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+# #265 capture-driven bisection — steep-slope response family
+
+**Status: verdict reached, S1 and S2 both CLEARED for the two concrete
+mined events; real mechanism identified as a pre-existing (frozen-phase)
+architecture, not a Campaign P regression.** This is a research/bisection
+pass; no production code was changed. The harness (committed,
+`tests/AcDream.Core.Tests/Physics/Issue265SteepSlopeCaptureBisectTests.cs`)
+and mining tool (`tools/analyze_265_steep_slope_capture.py`) are permanent;
+the A/B code toggles described below were applied and reverted locally and
+never committed.
+
+## 0. Scope recap
+
+Issue #265 (`docs/ISSUES.md`): after the TS-4-removal-then-revert
+(`2e27d066`+`a8a7d64b`), the live matrix gate (2026-07-30, scenarios 4/5)
+found three symptoms: (a) jumping INTO an uphill slope bounces (retail does
+not), (b) house-roof slides no longer happen, (c) occasional
+stuck-sliding-on-an-edge. Two remaining Campaign-P suspects were named:
+
+- **S1** — `db2889af` ("#116 shape-1"): `BSPQuery.cs` Path-6's `hasSphere1`
+ (head-sphere-only hit while airborne, foot sphere clear) branch changed
+ from a steepness-gated dual path (steep → slide-tangent-then-`Slid`;
+ shallow → `SetCollide`+`Adjusted`) to an unconditional
+ `SetCollisionNormal` + `return Collided`.
+- **S2** — the AP-7 `calc_friction` threshold rewrite (merge `26e0334a`):
+ `0.0` → `0.25`, unconditional into-plane velocity subtraction past the
+ threshold.
+
+## 1. Segment mining
+
+Captures used: `artifacts/matrix-session2-resolve.jsonl` (15,726 records,
+copied from the coordinator worktree's `artifacts/matrix-session2-resolve.jsonl`)
+and `artifacts/matrix-session3-resolve.jsonl` (12,145 records at copy time).
+
+**Session3 is not usable.** Every one of its 12,145 records shows the
+identical position `(60.372223, 9.071998, 79.344925)`, zero velocity, and
+`transientState=3` (Contact|OnWalkable) from tick 0 to tick 12144 — the
+player was standing perfectly still (likely AFK / alt-tabbed) for the
+entire ~7.2-minute capture window. It contains no motion at all and was
+excluded from further analysis.
+
+### 1.1 First pass — strict signature scan (`tools/analyze_265_steep_slope_capture.py`)
+
+Two signatures were scanned for directly on the JSONL fields:
+
+- **Signature A (uphill-jump bounce)**: an airborne record (`bodyBefore`
+ Contact bit clear) with `result.collisionNormalValid=true` and a "steep,
+ non-floor, non-wall" normal (`0.02 < normal.Z < FloorZ=0.6642`), followed
+ by a next-tick upward jump in `bodyBefore.velocity.z` while still
+ airborne.
+- **Signature B (lost-slide / edge-wedge)**: ≥6 consecutive ticks with
+ Contact set but OnWalkable clear (resting against a non-walkable steep
+ surface), a non-trivial requested move each tick, and near-zero net
+ advance.
+
+**Result: 0 hits for both signatures, in both files.** Session2 has only
+38 `collisionNormalValid=true` records total (out of 15,726), and every one
+of them has `normal.Z` in the `[0.85, 1.0]` bucket — i.e. every reported
+collision normal in this capture is CLOSE TO FLAT/floor-like, never in the
+"genuinely steep" `< FloorZ` band my first-pass signature targeted. This is
+an honest negative result for the specific "steep" heuristic; the actual
+symptom-bearing frames, mined below, are moderate-angle (Z≈0.86–0.95,
+above `FloorZ` — walkable BY THE THRESHOLD) and are found by a different
+signature.
+
+### 1.2 Second pass — velocity-annihilation scan
+
+Widened the signature to "a tick where `|horizontal velocity|` before is
+`>2 m/s` and after (next tick) is `<0.05 m/s`, then how long the position
+stays frozen afterward." This found exactly **two events**, both in
+session2:
+
+| idx (0-based) | tick | `|v_horiz|` before | frozen for | cell |
+|---|---|---|---|---|
+| 3153 | 3153 | 8.90 m/s | 46+ ticks (session2 continues past it; not EOF) | `0xAAB30007` |
+| **3434** | **3434** | **18.00 m/s** | **12,292 ticks — to EOF** | `0xAAB40011` |
+
+**Event at idx 3433/3434 (the primary oracle for this pass), full trace**
+(`records[3415..3434+41]`, printed via ad-hoc Python — see
+`tools/analyze_265_steep_slope_capture.py` for the reusable scanner):
+
+- Ticks 3415–3432: clean ballistic fall. `vBefore = (11.15, 14.13, vz)`
+ with `vz` accumulating from ‑16.72 to ‑23.14 (pure gravity, no further
+ horizontal drive — a jump/leap with residual momentum, exactly the kind
+ of trajectory the oracle plan's §1.3 predicted would NOT hit the
+ TS-4 degenerate case). `Z` falls from 92.79 to 79.90.
+- **Tick 3433 (the landing):** `result.collisionNormalValid=true`,
+ `result.collisionNormal=(0.2857143, 0.42857143, 0.85714287)` — exactly
+ `(2,3,6)/7`, a REAL polygon normal (not the `UnitZ` degenerate default).
+ `result.isOnGround=true`. `bodyAfter.contactPlaneValid=true`,
+ `bodyAfter.walkablePolygonValid=true`, `bodyAfter.walkableVertices` = the
+ triangle `(240,0,88), (264,0,80), (264,24,68)` — `normal.Z=0.857`, well
+ ABOVE `PhysicsGlobals.FloorZ` (0.6642): **a legitimately walkable roof
+ slope, not the "steep, non-walkable" case either S1 or the original TS-4
+ shortcut ever targeted.** `bodyAfter.velocity` is UNCHANGED
+ `(11.15,14.13,‑23.14)` — confirms (see `PhysicsEngine.cs:1489`, capture
+ fires inside `ResolveWithTransition`, before any caller-side velocity
+ response) that neither `calc_friction` nor `HandleAllCollisions` ran yet.
+- **Tick 3434 (the very next resolve call):** `input.currentPos ==
+ input.targetPos` (ZERO requested motion this tick — the previous frame's
+ integration already produced zero displacement). `bodyBefore.velocity =
+ (0, 0, 0)` — **already fully zeroed by the time THIS resolve call even
+ starts.** `transientState=7` (Contact|OnWalkable|Sliding). Every
+ subsequent record (12,292 of them, to the literal end of the file) is
+ byte-identical: same position, same zero velocity, same
+ `transientState=7`.
+
+**Event at idx 3152/3153** is the same shape at a shallower ~18° roof edge
+(`normal≈(0,0.32,0.95)`): the player glides/climbs cleanly along the edge
+for ~140 ticks (idx 3016–3152, gaining ~10 m of Z — this portion is
+healthy behavior), then at idx 3153 horizontal velocity is forced to
+exactly zero in one tick and the position freezes for the rest of the
+examined window.
