wip(assembler): round L11 -- fix 24 m+ crossing crash; near ring ready 2x sooner at spawn

Crash: crossing tiles were coalesced into one huge rectangle, and BuildSpatialBins tried to
resize to ~4.3e17 bytes (std::bad_alloc; the L7 32 m failure had the same cause). Analytic
regions now skip unread dense bins and compile in world-aligned 128-voxel pages, published
together; out-of-range keys error before allocation. 24 m, 32 m and 1 km crossings pass
(1 km: 72 pages, peak RSS 700 MiB).
Spawn: World::isTileShapeFree proves LOD0 SurfaceWorld tiles that never read the cave shape;
those start before shape compile, and all others wait. Reviewer W12 no-hash: near ring 0.337 ->
0.159 s, whole view +2.1%. All SurfaceWorld/FloatingIslands hashes unchanged (W1/W8/W12, both
compilers, forced-overlap run). Unreal VoxelWorld.cpp adapter changed but NOT built here.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CSFYgsdW8ejZSyiMf4qRSX

Standalone/Core/src/ShapeWorldInternal.h

@@ -487,7 +487,13 @@ public:
         const auto Stage=Clock::now();
         BuildLayerBounds();BuildOwnerPrimitives();
         if(RoundTunnelsEnabled)BuildRoundTunnelPrimitives();
-        BuildSpatialBins(LineBinSize);
+        // Analytic regions never build packed interval lines. Their exact-density fallback only
+        // reads the sparse 3D primitive bins; allocating the dense per-axis line-bin grids here
+        // scales with the region's XY bounding rectangle and is both unnecessary and unbounded.
+        // Les regions analytiques n'utilisent pas les intervalles compactes; leur repli exact lit
+        // les bins 3D clairsemes. Les grilles denses par axe croitraient avec la surface XY sans
+        // servir ce chemin.
+        BuildSpatialBins(LineBinSize,false);
         Stats.ShapeSeconds=std::chrono::duration<double>(Clock::now()-Stage).count();
         Stats.PrimitiveCount=Primitives.size();
         if(Primitives.empty())
@@ -497,6 +503,59 @@ public:
         return true;
     }
 
+    void InitializeNativeSurfaceOnly(FStandaloneOwnerWorld& World,
+        const VoxelForgeCore::WorldAssemblyManifest* InWorldAssembly,
+        const FIntVector& InMinimum,const FIntVector& InMaximum)
+    {
+        Owner=&World;WorldAssembly=InWorldAssembly;
+        NativeOnlyMinimum=InMinimum;NativeOnlyMaximum=InMaximum;
+        bNativeOnly=true;bAnalyticOnly=true;Built=true;
+        NativeOnlyViolations.store(0,std::memory_order_relaxed);
+    }
+
+    bool BuildShapeDependencyProof(FStandaloneOwnerWorld& World,
+        const FIntVector& MinVoxels,const FIntVector& MaxVoxels,bool bInRoundTunnels)
+    {
+        Owner=&World;WorkerCount=1;RoundTunnelsEnabled=bInRoundTunnels;
+        bAnalyticOnly=true;bNativeOnly=false;Stats={};
+        for(int32 Axis=0;Axis<3;++Axis)
+        {
+            Min[Axis]=(&MinVoxels.X)[Axis]-2;Max[Axis]=(&MaxVoxels.X)[Axis]+2;
+            ClipMin[Axis]=(&MinVoxels.X)[Axis];ClipMax[Axis]=(&MaxVoxels.X)[Axis];
+            Size[Axis]=Max[Axis]-Min[Axis]+1;
+            if(Size[Axis]<=0||Size[Axis]>4096||ClipMax[Axis]<ClipMin[Axis])return false;
+        }
+        BuildLayerBounds();BuildOwnerPrimitives();
+        if(RoundTunnelsEnabled)BuildRoundTunnelPrimitives();
+        return true;
+    }
+
+    bool HasShapeDependencyInBox(const FIntVector& Origin,int32 Step,int32 Cells) const
+    {
+        const int32 Pad=std::max(Step,1);
+        const int32 BMin[3]={Origin.X-Pad,Origin.Y-Pad,Origin.Z-Pad};
+        const int32 BMax[3]={Origin.X+(Cells+1)*Step,Origin.Y+(Cells+1)*Step,
+            Origin.Z+(Cells+1)*Step};
+        for(const FPrimitive& Primitive:Primitives)
+        {
+            bool bOverlaps=true;
+            for(int32 Axis=0;Axis<3;++Axis)
+                bOverlaps=bOverlaps&&Primitive.Max[Axis]+DetailBand>=BMin[Axis]
+                    &&Primitive.Min[Axis]-DetailBand<=BMax[Axis];
+            if(bOverlaps)return true;
+        }
+        for(const FInterval& Range:LayerRanges)
+            if(Range.Lo<=BMax[2]&&Range.Hi>=BMin[2]
+                &&(Range.Lo>=BMin[2]||Range.Hi<=BMax[2]))return true;
+        return false;
+    }
+
+    bool IsNativeOnly() const { return bNativeOnly; }
+    uint32 GetNativeOnlyViolationCount() const
+    { return NativeOnlyViolations.load(std::memory_order_relaxed); }
+    void RecordNativeOnlyViolation() const
+    { NativeOnlyViolations.fetch_add(1,std::memory_order_relaxed); }
+
     const FBuildStats& GetStats() const { return Stats; }
     bool IsBuilt() const { return Built; }
     bool HasFarWorld() const { return FarBuilt; }
@@ -951,6 +1010,15 @@ public:
     // edge interpolation and normals to the existing mesher.
     float DensityAt(float X,float Y,float Z) const
     {
+        if(bNativeOnly)
+        {
+            if(!NativeOnlyContains(X,Y,Z))
+            {RecordNativeOnlyViolation();return 0.0f;}
+            float NativeDensity=0.0f;
+            if(!NativeSurfaceDensityAt(X,Y,Z,NativeDensity))
+            {RecordNativeOnlyViolation();return 0.0f;}
+            return NativeDensity;
+        }
         float IslandDensity=0.0f;
         if(NativeFloatingIslandDensityAt(X,Y,Z,IslandDensity))
         {
@@ -975,6 +1043,17 @@ public:
 
