The player's outdoor cell froze at the last in-block cell the moment they
walked over a landblock boundary (10,449-frame playerCell freeze in the
2026-06-09 capture; whole neighbouring-block interiors unenterable, plus
the running-distortion from the stale render anchor). Root cause: the
add_all_outside_cells port clamped BOTH the candidate proposal and the
find_cell_list containing-cell pick to the current landblock's 8x8 grid,
in a frame that silently assumed the current block sits at world origin.
One step over the line -> zero candidates -> FindCellSet returns
currentCellId forever.
Retail has no such clamp. Its cell math runs in a GLOBAL landcell grid
(lcoord 0..2039 spanning the map): get_outside_lcoord = blockid_to_lcoord
+ floor(blockLocalPos/24) with no bounds besides the map edge, and
lcoord_to_gid re-derives the landblock id from the lcoord's upper bits —
crossings are inherent, never special-cased.
The fix, decomp-cited throughout:
- New AcDream.Core.Physics.LandDefs: in_bounds (pc:68509),
blockid_to_lcoord (pc:68520), inbound_valid_cellid (pc:163438),
gid_to_lcoord (pc:163500), lcoord_to_gid (pc:171859),
get_outside_lcoord (pc:438690), adjust_to_outside (pc:438719).
Cross-checked against ACE LandDefs.cs; three artifacts documented and
avoided: BN's int8_t mis-render of block_y, BN's dropped 192f
BlockLength constant, and ACE add_cell_block's "FIXME!" same-block
guard (an ACE divergence, not retail).
- CellTransit.AddAllOutsideCells rewritten as the faithful sphere
variant (pc:317499 @0x00533630): adjust_to_outside re-seats the
(cell, position) pair cross-block, check_add_cell_boundary (pc:317229)
adds up to 3 neighbours by global lcoord, add_outside_cell (pc:317056)
has no same-block filter. adjust_to_outside failure breaks the sphere
loop (pc:533699 verbatim).
- BuildCellSetAndPickContaining: the outdoor containing-cell pick is now
the global XY-column under the sphere centre (AdjustToOutside), not
the [0,8)-clamped current-prefix reconstruction. Interior-wins order
and current-cell-first hysteresis unchanged.
- World->block-local frame conversion via the landblock origin already
registered in CellGraph (new TryGetTerrainOrigin); Zero fallback
preserves the legacy anchor-block assumption for unregistered terrain.
- Cross-landblock building entry comes free: the candidate snapshot now
contains neighbour-block landcells, so GetBuilding/CheckBuildingTransit
fire for cottages across the line (the capture's one failing entry).
Investigated FIRST per the pickup brief: the b3ce505#98 stopgap gate is
definitively exonerated — it is a collision-object query gate that fires
only for indoor primary cells; no membership path touches
ShadowObjectRegistry.
Tests: 31 new (25 LandDefs conformance incl. capture-geometry goldens
0xA9B40031 -> 0xA9B30038/0xA9B30034 and the northbound return; 4
AddAllOutsideCells cross-block; 3 FindCellSet membership goldens incl.
the non-anchor-frame origin conversion). Full suite: 294+218+420 green;
Core 1369 green + the 4 pre-existing door/#99-era failures + 1 skip
(unchanged from baseline).
Pseudocode + artifact notes:
docs/research/2026-06-09-landdefs-outside-cells-pseudocode.md.
Remaining acceptance: live boundary walk with ACDREAM_PROBE_CELL=1
(ISSUES.md #106).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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