+
+**Both events are the SAME shape**: a real, correct, non-default collision
+normal is recorded on the landing tick; on the very next tick the mover's
+full horizontal velocity has already vanished and the position never
+changes again. This is what the user experiences as "roof slides no
+longer happen" (symptom b) and "occasional stuck-sliding-on-an-edge"
+(symptom c). Neither event's landing surface is steep by `FloorZ` — both
+are moderate, walkable-by-threshold roof pitches.
+
+## 2. Replay harness
+
+`Issue265SteepSlopeCaptureBisectTests.cs` builds a synthetic
+`PhysicsEngine` containing ONE polygon — the exact real triangle recovered
+from record 3433's `bodyAfter.walkableVertices` — registered via
+`ShadowObjectRegistry`, then replays the EXACT real captured ballistic
+state (position + velocity, record index 3415) forward with real gravity
+at 30 Hz, calling `PhysicsEngine.ResolveWithTransition` every tick exactly
+like `PlayerMovementController` does at the Core boundary. Once the mover
+reports `IsOnGround`, the harness keeps REQUESTING the same forward
+velocity every tick (simulating held input) — this is deliberate: it turns
+the harness from "replay what the live game did" (which trivially
+reproduces the freeze, since the live game's own subsequent inputs were
+already zero — see §4) into "does the physics engine itself allow
+continued advance across this surface," which is the actual question S1
+and S2 bear on.
+
+### 2.1 Harness commissioning (three real bugs found and fixed while building it — kept as code comments)
+
+1. `ShadowObjectRegistry.Register`'s broad-phase culls by distance from
+ `worldPos`. Registering at the literal real-world coordinates (X≈256)
+ while querying at world origin put the polygon ~264 units away — the
+ very first run found **zero collisions at all**. Fixed by re-anchoring
+ the whole synthetic scene (triangle + approach trajectory) at the
+ triangle's centroid.
+2. `CellTransit.BuildShadowCellSet`'s outdoor flood
+ (`CellTransit.AddAllOutsideCells`) treats world position as
+ landblock-local (an anchor-frame convention shared with
+ `Ts4SteepRoofWedgeCaptureTests`/`DoorBugTrajectoryReplayTests`, active
+ whenever `CellGraph.TryGetTerrainOrigin` has no real terrain to
+ consult). The real-world coordinates (X≈256) are outside the valid
+ `[0,192)` per-landblock range even after centroid re-anchoring picked a
+ bad cell id — still zero collisions.
+3. `LandDefs.AdjustToOutside` (inside the flood) **silently re-derives**
+ the actual `(lx,ly)` grid cell from the sphere's real position and
+ corrects a mismatched seed rather than honoring the literal
+ `seedCellId` passed to `Register` — an arbitrary chosen cell id
+ (`0x00000011`) registered successfully (`TotalRegistered=1`) but
+ `GetObjectsInCell(0x00000011)` came back empty; the entity had actually
+ landed in cell `0x00000001` (the canonical grid-(0,0) cell, matching
+ the re-anchored centroid). Switching the harness's cell id to
+ `0x00000001` fixed it.
+
+These are documented in the test file's code comments in case another
+harness hits the same three traps.
+
+## 3. A/B outcomes
+
+### (i) HEAD vs (ii) S1-reverted
+
+The S1 revert (`BSPQuery.cs`'s `hasSphere1` branch restored to the
+pre-`db2889af` steepness-gated dual path, mirroring the still-current
+`sphere0` branch — applied locally, verified `git diff --stat` clean
+before and after, never committed) produced **byte-identical output** to
+HEAD for the full 80-tick replay: same landing tick (19), same clean
+44-tick glide (ticks 20–62, `adv=0.5149` every tick, `cnv=false`), same
+freeze at tick 63 (`adv=0.0000` for 16+ consecutive ticks, capped by the
+harness's tick budget — it would continue indefinitely), same recorded
+`collisionNormal=(-0.958,0.128,0.256)` from that point on.
+
+**Why they're identical — confirmed by diagnostic instrumentation**
+(`PhysicsDiagnostics.ProbeIndoorBspEnabled`/`ProbeBuildingEnabled`, the
+`[path-dispatch]`/`[path5-diag]` probes `db2889af` itself added): across
+the entire 80-tick replay, **`hit1=True` never appears once.** The two
+`[path-dispatch] ... collide=True ... contact=False ...` lines (Path 6
+firing during the airborne approach) are followed by
+`insertType=Placement` (Phase 3's walkable-landing retry succeeding) —
+this is the STILL-UNCHANGED `sphere0` (foot) branch's graceful
+`SetCollide`→`Adjusted`→Phase-3-Placement chain, not the `hasSphere1`
+branch S1 touched. Once grounded, every subsequent Path-5 dispatch reports
+`hit0=False hitPoly0=False` then `hit1=False hitPoly1=False` — a genuinely
+clean glide with no collision at all, which is why the S1 edit (which only
+fires inside `if (hit1 || hitPoly1 is not null)`) never executes for this
+trajectory. **S1's site is provably unreached by the real mined
+trajectory that produced the freeze.** Reverting code that never runs
+cannot change the outcome — this is not a coincidence, it's the direct
+mechanical explanation.
+
+### (iii) S2 toggle
+
+**Not run as a harness A/B — proven inert by static analysis instead.**
+`grep -rn "\.calc_friction(" src/` returns **zero production call sites** —
+the only callers of `PhysicsBody.calc_friction` in the entire repository
+are its own unit tests (`tests/AcDream.Core.Tests/Physics/PhysicsBodyTests.cs`).
+`PlayerMovementController.cs` mentions it only in a code comment
+(line ~2021, "friction next frame") — it is never invoked. Neither
+`ResolveWithTransition` nor `PlayerMovementController`'s tick loop calls
+`calc_friction` anywhere. **S2's threshold value (0.0 vs 0.25) cannot
+affect any live or replayed behavior, full stop** — there is no toggle to
+run because there is no live code path to toggle.
+
+### (iv) Both reverted
+
+Follows immediately from (ii) and (iii): with S1 reverted producing
+byte-identical output to HEAD, and S2 provably inert, the "both" variant
+is mathematically identical to (ii), which is identical to (i). No
+separate run was needed.
+
+### A/B summary table
+
+| Variant | Landing tick | Clean glide (ticks 20-62) | Freeze at tick 63+ | Notes |
+|---|---|---|---|---|
+| (i) HEAD | 19 | yes, `adv=0.5149`/tick | yes, frozen forever | `hit1` never true |
+| (ii) S1 reverted | 19 (identical) | yes (identical) | yes (identical) | S1's branch unreached |
+| (iii) S2 toggle | n/a | n/a | n/a | dead code, no call sites |
+| (iv) both | 19 (identical) | yes (identical) | yes (identical) | follows from (ii)+(iii) |
+
+## 4. The actual mechanism (found by hand-tracing the live capture against `PlayerMovementController.cs`, independently confirming it explains BOTH mined freeze events exactly)
+
+Neither S1 nor S2 touch velocity. The full-zero-in-one-tick signature
+(§1.2) is produced by two pre-existing, Campaign-P-independent pieces
+working in sequence:
+
+1. **The landing tick** (`PlayerMovementController.cs`, the
+ `if (resolveResult.IsOnGround && _body.Velocity.Z <= 0f)` block):
+ Contact+OnWalkable are set, and — because `Velocity.Z < 0` — ONLY the
+ Z component is hand-zeroed: velocity becomes `(11.15, 14.13, 0)`.
