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feat(physics): C4 route 4a — remote steady-state Position through the seam

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Routes the classifier's two NO-PLACEMENT remote branches — Interpolate
(contact, PlayerDistance < 96 m) and NoPositionOperation (no contact) — through
a Runtime-owned seam, and fixes the two divergences they carried. Teleport,
far-snap and cell-less stay on the legacy App path; 4b owns them.

Route 4 was split into 4a/4b after scoping put the whole route at 1,500-2,500
lines against a ~400 budget. 4a's branches perform no SetPosition, so this slice
carries no deferred-cell park, no service-window guard and no allocation
exposure — which is what made the split worth doing.

Divergences fixed, both previously unfiled:

* D1 — the NPC airborne branch hard-snapped Body.Position/Orientation and
  branched on the client-tracked rmState.Airborne, never consulting the wire
  IsGrounded bit. Retail's MoveOrTeleport @0x00516330 returns 0 at 0x0051636D
  and writes nothing. Player remotes were already correct; NPCs were not.
* D2 — ConstrainTo was armed before the operation, unconditionally, so it fired
  on the airborne no-op retail skips and anchored to the PRE-move position.
  Retail arms it at 0x00454272, only when MoveOrTeleport returns nonzero,
  anchored to &arg2->m_position read live, i.e. post-move.

AP-87 and TS-44 were carried deliberately, not delegated away. AP-87's three
conditions — including firstUp, which one round silently dropped — are preserved
as an explicit acdream policy layer applied AFTER the classifier commits to
Interpolate; the two previously separate player/NPC copies are now one. TS-44
stays an NPC-only caller gate; extending sticky suppression to player remotes has
no retail basis and no live evidence, so it was declined rather than absorbed.

Landing is explicitly carved out of 4a's ownership on both arms. A landing packet
classifies Interpolate, so an ordering slip would ENQUEUE a body that must PLANT
and a creature knocked off a ledge would glide down over a packet interval. The
carve-out is a named entry point returning AirborneSnap/SteadyStateInterpolate/
Legacy precisely so the PRECEDENCE is observable and testable rather than implied
by statement order — that is how the slip happened once and was caught.

The player/NPC asymmetry on landing is real and NOT resolved here: retail draws
no such distinction, but converging them is a behaviour decision needing its own
evidence. Filed into the 4b plan.

Register: AP-135 filed for the two bookkeeping writes the airborne branch
deliberately retains (rmState.CellId, LastServerPos/Time) — not retail's model,
but load-bearing for our catch-up sweep and staleness timer, and verified not to
be a canonical cell commit for ordinary remotes. AP-87 and TS-44 rewritten to
describe the code.

Honest remainder: App still owns branch selection, the airborne return, the cell
write, the entity write and the shadow publish, and headless satisfies "both
hosts drive the identical entry point" only vacuously since it returns early for
remotes. That is written into the 4b bullet rather than left implicit.

Cost: 364 non-comment production lines, 91% of the ~400 budget — the split did
isolate the cheap half, but not by much. Do not carry "well under" into 4b's
scoping.

Gates: complete Release solution 10,938 passed / 4 skipped / 0 failed (pre-4a
baseline 10,909). Four review rounds; the first three each introduced a new
behavioural defect while fixing another, and each left a comment asserting
behaviour that no longer matched — the final round's precedence matrix was
traced cell-by-cell against HEAD with only the D1-intended difference. App tests
call production entry points against a real WorldEntity and real classifier
output, closing route 2's #292 gap rather than repeating it.

Connected acceptance NOT run — needs a live second character.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
This commit is contained in:
Erik 2026-08-04 00:19:05 +02:00
parent 19d9509497
commit 44830a0eb3
12 changed files with 1854 additions and 150 deletions
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502
src/AcDream.App/Physics/LiveEntityNetworkUpdateController.cs
View file

