Adds tests/AcDream.Core.Tests/Physics/CellarUpTrajectoryReplayTests.cs:
a deterministic harness that drives PhysicsEngine.ResolveWithTransition
through N ticks against pre-loaded cell fixtures, capturing per-tick
trajectory points. Pure indoor (no landblock registration needed),
runs 200 ticks in under 100 ms.
The harness MECHANICS work — engine constructs cleanly, DataCache
accepts test fixtures via RegisterCellStructForTest, PhysicsBody
carries ContactPlane state across ticks. 4/4 tests pass, baseline
maintained (1167 + 4 = 1171 + 8 pre-existing failures).
Two real findings surfaced during commissioning, both documented as
passing tests so they don't regress silently:
Finding 1 (Harness_FixtureLimitation_NoRampPolygon): the three
issue-#98 cell fixtures contain ONLY axis-aligned polygons. The
cellar fixture (0xA9B40147) has 37 polys: 8 floor (N=(0,0,1)), 7
ceiling (N=(0,0,-1)), 22 walls. The live capture's CELLAR RAMP
polygon (N ≈ (0, ±0.719, 0.695)) is NOT in any fixture. With no
ramp polygon, the harness can't reproduce the cellar-up climb —
the sphere would walk horizontally across the cellar floor without
ever encountering a slope. Re-capture needed; investigate whether
CellDumpSerializer is skipping polygons or whether the ramp lives
in a cell we didn't dump.
Finding 2 (Harness_Finding_SphereGoesAirborneAtTick1): at the
seeded grounded initial position (sphere center 0.48 m above cellar
floor, ContactPlane = (0,0,1,-90.95), OnWalkable bit set), the
engine reports `hit=yes n=(0,0,1) walkable=False` on tick 1 and
the body's IsOnGround flips to false. Subsequent ticks proceed as
airborne (Y advances, Z stays put — no gravity in the input offset).
Unclear whether this is an engine bug (floor contact classified
as non-walkable collision) or a fixture issue (cellar floor
polygon's containment test mis-firing at the seeded XY). Either
way, the harness now exposes it deterministically.
Net value of this commit: the harness CODE is ready. Once the
fixture issue is solved, fix attempts on #98 (or any trajectory-
dependent bug) iterate in <100 ms instead of 5-minute live-launch
cycles. The "why is this so hard" point #4 from the session-pause
handoff is addressed for everything except the missing-ramp gap.
Test baseline: 1171 (1167 + 4 new) + 8 pre-existing failures.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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