From a2e7a87c25459d336a784009d06fe4288978bdab Mon Sep 17 00:00:00 2001
From: Erik <erik.nihlen@gmail.com>
Date: Wed, 20 May 2026 10:38:53 +0200
Subject: [PATCH] feat(physics): [walk-miss] + [floor-polys] diagnostic
 emissions

Wires the WalkMissDiagnostic aggregator + flag into the two emission
sites per docs/superpowers/specs/2026-05-21-indoor-walk-miss-probe-design.md.

- [walk-miss] (per-frame, MISS branch of TryFindIndoorWalkablePlane):
  foot world+local position, nearest walkable poly with XY-containment
  flag and vertical gap, and LandCell terrain probe at the same XY.
- [floor-polys] (one-shot per cell at cache time): walkable poly id,
  normal Z, local-XY bbox, plane Z at bbox center.

Both gated on ACDREAM_PROBE_WALK_MISS=1. No physics behavior changes.
The live capture at the Holtburg cottage doorway + inn 2nd floor +
cellar descent disambiguates H1 (multi-cell iteration), H2 (probe
distance), H3 (poly absent / walkable_hits_sphere rejection) for
ISSUES #83.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 src/AcDream.Core/Physics/PhysicsDataCache.cs | 18 ++++++++
 src/AcDream.Core/Physics/TransitionTypes.cs  | 45 ++++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/src/AcDream.Core/Physics/PhysicsDataCache.cs b/src/AcDream.Core/Physics/PhysicsDataCache.cs
index ee58a7c..934b3a1 100644
--- a/src/AcDream.Core/Physics/PhysicsDataCache.cs
+++ b/src/AcDream.Core/Physics/PhysicsDataCache.cs
@@ -218,6 +218,24 @@ public sealed class PhysicsDataCache
             Console.WriteLine(System.FormattableString.Invariant(
                 $"[cell-cache] envCellId=0x{envCellId:X8} physicsPolyCount={cellStruct.PhysicsPolygons?.Count ?? 0} resolvedCount={resolved.Count} bspTotalLeafPolys={bspTotalLeafPolys} bspUnmatchedIds={bspUnmatchedIds} {bsStr} portalCount={portals.Count} visibleCells={visibleCellIds.Count} cellBspRoot={(cellStruct.CellBSP?.Root is null ? "null" : "ok")} worldOrigin=({worldOrigin.X:F2},{worldOrigin.Y:F2},{worldOrigin.Z:F2})"));
         }
+
+        if (PhysicsDiagnostics.ProbeWalkMissEnabled)
+        {
+            int walkableCount = 0;
+            foreach (var entry in WalkMissDiagnostic.EnumerateWalkable(
+                         resolved, PhysicsGlobals.FloorZ))
+                walkableCount++;
+
+            Console.Write(System.FormattableString.Invariant(
+                $"[floor-polys] cellId=0x{envCellId:X8} walkableCount={walkableCount}"));
+            foreach (var entry in WalkMissDiagnostic.EnumerateWalkable(
+                         resolved, PhysicsGlobals.FloorZ))
+            {
+                Console.Write(System.FormattableString.Invariant(
+                    $" [id=0x{entry.PolyId:X4} nz={entry.NormalZ:F3} bbox=({entry.BboxMin.X:F2},{entry.BboxMin.Y:F2})..({entry.BboxMax.X:F2},{entry.BboxMax.Y:F2}) planeZ@center={entry.PlaneZAtBboxCenter:F3}]"));
+            }
+            Console.WriteLine();
+        }
     }
 
     /// <summary>
diff --git a/src/AcDream.Core/Physics/TransitionTypes.cs b/src/AcDream.Core/Physics/TransitionTypes.cs
index c941f67..977cd8a 100644
--- a/src/AcDream.Core/Physics/TransitionTypes.cs
+++ b/src/AcDream.Core/Physics/TransitionTypes.cs
@@ -1540,6 +1540,51 @@ public sealed class Transition
                     }
                 }
 
+                if (!walkableHit && PhysicsDiagnostics.ProbeWalkMissEnabled)
+                {
+                    var agg = WalkMissDiagnostic.AggregateNearestWalkable(
+                        cellPhysics.Resolved,
+                        footLocal: localCenter,
+                        floorZ: PhysicsGlobals.FloorZ);
+
+                    // Count walkable polys for the line (cheap re-scan; the
+                    // probe is opt-in so cost is bounded to MISS frames).
+                    int walkableCount = 0;
+                    foreach (var kvp in cellPhysics.Resolved)
+                    {
+                        if (kvp.Value.Plane.Normal.Z >= PhysicsGlobals.FloorZ
+                            && kvp.Value.Vertices.Length >= 3)
+                            walkableCount++;
+                    }
+
+                    // Outdoor terrain probe at the same world XY — the
+                    // "would multi-cell iteration have grounded us?" check.
+                    var terrain = engine.SampleTerrainWalkable(footCenter.X, footCenter.Y);
+                    string terrainPart;
+                    if (terrain is null)
+                    {
+                        terrainPart = "landcell.hasTerrain=false";
+                    }
+                    else
+                    {
+                        var tp = terrain.Value.Plane;
+                        float terrainZ = -(tp.D + tp.Normal.X * footCenter.X
+                                                + tp.Normal.Y * footCenter.Y)
+                                         / tp.Normal.Z;
+                        float terrainDz = footCenter.Z - terrainZ;
+                        terrainPart = System.FormattableString.Invariant(
+                            $"landcell.hasTerrain=true landcell.terrainZ={terrainZ:F3} landcell.dz={terrainDz:+0.000;-0.000;+0.000}");
+                    }
+
+                    string nearestPart = agg.Found
+                        ? System.FormattableString.Invariant(
+                            $"nearest.polyId=0x{agg.PolyId:X4} nearest.containsFootXY={agg.ContainsFootXY} nearest.dz={agg.Dz:+0.000;-0.000;+0.000} nearest.normalZ={agg.NormalZ:F3}")
+                        : "nearest=none";
+
+                    Console.WriteLine(System.FormattableString.Invariant(
+                        $"[walk-miss] cell=0x{sp.CheckCellId:X8} foot.W=({footCenter.X:F3},{footCenter.Y:F3},{footCenter.Z:F3}) foot.L=({localCenter.X:F3},{localCenter.Y:F3},{localCenter.Z:F3}) floorPolyCount={walkableCount} {nearestPart} {terrainPart}"));
+                }
+
                 if (walkableHit)
                 {
                     return ValidateWalkable(