perf(gen): interval propagation -- blocks can finally be PROVEN empty. 1.55s -> 1.21s

Task 4 ran 11 hours and was killed by system memory pressure before it could file a report. The work survived, builds clean (0 errors), and is verified faster with byte-identical output. This commit is my verification, not its summary -- it never got to write one. THE STRUCTURAL FIX 0e9df9e established why no block could ever be skipped: OriginSpineOp, PassageCarveOp and the active seals Lerp/Min/Max against the CURRENT density, so with an unknown incoming density their supremum is genuinely unbounded. Not a missing bound -- the operator semantics. The answer is to propagate a density INTERVAL through the stack, and that is what landed: FVoxelBoxSdfInterval + PropagateSdfOverBox on the operator interface, an interval fold through every converter and modifier, interval arithmetic down into the noise primitives themselves (gradient corners, warp, worm frequencies), and a BlockSkip lattice the mesher consults per 8^3 block. Its own guiding comment, which is the right default: "no finite interval is a proof. Unknown costs the skip and protects the geometry." 128^3 TunnelNetwork seed 1337 slot 1, freshly built binary, 3 runs each: before 1.515 / 1.554 / 1.569 s after 1.213 / 1.258 / 1.171 s -22.5%, 1.28x -- clears the 17% floor Geometry SHA-256 98eaad61..d3c4f IDENTICAL to 0e9df9e. 153,740 triangles either way. It skips only provably-empty work; nothing about the world changed. It also fixed one cause of the 5.6 s empty tiles found in 0e9df9e: an LOD4 tile legitimately spans 19^3 = 6,859 chunk keys and was rebuilding per-chunk state thousands of times within a single tile. A shared cache removed that failure mode; remaining slow empties were LOD0 and are a separate fast-classifier bail, still open. Partially landed, unfinished when killed: RequestStartCycles on FChunkResult, to report request-to-ready latency rather than worker generation time. Harmless as is. ⚠️ WHAT KILLED IT, AND IT IS OURS A single UnrealEditor-Cmd commandlet grew to 19.5 GB, leaving 1.3 GB free on a 32 GB machine, and the OS killed the agent. Freeing it restored 21.6 GB. The owner said twice that his machine should not be under memory pressure and he was right both times: first the 411 MiB worker caches, now a 19.5 GB commandlet. A generation run must not need 19.5 GB. Next task. Cumulative on this region: 342.2 -> 16.2 -> 2.62 -> 1.49 -> 1.21 s (~283x). 3,374 insertions / 342 deletions across 12 files. Build 0 errors. Nothing outside Plugins/VoxelForge; RealtimeMeshComponent untouched. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_012aheo2crrZmHuYtPpdY2Cb
2026-09-09 21:11:13 +02:00
1 parent 0e9df9e5a7
commit d38d4cabef
@@ -1207,6 +1207,14 @@ bool AVoxelWorld::ApplyTileResult(FChunkResult& Result)
        return false;
    }

+    if (GVoxelForgeProfileTileGeneration != 0 && Result.RequestStartCycles != 0)
+    {
+        UE_LOG(LogTemp, Display,
+            TEXT("[VoxelForgeTileReady] level=%d empty=%d request_to_ready=%.6f"),
+            Result.Tile.Level, Result.bEmpty || !Result.Streams ? 1 : 0,
+            FPlatformTime::ToSeconds64(FPlatformTime::Cycles64() - Result.RequestStartCycles));
+    }
+
    // Mark the tile loaded (even if empty — so we don't re-submit it).
    LoadedTiles.Add(Result.Tile);

@@ -1270,6 +1278,8 @@ void AVoxelWorld::SyncRemeshTile(const FVoxelTileKey& Tile)
    }

    FChunkResult Result;
+    Result.RequestStartCycles = GVoxelForgeProfileTileGeneration != 0
+        ? FPlatformTime::Cycles64() : 0;
    GenerateTileResult(Tile, OriginVoxels, Step, Cells, GenerationEpoch, /*bWantCapture*/ false,
                       BandVoxLo, BandVoxHi, BandChunkLo, BandChunkHi,
                       /*bSheetTile*/ false, /*SheetChunkZ*/ 0,
@@ -1966,6 +1976,8 @@ void AVoxelWorld::LoadTile(const FVoxelTileKey& Tile, bool bHighPriority)
        return;  // Budget full — wait for a task to finish.
    }
    PendingTiles.Add(Tile);
+    const uint64 RequestStartCycles = GVoxelForgeProfileTileGeneration != 0
+        ? FPlatformTime::Cycles64() : 0;

    const FIntVector OriginVoxels = Tile.OriginVoxels();   // min corner, voxel coords