+ `PhysicsObjUpdate.HandleAllCollisions` then runs with `shouldReflect =
+ true` (the mover was airborne the frame before: `prevOnWalkable=false`
+ makes `shouldReflect` unconditionally true regardless of the new
+ grounded state — see `PhysicsObjUpdate.cs:163-164`). But
+ `dot(velocity, collisionNormal) = dot((11.15,14.13,0),
+ (0.286,0.429,0.857)) ≈ +9.25` — POSITIVE (moving away from, not into,
+ the surface, because the Z component that would have made it negative
+ was just zeroed) — so the `if (dot < 0f)` reflection guard
+ (`PhysicsObjUpdate.cs:177`) never fires. Velocity survives this tick as
+ `(11.15, 14.13, 0)`.
+2. **The very next tick** (`PlayerMovementController.cs:1868-1882`, added
+ 2026-07-20 by `f961d700`, "port retail complete object frame
+ pipeline" — R6, well before Campaign P):
+ ```csharp
+ if (_body.OnWalkable)
+ {
+ float savedWorldVz = _body.Velocity.Z;
+ if (hasAnimationRootMotion)
+ {
+ _body.Velocity = new Vector3(0f, 0f, savedWorldVz);
+ }
+ ...
+ }
+ ```
+ `OnWalkable` is now true (set last tick), so this runs UNCONDITIONALLY,
+ EVERY tick, for as long as the mover stays grounded: it zeros
+ `Velocity.X/Y` to exactly zero (`savedWorldVz` is already 0 from step
+ 1), replacing physics-integrated horizontal velocity with
+ animation-root-motion-driven displacement (`pmDelta.Origin`, populated
+ from `_advanceAnimationRootMotion`, which only produces nonzero
+ displacement when a movement key is actually held). **With no key held
+ at the instant of landing, `pmDelta.Origin` stays `Vector3.Zero` forever,
+ and the mover never advances again.** This reproduces `bodyBefore.velocity
+ = (0,0,0)` at record 3434 exactly, and the permanent freeze that follows.
+
+This is the R6 "local player animation-owned grounded movement"
+architecture: once grounded, walking is driven entirely by held-input +
+animation root motion, not by integrating `Velocity`. It has been in
+place since 2026-07-20 — **ten days before Campaign P and the TS-4
+removal/revert (2026-07-29/30)** — and is explicitly a frozen-phase
+architecture per the milestones doc (R6 shipped; the freeze list bars
+rework without a dedicated brainstorm). It is retail-DIVERGENT in one
+specific way that matters here: retail does not need a held key to carry
+residual momentum across a landing — a fast fall onto a walkable-but-
+sloped surface should glide/sled per `docs/ISSUES.md` #166 ("Slope-landing
+glide + bounce absent... acdream lands clean and dead"), which is filed,
+open, and explicitly OUT OF SCOPE for this pass (the `Sledding`
+`PhysicsStateFlags` bit that would let `calc_friction`'s Sledding-gated
+overrides engage is never set anywhere in the codebase — a separate,
+already-tracked gap).
+
+`git log --oneline -3 -- src/AcDream.Core/Physics/PhysicsObjUpdate.cs`
+confirms `HandleAllCollisions` itself was also last touched by an
+unrelated water fix (AP-10, `cc8d57a2`) — Campaign P did not modify it
+either.
+
+## 5. Re-reading the oracle plan's S1 claim against the mined evidence
+
+The task asked specifically: if S1's port is faithful but its SCOPE is
+wrong, say exactly that. Re-checked against
+`docs/research/2026-07-30-ts4-116-oracle-plan.md` §2.3-§2.4 and §3, plus
+this pass's own finding:
+
+- **S1's port IS faithful in isolation.** Its cited sources
+ (`acclient_2013_pseudo_c.txt:323824-323834`, ACE `BSPTree.cs:221-230`)
+ are an exact structural match — not a BN misdecompile, not a citation
+ error. This was independently re-verified by reading the current
+ `BSPQuery.cs:2259-2302` against the same two sources again this pass; no
+ discrepancy found.
+- **S1's scope is narrower than any symptom this pass could reproduce —
+ not wider.** The oracle plan's own Addendum 2 (§"implementation
+ session") already found this exact pattern once, for the door
+ tick-22760 capture: the hypothesis assumed the "not-yet-in-Contact"
+ branch would fire, but the mover was actually GROUNDED (`Contact` set),
+ so dispatch went to Path 5 instead and S1's site was never reached. This
+ pass finds the SAME pattern a second, independent time, for a
+ DIFFERENT capture (a genuine airborne fall, not a grounded door-push):
+ the foot sphere (`sphere0`) reaches the rising/sloped polygon at the
+ same moment as or before the head sphere, so the `if (hit0 ||
+ hitPoly0 is not null)` branch above `hasSphere1`'s check fires first and
+ RETURNS before `hasSphere1`'s block is ever entered
+ (`BSPQuery.cs:2188` gates the whole `hasSphere1` block behind falling
+ through that first `if`). `hit1=True` never appears once across the
+ entire 80-tick replay, confirming this mechanically, not just by
+ inference.
+- **Two independent capture families (a grounded door-push, and now an
+ airborne fall-and-land) both show S1's site going unreached.** This
+ strongly suggests S1's real-world reach is much narrower than its
+ authors worried — for it to matter, a trajectory would need the FOOT
+ sphere to stay clear while the HEAD sphere alone grazes a polygon
+ during an airborne (not-yet-grounded) frame — e.g. jumping up under an
+ overhang, or clipping a roof's underside while airborne with the feet
+ still below the eave line. **Neither of #265's two concrete mined
+ freeze events is that geometry.** S1 remains a real, citable, retail-
+ faithful port-accuracy improvement and should NOT be reverted on this
+ evidence (it fixes a genuine, if narrow, divergence for whenever its
+ exact geometry does occur) — but it is not implicated in the symptoms
+ #265 was filed against.
+
+## 6. Named culprit
+
+**Neither S1 nor S2. This is S3 — but not a NEW regression: it is the
+pre-existing, frozen-phase R6 "grounded movement is animation-root-motion-
+owned" architecture (`PlayerMovementController.cs:1868-1882`, landed
+2026-07-20 via `f961d700`, ten days before Campaign P), which
+unconditionally zeros the mover's horizontal `Velocity` every tick once
+`OnWalkable` is true, with no gate on approach speed, surface steepness,
+or how the mover became grounded.** It was mechanically traced, tick by
+tick, against BOTH of #265's concrete mined freeze events and reproduces
+the observed `(0,0,0)` velocity and permanent position-freeze exactly.
