     returnBreakpoint, frame,
-                                                    new BreakpointInfo[] { cameraBreakpoint, projectionBreakpoint, geometryProjectionBreakpoint,
+                                                    new BreakpointInfo[] { cameraBreakpoint, projectionBreakpoint, geometryProjectionBreakpoint, skyUvBreakpoint,
                                                         returnBreakpoint, atmosphereBreakpoint, beginSceneBreakpoint,
                                                         fogConsumerBreakpoint,
                                                         endSceneBreakpoint, presentBreakpoint,
@@ -4234,7 +4351,7 @@ internal static partial class NativeFrameCapture
                                             {
                                                 remote = StartRemoteSurfaceProbe(process, eventTid, ngiBase,
                                                     endSceneBreakpoint, frame,
-                                                    new BreakpointInfo[] { cameraBreakpoint, projectionBreakpoint, geometryProjectionBreakpoint,
+                                                    new BreakpointInfo[] { cameraBreakpoint, projectionBreakpoint, geometryProjectionBreakpoint, skyUvBreakpoint,
                                                         returnBreakpoint, atmosphereBreakpoint, beginSceneBreakpoint,
                                                         endSceneBreakpoint,
                                                         fogConsumerBreakpoint, presentBreakpoint,
@@ -4282,7 +4399,7 @@ internal static partial class NativeFrameCapture
                                             {
                                                 remote = StartRemoteBoundaryReadback(process, eventTid, ngiBase,
                                                     endSceneBreakpoint, frame, outputPath,
-                                                    new BreakpointInfo[] { cameraBreakpoint, projectionBreakpoint, geometryProjectionBreakpoint,
+                                                    new BreakpointInfo[] { cameraBreakpoint, projectionBreakpoint, geometryProjectionBreakpoint, skyUvBreakpoint,
                                                         returnBreakpoint, atmosphereBreakpoint, beginSceneBreakpoint,
                                                         endSceneBreakpoint,
                                                         fogConsumerBreakpoint, presentBreakpoint,
@@ -4502,6 +4619,8 @@ internal static partial class NativeFrameCapture
                                             && !frame.NativeFogSampleLimitExceeded;
                                     if (hitBreakpoint == geometryProjectionBreakpoint)
                                         rearmAfterStep = frame.GeometryProjection == null;
+                                    if (hitBreakpoint == skyUvBreakpoint)
+                                        rearmAfterStep = frame.SkyUv == null;
                                     BeginSingleStep(process, eventTid, hitBreakpoint, stoppedContext,
                                         out pendingStep, rearmAfterStep);
                                     Log("SINGLE_STEP_STARTED boundary=" + hitBreakpoint.Name + " tid=" + eventTid);
@@ -4574,7 +4693,7 @@ internal static partial class NativeFrameCapture
                     captureFailure = captureFailure ?? "No matching native camera/projection/present frame completed before the bounded timeout.";
                     Log("NO_FRAME_CAPTURE bounded timeout at stopped debug event");
                     if (!RestoreArmedBreakpointsWhileStopped(process,
-                        cameraBreakpoint, projectionBreakpoint, geometryProjectionBreakpoint, returnBreakpoint, atmosphereBreakpoint,
+                        cameraBreakpoint, projectionBreakpoint, geometryProjectionBreakpoint, skyUvBreakpoint, returnBreakpoint, atmosphereBreakpoint,
                         beginSceneBreakpoint,
                         endSceneBreakpoint, fogConsumerBreakpoint, presentBreakpoint,
                         presentCompletionBreakpoint, missionBreakpoint))
@@ -4595,6 +4714,7 @@ internal static partial class NativeFrameCapture
                     && (cameraBreakpoint != null && cameraBreakpoint.Armed
                         || projectionBreakpoint != null && projectionBreakpoint.Armed
                         || geometryProjectionBreakpoint != null && geometryProjectionBreakpoint.Armed
+                        || skyUvBreakpoint != null && skyUvBreakpoint.Armed
                         || returnBreakpoint != null && returnBreakpoint.Armed
                         || atmosphereBreakpoint != null && atmosphereBreakpoint.Armed
                         || beginSceneBreakpoint != null && beginSceneBreakpoint.Armed
@@ -4605,7 +4725,7 @@ internal static partial class NativeFrameCapture
                         || missionBreakpoint != null && missionBreakpoint.Armed))
                 {
                     if (!RestoreArmedBreakpointsWhileStopped(process,
-                        cameraBreakpoint, projectionBreakpoint, geometryProjectionBreakpoint, returnBreakpoint, atmosphereBreakpoint,
+                        cameraBreakpoint, projectionBreakpoint, geometryProjectionBreakpoint, skyUvBreakpoint, returnBreakpoint, atmosphereBreakpoint,
                         beginSceneBreakpoint,
                         endSceneBreakpoint, fogConsumerBreakpoint, presentBreakpoint,
                         presentCompletionBreakpoint, missionBreakpoint))
@@ -4655,6 +4775,7 @@ internal static partial class NativeFrameCapture
                 || cameraBreakpoint != null && cameraBreakpoint.Armed
                 || projectionBreakpoint != null && projectionBreakpoint.Armed
                 || geometryProjectionBreakpoint != null && geometryProjectionBreakpoint.Armed
+                || skyUvBreakpoint != null && skyUvBreakpoint.Armed
                 || returnBreakpoint != null && returnBreakpoint.Armed
                 || atmosphereBreakpoint != null && atmosphereBreakpoint.Armed
                 || beginSceneBreakpoint != null && beginSceneBreakpoint.Armed
@@ -4684,7 +4805,7 @@ internal static partial class NativeFrameCapture
                     if (DrainFrameTerminationEvents(process, eventBuffer, processId,
                         ref eventOutstanding, ref outstandingPid, ref outstandingTid, ref outstandingCode,
                         ref outstandingContinueStatus, ref outstandingFileHandleClosed,
-                        new BreakpointInfo[] { cameraBreakpoint, projectionBreakpoint, geometryProjectionBreakpoint, returnBreakpoint,
+                        new BreakpointInfo[] { cameraBreakpoint, projectionBreakpoint, geometryProjectionBreakpoint, skyUvBreakpoint, returnBreakpoint,
                             atmosphereBreakpoint, beginSceneBreakpoint, endSceneBreakpoint, fogConsumerBreakpoint,
                             presentBreakpoint, presentCompletionBreakpoint, missionBreakpoint },
                         out drainEvidence))
@@ -4753,7 +4874,7 @@ internal static partial class NativeFrameCapture
                                 if (DrainFrameTerminationEvents(process, eventBuffer, processId,
                                     ref eventOutstanding, ref outstandingPid, ref outstandingTid, ref outstandingCode,
                                     ref outstandingContinueStatus, ref outstandingFileHandleClosed,
-                                    new BreakpointInfo[] { cameraBreakpoint, projectionBreakpoint, geometryProjectionBreakpoint, returnBreakpoint,
+                                    new BreakpointInfo[] { cameraBreakpoint, projectionBreakpoint, geometryProjectionBreakpoint, skyUvBreakpoint, returnBreakpoint,
                                         atmosphereBreakpoint, beginSceneBreakpoint, endSceneBreakpoint, fogConsumerBreakpoint,
                                         presentBreakpoint, presentCompletionBreakpoint, missionBreakpoint },
                                     out drainEvidence))
@@ -4791,7 +4912,7 @@ internal static partial class NativeFrameCapture
                 else Log("PROCESS_STATE_AFTER_DETACH unreadable error=" + Marshal.GetLastWin32Error());
             }
             breakpointsRestored = processExited || AreBreakpointsRestored(cameraBreakpoint,
-                projectionBreakpoint, geometryProjectionBreakpoint, returnBreakpoint, atmosphereBreakpoint, beginSceneBreakpoint,
+                projectionBreakpoint, geometryProjectionBreakpoint, skyUvBreakpoint, returnBreakpoint, atmosphereBreakpoint, beginSceneBreakpoint,
                 endSceneBreakpoint, fogConsumerBreakpoint, presentBreakpoint,
                 presentCompletionBreakpoint, missionBreakpoint);
             Log("FINAL_BREAKPOINT_STATE restored=" + breakpointsRestored + " processExited=" + processExited);
@@ -4923,7 +5044,7 @@ internal static partial class NativeFrameCapture
     }
 