@@ -2019,6 +2031,7 @@ void AVoxelWorld::LoadTile(const FVoxelTileKey& Tile, bool bHighPriority)
            FChunkResult Empty;
            Empty.Tile  = Tile;
            Empty.Epoch = TaskEpoch;
+            Empty.RequestStartCycles = RequestStartCycles;
            ProcessQueue.Enqueue(MoveTemp(Empty));
            return;
        }
@@ -2048,6 +2061,7 @@ void AVoxelWorld::LoadTile(const FVoxelTileKey& Tile, bool bHighPriority)
            FChunkResult Empty;
            Empty.Tile        = Tile;
            Empty.Epoch       = TaskEpoch;
+            Empty.RequestStartCycles = RequestStartCycles;
            Empty.BandChunkLo = BandChunkLo;
            Empty.BandChunkHi = BandChunkHi;
            ProcessQueue.Enqueue(MoveTemp(Empty));
@@ -2069,7 +2083,8 @@ void AVoxelWorld::LoadTile(const FVoxelTileKey& Tile, bool bHighPriority)
        : UE::Tasks::ETaskPriority::BackgroundNormal;
    UE::Tasks::Launch(TEXT("ChunkGen"), [this, Tile, OriginVoxels, Step, Cells, TaskEpoch, bWantCapture,
                                         BandVoxLo, BandVoxHi, BandChunkLo, BandChunkHi,
-                                         bSheetTile, SheetChunkZ, HoleMinX, HoleMinY, HoleMaxX, HoleMaxY]()
+                                         bSheetTile, SheetChunkZ, HoleMinX, HoleMinY, HoleMaxX, HoleMaxY,
+                                         RequestStartCycles]()
    {
        // RAII: decrement the counter on every exit path.
        struct FTaskGuard
@@ -2084,6 +2099,7 @@ void AVoxelWorld::LoadTile(const FVoxelTileKey& Tile, bool bHighPriority)
        GenerateTileResult(Tile, OriginVoxels, Step, Cells, TaskEpoch, bWantCapture,
                           BandVoxLo, BandVoxHi, BandChunkLo, BandChunkHi,
                           bSheetTile, SheetChunkZ, HoleMinX, HoleMinY, HoleMaxX, HoleMaxY, Result);
+        Result.RequestStartCycles = RequestStartCycles;

        if (!ShouldAbortWork())
        {
@@ -2103,14 +2119,21 @@ void AVoxelWorld::GenerateTileResult(const FVoxelTileKey& Tile, const FIntVector
 {
    const bool bProfileTile = GVoxelForgeProfileTileGeneration != 0;
    const double TileStartSeconds = bProfileTile ? FPlatformTime::Seconds() : 0.0;
+    double ClassifySeconds = 0.0;
+    double MeshSeconds = 0.0;
+    double StreamSeconds = 0.0;
+    int32 ClassifyVerdict = -1; // Mixed = 0, AllSolid = 1, AllAir = 2
    auto EmitTileProfile = [&]()
    {
        if (bProfileTile)
        {
            UE_LOG(LogTemp, Display,
-                TEXT("[VoxelForgeTileProfile] level=%d step=%d cells=%d sheet=%d aborted=%d empty=%d seconds=%.6f"),
-                Tile.Level, Step, Cells, bSheetTile ? 1 : 0, Result.bAborted ? 1 : 0,
-                Result.bEmpty ? 1 : 0, FPlatformTime::Seconds() - TileStartSeconds);
+                TEXT("[VoxelForgeTileProfile] tile=(%d,%d,%d) level=%d step=%d cells=%d sheet=%d aborted=%d empty=%d "
+                     "verdict=%d classify=%.6f mesh=%.6f streams=%.6f seconds=%.6f"),
+                Tile.Coord.X, Tile.Coord.Y, Tile.Coord.Z, Tile.Level, Step, Cells,
+                bSheetTile ? 1 : 0, Result.bAborted ? 1 : 0,
+                Result.bEmpty ? 1 : 0, ClassifyVerdict, ClassifySeconds, MeshSeconds, StreamSeconds,
+                FPlatformTime::Seconds() - TileStartSeconds);
        }
    };

@@ -2151,7 +2174,10 @@ void AVoxelWorld::GenerateTileResult(const FVoxelTileKey& Tile, const FIntVector
    {
        TRACE_CPUPROFILER_EVENT_SCOPE(VoxelForge_ClassifyTile);
        INC_DWORD_STAT(STAT_VoxelForgeTilesClassified);
+        const double ClassifyStartSeconds = bProfileTile ? FPlatformTime::Seconds() : 0.0;
        const EVoxelTileClass Verdict = Generator->ClassifyTile(OriginVoxels, Step, Cells);
+        ClassifySeconds = bProfileTile ? FPlatformTime::Seconds() - ClassifyStartSeconds : 0.0;
+        ClassifyVerdict = static_cast<int32>(Verdict);
        if (ShouldAbortWork())
        {
            AbortResult();
@@ -2178,12 +2204,14 @@ void AVoxelWorld::GenerateTileResult(const FVoxelTileKey& Tile, const FIntVector
    if (!bTrivialEmpty)
    {
        TRACE_CPUPROFILER_EVENT_SCOPE(VoxelForge_GenerateMesh);
+        const double MeshStartSeconds = bProfileTile ? FPlatformTime::Seconds() : 0.0;
        MeshData = bSheetTile
            ? Mesher->GenerateSheetMesh(OriginVoxels, Step, Cells, SheetChunkZ,
                                        HoleMinX, HoleMinY, HoleMaxX, HoleMaxY)
            : Mesher->GenerateMesh(OriginVoxels, Step, Cells,
                                   bWantCapture ? &Result.CaptureGrid : nullptr,
                                   BandVoxLo, BandVoxHi);
+        MeshSeconds = bProfileTile ? FPlatformTime::Seconds() - MeshStartSeconds : 0.0;
        INC_DWORD_STAT(STAT_VoxelForgeTilesMeshed);
        if (ShouldAbortWork())
        {
@@ -2198,8 +2226,10 @@ void AVoxelWorld::GenerateTileResult(const FVoxelTileKey& Tile, const FIntVector
    if (!MeshData.IsEmpty())
    {
        TRACE_CPUPROFILER_EVENT_SCOPE(VoxelForge_BuildStreams);
+        const double StreamStartSeconds = bProfileTile ? FPlatformTime::Seconds() : 0.0;
        Result.Streams = MakeShared<RealtimeMesh::FRealtimeMeshStreamSet>();
        BuildTileStreamSet(*Result.Streams, MeshData);
+        StreamSeconds = bProfileTile ? FPlatformTime::Seconds() - StreamStartSeconds : 0.0;
        if (ShouldAbortWork())
        {
            AbortResult();