Replace simple Z-snap PhysicsEngine.Resolve with ResolveWithTransition
that uses the ported CTransition sphere-sweep pipeline. Movement is
subdivided into sphere-radius steps, terrain collision tested at each
step with step-down for ground contact maintenance.
Falls back to simple Resolve if transition fails. Player controller
now passes pre/post integration positions to the transition system.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Port FindTransitionalPosition, TransitionalInsert, FindEnvCollisions,
AdjustOffset, DoStepDown, ValidateTransition from transition_pseudocode.md.
Outdoor terrain collision with step-down ground contact. Indoor BSP and
object collision deferred to subsequent tasks.
Also adds PhysicsEngine.SampleTerrainZ() which dispatches the terrain Z
query to the right registered landblock by world-space XY position.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Sprint 2 of the audit remediation plan.
Re-enables the outdoor→indoor portal transition in PhysicsEngine with
an added containment check: after detecting a portal plane crossing,
verify the target cell's floor polygon actually covers the candidate
position AND the floor Z is within step height of the player's Z.
This prevents the wall-bounce bug (where portal planes on upper
floors captured outdoor positions) while allowing genuine doorway
transitions. Without full CellBSP, the SampleFloorZ + Z-proximity
check is the best available approximation per the indoor transition
research (docs/research/acclient_indoor_transitions_pseudocode.md).
Source: ACE EnvCell.find_transit_cells validates via
sphere_intersects_cell in the target cell's local space. Our
SampleFloorZ + Z check is the equivalent without BSP.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Three attempts at guarding the indoor transition (cellId mask,
Z threshold, terrainZ comparison) all failed because CellSurface
floor polygons are too aggressive — building footprints, roofs, and
upper floors all have PhysicsPolygons that cover wide XY areas at
various Z levels, and ANY outdoor position near a building matches
a cell floor. The proper solution is portal-based transition
(CellPortal boundary crossing), not floor-polygon containment —
but that's Phase E scope.
For the B.2 MVP: outdoor players NEVER transition to indoor cells.
The else-if branch is compiled out with `if (false)`. Indoor→outdoor
transition (walking OUT of a building) is also effectively disabled
since you can't get indoors in the first place. Walking on outdoor
terrain works correctly; walking into buildings will be blocked by
the terrain heightmap (you walk on the roof-level terrain, not
through the building).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Previous cellId-mask fix was necessary but insufficient: the engine
correctly identified the player as outdoor, but then immediately
transitioned to an indoor cell because a CellSurface floor polygon
covered the player's XY at a Z within stepUpHeight. The floor
polygon was a roof or upper floor of a nearby building that happens
to sit at terrain level — not a walkable indoor floor the player
should snap to.
Fix: outdoor→indoor transition now requires bestCellZ < terrainZ - 1.
A genuine indoor transition is into a cell whose floor is BELOW the
terrain surface (basement, ground floor of elevated building). Cells
at or above terrain Z are roofs/upper floors viewed from outside and
must not capture the player.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
ROOT CAUSE of the fall-through-ground bug. The currentlyIndoor check
compared the FULL 32-bit cell ID (0xA9B40001, includes landblock
prefix) against 0x0100. Every outdoor cell ID with a landblock
prefix is >= 0x0100, so the engine ALWAYS took the "stay indoors"
path, snapping the player to the nearest EnvCell floor at Z=66
instead of the outdoor terrain at Z=94.
ACE confirmed the bug: "AddWorldObjectInternal: couldn't spawn
+Acdream at 0xA9B40121 [84.2 37.7 66.0]" — we were sending the
server an indoor cell ID with a below-terrain Z position.
Fix: mask cellId with 0xFFFF before the indoor check (outdoor
cells are 0x0001–0x0040; indoor are 0x0100+; the high 16 bits
are the landblock prefix and must be stripped). Also mask the
returned targetCellId from CellSurface (which carries the full
EnvCell dat id) to just the cell index.
265 tests still green.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Three more fixes from the diagnostic dump:
1. Initial position: PhysicsEngine.Resolve was mapping the player
into an indoor EnvCell (foundry at Z=66) when they're standing
on outdoor terrain at Z=93+. The cell-containment check was too
aggressive for initial placement. Now uses the server-sent
position directly — the server already gave us a valid position.
2. Yaw unbounded: mouse delta accumulated without wrapping, growing
to 24+ radians. Now wraps to [-PI, PI] after every turn.
3. Turn command spam: MouseDeltaX > 0.5 threshold was too low for
raw pixel deltas. Any mouse jitter triggered turnCmd flips every
frame → stateChanged=True → MoveToState flood to the server.
Mouse turning now only affects yaw directly; turn COMMANDS only
come from A/D keyboard (matching retail client behavior where
mouse-look doesn't generate a TurnRight/TurnLeft command).
265 tests still green.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Combines TerrainSurface + CellSurface into a single Resolve() API
that handles outdoor terrain walking, indoor floor walking,
outdoor<->indoor cell transitions, step-height enforcement, and
ground detection.
Step-height blocks upward Z deltas exceeding the limit (walls,
cliffs); downhill movement is always accepted. Indoor transitions
pick the cell whose floor Z is closest to the entity's current Z
(handles multi-story buildings). Reports IsOnGround=false when
no landblock or surface covers the entity's position (gravity
applied by the caller).
One API mismatch fixed vs plan: plan encoded the upper 16 landblock
bits into the returned cell ID, but the tests assert the raw cell ID
(0x0100, <0x0100) — so Resolve returns targetCellId directly.
6 new tests covering flat terrain, slopes, step-height rejection,
indoor entry/exit, and void detection. 243 total, all green.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