     float DensityAtLattice(int32 X,int32 Y,int32 Z) const
     {
+        if(bNativeOnly)
+        {
+            if(!NativeOnlyContains(static_cast<float>(X),static_cast<float>(Y),
+                static_cast<float>(Z)))
+            {RecordNativeOnlyViolation();return 0.0f;}
+            float NativeDensity=0.0f;
+            if(!NativeSurfaceDensityAt(static_cast<float>(X),static_cast<float>(Y),
+                static_cast<float>(Z),NativeDensity))
+            {RecordNativeOnlyViolation();return 0.0f;}
+            return NativeDensity;
+        }
         float IslandDensity=0.0f;
         if(NativeFloatingIslandDensityAt(static_cast<float>(X),static_cast<float>(Y),
             static_cast<float>(Z),IslandDensity))
@@ -1003,6 +1082,15 @@ public:
 
     float DensityAtUnclamped(float X,float Y,float Z) const
     {
+        if(bNativeOnly)
+        {
+            if(!NativeOnlyContains(X,Y,Z))
+            {RecordNativeOnlyViolation();return 0.0f;}
+            float NativeDensity=0.0f;
+            if(!NativeSurfaceDensityAt(X,Y,Z,NativeDensity))
+            {RecordNativeOnlyViolation();return 0.0f;}
+            return NativeDensity;
+        }
         float IslandDensity=0.0f;
         if(NativeFloatingIslandDensityAt(X,Y,Z,IslandDensity))
         {
@@ -1023,6 +1111,8 @@ public:
     VoxelForgeCore::DetailFieldSample DetailSampleAt(float X,float Y,float Z) const
     {
         VoxelForgeCore::DetailFieldSample Sample;
+        if(bNativeOnly)
+        {RecordNativeOnlyViolation();return Sample;}
         AnalyticDensityAt(X,Y,Z,false,&Sample.displacement,
             &Sample.caveInfluence,&Sample.floorInfluence);
         return Sample;
@@ -1040,6 +1130,12 @@ public:
     {
         Count=std::clamp(Count,0,8);
         if(Count==0)return;
+        if(bNativeOnly)
+        {
+            for(int32 Lane=0;Lane<Count;++Lane)
+                OutDensity[Lane]=DensityAtLattice(XStart+Lane*XStep,Y,Z);
+            return;
+        }
         bool bHasLegacySurfaceSample=false;
         bool bHasNativeIslandSample=false;
         for(int32 Lane=0;Lane<Count;++Lane)
@@ -1202,10 +1298,17 @@ public:
     {
         if(!WorldAssembly||!Owner||!Owner->Manager||!Owner->Generator
             ||!std::isfinite(X)||!std::isfinite(Y))return false;
+        const std::int64_t chunkMinimum=static_cast<std::int64_t>(ChunkZ)*CHUNK_SIZE;
+        const std::int64_t chunkMaximum=chunkMinimum+CHUNK_SIZE;
+        if(bNativeOnly&&(!NativeOnlyContainsColumn(X,Y)
+            ||chunkMaximum<NativeOnlyMinimum.Z||chunkMinimum>NativeOnlyMaximum.Z
+            ||Owner->Manager->GetGeneratorTypeForChunk(FIntVector(0,0,ChunkZ))
+                !=ECaveGeneratorType::SurfaceWorld))
+        {RecordNativeOnlyViolation();return false;}
         if(Owner->Manager->GetGeneratorTypeForChunk(FIntVector(0,0,ChunkZ))
             !=ECaveGeneratorType::SurfaceWorld)return false;
         const int32 StrateIndex=Owner->Manager->GetStrateIndex(
-            static_cast<float>((static_cast<double>(ChunkZ*CHUNK_SIZE+CHUNK_SIZE/2))*VOXEL_SIZE));
+            static_cast<float>((static_cast<double>(ChunkZ)*CHUNK_SIZE+CHUNK_SIZE/2)*VOXEL_SIZE));
         const auto* Plan=FindWorldAssemblyStratum(StrateIndex,ChunkZ);
         if(!Plan)return false;
         constexpr double Scale=static_cast<double>(VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel);
@@ -1250,6 +1353,17 @@ public:
                 !=ECaveGeneratorType::SurfaceWorld)return false;
             Plan=Candidate;
         }
+        if(bNativeOnly)
+        {
+            const int32 BMinX=Origin.X-Pad,BMinY=Origin.Y-Pad;
+            const int32 BMaxX=Origin.X+(Cells+1)*Step;
+            const int32 BMaxY=Origin.Y+(Cells+1)*Step;
+            if(BMinX<NativeOnlyMinimum.X||BMinY<NativeOnlyMinimum.Y
+                ||BMin<NativeOnlyMinimum.Z||BMaxX>NativeOnlyMaximum.X
+                ||BMaxY>NativeOnlyMaximum.Y||BMax>NativeOnlyMaximum.Z)
+            {RecordNativeOnlyViolation();return false;}
+        }
+        if(bNativeOnly&&!Plan)RecordNativeOnlyViolation();
         return Plan!=nullptr;
     }
 