+
+This explains symptom (b) (roof slides don't continue — there is no
+"continue," walking requires a held key that landing doesn't supply) and
+symptom (c) (stuck at the landing spot indefinitely) completely, for both
+mined events. It does **not**, by itself, explain symptom (a) (the
+"bounce" on jumping into an uphill slope) — that is a property of
+`PhysicsObjUpdate.HandleAllCollisions`'s elastic reflection (`shouldReflect
+= true` whenever the mover was NOT already on walkable ground before AND
+after the resolve — `PhysicsObjUpdate.cs:163-164`), which is ALSO
+pre-existing (from the #182 rebuild, well before Campaign P) and fires for
+ANY valid `CollisionNormal` reported while airborne, regardless of which
+BSPQuery branch produced it. This pass did not find or replay a concrete
+"bounce" event in the captures (the closest analogue — the tick-63
+edge-freeze in the replay harness — shows a suspicious secondary normal,
+`(-0.958,0.128,0.256)`, unrelated to the registered polygon's own plane
+normal, with Path-5 diagnostics showing no fresh BSP hit during the frozen
+ticks; this smells like stale `ContactPlane`/`CollisionNormal` persistence
+at a polygon boundary rather than a fresh reflection, and — like the S1
+revert — was unaffected by reverting S1. It is flagged as a genuine open
+question, not resolved this pass, and may be an artifact of this
+harness's single small (24-unit) synthetic triangle rather than a general
+production bug; a real roof's continuous mesh would not present a "run off
+the edge of a 24-unit patch" boundary at all. See §7).
+
+## 7. What's still open (do not guess, per CLAUDE.md)
+
+1. **Why does the user perceive this as a NEW regression coinciding with
+ Campaign P**, if the freeze mechanism (§4) predates it by ten days and
+ is unaffected by S1/S2? Two honest hypotheses, neither confirmed:
+ (a) the roof-jump/fall scenario was specifically exercised for the
+ FIRST time as part of the Campaign P visual matrix (scenarios 4/5),
+ surfacing a pre-existing bug rather than a new one; (b) a genuinely
+ separate, not-yet-isolated interaction exists. Resolving this needs
+ either a live retail-vs-acdream side-by-side of the EXACT same
+ fall-and-land-with-no-input scenario pre-Campaign-P (to confirm the
+ freeze is not new), or a fresh capture of the user's ACTUAL "roof
+ slide" repro (holding a movement key throughout, not a passive fall) to
+ see whether the animation-root-motion path (which DOES produce
+ displacement while a key is held) also fails.
+2. **The tick-63 edge freeze** in this pass's own harness (§6, closing
+ parenthetical) — a `CollisionNormal` unrelated to the registered
+ polygon's plane, reported while Path-5 diagnostics show no fresh hit.
+ Candidate next step: extend the harness's synthetic roof to several
+ contiguous polygons (removing the small-triangle-edge artifact) and
+ re-run; if the freeze persists on a much larger interior region, it is
+ a real, separate, third mechanism worth its own root-cause pass
+ (possibly `SpherePath.PrecipiceSlide`'s edge-crossing test, or stale
+ `LastKnownContactPlane` persistence — NOT yet confirmed, do not guess
+ further).
+3. **Symptom (a)'s bounce** was analyzed only by static code reading
+ (`HandleAllCollisions`'s reflection math), not independently reproduced
+ against a live-captured bounce event — none of the 38
+ `collisionNormalValid=true` records in session2 showed the "airborne,
+ then a large upward `Velocity.Z` jump next tick" signature this pass's
+ Signature-A scanner looked for. A fresh capture specifically of a
+ jump-into-an-upward-slope repro (ideally with `ACDREAM_PROBE_RESOLVE=1`
+ or `ACDREAM_CAPTURE_RESOLVE` active for the WHOLE approach, not just
+ the moment of impact) would let Signature A actually fire and give a
+ concrete oracle the way records 3433/3434 did for the freeze.
+
+## 8. Recommended fix direction
+
+**Do not touch S1** (`BSPQuery.cs`'s `hasSphere1` branch) — it is a real,
+narrow, retail-faithful improvement unrelated to #265's two concrete mined
+events; reverting it would only reopen the #116 shape-1 door-collision gap
+it was written to close, for zero benefit here.
+
+**Do not spend further effort on S2** (`calc_friction`'s threshold) until
+it is actually wired into a live code path — right now changing it changes
+nothing observable, in either direction. If/when `calc_friction` IS wired
+into `PlayerMovementController` (a legitimate future piece of closing #166,
+the downhill-sled issue), the 0.25 threshold becomes live and worth
+re-testing at that point, not before.
+
+**The real target is #166 + the grounded-movement architecture (§4/§6),
+which is a frozen-phase design question, not a quick fix.** Per CLAUDE.md's
+"the roadmap and the observed bug disagree → brainstorm before writing
+code" rule, this needs `superpowers:brainstorming` before any
+implementation: does acdream want a genuine physics-driven momentum carry
+across a landing (porting the retail `Sledding` state + a real
+`calc_friction` wiring), or a narrower "if IsOnGround at high incoming
+speed, force a minimum coast distance regardless of held input" patch? The
+former is retail-faithful and already has a filed target (#166); the
+latter would be a new, unfiled design decision. Either way, this is
+explicitly NOT an S1/S2 code change — it is new work against
+`PlayerMovementController.cs`'s grounded-movement block and
+`PhysicsBody.calc_friction`'s wiring, gated on a design conversation, not a
+revert.
diff --git a/tests/AcDream.Core.Tests/Physics/Issue265SteepSlopeCaptureBisectTests.cs b/tests/AcDream.Core.Tests/Physics/Issue265SteepSlopeCaptureBisectTests.cs
new file mode 100644
index 00000000..da53acf6
--- /dev/null
+++ b/tests/AcDream.Core.Tests/Physics/Issue265SteepSlopeCaptureBisectTests.cs
@@ -0,0 +1,366 @@
+using System.Collections.Generic;
+using System.Numerics;
+using DatReaderWriter.Enums;
+using DatReaderWriter.Types;
+using AcDream.Core.Physics;
+using Xunit;
+using Xunit.Abstractions;
+
+namespace AcDream.Core.Tests.Physics;
+
+///
+/// Issue #265 capture-driven bisection: "Steep-slope response set" (uphill-jump
+/// bounce, lost roof slide, edge wedge). This harness replays a REAL trajectory
+/// mined from a live capture (ACDREAM_CAPTURE_RESOLVE,
+/// artifacts/matrix-session2-resolve.jsonl, records 3415-3434) through a
+/// synthetic single-polygon built from the EXACT
+/// polygon the live capture landed on
+/// (bodyAfter.walkableVertices: (240,0,88),(264,0,80),(264,24,68),
+/// normal (2,3,6)/7 = (0.2857,0.4286,0.8571) — a moderate, WALKABLE-BY-THRESHOLD
+/// roof slope, normal.Z=0.857 > PhysicsGlobals.FloorZ (0.6642)).
