Campaign P Slice P2 step 1 (docs/research/2026-07-30-response-layer-edge-family-pseudocode.md
§2, §6 Step 1/2). The TS-1 register row (retail-divergence-register.md:238)
described work that is already done: SpherePath.PrecipiceSlide,
Transition.CliffSlide, and Transition.EdgeSlideAfterStepDownFailed are real,
tested ports of retail's edge_slide -> precipice_slide/cliff_slide chain
(pc:274316, pc:272397, pc:273001-273090). Its cited :1254 line was stale
stepping-loop code the file moved past.
The one real remaining gap (the back-probe fallback skipping retail's
walkable_check_pos/localspace_sphere recache before its second
precipice_slide call, pc:274318-274326 / 0050b4e0-0050b507) needed no
production code change: a fresh read of SPHEREPATH::get_walkable_pos
(0050a8f0), cache_localspace_sphere (0050c9d0), and set_walkable_check_pos
(00509ce0) shows that machinery exists to re-project a sphere across
retail's PER-CELL local coordinate frames. acdream's SpherePath.WalkableVertices
and GlobalSphere are populated in UNIFIED WORLD SPACE at assignment time
(SetWalkable/SetWalkableTransformed, SetCheckPos/RestoreCheckPos), so both
operands BSPQuery.FindCrossedEdge compares are already commensurable --
retail's recache is a no-op correction under this architecture, and
FindCrossedEdge never reads a sphere radius, so retail's walkable_scale
radius correction has no acdream counterpart either. Documented in-code at
the back-probe site with full citations, and pinned with
EdgeSlideBackProbePrecipiceSlideTests: a walkable polygon rediscovered near
GlobalCurrCenter, tested against GlobalSphere[0] restored to the original
failed target, crosses the edge and slides -- it does not wedge into
Collided (and the inverse case, standing inside the polygon with no edge
crossed, correctly still returns Collided matching retail's own
precipice_slide on a false find_crossed_edge).
TS-1's other two flagged gaps are real acdream-only compensating branches,
not retail reads, and get their own rows rather than being silently
retired alongside it:
- AD-53: CliffSlide's three-source reference-normal fallback chain
(LastWalkablePlane -> LastKnownContactPlane -> world-up) vs retail's
direct last_known_contact_plane.N use. A fresh read of
last_known_contact_plane's maintenance (pc:272659-272668) confirms retail
overwrites it unconditionally every validate_transition pass, including
with a steep plane -- so the fallback chain compensates for AP-4's
incomplete OnWalkable bookkeeping, not a retail-matching read.
- AD-54: the walkable-steepness reroute to CliffSlide before PrecipiceSlide
when the stored walkable polygon itself is steeper than FloorZ. Retail's
raw edge_slide has no such branch; the permissive LandingZ acceptance
that makes this state reachable IS retail-faithful (TS-4's own
BSPTREE::find_collisions citation), but whether retail's outer
transitional_insert retry loop absorbs the resulting COLLIDED_TS some
other way is not yet independently verified -- flagged open in the row.
Physics test suite: 1836 passed, 1 skipped (D4, unrelated to this change).
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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