Packed monster remotes interpenetrate in acdream but barely in retail on the same
ACE. Retail de-overlaps them CLIENT-side: it sweeps every remote creature every
tick against neighbours' LIVE resolved positions (the collision shadow == the
resolved m_position, re-registered every moved transition step), with the server
position a gentle catch-up target (CPhysicsObj::MoveOrTeleport 0x00516330), not a
hard-snap. The collision math was already faithful; the bug was the reconciliation
(hard-snap) + the movement model (synth-velocity) + a stale shadow.
A first attempt (reverted) enqueued EVERYTHING and left the shadow at the raw
server position — it gate-failed with invisible monsters (an unplaced body blipped
over a huge distance into the sweep -> garbage pos) and the player stuck on offset
shadows. This redo fixes both root causes, mechanism-proven in a Core test first:
- NPC UpdatePosition routes through MoveOrTeleport with a PLACEMENT-SNAP: the body
is snapped to the server pos when it is not already near it (first UP, no
Sequencer to consume the queue, >96 m, or |Body - worldPos| > 4 m); only near DR
corrections enqueue. This restores the body's placement authority (no invisible
monsters). Airborne keeps the authoritative hard-snap.
- Grounded movement drives the body from the interp CATCH-UP (ComputeOffset ->
InterpolationManager::adjust_offset, REPLACE dichotomy) instead of synth-velocity
(get_state_velocity / SERVERVEL); MovementManager::UseTime runs unconditionally.
- SHADOW-FOLLOWS-RESOLVED: after each tick's sweep the collision shadow is
re-registered at the resolved body (SyncRemoteShadowToBody), movement-gated
(|Body - LastShadowSyncPos| > 1 cm). The per-UP :5669 raw-pos sync is now
PLAYERS-ONLY, so an NPC's shadow is only ever written to its resolved body ->
neighbours de-overlap against resolved bodies, the spread PERSISTS, and collision
== render (no stuck-on-nothing). Landing clears the interp queue.
Preserved: airborne path, sticky #171 (gate + StickyManager overwrite of the seeded
frame), omega, the #173 bounce, landing, the node_fail_counter watchdog, and Path A
(player remotes, untouched -- Slice 2 unifies it).
Tests (RemoteDeOverlapMechanismTests): converging pair settles STABLE at 0.86 m
(barely overlapping = the retail look) WITH the shadow-sync vs <0.40 m (full
overlap) WITHOUT it; a third test drives the REAL InterpolationManager loop and
confirms the sweep absorbs the stall-blip (no pop-into-neighbour). 2-lens Opus
review (CONCERNS) addressed: movement-gated re-flood for the town-FPS risk;
players-only :5669; the blip-absorption test.
Register: retires TS-41 (SERVERVEL synth-velocity -> catch-up), narrows TS-44 (NPC
UP unified onto the interp queue; gate kept for orientation), adds AP-86
(shadow-follows-resolved impl) + AP-87 (MoveOrTeleport 4 m/no-Sequencer placement
snap). Known residual: the de-overlap sweep uses the human sphere for the mover, so
large creatures de-overlap at human radii (TS-46; Slice 3 plumbs Setup dims).
Visual gate PASSED (user: monsters visible + spacing much better). Core 2620 /
App 741 green.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Erik