     private static bool RestoreArmedBreakpointsWhileStopped(IntPtr process,
-        BreakpointInfo cameraBreakpoint, BreakpointInfo projectionBreakpoint, BreakpointInfo geometryProjectionBreakpoint, BreakpointInfo returnBreakpoint,
+        BreakpointInfo cameraBreakpoint, BreakpointInfo projectionBreakpoint, BreakpointInfo geometryProjectionBreakpoint, BreakpointInfo skyUvBreakpoint, BreakpointInfo returnBreakpoint,
         BreakpointInfo atmosphereBreakpoint, BreakpointInfo beginSceneBreakpoint, BreakpointInfo endSceneBreakpoint,
         BreakpointInfo fogConsumerBreakpoint,
         BreakpointInfo presentBreakpoint, BreakpointInfo presentCompletionBreakpoint,
@@ -4932,6 +5053,7 @@ internal static partial class NativeFrameCapture
         return RestoreBreakpointWhileStopped(process, cameraBreakpoint)
             && RestoreBreakpointWhileStopped(process, projectionBreakpoint)
             && RestoreBreakpointWhileStopped(process, geometryProjectionBreakpoint)
+            && RestoreBreakpointWhileStopped(process, skyUvBreakpoint)
             && RestoreBreakpointWhileStopped(process, returnBreakpoint)
             && RestoreBreakpointWhileStopped(process, atmosphereBreakpoint)
             && RestoreBreakpointWhileStopped(process, beginSceneBreakpoint)
@@ -4943,7 +5065,7 @@ internal static partial class NativeFrameCapture
     }
 