@@ -1281,7 +1395,7 @@ public:
                 {
                     bSurfaceOverlap=true;
                     const int32 StrateIndex=Owner->Manager->GetStrateIndex(
-                        static_cast<float>((static_cast<double>(ChunkZ*CHUNK_SIZE+CHUNK_SIZE/2))*VOXEL_SIZE));
+                        static_cast<float>((static_cast<double>(ChunkZ)*CHUNK_SIZE+CHUNK_SIZE/2)*VOXEL_SIZE));
                     const auto* Candidate=FindWorldAssemblyStratum(StrateIndex,ChunkZ);
                     if(!Candidate||(SurfacePlan&&SurfacePlan!=Candidate))
                         bBadPlan=true;
@@ -1306,7 +1420,7 @@ public:
                 {
                     bIslandOverlap=true;
                     const int32 StrateIndex=Owner->Manager->GetStrateIndex(
-                        static_cast<float>((static_cast<double>(ChunkZ*CHUNK_SIZE+CHUNK_SIZE/2))*VOXEL_SIZE));
+                        static_cast<float>((static_cast<double>(ChunkZ)*CHUNK_SIZE+CHUNK_SIZE/2)*VOXEL_SIZE));
                     const auto* Candidate=FindWorldAssemblyFloatingIslandStratum(StrateIndex,ChunkZ);
                     if(!Candidate||(IslandPlan&&IslandPlan!=Candidate))bBadPlan=true;
                     IslandPlan=Candidate;
@@ -1327,6 +1441,19 @@ public:
             else ++Counts.MixedBoxes;
             return Result;
         };
+        if(bNativeOnly)
+        {
+            const bool bInsideProofBox=BMin[0]>=NativeOnlyMinimum.X
+                &&BMin[1]>=NativeOnlyMinimum.Y&&BMin[2]>=NativeOnlyMinimum.Z
+                &&BMax[0]<=NativeOnlyMaximum.X&&BMax[1]<=NativeOnlyMaximum.Y
+                &&BMax[2]<=NativeOnlyMaximum.Z;
+            if(!bInsideProofBox||!bSurfaceOverlap||bIslandOverlap||bOtherStrateOverlap
+                ||bBadPlan||!EditBrushes.empty())
+            {
+                RecordNativeOnlyViolation();
+                return Finish(EVoxelTileClass::Mixed,true);
+            }
+        }
         // A box crossing recipes cannot use one field interval; unknown composition stays Mixed.
         // Une boite qui traverse plusieurs recettes reste Mixed, car l'intervalle d'un seul champ ne suffit pas.
         if(bBadPlan||(bSurfaceOverlap&&(bIslandOverlap||bOtherStrateOverlap))
@@ -1341,7 +1468,7 @@ public:
         // for SurfaceWorld and FloatingIslands. Legacy analytic primitives/layer bounds cannot
         // modify that field; only the explicit edit transaction above can. Keep their guards on
         // the legacy classifier path, where those overlays do participate in density.
-        if(!bUseNativeLatticeProof||(!bSurfaceOverlap&&!bIslandOverlap))
+        if(!bNativeOnly&&(!bUseNativeLatticeProof||(!bSurfaceOverlap&&!bIslandOverlap)))
         {
             for(int32 BZ=FloorDiv(BMin[2],ActiveSpatialBinSize);BZ<=FloorDiv(BMax[2],ActiveSpatialBinSize);++BZ)
             for(int32 BY=FloorDiv(BMin[1],ActiveSpatialBinSize);BY<=FloorDiv(BMax[1],ActiveSpatialBinSize);++BY)
@@ -1880,6 +2007,21 @@ public:
     }
 
