diag: passage vs boundary-band ceiling split (L88); coarse passage cache rejected

Verified ablations (zero passage work / zero band calls). LOD0-2 @W12: exact FI 2.27 / TN 2.25 s;
passages off FI 0.81 / TN 0.85; bands off FI 2.11 / TN 2.06. Passages cost ~1.4-1.6 s of near
readiness, bands ~0.1-0.2 s. A tile-local 4-voxel trilinear passage-delta cache increased carve
segment visits (FI 34.5M -> 56.2M) and slowed LOD0-2 (FI 2.58 -> 3.77 s); removed. No world change.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016dhxM43dnWvUu2B5Ph1iG1

Standalone/Core/src/ShapeWorldInternal.h

@@ -31,19 +31,37 @@
 #include <variant>
 #include <vector>
 
-// L86-only ceiling measurement. This removes passage carving/support and the transition-mouth
-// passage fade so timing can measure the best possible passage-representation gain. Never ship
-// or expose this diagnostic as a world setting.
-static bool VF_IsL86PassageCompositionDisabled()
+// L88-only composition split. These switches let the timing harness remove passage work and
+// resolved boundary-band work independently. They are diagnostic only, never world settings.
+static bool VF_IsL88DiagnosticSwitchEnabled(const char* Name)
 {
-    static const bool bDisabled = []()
-    {
-        const char* Value = std::getenv("VOXELFORGE_L86_DISABLE_PASSAGE_COMPOSITION");
-        return Value && Value[0] == '1' && Value[1] == '\0';
-    }();
+    const char* Value=std::getenv(Name);
+    return Value&&Value[0]=='1'&&Value[1]=='\0';
+}
+
+static bool VF_IsL88PassageCompositionDisabled()
+{
+    static const bool bDisabled=VF_IsL88DiagnosticSwitchEnabled(
+        "VOXELFORGE_L88_DISABLE_PASSAGES")
+        ||VF_IsL88DiagnosticSwitchEnabled("VOXELFORGE_L86_DISABLE_PASSAGE_COMPOSITION");
     return bDisabled;
 }
 
+static bool VF_IsL88BoundaryBandsDisabled()
+{
+    static const bool bDisabled=VF_IsL88DiagnosticSwitchEnabled(
+        "VOXELFORGE_L88_DISABLE_BOUNDARY_BANDS")
+        ||VF_IsL88DiagnosticSwitchEnabled("VOXELFORGE_L86_DISABLE_PASSAGE_COMPOSITION");
+    return bDisabled;
+}
+
+static bool VF_IsL88AllowPassageAblationWalkabilityFailure()
+{
+    static const bool bEnabled=VF_IsL88DiagnosticSwitchEnabled(
+        "VOXELFORGE_L88_ALLOW_PASSAGE_ABLATION_WALKABILITY_FAILURE");
+    return bEnabled;
+}
+
 // Standalone-only world compiler. It compiles the runtime room/tunnel/passages into
 // axis-line intervals, composes rock/cave signs into packed Z-column words, then displaces
 // only the conservative surface band. The copied Unreal generator remains the A/B reference.
@@ -197,7 +215,6 @@ public:
             std::ptrdiff_t first=-1,end=-1;
             std::vector<std::uint8_t> activeNodes;
         };
-
         FScopedPassageTileQueries(const FStandaloneShapeWorld& shape,
             const std::array<std::int64_t,3>& minimumSubvoxels,
             const std::array<std::int64_t,3>& maximumSubvoxels,
@@ -208,7 +225,9 @@ public:
         {
             mayContainResolvedBoundaryBand_=shape.ResolvedBoundaryBandsIntersectSubvoxelRange(
                 minimumSubvoxels_[2],maximumSubvoxels_[2]);
-            const bool disablePassageComposition = VF_IsL86PassageCompositionDisabled();
+            const bool disablePassageComposition=VF_IsL88PassageCompositionDisabled();
+            const bool disableBoundaryBands=VF_IsL88BoundaryBandsDisabled();
+            if(disableBoundaryBands)mayContainResolvedBoundaryBand_=false;
             mayContainTransitionPassageFade_ = !disablePassageComposition
                 && shape.ResolvedTransitionPassageFadeIntersectsTileXY(
                     minimumSubvoxels_, maximumSubvoxels_);
@@ -930,6 +949,9 @@ public:
 #endif
         (void)X;(void)Y;
         const auto* tileQueries=ActivePassageTileQueries;
+        if(tileQueries&&tileQueries->matches(*this))
+            if(auto* profile=tileQueries->profileStats())
+                ++profile->resolvedBoundaryBandQueries;
         if(tileQueries&&tileQueries->matches(*this))
         {
             if(!tileQueries->mayContainResolvedBoundaryBand())
@@ -2256,9 +2278,11 @@ public:
         // mouth that crosses a wide transition band. Keep that opt-in field whole;
         // its host-rock value already supplies the ceiling and bedrock.
         const bool disablePassageComposition=!nativeLattice
-            &&VF_IsL86PassageCompositionDisabled();
+            &&VF_IsL88PassageCompositionDisabled();
+        const bool disableBoundaryBands=!nativeLattice
+            &&VF_IsL88BoundaryBandsDisabled();
         float boundary=graphDensity;
-        if(!nativeLattice&&!disablePassageComposition)
+        if(!nativeLattice&&!disableBoundaryBands)
         {
             VoxelForgeCore::Linux77Profiler::FScopedPhase l77BandsPhase(
                 VoxelForgeCore::Linux77Profiler::EPhase::Bands);
@@ -3019,10 +3043,21 @@ public:
         // Route validation is world-wide. Detail regions reuse the same authored route data and
         // do not need to repeat the 5,642-point world audit for every entering tile group.
         Substage=Clock::now();
-        if(bValidatePassageRoutes&&!ValidatePassageRoutes())
+        const bool bPassageRoutesValid=!bValidatePassageRoutes||ValidatePassageRoutes();
+        if(!bPassageRoutesValid)
         {
-            Error="compiled shape world contains a solid passage centreline sample";
-            return false;
+            if(VF_IsL88PassageCompositionDisabled()
+                &&!VF_IsL88BoundaryBandsDisabled()
+                &&VF_IsL88AllowPassageAblationWalkabilityFailure())
+            {
+                std::printf("[L88PassageAblation] route walkability failed as expected; "
+                    "continuing only to measure passage-off/bands-on readiness\n");
+            }
+            else
+            {
+                Error="compiled shape world contains a solid passage centreline sample";
+                return false;
+            }
         }
         Stats.PassageValidationSeconds=std::chrono::duration<double>(Clock::now()-Substage).count();
         Built=true;