perf(streaming): cursor publication across frame budgets

tests/AcDream.App.Tests/Rendering/Wb/BuildingLoaderTests.cs

@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Numerics;
+using AcDream.App.Rendering;
 using AcDream.App.Rendering.Wb;
 using DatReaderWriter.DBObjs;
 using DatReaderWriter.Types;
@@ -86,6 +87,43 @@ public class BuildingLoaderTests
         Assert.Equal(new SortedSet<uint> { 1, 2 }, ids);  // sequential 1, 2
     }
 
+    [Fact]
+    public void RetainedPublication_AdvancesOneBuildingAndCommitsCellStampsAtomically()
+    {
+        LandBlockInfo info = MakeInfo(
+            (0x02000001u, new[] { 0x0150u }),
+            (0x02000002u, new[] { 0x0160u }));
+        LoadedCell cell150 = MinimalCell(0xA9B40150u);
+        LoadedCell cell160 = MinimalCell(0xA9B40160u);
+        var cells = new Dictionary<uint, LoadedCell>
+        {
+            [cell150.CellId] = cell150,
+            [cell160.CellId] = cell160,
+        };
+
+        BuildingRegistryPublication publication =
+            BuildingLoader.PreparePublication(info, 0xA9B40000u, cells);
+
+        Assert.False(publication.PreparationCommitted);
+        Assert.False(BuildingLoader.AdvancePreparationOne(publication));
+        Assert.Equal(1, publication.BuildingCursor);
+        Assert.Equal(1, publication.Registry.Count);
+        Assert.Null(cell150.BuildingId);
+        Assert.Null(cell160.BuildingId);
+
+        Assert.True(BuildingLoader.AdvancePreparationOne(publication));
+        Assert.Equal(2, publication.BuildingCursor);
+        Assert.Equal(2, publication.Registry.Count);
+        Assert.Null(cell150.BuildingId);
+        Assert.Null(cell160.BuildingId);
+
+        BuildingLoader.CommitPublication(publication);
+
+        Assert.Equal(1u, cell150.BuildingId);
+        Assert.Equal(2u, cell160.BuildingId);
+        Assert.True(publication.PublicationCommitted);
+    }
+
     [Fact]
     public void Build_StampsLoadedCellBuildingId()
     {
@@ -166,4 +204,16 @@ public class BuildingLoaderTests
         Assert.Equal(new Vector3(9, 12, 33), b.PortalBounds.Min);
         Assert.Equal(new Vector3(17, 25, 39), b.PortalBounds.Max);
     }
+
+    private static LoadedCell MinimalCell(uint cellId) => new()
+    {
+        CellId = cellId,
+        Portals = new List<AcDream.App.Rendering.CellPortalInfo>(),
+        PortalPolygons = new List<Vector3[]>(),
+        WorldTransform = Matrix4x4.Identity,
+        InverseWorldTransform = Matrix4x4.Identity,
+        LocalBoundsMin = new Vector3(-5, -5, -5),
+        LocalBoundsMax = new Vector3(5, 5, 5),
+        ClipPlanes = new List<AcDream.App.Rendering.PortalClipPlane>(),
+    };
 }