+///
+///
+/// Live symptom this reproduces (mining evidence): the player falls
+/// (v ≈ (11.15, 14.13, -23.14) m/s at landing) onto this roof slope. Live capture
+/// record 3433 shows collisionNormalValid=true, the correct real polygon
+/// normal, and walkablePolygonValid=true — a legitimate walkable landing.
+/// Record 3434 (the very next tick) shows the body FROZEN: velocity forced to
+/// exactly (0,0,0), transientState=7 (Contact|OnWalkable|Sliding), and the
+/// position stays byte-identical for the remaining 12,292 captured ticks (to
+/// the end of the file) — i.e. the player never moves again. A second,
+/// independent instance of the same shape appears at records 3153-3199+ (a
+/// shallower ~18° roof edge, frozen for 46+ captured ticks). Full mining
+/// evidence: docs/research/2026-07-30-265-capture-bisect.md.
+///
+///
+///
+/// Candidate mechanism (S1): commit db2889af ("#116 shape-1")
+/// changed BSPQuery.cs's Path-6 hasSphere1 (head-sphere-only hit
+/// while airborne, foot sphere clear) branch from a steepness-gated
+/// SetCollide→Adjusted (shallow, Z≥FloorZ) / slide-tangent-then-Slid (steep,
+/// Z<FloorZ) dual path — IDENTICAL in shape to the still-unchanged sphere0
+/// (foot) branch a few lines above it — to an UNCONDITIONAL
+/// SetCollisionNormal + return Collided, regardless of steepness. A
+/// `Collided` return short-circuits TransitionalInsert immediately
+/// (if (transitState == TransitionState.Collided) return
+/// TransitionState.Collided;) — it never reaches the retry loop's Phase 3
+/// (if (sp.Collide) ...DoCheckWalkable...Placement retry...), which is
+/// the ONLY place a shallow/walkable head-sphere hit can smoothly commit to a
+/// real ContactPlane + OnWalkable via the SetCollide+Adjusted
+/// path. This test's real captured polygon has normal.Z=0.857 — well
+/// ABOVE FloorZ (0.6642) — so it is the SHALLOW case, not the steep one;
+/// S1 removed the steepness branch entirely, so this shallow graze now takes
+/// the SAME hard-stop path a steep hit would.
+///
+///
+///
+/// Method: integrates the EXACT
+/// captured ballistic state (position + velocity) from record 3415 forward
+/// with real gravity (dt=1/30s, matching retail's tick rate), calling
+/// every tick exactly like
+/// does at the
+/// Core boundary (this harness intentionally stops at that boundary — it does
+/// NOT call PhysicsObjUpdate.HandleAllCollisions or model the R6
+/// animation-root-motion grounded-movement zeroing, both of which live outside
+/// Core and are confirmed NOT part of the S1/S2 candidate set — see the research
+/// doc). Once the mover reports IsOnGround, the harness keeps REQUESTING
+/// forward motion each tick (simulating held input) so a genuine "does the
+/// engine allow continued advance across this surface" signal is observable,
+/// rather than trivially replaying the live capture's own (already-frozen,
+/// no-input) subsequent targets.
+///
+///
+///
+/// A/B protocol (see the research doc for the executed results): this
+/// same test is run unmodified against (i) HEAD, (ii) BSPQuery.cs with
+/// the S1 sphere1 branch reverted to mirror the still-current sphere0 shape
+/// (local, uncommitted diagnostic edit), (iii) production unaffected by S2
+/// (calc_friction's AP-7 threshold) since S2 has zero call sites outside its
+/// own unit test — confirmed by grep -rn "\.calc_friction(" src/ — so no
+/// S2 toggle is needed for THIS harness, and (iv) both. The per-tick dump
+/// ( list, printed via )
+/// is the diff target.
+///
+///
+public class Issue265SteepSlopeCaptureBisectTests
+{
+ private readonly ITestOutputHelper _out;
+ public Issue265SteepSlopeCaptureBisectTests(ITestOutputHelper output) => _out = output;
+
+ // ── Real captured polygon (bodyAfter.walkableVertices, record 3433) ──────
+ // artifacts/matrix-session2-resolve.jsonl, tick 3433, cell 0xAAB40011.
+ // normal = cross(v1-v0, v2-v0) normalized = (2,3,6)/7 exactly.
+ private static readonly Vector3 RoofV0 = new(240f, 0f, 88f);
+ private static readonly Vector3 RoofV1 = new(264f, 0f, 80f);
+ private static readonly Vector3 RoofV2 = new(264f, 24f, 68f);
+
+ // Outdoor cell suffix MUST be < 0x0100 (retail's indoor/outdoor LandCell
+ // convention — CellTransit.BuildShadowCellSet branches on it) and its
+ // block index must be (0,0) so that the flood's landblock-local grid math
+ // (CellTransit.AddAllOutsideCells, an 8x8 24-m-cell grid over the 192-m
+ // landblock) treats this harness's coordinates as directly landblock-local
+ // — CellGraph.TryGetTerrainOrigin has no registered terrain for this
+ // synthetic landblock so it Zero-falls-back, meaning raw "world" position
+ // IS landblock-local position (documented anchor-frame convention, same
+ // one Ts4SteepRoofWedgeCaptureTests/DoorBugTrajectoryReplayTests rely on).
+ // The harness's very first run registered the shadow object at the REAL
+ // captured world coordinates (X≈256) under this convention — 256 is
+ // outside the valid [0,192) landblock-local range, so the flood produced
+ // an empty cell set and the object was silently never registered at all
+ // (zero collisions the whole replay). Fix: re-anchor the entire synthetic
+ // scene (triangle + approach trajectory) at the roof centroid so every
+ // coordinate here is small and landblock-local (see the research doc's
+ // harness-commissioning note).
+ // Suffix 0x0001 is the canonical (gridX=0, gridY=0) outdoor LandCell — the
+ // grid cell whose local origin is (0,0) — matching this harness's
+ // re-anchored roof centroid at world (0,0,0) (see the note above). An
+ // earlier attempt used suffix 0x0011; CellTransit.AddAllOutsideCells'
+ // LandDefs.AdjustToOutside re-derives the (lx,ly) grid cell from the
+ // sphere's ACTUAL position and silently corrects a mismatched seed, so the
+ // registration landed in cell 0x00000001 regardless of the literal seed
+ // passed — GetObjectsInCell(0x00000011) found nothing (see the research
+ // doc's harness-commissioning note).
+ private const uint CellId = 0x00000001u;
+ private const uint LandblockId = 0x00000000u;
+ private const uint SyntheticGfxId = 0x265BEEF1u;
+
+ private const int TicksPerSecond = 30;
+ private const float Gravity = -9.8f;
+ private const float SphereRadius = 0.48f; // production human Setup 0x02000001
+ private const float SphereHeight = 1.835f; // production human Setup 0x02000001
+
+ // Real captured state, record index 3415 (session2, tick 3415) — 18 ticks
+ // before the landing/freeze at record 3433/3434. vx/vy are constant across
+ // this whole approach (pure ballistic fall, no further horizontal drive).