     private static bool AreBreakpointsRestored(BreakpointInfo cameraBreakpoint,
-        BreakpointInfo projectionBreakpoint, BreakpointInfo geometryProjectionBreakpoint, BreakpointInfo returnBreakpoint,
+        BreakpointInfo projectionBreakpoint, BreakpointInfo geometryProjectionBreakpoint, BreakpointInfo skyUvBreakpoint, BreakpointInfo returnBreakpoint,
         BreakpointInfo atmosphereBreakpoint, BreakpointInfo beginSceneBreakpoint, BreakpointInfo endSceneBreakpoint,
         BreakpointInfo fogConsumerBreakpoint,
         BreakpointInfo presentBreakpoint, BreakpointInfo presentCompletionBreakpoint,
@@ -4952,6 +5074,7 @@ internal static partial class NativeFrameCapture
         return (cameraBreakpoint == null || !cameraBreakpoint.Armed)
             && (projectionBreakpoint == null || !projectionBreakpoint.Armed)
             && (geometryProjectionBreakpoint == null || !geometryProjectionBreakpoint.Armed)
+            && (skyUvBreakpoint == null || !skyUvBreakpoint.Armed)
             && (returnBreakpoint == null || !returnBreakpoint.Armed)
             && (atmosphereBreakpoint == null || !atmosphereBreakpoint.Armed)
             && (beginSceneBreakpoint == null || !beginSceneBreakpoint.Armed)
diff --git a/tools/native-frame-capture/README.md b/tools/native-frame-capture/README.md
index 145bb8a..d8f621c 100644
--- a/tools/native-frame-capture/README.md
+++ b/tools/native-frame-capture/README.md
@@ -4,6 +4,8 @@ Capture modes attach only to the isolated GOG-compatible scratch copy of `Parkan
 
 `geometry_projection` records the renderer's perspective values at the first indexed geometry draw (`Terrain+0x1D110`) using that world's camera matrix and renderer. It is emitted only when thread, generation, renderer, viewport, far plane and FOV match the later World3D boundary. The near plane may differ: the observed world draw uses `0.5`, while the restored camera boundary contains `5`. FParkan prefers this verified object when replaying the capture. The top-level projection fields remain the camera-boundary tuple used for selected-camera preflight. Older captures without this object still load, with `render_coverage captured_projection_unverified=1`; nearby surfaces in those replays can be clipped incorrectly. Capture a fresh frame to verify them.
 
+`sky_uv_clock` records the independent scrolling-texture clock at sky render entry (`Terrain+0x48110`). It requires a verified module/prologue, the selected camera, matching render thread/generation/world clock, and zenith UV values matching all three native scroll formulas. It preserves wrapping `u32` subtraction from the sky object's origin clock. FParkan holds this phase during exact capture replay; ordinary application frames animate the cloud, star and nebula UVs with periods of 50, 100 and 300 seconds. Older captures without this object still load and report `render_coverage captured_sky_phase_unverified=1`; their sky texture phase is not a native reference.
+
 The JSON keeps the `fparkan-legacy-camera-v1` schema and adds `native_fog_status`, diagnostic counts, and `native_fog`. The latter is an optional passive CPU-side snapshot of the effective sink flags/RGB/range plus the paired calls to the `Terrain+0x2F230` consumer. The flags byte is raw and not a decoded fog mode. Each draw record preserves the distance argument, raw bypass dword and effective low byte, source color, output pointers, and return address. Geometry at `EBP` is included only for the verified `Terrain+0x18A6A` caller with the expected geometry vtable and slot+0x14 target; other callers have `distance_geometry: null`. The fog object is `null` unless the samples match the same render thread, camera, generation, and projection matrix and agree on sink settings. `native_fog_status` is `paired`, `conflict`, `unpaired`, or `incomplete`; `native_fog_status_reason` explains an unpaired, conflicting, or incomplete result. The counts include processed, overflow, paired, rejected, other-thread, and matrix-mismatch calls. At most 512 calls are processed per camera generation; reaching the limit stops sampling and reports an incomplete result. These fields are additive: camera-input validation continues to accept older JSON without them. This probe observes CPU consumer state; it does not set fog or change GPU state.
 
 The capture helper expects an isolated copy at `target\shadow-probe\Parkan - Iron Strategy`; the original GOG installation stays untouched. For the default local install path, create that scratch copy from the repository root with: