perf(rendering): retain synchronous frame scratch

Reuse the PView frame input, publish mutation-invalidated landblock views, and avoid constructing optional shadow iterators while preserving title and lifecycle visibility facts.

docs/plans/2026-07-25-modern-runtime-slice-h.md

@@ -80,21 +80,26 @@ subtree-withdrawal suites preserve exact event and resource counts.
 Landed evidence:
 [`../research/2026-07-25-slice-h-a3-attached-pose-reconcile.md`](../research/2026-07-25-slice-h-a3-attached-pose-reconcile.md).
 
-### H-a4 — diagnostics and frame scratch
+### H-a4 — diagnostics and frame scratch — COMPLETE
 
 1. Reuse one synchronous `RetailPViewFrameInput` owned by
    `WorldSceneRenderer`; reset every field before each draw.
 2. Expose stable borrowed landblock entry/bounds views instead of creating
    iterator state in each frame.
-3. Consumer-gate diagnostic landblock visibility counting and shadow
+3. Consumer-gate optional shadow enumeration. Preserve landblock visibility
-   enumeration. When no DebugVM/collision/probe consumer exists, publish a
+   counting because the normal title and lifecycle checkpoints are active
-   neutral diagnostic outcome without scanning resident landblocks.
+   consumers of `lb V/T`; neutralizing it would be a visible/automation
+   behavior change.
 4. Do not rework `InteriorEntityPartition` while the G4 referee remains.
    Issue #241 closes with G5 old-route deletion, not by editing the fallback.
 5. Profile capped and uncapped production paths and retain evidence.
 
 Gate: identical framebuffer/scene digest, no per-frame PView input allocation,
-and no diagnostic world traversal with all consumers disabled.
+no iterator allocation for stable landblock views, and no shadow traversal
+with all optional consumers disabled.
+
+Landed evidence:
+[`../research/2026-07-25-slice-h-a4-frame-scratch.md`](../research/2026-07-25-slice-h-a4-frame-scratch.md).
 
 ## 3. H-b — exact light top-k
 

docs/research/2026-07-25-slice-h-a4-frame-scratch.md

@@ -0,0 +1,69 @@
+# Slice H-a4 — retained frame scratch and diagnostic traversal
+
+## Scope
+
+This is a behavior-preserving ownership/allocation correction. It does not
+change retail visibility, PView construction, spatial ordering, collision
+debug drawing, title facts, or lifecycle checkpoint facts.
+
+## Findings
+
+Three independent steady-frame allocation sources remained:
+
+1. `WorldSceneRenderer` constructed one `RetailPViewFrameInput` reference
+   object for every PView frame even though `DrawInside` consumes it
+   synchronously.
+2. `GpuWorldState.LandblockEntries` and `LandblockBounds` were C# iterator
+   methods, so merely obtaining each sequence constructed fresh iterator
+   state. The underlying spatial membership changed only at update-thread
+   publication boundaries.
+3. `WorldSceneDiagnosticsController` passed
+   `ShadowObjectRegistry.AllEntriesForDebug()` to the DebugVM publisher even
+   when no developer UI consumer existed. The publisher correctly avoided
+   enumeration, but the yield sequence itself had already been constructed.
+
+The execution plan initially described landblock visibility counting as an
+unconsumed diagnostic. That was incorrect in the current application:
+`WorldRenderFrameOutcome` feeds the always-visible FPS/title `lb V/T` values
+and connected lifecycle snapshots. Returning a neutral count would therefore
+change observable behavior and invalidate lifecycle evidence. The count is
+retained; only its iterator allocation is removed.
+
+## Implementation
+
+- `WorldSceneRenderer` owns one `RetailPViewFrameInput` and resets every field
+  before the synchronous `DrawInside` call. The input is publicly read-only
+  and internally mutable so downstream render owners cannot change borrowed
+  frame facts.
+- `GpuWorldState` exposes retained entry, no-animated-index entry, and bounds
+  lists. They rebuild only after landblock membership, resident entity-list,
+  animated-index, or AABB changes. Existing render-traversal slot order is
+  preserved exactly.
+- Landblock diagnostic counting uses indexed access over the retained bounds
+  view.
+- Shadow enumeration is constructed only when the DebugVM is mounted. The
+  independent collision-wireframe switch keeps its existing enumeration.
+- `InteriorEntityPartition` remains untouched while the G4 referee is still
+  retained. Its removal and issue #241 close remain G5 work after the user
+  accepts the G4 visual gate.
+
+## Conformance
+
+- Stable retained render-view getters allocate zero bytes over 1,000 polls.
+- A spatial mutation refreshes the same borrowed list identity and publishes
+  the new count.
+- Two successive PView frames receive the same input object, reset with the
+  current frame values.
+- Existing quiescence, render traversal, animated-index, PView executor,
+  abort/recovery, and DebugVM tests remain unchanged in behavior.
+
+## Rollback boundary
+
+This work is independent of the G4 production-source cutover. If tomorrow's
+visual gate rejects G4, use:
+
+```text
+git revert ef1d263337997bb030eadb7b8e71d73dc659907a
+```
+
+Do not revert this Slice H-a4 commit, G3, or the portal-warmup corrections.

src/AcDream.App/Rendering/RetailPViewRenderer.cs

@@ -1321,41 +1321,100 @@ internal sealed class BuildingGroupScratch
 
 public sealed class RetailPViewFrameInput
 {
-    public required LoadedCell RootCell { get; init; }
+    public LoadedCell RootCell { get; private set; } = null!;
 
     /// <summary>R-A2: nearby building cells (BuildingId-tagged) flooded per-building when the root is the
     /// outdoor node. Null for interior roots. Grouped by BuildingId inside <see cref="DrawInside"/>.</summary>
-    public IReadOnlyList<LoadedCell>? NearbyBuildingCells { get; init; }
+    public IReadOnlyList<LoadedCell>? NearbyBuildingCells { get; private set; }
 
-    public required Vector3 ViewerEyePos { get; init; }
+    public Vector3 ViewerEyePos { get; private set; }
-    public required Matrix4x4 ViewProjection { get; init; }
+    public Matrix4x4 ViewProjection { get; private set; }
-    public required IRetailPViewCellSource Cells { get; init; }
+    public IRetailPViewCellSource Cells { get; private set; } = null!;
-    public required ICamera Camera { get; init; }
+    public ICamera Camera { get; private set; } = null!;
-    public required Vector3 CameraWorldPosition { get; init; }
+    public Vector3 CameraWorldPosition { get; private set; }
-    public required FrustumPlanes? Frustum { get; init; }
+    public FrustumPlanes? Frustum { get; private set; }
-    public required uint? PlayerLandblockId { get; init; }
+    public uint? PlayerLandblockId { get; private set; }
-    public required HashSet<uint>? AnimatedEntityIds { get; init; }
+    public HashSet<uint>? AnimatedEntityIds { get; private set; }
-    public required int RenderCenterLbX { get; init; }
+    public int RenderCenterLbX { get; private set; }
-    public required int RenderCenterLbY { get; init; }
+    public int RenderCenterLbY { get; private set; }
-    public required int RenderRadius { get; init; }
+    public int RenderRadius { get; private set; }
-    public required IEnumerable<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
+    public IReadOnlyList<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
         IReadOnlyList<WorldEntity> Entities,
         IReadOnlyDictionary<uint, WorldEntity>? AnimatedById)> LandblockEntries
-    { get; init; }
+    { get; private set; } = Array.Empty<(uint, Vector3, Vector3,
+        IReadOnlyList<WorldEntity>,
+        IReadOnlyDictionary<uint, WorldEntity>?)>();
 
     // Pass-presentation and diagnostic values consumed synchronously by the
     // typed executor. This input is data-only and is never retained.
-    public required bool RenderSky { get; init; }
+    public bool RenderSky { get; private set; }
-    public required bool RenderWeather { get; init; }
+    public bool RenderWeather { get; private set; }
-    public required float DayFraction { get; init; }
+    public float DayFraction { get; private set; }
-    public required DayGroupData? ActiveDayGroup { get; init; }
+    public DayGroupData? ActiveDayGroup { get; private set; }
-    public required SkyKeyframe SkyKeyframe { get; init; }
+    public SkyKeyframe SkyKeyframe { get; private set; }
-    public required bool EnvironOverrideActive { get; init; }
+    public bool EnvironOverrideActive { get; private set; }
-    public required uint ViewerCellId { get; init; }
+    public uint ViewerCellId { get; private set; }
-    public required uint PlayerCellId { get; init; }
+    public uint PlayerCellId { get; private set; }
-    public required Vector3 PlayerViewPosition { get; init; }
+    public Vector3 PlayerViewPosition { get; private set; }
-    public required Matrix4x4 CameraView { get; init; }
+    public Matrix4x4 CameraView { get; private set; }
-    public required CameraCellResolution CameraCellResolution { get; init; }
+    public CameraCellResolution CameraCellResolution { get; private set; }
+
+    internal RetailPViewFrameInput Reset(
+        LoadedCell rootCell,
+        IReadOnlyList<LoadedCell>? nearbyBuildingCells,
+        Vector3 viewerEyePos,
+        Matrix4x4 viewProjection,
+        IRetailPViewCellSource cells,
+        ICamera camera,
+        Vector3 cameraWorldPosition,
+        FrustumPlanes? frustum,
+        uint? playerLandblockId,
+        HashSet<uint>? animatedEntityIds,
+        int renderCenterLbX,
+        int renderCenterLbY,
+        int renderRadius,
+        IReadOnlyList<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
+            IReadOnlyList<WorldEntity> Entities,
+            IReadOnlyDictionary<uint, WorldEntity>? AnimatedById)> landblockEntries,
+        bool renderSky,
+        bool renderWeather,
+        float dayFraction,
+        DayGroupData? activeDayGroup,
+        SkyKeyframe skyKeyframe,
+        bool environOverrideActive,
+        uint viewerCellId,
+        uint playerCellId,
+        Vector3 playerViewPosition,
+        Matrix4x4 cameraView,
+        CameraCellResolution cameraCellResolution)
+    {
+        RootCell = rootCell;
+        NearbyBuildingCells = nearbyBuildingCells;
+        ViewerEyePos = viewerEyePos;
+        ViewProjection = viewProjection;
+        Cells = cells;
+        Camera = camera;
+        CameraWorldPosition = cameraWorldPosition;
+        Frustum = frustum;
+        PlayerLandblockId = playerLandblockId;
+        AnimatedEntityIds = animatedEntityIds;
+        RenderCenterLbX = renderCenterLbX;
+        RenderCenterLbY = renderCenterLbY;
+        RenderRadius = renderRadius;
+        LandblockEntries = landblockEntries;
+        RenderSky = renderSky;
+        RenderWeather = renderWeather;
+        DayFraction = dayFraction;
+        ActiveDayGroup = activeDayGroup;
+        SkyKeyframe = skyKeyframe;
+        EnvironOverrideActive = environOverrideActive;
+        ViewerCellId = viewerCellId;
+        PlayerCellId = playerCellId;
+        PlayerViewPosition = playerViewPosition;
+        CameraView = cameraView;
+        CameraCellResolution = cameraCellResolution;
+        return this;
+    }
 }
 
 /// <summary>

src/AcDream.App/Rendering/WorldSceneDiagnosticsController.cs

@@ -44,7 +44,7 @@ internal interface IWorldSceneDiagnostics
 
     WorldSceneDiagnosticOutcome DrawAndPublish(
         in WorldCameraFrame camera,
-        IEnumerable<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax)> bounds);
+        IReadOnlyList<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax)> bounds);
 }
 
 /// <summary>
@@ -168,16 +168,16 @@ internal sealed class WorldSceneDiagnosticsController : IWorldSceneDiagnostics
 
     public WorldSceneDiagnosticOutcome DrawAndPublish(
         in WorldCameraFrame camera,
-        IEnumerable<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax)> bounds)
+        IReadOnlyList<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax)> bounds)
     {
         ArgumentNullException.ThrowIfNull(bounds);
         DrawCollisionWireframes(in camera);
 
         int visible = 0;
-        int total = 0;
+        int total = bounds.Count;
-        foreach (var entry in bounds)
+        for (int index = 0; index < bounds.Count; index++)
         {
-            total++;
+            var entry = bounds[index];
             if (FrustumCuller.IsAabbVisible(
                     camera.Frustum,
                     entry.AabbMin,
@@ -187,16 +187,21 @@ internal sealed class WorldSceneDiagnosticsController : IWorldSceneDiagnostics
             }
         }
 
-        Vector3 nearestOrigin =
+        // AllEntriesForDebug is a yield sequence. Do not even construct its
-            _mode.IsPlayerMode && _player.Controller is { } controller
+        // iterator unless the developer UI is mounted and consumes the facts.
-                ? controller.Position
+        if (_debugVmConsumerActive)
-                : camera.Position;
+        {
-        _debugVm.PublishDebugVmFacts(
+            Vector3 nearestOrigin =
-            _debugVmConsumerActive,
+                _mode.IsPlayerMode && _player.Controller is { } controller
-            visible,
+                    ? controller.Position
-            total,
+                    : camera.Position;
-            nearestOrigin,
+            _debugVm.PublishDebugVmFacts(
-            _physics.ShadowObjects.AllEntriesForDebug());
+                consumerActive: true,
+                visible,
+                total,
+                nearestOrigin,
+                _physics.ShadowObjects.AllEntriesForDebug());
+        }
         return new WorldSceneDiagnosticOutcome(visible, total);
     }
 

src/AcDream.App/Rendering/WorldSceneRenderer.cs

@@ -61,6 +61,7 @@ internal sealed class WorldSceneRenderer : IWorldSceneFramePhase
     private readonly IWorldRenderRangeSource _renderRange;
     private readonly IWorldSceneDiagnostics _diagnostics;
     private readonly IWorldGenerationAvailability _availability;
+    private readonly RetailPViewFrameInput _pviewFrameInput = new();
 
     public WorldSceneRenderer(
         IRenderFrameFoundationSource foundation,
@@ -174,34 +175,32 @@ internal sealed class WorldSceneRenderer : IWorldSceneFramePhase
             {
                 pviewFrameStarted = true;
                 pviewResult = _pview.DrawInside(
-                    new RetailPViewFrameInput
+                    _pviewFrameInput.Reset(
-                    {
+                        clipRoot,
-                        RootCell = clipRoot,
+                        world.Buildings.NearbyBuildingCells,
-                        NearbyBuildingCells = world.Buildings.NearbyBuildingCells,
+                        roots.ViewerEyePosition,
-                        ViewerEyePos = roots.ViewerEyePosition,
+                        camera.ViewProjection,
-                        ViewProjection = camera.ViewProjection,
+                        _pviewCells,
-                        Cells = _pviewCells,
+                        camera.Camera,
-                        Camera = camera.Camera,
+                        camera.Position,
-                        CameraWorldPosition = camera.Position,
+                        camera.Frustum,
-                        Frustum = camera.Frustum,
+                        roots.PlayerLandblockId,
-                        PlayerLandblockId = roots.PlayerLandblockId,
+                        world.AnimatedEntityIds,
-                        AnimatedEntityIds = world.AnimatedEntityIds,
+                        roots.RenderCenterLandblockX,
-                        RenderCenterLbX = roots.RenderCenterLandblockX,
+                        roots.RenderCenterLandblockY,
-                        RenderCenterLbY = roots.RenderCenterLandblockY,
+                        _renderRange.NearRadius,
-                        RenderRadius = _renderRange.NearRadius,
+                        _entities.LandblockEntries,
-                        LandblockEntries = _entities.LandblockEntries,
+                        renderSky,
-                        RenderSky = renderSky,
+                        roots.PlayerSeenOutside,
-                        RenderWeather = roots.PlayerSeenOutside,
+                        _sky.DayFraction,
-                        DayFraction = _sky.DayFraction,
+                        _sky.ActiveDayGroup,
-                        ActiveDayGroup = _sky.ActiveDayGroup,
+                        foundation.Sky,
-                        SkyKeyframe = foundation.Sky,
+                        foundation.EnvironOverrideActive,
-                        EnvironOverrideActive = foundation.EnvironOverrideActive,
+                        roots.ViewerCellId,
-                        ViewerCellId = roots.ViewerCellId,
+                        roots.PlayerCellId,
-                        PlayerCellId = roots.PlayerCellId,
+                        roots.PlayerViewPosition,
-                        PlayerViewPosition = roots.PlayerViewPosition,
+                        camera.Camera.View,
-                        CameraView = camera.Camera.View,
+                        _diagnostics.CameraCellResolution));
-                        CameraCellResolution = _diagnostics.CameraCellResolution,
-                    });
 
                 _particleVisibility.MarkVisibleCells(pviewResult.DrawableCells);
                 _frames.ObserveDrawableCells(pviewResult.DrawableCells);

src/AcDream.App/Rendering/WorldSceneRuntimeSources.cs

@@ -15,12 +15,12 @@ internal interface IWorldSceneSkyStateSource
 
 internal interface IWorldSceneEntitySource
 {
-    IEnumerable<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
+    IReadOnlyList<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
         IReadOnlyList<WorldEntity> Entities,
         IReadOnlyDictionary<uint, WorldEntity>? AnimatedById)> LandblockEntries
     { get; }
 
-    IEnumerable<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax)> LandblockBounds { get; }
+    IReadOnlyList<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax)> LandblockBounds { get; }
 }
 
 internal sealed class RuntimeWorldSceneEntitySource : IWorldSceneEntitySource
@@ -32,12 +32,12 @@ internal sealed class RuntimeWorldSceneEntitySource : IWorldSceneEntitySource
         _world = world ?? throw new ArgumentNullException(nameof(world));
     }
 
-    public IEnumerable<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
+    public IReadOnlyList<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
         IReadOnlyList<WorldEntity> Entities,
         IReadOnlyDictionary<uint, WorldEntity>? AnimatedById)> LandblockEntries =>
         _world.LandblockEntries;
 
-    public IEnumerable<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax)> LandblockBounds =>
+    public IReadOnlyList<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax)> LandblockBounds =>
         _world.LandblockBounds;
 }
 

src/AcDream.App/Streaming/GpuWorldState.cs

@@ -97,6 +97,21 @@ public sealed class GpuWorldState : ILiveEntitySpatialQuery
     private readonly Dictionary<uint, LandblockStreamTier> _tierByLandblock = new();
     private readonly Dictionary<uint, (Vector3 Min, Vector3 Max)> _aabbs = new();
     private readonly Dictionary<uint, AnimatedEntityIndex> _animatedIndexByLandblock = new();
+    // H-a4: synchronous render borrows. The former yield properties created
+    // fresh iterator state at every per-frame call site.
+    private readonly List<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
+        IReadOnlyList<WorldEntity> Entities,
+        IReadOnlyDictionary<uint, WorldEntity>? AnimatedById)>
+        _landblockEntriesView = [];
+    private readonly List<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
+        IReadOnlyList<WorldEntity> Entities,
+        IReadOnlyDictionary<uint, WorldEntity>? AnimatedById)>
+        _landblockEntriesWithoutAnimatedIndexView = [];
+    private readonly List<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax)>
+        _landblockBoundsView = [];
+    private bool _landblockEntriesViewDirty = true;
+    private bool _landblockEntriesWithoutAnimatedIndexViewDirty = true;
+    private bool _landblockBoundsViewDirty = true;
 
     private sealed record AnimatedEntityIndex(
         LoadedLandblock Source,
@@ -201,6 +216,7 @@ public sealed class GpuWorldState : ILiveEntitySpatialQuery
     public void SetLandblockAabb(uint landblockId, Vector3 min, Vector3 max)
     {
         _aabbs[landblockId] = (min, max);
+        InvalidateLandblockRenderViews(entries: true, bounds: true);
     }
 
     /// <summary>
@@ -219,49 +235,77 @@ public sealed class GpuWorldState : ILiveEntitySpatialQuery
     /// explicitly invalidate exactly the affected index generation.
     /// </para>
     /// </summary>
-    public IEnumerable<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
+    public IReadOnlyList<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
-                        IReadOnlyList<WorldEntity> Entities,
+                         IReadOnlyList<WorldEntity> Entities,
-                        IReadOnlyDictionary<uint, WorldEntity>? AnimatedById)> LandblockEntries
+                         IReadOnlyDictionary<uint, WorldEntity>? AnimatedById)> LandblockEntries
-        => EnumerateLandblockEntries(includeAnimatedIndex: true);
+        => GetLandblockEntriesView(includeAnimatedIndex: true);
 
     /// <summary>
     /// Per-landblock render entries without the animated lookup dictionary.
     /// Static render passes use this to avoid rebuilding an index they cannot
     /// consume.
     /// </summary>
-    public IEnumerable<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
+    public IReadOnlyList<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
-                        IReadOnlyList<WorldEntity> Entities,
+                         IReadOnlyList<WorldEntity> Entities,
-                        IReadOnlyDictionary<uint, WorldEntity>? AnimatedById)> LandblockEntriesWithoutAnimatedIndex
+                         IReadOnlyDictionary<uint, WorldEntity>? AnimatedById)> LandblockEntriesWithoutAnimatedIndex
-        => EnumerateLandblockEntries(includeAnimatedIndex: false);
+        => GetLandblockEntriesView(includeAnimatedIndex: false);
 
     /// <summary>
     /// Lightweight bounds-only enumeration for overlays and diagnostics.
     /// Does not walk entity lists.
     /// </summary>
-    public IEnumerable<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax)> LandblockBounds
+    public IReadOnlyList<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax)> LandblockBounds
     {
         get
         {
             if (!_availability.IsWorldAvailable)
-                yield break;
+                return Array.Empty<(uint, Vector3, Vector3)>();
+            if (!_landblockBoundsViewDirty)
+                return _landblockBoundsView;
 
-            foreach (var kvp in _loaded)
+            _landblockBoundsView.Clear();
+            for (int slot = 0; slot < _renderTraversalLandblockSlots.Count; slot++)
             {
-                if (_aabbs.TryGetValue(kvp.Key, out var aabb))
+                uint landblockId = _renderTraversalLandblockSlots[slot];
-                    yield return (kvp.Key, aabb.Min, aabb.Max);
+                if (landblockId == 0)
+                    continue;
+                if (_aabbs.TryGetValue(landblockId, out var aabb))
+                    _landblockBoundsView.Add((landblockId, aabb.Min, aabb.Max));
                 else
-                    yield return (kvp.Key, Vector3.Zero, Vector3.Zero);
+                    _landblockBoundsView.Add(
+                        (landblockId, Vector3.Zero, Vector3.Zero));
             }
+
+            _landblockBoundsViewDirty = false;
+            return _landblockBoundsView;
         }
     }
 
-    private IEnumerable<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
+    private IReadOnlyList<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
-                         IReadOnlyList<WorldEntity> Entities,
+                           IReadOnlyList<WorldEntity> Entities,
-                         IReadOnlyDictionary<uint, WorldEntity>? AnimatedById)> EnumerateLandblockEntries(
+                           IReadOnlyDictionary<uint, WorldEntity>? AnimatedById)> GetLandblockEntriesView(
         bool includeAnimatedIndex)
     {
         if (!_availability.IsWorldAvailable)
-            yield break;
+        {
+            return Array.Empty<(uint, Vector3, Vector3,
+                IReadOnlyList<WorldEntity>,
+                IReadOnlyDictionary<uint, WorldEntity>?)>();
+        }
+
+        List<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
+            IReadOnlyList<WorldEntity> Entities,
+            IReadOnlyDictionary<uint, WorldEntity>? AnimatedById)> view =
+            includeAnimatedIndex
+                ? _landblockEntriesView
+                : _landblockEntriesWithoutAnimatedIndexView;
+        bool dirty = includeAnimatedIndex
+            ? _landblockEntriesViewDirty
+            : _landblockEntriesWithoutAnimatedIndexViewDirty;
+        if (!dirty)
+            return view;
+
+        view.Clear();
 
         for (int slot = 0; slot < _renderTraversalLandblockSlots.Count; slot++)
         {
@@ -287,10 +331,29 @@ public sealed class GpuWorldState : ILiveEntitySpatialQuery
             }
 
             if (_aabbs.TryGetValue(landblockId, out var aabb))
-                yield return (landblockId, aabb.Min, aabb.Max, landblock.Entities, byId);
+                view.Add(
+                    (landblockId, aabb.Min, aabb.Max, landblock.Entities, byId));
             else
-                yield return (landblockId, Vector3.Zero, Vector3.Zero, landblock.Entities, byId);
+                view.Add(
+                    (landblockId, Vector3.Zero, Vector3.Zero, landblock.Entities, byId));
         }
+
+        if (includeAnimatedIndex)
+            _landblockEntriesViewDirty = false;
+        else
+            _landblockEntriesWithoutAnimatedIndexViewDirty = false;
+        return view;
+    }
+
+    private void InvalidateLandblockRenderViews(bool entries, bool bounds)
+    {
+        if (entries)
+        {
+            _landblockEntriesViewDirty = true;
+            _landblockEntriesWithoutAnimatedIndexViewDirty = true;
+        }
+        if (bounds)
+            _landblockBoundsViewDirty = true;
     }
 
     internal bool TryGetRenderTraversalSortKey(
@@ -361,6 +424,7 @@ public sealed class GpuWorldState : ILiveEntitySpatialQuery
             throw new InvalidOperationException(
                 $"Landblock 0x{landblockId:X8} already owns a render traversal slot.");
         }
+        InvalidateLandblockRenderViews(entries: true, bounds: true);
     }
 
     private bool RemoveLoadedLandblock(
@@ -381,6 +445,7 @@ public sealed class GpuWorldState : ILiveEntitySpatialQuery
 
         _renderTraversalLandblockSlots[slot] = 0;
         _freeRenderTraversalLandblockSlots.Push(slot);
+        InvalidateLandblockRenderViews(entries: true, bounds: true);
         return true;
     }
 
@@ -726,6 +791,7 @@ public sealed class GpuWorldState : ILiveEntitySpatialQuery
         int bucketIndex = entities.Count;
         entities.Add(entity);
         _animatedIndexByLandblock.Remove(landblockId);
+        InvalidateLandblockRenderViews(entries: true, bounds: false);
         AddFlatEntity(entity);
         SetProjectionLocation(entity, landblockId, isLoaded: true, bucketIndex);
         AdjustVisibleLiveProjection(entity, +1);
@@ -765,6 +831,7 @@ public sealed class GpuWorldState : ILiveEntitySpatialQuery
         entities.RemoveAt(lastIndex);
 
         _animatedIndexByLandblock.Remove(location.LandblockId);
+        InvalidateLandblockRenderViews(entries: true, bounds: false);
         RemoveFlatEntity(entity);
         RemoveProjectionLocation(entity);
         AdjustVisibleLiveProjection(entity, -1);
@@ -1463,6 +1530,7 @@ public sealed class GpuWorldState : ILiveEntitySpatialQuery
         }
         _loaded[canonical] = NormalizeLoadedLandblock(lb, retainedLive);
         _animatedIndexByLandblock.Remove(canonical);
+        InvalidateLandblockRenderViews(entries: true, bounds: false);
         _tierByLandblock[canonical] = LandblockStreamTier.Far;
         }
 
@@ -1595,6 +1663,7 @@ public sealed class GpuWorldState : ILiveEntitySpatialQuery
             AdjustVisibleLiveProjection(entity, +1);
         }
         _animatedIndexByLandblock.Remove(canonical);
+        InvalidateLandblockRenderViews(entries: true, bounds: false);
         _tierByLandblock[canonical] = LandblockStreamTier.Near;
         ulong[] effectiveRenderIds = additionalRenderIds?.ToArray() ?? Array.Empty<ulong>();
         WorldEntity[] staticEntities = entities

tests/AcDream.App.Tests/Rendering/RetailPViewPassExecutorTests.cs

@@ -418,34 +418,32 @@ public sealed class RetailPViewPassExecutorTests
                 null));
         }
 
-        return new RetailPViewFrameInput
+        return new RetailPViewFrameInput().Reset(
-        {
+            root,
-            RootCell = root,
+            nearbyBuildingCells,
-            NearbyBuildingCells = nearbyBuildingCells,
+            Vector3.Zero,
-            ViewerEyePos = Vector3.Zero,
+            TestCamera.ViewProjection,
-            ViewProjection = TestCamera.ViewProjection,
+            new DictionaryCellSource(cells),
-            Cells = new DictionaryCellSource(cells),
+            new TestCamera(),
-            Camera = new TestCamera(),
+            Vector3.Zero,
-            CameraWorldPosition = Vector3.Zero,
+            frustum: null,
-            Frustum = null,
+            playerLandblockId: root.CellId & 0xFFFF0000u,
-            PlayerLandblockId = root.CellId & 0xFFFF0000u,
+            animatedEntityIds: null,
-            AnimatedEntityIds = null,
+            renderCenterLbX: 0,
-            RenderCenterLbX = 0,
+            renderCenterLbY: 0,
-            RenderCenterLbY = 0,
+            renderRadius: 1,
-            RenderRadius = 1,
+            landblockEntries: entries,
-            LandblockEntries = entries,
+            renderSky: true,
-            RenderSky = true,
+            renderWeather: true,
-            RenderWeather = true,
+            dayFraction: 0f,
-            DayFraction = 0f,
+            activeDayGroup: null,
-            ActiveDayGroup = null,
+            skyKeyframe: default,
-            SkyKeyframe = default,
+            environOverrideActive: false,
-            EnvironOverrideActive = false,
+            viewerCellId: root.CellId,
-            ViewerCellId = root.CellId,
+            playerCellId: root.CellId,
-            PlayerCellId = root.CellId,
+            playerViewPosition: Vector3.Zero,
-            PlayerViewPosition = Vector3.Zero,
+            cameraView: TestCamera.ViewMatrix,
-            CameraView = TestCamera.ViewMatrix,
+            cameraCellResolution: CameraCellResolution.None);
-            CameraCellResolution = CameraCellResolution.None,
-        };
     }
 
     private static LoadedCell InteriorWithExit(uint cellId)

tests/AcDream.App.Tests/Rendering/WorldSceneRendererTests.cs

@@ -153,6 +153,32 @@ public sealed class WorldSceneRendererTests
         Assert.Equal(4, rig.PView.LastInput.RenderRadius);
     }
 