+ // Re-anchored: subtract RoofCentroid from the real captured world position
+ // (see the landblock-local note above) — the RELATIVE approach geometry
+ // (distance, direction, velocity) is preserved exactly.
+ private static readonly Vector3 ApproachStartPosReal = new(244.59f, -0.81f, 92.79f);
+ private static readonly Vector3 ApproachStartVel = new(11.1509495f, 14.129979f, -16.72f);
+
+ // ShadowObjects.Register's broad-phase culls candidates by distance from
+ // `worldPos` within `radius` — registering at Vector3.Zero with the real
+ // (far-from-origin) captured world coordinates put the polygon ~264 units
+ // from the query point, well outside any sane radius, so the very first
+ // run of this harness found ZERO collisions at all (see the research doc's
+ // "harness commissioning" note). Fix: register the entity at the
+ // triangle's centroid and express the polygon in LOCAL coordinates
+ // relative to that centroid (identity rotation, scale 1 — world = local +
+ // worldPos reconstructs the exact real-world triangle).
+ private static readonly Vector3 RoofCentroid = (RoofV0 + RoofV1 + RoofV2) / 3f;
+
+ private static PhysicsEngine MakeRoofEngine()
+ {
+ var resolved = new Dictionary();
+ var verts = new[] { RoofV0 - RoofCentroid, RoofV1 - RoofCentroid, RoofV2 - RoofCentroid };
+ var normal = Vector3.Normalize(Vector3.Cross(verts[1] - verts[0], verts[2] - verts[0]));
+ float d = -Vector3.Dot(normal, verts[0]);
+ resolved[1] = new ResolvedPolygon
+ {
+ Vertices = verts,
+ Plane = new Plane(normal, d),
+ NumPoints = 3,
+ SidesType = CullMode.None,
+ };
+
+ var leaf = new PhysicsBSPNode
+ {
+ Type = BSPNodeType.Leaf,
+ BoundingSphere = new Sphere { Origin = Vector3.Zero, Radius = 30f },
+ };
+ leaf.Polygons.Add(1);
+
+ var heights = new byte[81];
+ var heightTab = new float[256];
+ for (int i = 0; i < 256; i++) heightTab[i] = -1000f; // terrain never interferes
+
+ var engine = new PhysicsEngine();
+ engine.AddLandblock(
+ LandblockId,
+ new TerrainSurface(heights, heightTab),
+ System.Array.Empty(),
+ System.Array.Empty(),
+ worldOffsetX: 0f, worldOffsetY: 0f);
+
+ var cache = new PhysicsDataCache();
+ var bspTree = new PhysicsBSPTree { Root = leaf };
+ var physics = new GfxObjPhysics
+ {
+ BSP = bspTree,
+ PhysicsPolygons = new Dictionary(),
+ Vertices = new VertexArray(),
+ Resolved = resolved,
+ BoundingSphere = new Sphere { Origin = Vector3.Zero, Radius = 30f },
+ };
+ cache.RegisterGfxObjForTest(SyntheticGfxId, physics);
+ engine.DataCache = cache;
+
+ // ShadowObjectRegistry is the per-cell shadow-object index (BR-7/A6.P4):
+ // Register() FLOODS from a SEED CELL outward and registers the entity
+ // into the resulting cell set; the query side (GetObjectsInCell) looks
+ // up strictly by the mover's CURRENT cell id. Leaving seedCellId at its
+ // default (0u) makes Register() call DeriveOutdoorSeed(worldPos, ...),
+ // which computes its OWN outdoor landcell id from world position — for
+ // the real captured coordinates used here (worldPos.X=256, well outside
+ // landblock 0xAAB40000's own 192 m span) that derives to a DIFFERENT
+ // cell than the literal CellId this harness resolves against, so the
+ // very first run of this fixture found zero collisions (see the
+ // research doc's harness-commissioning note). Passing seedCellId
+ // explicitly bypasses the derivation and floods from the exact cell
+ // the replay loop queries.
+ engine.ShadowObjects.Register(
+ entityId: SyntheticGfxId,
+ gfxObjId: SyntheticGfxId,
+ worldPos: Vector3.Zero,
+ rotation: Quaternion.Identity,
+ radius: 30f,
+ worldOffsetX: 0f,
+ worldOffsetY: 0f,
+ landblockId: LandblockId,
+ collisionType: ShadowCollisionType.BSP,
+ scale: 1.0f,
+ seedCellId: CellId);
+
+ return engine;
+ }
+
+ public sealed record TickSample(
+ int Tick,
+ Vector3 Pos,
+ float Advance,
+ bool CollisionNormalValid,
+ Vector3 CollisionNormal,
+ bool OnGround,
+ int FrozenStreak);
+
+ ///
+ /// Replays the real captured ballistic approach + landing, then keeps
+ /// REQUESTING forward motion (simulating held input) for
+ /// additional ticks once grounded, to
+ /// see whether the engine allows continued advance across the roof surface
+ /// or wedges in place. Returns one per tick.
+ ///
+ public static List ReplayRealRoofLanding(int postLandingTicks = 60)
+ {
+ var engine = MakeRoofEngine();
+ const float dt = 1f / TicksPerSecond;
+
+ var body = new PhysicsBody { TransientState = TransientStateFlags.Active };
+
+ Vector3 pos = ApproachStartPosReal - RoofCentroid;
+ Vector3 vel = ApproachStartVel;
+ uint cell = CellId;
+ bool grounded = false;
+ int frozenStreak = 0;
+ int ticksSinceGrounded = -1;
+
+ var samples = new List();
+
+ // Budget: enough ticks to cover the ~18-tick ballistic approach plus the
+ // requested post-landing continuation window.
+ int maxTicks = 18 + postLandingTicks + 20;
+
+ for (int tick = 0; tick < maxTicks; tick++)
+ {
+ if (!grounded)
+ vel = new Vector3(vel.X, vel.Y, vel.Z + Gravity * dt);
+ // Once grounded, keep requesting the SAME horizontal advance each
+ // tick (simulating held forward input) — this is the "does a
+ // slide continue" probe. Vertical requested delta is zero (resting
+ // against the surface, not still falling).
+ Vector3 requestedVel = grounded ? new Vector3(vel.X, vel.Y, 0f) : vel;
+ Vector3 target = pos + requestedVel * dt;
+
+ var result = engine.ResolveWithTransition(
+ currentPos: pos,
+ targetPos: target,
+ cellId: cell,
+ sphereRadius: SphereRadius,
+ sphereHeight: SphereHeight,
+ stepUpHeight: 0.6f,
+ stepDownHeight: 1.5f,
+ isOnGround: grounded,
+ body: body,
+ moverFlags: ObjectInfoState.IsPlayer | ObjectInfoState.EdgeSlide,
+ movingEntityId: 0x01000000u);
+
+ float advance = Vector3.Distance(result.Position, pos);
+ if (advance < 0.001f)
+ frozenStreak++;
+ else
+ frozenStreak = 0;
+
+ samples.Add(new TickSample(
+ tick, result.Position, advance,
+ result.CollisionNormalValid, result.CollisionNormal,
+ result.IsOnGround, frozenStreak));
+
+ pos = result.Position;
+ cell = result.CellId;
+ body.Position = pos;
+
+ if (!grounded && result.IsOnGround)
+ {
+ grounded = true;
+ ticksSinceGrounded = 0;
+ }
+ else if (grounded)
+ {
+ ticksSinceGrounded++;
+ if (ticksSinceGrounded >= postLandingTicks)
+ break;
+ }
+ }
+
+ return samples;
+ }
+
+ ///
+ /// Characterization test: dumps the full per-tick trajectory so the A/B
+ /// bisect (this file's class doc) can diff HEAD vs the S1-reverted local
+ /// edit. Always passes — this is a diagnostic capture, matching the
+ /// project's existing LiveCompare_FirstCap_DiagnosticDump-style
+ /// tests. The actual pass/fail verdict is recorded in
+ /// docs/research/2026-07-30-265-capture-bisect.md, not as a
+ /// hardcoded assertion here, because the correct fix shape (and therefore
+ /// the correct future regression assertion) is still being decided.
+ ///
+ [Fact]
+ public void RealCapturedRoofLanding_CharacterizeCurrentBehavior()
+ {
+ PhysicsDiagnostics.ResetForTest();
+ PhysicsDiagnostics.ProbeIndoorBspEnabled = true;
+ PhysicsDiagnostics.ProbeBuildingEnabled = true;
+ try
+ {
+ var samples = ReplayRealRoofLanding();
+
+ int maxFrozen = 0;
+ int landedAtTick = -1;
+ foreach (var s in samples)
+ {
+ maxFrozen = System.Math.Max(maxFrozen, s.FrozenStreak);
+ if (landedAtTick < 0 && s.OnGround) landedAtTick = s.Tick;
+ _out.WriteLine(string.Format(
+ System.Globalization.CultureInfo.InvariantCulture,
+ "t{0,3}: pos=({1:F3},{2:F3},{3:F3}) adv={4:F4} cnv={5} n=({6:F3},{7:F3},{8:F3}) onGround={9} frozen={10}",
+ s.Tick, s.Pos.X, s.Pos.Y, s.Pos.Z, s.Advance,
+ s.CollisionNormalValid, s.CollisionNormal.X, s.CollisionNormal.Y, s.CollisionNormal.Z,
+ s.OnGround, s.FrozenStreak));
+ }
+
+ _out.WriteLine($"=== landedAtTick={landedAtTick} maxFrozenStreak={maxFrozen} totalTicks={samples.Count} ===");
+
+ // Sanity-only assertion: the replay must actually reach the roof
+ // (land) within the ballistic approach window — if this fails the
+ // synthetic fixture itself is wrong, not a physics-engine finding.
+ Assert.True(landedAtTick is >= 0 and < 30,
+ $"Replay never reached the synthetic roof polygon (landedAtTick={landedAtTick}); " +
+ "fixture geometry or approach trajectory needs adjustment before this is a valid oracle.");
+ }
+ finally
+ {
+ PhysicsDiagnostics.ResetForTest();
+ }
+ }
+}
diff --git a/tools/analyze_265_steep_slope_capture.py b/tools/analyze_265_steep_slope_capture.py
new file mode 100644
index 00000000..a79f8e7b
--- /dev/null
+++ b/tools/analyze_265_steep_slope_capture.py
@@ -0,0 +1,234 @@
+#!/usr/bin/env python3
+"""Issue #265 segment miner: steep-slope response family (uphill-jump bounce,
+lost roof slide, edge wedge) from ACDREAM_CAPTURE_RESOLVE JSONL captures.
+
+Companion to tools/analyze_resolve_capture.py (the #182 OK/partial/stuck
+classifier). This script targets the #265 symptom set specifically:
+
+ (a) uphill-jump bounce — jumping INTO an upward slope reflects velocity
+ upward instead of sliding (retail does not bounce here).
+ (b) lost roof slide — a body resting on a steep (non-walkable) roof
+ surface stops advancing instead of gliding/sliding off.
+ (c) edge wedge — the body oscillates near-motionless at a
+ collision point for many consecutive ticks.
+
+Each JSONL record (PhysicsResolveCapture.ResolveCaptureRecord) has:
+ input.{currentPos,targetPos,cellId,...}
+ bodyBefore/bodyAfter (PhysicsBodySnapshot incl. velocity, transientState —
+ bit 0 = Contact, bit 1 = OnWalkable)
+ result.{position,cellId,isOnGround,collisionNormalValid,collisionNormal}
+
+IMPORTANT ordering fact (verified against source, 2026-07-30): capture happens
+INSIDE PhysicsEngine.ResolveWithTransition (PhysicsEngine.cs:1489), so
+bodyAfter reflects state at the end of the resolve call — BEFORE
+PhysicsObjUpdate.HandleAllCollisions runs (that happens later in
+PlayerMovementController, using resolveResult.CollisionNormal directly). So a
+velocity REFLECTION from HandleAllCollisions shows up as a jump in the NEXT
+record's bodyBefore.velocity, not in the current record's bodyAfter.velocity.
+This script's bounce heuristic accounts for that one-tick lag.
+
+Usage: py tools/analyze_265_steep_slope_capture.py capture1.jsonl [capture2.jsonl ...]
+"""
+import sys
+import json
+import math
+
+FLOOR_Z = 0.6642 # PhysicsGlobals.FloorZ — walkable/steep boundary
+CONTACT_BIT = 0x1 # TransientStateFlags.Contact
+WALKABLE_BIT = 0x2 # TransientStateFlags.OnWalkable
+
+STEEP_NORMAL_MIN = 0.02 # exclude near-vertical walls (normal.z ~ 0)
+STEEP_NORMAL_MAX = FLOOR_Z # exclude walkable/floor-like surfaces
+
+BOUNCE_VZ_JUMP = 0.5 # m/s — next-tick upward Z-velocity jump considered a "bounce"
+STALL_EPS = 0.01 # m — position barely advanced
+STALL_MIN_RUN = 6 # consecutive stalled ticks to call it a "lost slide" / wedge
+
+
+def vlen(v):
+ return math.sqrt(v["x"] ** 2 + v["y"] ** 2 + v["z"] ** 2)
+
+
+def vsub(a, b):
+ return {"x": a["x"] - b["x"], "y": a["y"] - b["y"], "z": a["z"] - b["z"]}
+
+
+def dist(a, b):
+ return vlen(vsub(a, b))
+
+
+def load(path):
+ records = []
+ with open(path, "r", encoding="utf-8") as f:
+ for line in f:
+ line = line.strip()
+ if not line:
+ continue
+ try:
+ records.append(json.loads(line))
+ except json.JSONDecodeError:
+ continue
+ return records
+
+
+def is_airborne(bb):
+ return (bb.get("transientState", 0) & CONTACT_BIT) == 0
+
+
+def is_contact_not_walkable(bb):
+ ts = bb.get("transientState", 0)
+ return (ts & CONTACT_BIT) != 0 and (ts & WALKABLE_BIT) == 0
+
+
+def is_steep_normal(n):
+ z = n["z"]
+ return STEEP_NORMAL_MIN < z < STEEP_NORMAL_MAX
+
+
+def find_uphill_bounce_candidates(records, path_label):
+ """Signature A: airborne mover hits a steep (non-floor, non-wall) normal,
+ then the NEXT record's bodyBefore.velocity.z jumps up noticeably while
+ still airborne — the fingerprint of an elastic reflection off a slope
+ (PhysicsObjUpdate.HandleAllCollisions, gated by CollisionNormalValid and
+ shouldReflect=true-while-airborne)."""
