standalone: the owner's world outside Unreal -- bit-identical density, D3D11 fly-through viewer

Standalone/ (C++20, MSVC /O2 /arch:AVX2 /fp:precise, Build.ps1): copied density pipeline, op stack,
cave morphology, passages, strate manager/composer, noise, DetSinCos, mesher, clipmap selection,
with a UE compatibility layer (Compat/). Owner data exported once to Standalone/data/owner_world.json
by a default-off explore-commandlet exporter (the only plugin-source change). 25 cm voxels.
Parity: seed 0, 3,436 samples (strate edges, negative/far coords, rooms, tunnels, passages,
landings): bit-identical. Viewer: full 7-level clipmap, per-level toggles 1-7, T = round winding
tunnels (standalone option), N/P seed, F wireframe.
Timing NOT yet a baseline: 515 s for 12,054 tiles (L0 70 s, L6 296 s); the compat TMap/TSet are
vector-backed with linear lookup, which the plugin's caches do not expect.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MmSoF64BbRFmk9C3p1VsBJ

Standalone/Source/parity_main.cpp

@@ -0,0 +1,56 @@
+#include "OwnerWorldLoader.h"
+#include "WorldMesher.h"
+
+#include <bit>
+#include <iostream>
+#include <map>
+
+int main(int argc, char** argv)
+{
+    const std::string DataPath = argc > 1 ? argv[1] : "Standalone/data/owner_world.json";
+    FStandaloneOwnerWorld World;
+    std::string Error;
+    if (!StandaloneOwnerLoader::Load(DataPath,World,Error))
+    {
+        std::cerr << "LOAD FAILED: " << Error << '\n';
+        return 2;
+    }
+    std::cout << "Loaded owner world: seed=" << World.Seed
+              << " strates=" << World.Manager->GetNumStrates()
+              << " passages=" << World.Manager->GetPassages().Num()
+              << " samples=" << World.DensitySamples.size() << '\n';
+
+    struct FMismatch { size_t Index; float Actual; };
+    std::vector<FMismatch> Mismatches;
+    Mismatches.reserve(World.DensitySamples.size());
+    std::map<std::string,size_t> SampleKinds;
+    for (size_t I = 0; I < World.DensitySamples.size(); ++I)
+    {
+        const FStandaloneParitySample& Sample = World.DensitySamples[I];
+        const float Actual = World.Generator->GetDensityAt(
+            static_cast<float>(Sample.PositionVoxels.X),
+            static_cast<float>(Sample.PositionVoxels.Y),
+            static_cast<float>(Sample.PositionVoxels.Z));
+        ++SampleKinds[Sample.Kind];
+        if (std::bit_cast<uint32>(Actual) != std::bit_cast<uint32>(Sample.PluginDensity))
+            Mismatches.push_back({I,Actual});
+    }
+    std::cout << "Parity samples by kind:\n";
+    for (const auto& [Kind,Count] : SampleKinds) std::cout << "  " << Kind << ": " << Count << '\n';
+    for (const FMismatch& M : Mismatches)
+    {
+        const FStandaloneParitySample& S = World.DensitySamples[M.Index];
+        std::cerr << "MISMATCH index=" << M.Index << " kind=" << S.Kind
+                  << " strate=" << S.StrateIndex << " at_voxels=("
+                  << S.PositionVoxels.X << ',' << S.PositionVoxels.Y << ',' << S.PositionVoxels.Z
+                  << ") plugin=" << S.PluginDensity << " standalone=" << M.Actual
+                  << " plugin_bits=0x" << std::hex << std::bit_cast<uint32>(S.PluginDensity)
+                  << " standalone_bits=0x" << std::bit_cast<uint32>(M.Actual) << std::dec << '\n';
+    }
+    std::cout << "Parity: " << (World.DensitySamples.size()-Mismatches.size()) << '/'
+              << World.DensitySamples.size() << " bit-identical; mismatches=" << Mismatches.size() << '\n';
+    const FStandaloneCpuClipmap Clipmap = StandaloneWorldMesher::Build(
+        World,World.ViewerStartVoxels,6);
+    std::cout << "Clipmap build finished in " << Clipmap.TotalSeconds << " seconds.\n";
+    return Mismatches.empty() ? 0 : 1;
+}