+    [Fact]
+    public void PViewWorld_ReusesOneSynchronousFrameInputAcrossFrames()
+    {
+        var root = new LoadedCell
+        {
+            CellId = 0x01010001u,
+            IsOutdoorNode = false,
+        };
+        var rig = new Rig(
+            portalVisible: false,
+            waitingForLogin: false,
+            clipRoot: root);
+
+        rig.Renderer.Render(default);
+        RetailPViewFrameInput first = Assert.IsType<RetailPViewFrameInput>(
+            rig.PView.LastInput);
+        rig.Calls.Clear();
+
+        rig.Renderer.Render(default);
+
+        Assert.Same(first, rig.PView.LastInput);
+        Assert.Same(root, rig.PView.LastInput!.RootCell);
+        Assert.Equal(rig.DayFraction, rig.PView.LastInput.DayFraction);
+        Assert.Contains("pview:draw", rig.Calls);
+    }
+
     [Fact]
     public void OutdoorPView_UsesPViewOwnersForPostWorldParticlesWithoutFlatWeather()
     {
@@ -474,13 +500,13 @@ public sealed class WorldSceneRendererTests
 
     private sealed class EntitySource : IWorldSceneEntitySource
     {
-        public IEnumerable<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
+        public IReadOnlyList<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax,
             IReadOnlyList<WorldEntity> Entities,
             IReadOnlyDictionary<uint, WorldEntity>? AnimatedById)> LandblockEntries =>
             Array.Empty<(uint, Vector3, Vector3, IReadOnlyList<WorldEntity>,
                 IReadOnlyDictionary<uint, WorldEntity>?)>();
 
-        public IEnumerable<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax)> LandblockBounds =>
+        public IReadOnlyList<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax)> LandblockBounds =>
             Array.Empty<(uint, Vector3, Vector3)>();
     }
 
@@ -697,7 +723,7 @@ public sealed class WorldSceneRendererTests
 
         public WorldSceneDiagnosticOutcome DrawAndPublish(
             in WorldCameraFrame camera,
-            IEnumerable<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax)> bounds)
+            IReadOnlyList<(uint LandblockId, Vector3 AabbMin, Vector3 AabbMax)> bounds)
         {
             calls.Add("diagnostics:draw");
             return new WorldSceneDiagnosticOutcome(3, 8);

tests/AcDream.App.Tests/Streaming/GpuWorldStateRenderTraversalTests.cs

@@ -68,6 +68,44 @@ public sealed class GpuWorldStateRenderTraversalTests
         Assert.False(state.TryGetRenderTraversalSortKey(pending, out _));
     }
 
+    [Fact]
+    public void StableRenderViews_AllocateOnlyWhenSpatialContentChanges()
+    {
+        var state = new GpuWorldState();
+        state.AddLandblock(Landblock(
+            FirstLandblock,
+            Entity(1, 0x80000001u)));
+        state.SetLandblockAabb(
+            FirstLandblock,
+            new Vector3(1f, 2f, 3f),
+            new Vector3(4f, 5f, 6f));
+
+        var entries = state.LandblockEntries;
+        var bounds = state.LandblockBounds;
+        _ = entries.Count;
+        _ = bounds.Count;
+        long before = GC.GetAllocatedBytesForCurrentThread();
+        for (int iteration = 0; iteration < 1_000; iteration++)
+        {
+            _ = state.LandblockEntries.Count;
+            _ = state.LandblockBounds.Count;
+        }
+        long allocated = GC.GetAllocatedBytesForCurrentThread() - before;
+
+        Assert.Equal(0, allocated);
+        Assert.Same(entries, state.LandblockEntries);
+        Assert.Same(bounds, state.LandblockBounds);
+
+        state.AddLandblock(Landblock(
+            SecondLandblock,
+            Entity(2, 0x80000002u)));
+
+        Assert.Same(entries, state.LandblockEntries);
+        Assert.Same(bounds, state.LandblockBounds);
+        Assert.Equal(2, entries.Count);
+        Assert.Equal(2, bounds.Count);
+    }
+
     private static void AssertSort(
         GpuWorldState state,
         WorldEntity entity,