+ hits = []
+ for i in range(len(records) - 1):
+ rec = records[i]
+ bb = rec.get("bodyBefore") or {}
+ res = rec.get("result") or {}
+ if not is_airborne(bb):
+ continue
+ if not res.get("collisionNormalValid"):
+ continue
+ n = res.get("collisionNormal") or {"x": 0, "y": 0, "z": 0}
+ if not is_steep_normal(n):
+ continue
+
+ nxt = records[i + 1]
+ nbb = nxt.get("bodyBefore") or {}
+ vz_now = bb.get("velocity", {}).get("z", 0.0)
+ vz_next = nbb.get("velocity", {}).get("z", 0.0)
+ still_airborne_next = is_airborne(nbb)
+
+ if still_airborne_next and (vz_next - vz_now) > BOUNCE_VZ_JUMP:
+ hits.append({
+ "file": path_label,
+ "tick": rec.get("tick"),
+ "index": i,
+ "normal": n,
+ "vz_before": vz_now,
+ "vz_after_next_tick": vz_next,
+ "pos": rec.get("input", {}).get("currentPos"),
+ "cellId": rec.get("input", {}).get("cellId"),
+ })
+ return hits
+
+
+def find_lost_slide_runs(records, path_label):
+ """Signature B: a run of >= STALL_MIN_RUN consecutive ticks where the
+ body is in Contact-but-not-OnWalkable (resting against a steep surface,
+ the retail-faithful state for a roof/slope per the R6/#182 digest), a
+ move was requested each tick, but net advance stays near zero — the
+ "lost roof slide" / edge-wedge fingerprint. Runs adjacent in tick order
+ are merged; only runs of qualifying length are reported."""
+ runs = []
+ i = 0
+ n = len(records)
+ while i < n:
+ rec = records[i]
+ bb = rec.get("bodyBefore") or {}
+ inp = rec.get("input") or {}
+ res = rec.get("result") or {}
+
+ requested = dist(inp.get("targetPos", inp.get("currentPos", {"x":0,"y":0,"z":0})),
+ inp.get("currentPos", {"x": 0, "y": 0, "z": 0}))
+ advanced = dist(res.get("position", inp.get("currentPos", {"x":0,"y":0,"z":0})),
+ inp.get("currentPos", {"x": 0, "y": 0, "z": 0}))
+
+ qualifies = (is_contact_not_walkable(bb)
+ and requested > STALL_EPS
+ and advanced <= STALL_EPS)
+
+ if not qualifies:
+ i += 1
+ continue
+
+ start = i
+ while i < n:
+ rec2 = records[i]
+ bb2 = rec2.get("bodyBefore") or {}
+ inp2 = rec2.get("input") or {}
+ res2 = rec2.get("result") or {}
+ requested2 = dist(inp2.get("targetPos", inp2.get("currentPos", {"x":0,"y":0,"z":0})),
+ inp2.get("currentPos", {"x": 0, "y": 0, "z": 0}))
+ advanced2 = dist(res2.get("position", inp2.get("currentPos", {"x":0,"y":0,"z":0})),
+ inp2.get("currentPos", {"x": 0, "y": 0, "z": 0}))
+ ok2 = (is_contact_not_walkable(bb2) and requested2 > STALL_EPS and advanced2 <= STALL_EPS)
+ if not ok2:
+ break
+ i += 1
+ end = i - 1
+
+ run_len = end - start + 1
+ if run_len >= STALL_MIN_RUN:
+ first = records[start]
+ last = records[end]
+ runs.append({
+ "file": path_label,
+ "start_tick": first.get("tick"),
+ "end_tick": last.get("tick"),
+ "start_index": start,
+ "end_index": end,
+ "length": run_len,
+ "cellId": first.get("input", {}).get("cellId"),
+ "pos_start": first.get("input", {}).get("currentPos"),
+ "pos_end": last.get("input", {}).get("currentPos"),
+ "contactPlaneNormal": (first.get("bodyBefore") or {}).get("contactPlane", {}).get("normal"),
+ })
+ return runs
+
+
+def main(paths):
+ all_bounce = []
+ all_stall = []
+ for path in paths:
+ records = load(path)
+ label = path
+ bounce = find_uphill_bounce_candidates(records, label)
+ stall = find_lost_slide_runs(records, label)
+ all_bounce.extend(bounce)
+ all_stall.extend(stall)
+
+ print(f"=== {path}: {len(records)} records ===")
+ print(f" uphill-jump-bounce candidates: {len(bounce)}")
+ print(f" lost-slide/edge-wedge runs (>= {STALL_MIN_RUN} ticks): {len(stall)}")
+
+ print()
+ print("=== Signature A: uphill-jump bounce (first 15) ===")
+ for h in all_bounce[:15]:
+ print(f" {h['file']} tick={h['tick']} idx={h['index']} cell=0x{h['cellId']:08X} "
+ f"normal=({h['normal']['x']:.3f},{h['normal']['y']:.3f},{h['normal']['z']:.3f}) "
+ f"vz {h['vz_before']:.3f} -> {h['vz_after_next_tick']:.3f} "
+ f"pos=({h['pos']['x']:.2f},{h['pos']['y']:.2f},{h['pos']['z']:.2f})")
+
+ print()
+ print("=== Signature B: lost-slide / edge-wedge runs (first 15, sorted by length desc) ===")
+ all_stall.sort(key=lambda r: -r["length"])
+ for r in all_stall[:15]:
+ cn = r["contactPlaneNormal"] or {"x": 0, "y": 0, "z": 0}
+ print(f" {r['file']} ticks=[{r['start_tick']}..{r['end_tick']}] "
+ f"idx=[{r['start_index']}..{r['end_index']}] len={r['length']} "
+ f"cell=0x{r['cellId']:08X} cpNormal=({cn['x']:.3f},{cn['y']:.3f},{cn['z']:.3f}) "
+ f"pos {r['pos_start']['x']:.2f},{r['pos_start']['y']:.2f},{r['pos_start']['z']:.2f} "
+ f"-> {r['pos_end']['x']:.2f},{r['pos_end']['y']:.2f},{r['pos_end']['z']:.2f}")
+
+ print()
+ print(f"TOTAL: {len(all_bounce)} bounce candidates, {len(all_stall)} stall runs "
+ f"across {len(paths)} file(s).")
+
+
+if __name__ == "__main__":
+ if len(sys.argv) < 2:
+ print(__doc__)
+ sys.exit(1)
+ main(sys.argv[1:])