 private:
+    bool NativeOnlyContainsColumn(float X,float Y) const
+    {
+        return std::isfinite(X)&&std::isfinite(Y)
+            &&X>=NativeOnlyMinimum.X&&X<=NativeOnlyMaximum.X
+            &&Y>=NativeOnlyMinimum.Y&&Y<=NativeOnlyMaximum.Y;
+    }
+
+    bool NativeOnlyContains(float X,float Y,float Z) const
+    {
+        return std::isfinite(X)&&std::isfinite(Y)&&std::isfinite(Z)
+            &&X>=NativeOnlyMinimum.X&&X<=NativeOnlyMaximum.X
+            &&Y>=NativeOnlyMinimum.Y&&Y<=NativeOnlyMaximum.Y
+            &&Z>=NativeOnlyMinimum.Z&&Z<=NativeOnlyMaximum.Z;
+    }
+
     static FClassificationThreadStats& ThreadClassificationStats()
     {
         static thread_local FClassificationThreadStats Stats;
@@ -1914,7 +2056,7 @@ private:
         if(Owner->Manager->GetGeneratorTypeForChunk(FIntVector(0,0,ChunkZ))
             !=ECaveGeneratorType::SurfaceWorld)return false;
         const int32 StrateIndex=Owner->Manager->GetStrateIndex(
-            static_cast<float>((static_cast<double>(ChunkZ*CHUNK_SIZE+CHUNK_SIZE/2))*VOXEL_SIZE));
+            static_cast<float>((static_cast<double>(ChunkZ)*CHUNK_SIZE+CHUNK_SIZE/2)*VOXEL_SIZE));
         const auto* Plan=FindWorldAssemblyStratum(StrateIndex,ChunkZ);
         if(!Plan)return false;
         constexpr double Scale=static_cast<double>(VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel);
@@ -1942,7 +2084,7 @@ private:
         if(Owner->Manager->GetGeneratorTypeForChunk(FIntVector(0,0,ChunkZ))
             !=ECaveGeneratorType::FloatingIslands)return false;
         const int32 StrateIndex=Owner->Manager->GetStrateIndex(
-            static_cast<float>((static_cast<double>(ChunkZ*CHUNK_SIZE+CHUNK_SIZE/2))*VOXEL_SIZE));
+            static_cast<float>((static_cast<double>(ChunkZ)*CHUNK_SIZE+CHUNK_SIZE/2)*VOXEL_SIZE));
         const auto* Plan=FindWorldAssemblyFloatingIslandStratum(StrateIndex,ChunkZ);
         if(!Plan)return false;
         constexpr double Scale=static_cast<double>(VoxelForgeCore::WorldAssemblySubvoxelsPerVoxel);
@@ -4675,6 +4817,12 @@ public:
                               int32 Count,float* OutDensity) const
     {
         if(Count<=0||OutDensity==nullptr)return;
+        if(bNativeOnly)
+        {
+            for(int32 Lane=0;Lane<Count;++Lane)
+                OutDensity[Lane]=DensityAtLattice(X,Y,ZStart+Lane*ZStep);
+            return;
+        }
         bool bHasLegacySurfaceSample=false;
         for(int32 Lane=0;Lane<Count;++Lane)
             bHasLegacySurfaceSample|=UsesLegacySurfaceField(static_cast<float>(X),
@@ -5211,6 +5359,10 @@ private:
     size_t WordsPerZ=0;
     EDetailVariant DetailVariant=EDetailVariant::Coherent;
     bool Built=false;
+    bool bNativeOnly=false;
+    FIntVector NativeOnlyMinimum=FIntVector::ZeroValue;
+    FIntVector NativeOnlyMaximum=FIntVector::ZeroValue;
+    mutable std::atomic<uint32> NativeOnlyViolations{0};
     bool FarBuilt=false;
     std::vector<FInterval> LayerRanges;
     std::vector<FLayerField> LayerFields;