@ -817,6 +817,163 @@ internal sealed class LiveEntityNetworkUpdateController
&& runtime.IsCurrentSpatialRemoteMotion(record, remote);
}
/// <summary>
/// C4 route 4a: asks Runtime to classify one remote's accepted Position.
/// App contributes only retail's <c>player_distance</c> — the live
/// physics-controller distance, and <see langword="null"/> (never a
/// fabricated <c>Vector3.Zero</c>) when no controller exists yet, which
/// makes Runtime decline and leaves the legacy path untouched. Callers
/// must only invoke this for a genuinely remote (never local-player)
/// entity whose <c>remotePlacementRequired</c> gate is already false.
/// </summary>
private RuntimeAuthoritativePositionRoute? ClassifyRemoteAcceptedPosition(
AcDream.Core.Net.WorldSession.EntityPositionUpdate update,
RuntimeEntityRecord canonical,
AcDream.Core.Physics.PositionTimestampDisposition timestampDisposition,
AcceptedPhysicsTimestamps timestamps,
System.Numerics.Vector3 worldPos) =>
_liveEntities.ClassifyRemoteAcceptedPosition(
canonical,
update,
timestampDisposition,
timestamps,
_playerController is { } controller
? System.Numerics.Vector3.Distance(worldPos, controller.Position)
: null);
/// <summary>
/// C4 route 4a: the generic top-of-<c>OnPosition</c> render-pose write and
/// its ONE suppression rule, extracted so the rule is exercised by
/// production and by test through the same entry point rather than
/// restated in a test body.
///
/// <para>
/// For the two classifications route 4a owns, the canonical body — not
/// the raw wire packet — is the only writer of the render entity: the
/// near-interpolate branch's tail syncs the entity to the resolved body,
/// and the airborne no-op writes nothing at all (retail
/// <c>MoveOrTeleport</c> 0x00516330 returns 0 @0x0051636D). Writing the
/// wire pose here first would be the second writer route 2's original
/// defect consisted of. Every other classification keeps the pre-existing
/// write, unchanged, until route 4b.
/// </para>
///
/// <para>
/// The spatial bucket transaction deliberately does NOT live behind this
/// gate: unlike route 2, neither 4a branch performs a placement, so there
/// is no committed placement receipt to project in its stead. The per-UP
/// <c>RebucketLiveEntity</c> is the only site that moves an ordinary
/// moving remote's draw bucket, commits its canonical <c>FullCellId</c>,
/// and recovers a pending bucket promotion, and it must keep running for
/// both 4a classifications.
/// </para>
///
/// <para>
/// The <see langword="bool"/> result is this seam's observable outcome and
/// is what the acceptance tests assert on; production does not need it.
/// Do not delete it as dead — returning nothing would leave the
/// suppression rule unobservable, which is the #292 gap this closes.
/// Returns true when the wire pose was written.
/// </para>
/// </summary>
internal static bool TryApplyGenericRemoteRenderPose(
AcDream.Core.World.WorldEntity entity,
RuntimeAuthoritativePositionRoute? route,
System.Numerics.Vector3 worldPos,
uint landblockId,
System.Numerics.Quaternion rotation)
{
ArgumentNullException.ThrowIfNull(entity);
if (RuntimeRemoteSteadyStatePosition.OwnsSteadyState(route))
return false;
entity.SetPosition(worldPos);
entity.ParentCellId = landblockId;
entity.Rotation = rotation;
return true;
}
/// <summary>Which arm of the non-player-remote contact routing claimed a
/// packet. The value is the seam's observable outcome, asserted by the
/// acceptance tests; production only distinguishes
/// <see cref="RemoteContactArm.Legacy"/>, but the finer result is what
/// makes the PRECEDENCE testable and must not be collapsed to a
/// bool.</summary>
internal enum RemoteContactArm : byte
{
/// <summary>The body was airborne. Hard-snapped, exactly as before
/// route 4a. Gated on <c>remote.Airborne</c> ALONE — the wire contact
/// bit is never read here. The common case is the landing packet, but
/// a not-in-contact packet also reaches this arm whenever the
/// classification is one route 4a does not own (null, cell-less
/// <c>SetPosition</c>, or rejected), because the
/// <c>IsAirborneNoOperation</c> early return fires only for
/// classifications it does own. That matches pre-4a behaviour.</summary>
AirborneSnap,
/// <summary>Route 4a's near InterpolateTo branch.</summary>
SteadyStateInterpolate,
/// <summary>Neither: the caller runs its own untouched legacy
/// near/far routing.</summary>
Legacy,
}
/// <summary>
/// C4 route 4a: the ORDERING carve-out for the non-player-remote arm. An
/// airborne body's contact packet keeps its pre-existing authoritative
/// hard-snap and is decided BEFORE route 4a's near-Interpolate branch can
/// claim it — the player-remote arm gets the same precedence structurally,
/// because its landing block sits ahead of its own routing and returns.
///
/// <para>
/// This exists as one entry point precisely so the precedence is
/// observable: a landing packet classifies <c>Interpolate</c>, so if the
/// 4a test came first it would ENQUEUE a body that must PLANT, and a
/// creature knocked off a ledge would glide down over a packet interval.
/// Landing is not a behaviour route 4a is scoped to change.
/// </para>
/// </summary>
internal static RemoteContactArm ApplyRemoteContactRouting(
RemoteMotion remote,
RuntimeAuthoritativePositionRoute? route,
System.Numerics.Vector3 worldPos,
System.Numerics.Quaternion rotation,
bool willBeDrTicked)
{
ArgumentNullException.ThrowIfNull(remote);
if (remote.Airborne)
{
// Verbatim from the pre-4a branch, queue deliberately NOT
// cleared: the arc integrates locally (K-fix15), and clearing
// stale waypoints is owned by the per-tick LANDING detection
// (RuntimeRemotePhysicsUpdater.cs:497-502), not by this snap.
//
// Do NOT restate this as "the queue is already empty here" — it
// is not. Nothing that sets Airborne clears the queue except the
// teleport hook's StopInterpolating: neither the 0xF74E
// VectorUpdate (:1059) nor the three `Airborne = !Body.OnWalkable`
// sites do. A walking NPC can enqueue a near waypoint and then
// step off a lip, arriving here with a populated queue. That is
// exactly why the landing clear exists, and a reader who believes
// the queue is empty here could delete it.
remote.Body.Position = worldPos;
remote.Body.Orientation = rotation;
return RemoteContactArm.AirborneSnap;
}
if (!RuntimeRemoteSteadyStatePosition.IsNearInterpolate(route))
return RemoteContactArm.Legacy;
RuntimeRemoteSteadyStatePosition.ApplyInterpolate(
remote,
worldPos,
rotation,
isMovingTo: remote.Movement.IsMovingTo(),
willBeDrTicked);
return RemoteContactArm.SteadyStateInterpolate;
}
/// <summary>
/// K-fix9 (2026-04-26): handle 0xF74E VectorUpdate from remote jumps.
/// The payload seeds the world-space launch velocity and angular velocity.
@ -1302,15 +1459,41 @@ internal sealed class LiveEntityNetworkUpdateController
return;
}
// Capture the pre-update render position for the soft-snap residual
// calculation below. Assign entity.Position to the server truth up
// front; if we then compute a snap residual, we restore the rendered
// position by adding the residual back (so the visual doesn't jerk
// for one frame before the residual decay kicks in on the next tick).
System.Numerics.Vector3 preSnapPos = entity.Position;
entity.SetPosition(worldPos);
entity.ParentCellId = p.LandblockId;
entity.Rotation = rot;
// C4 route 4a: classify BEFORE the generic write below so a remote
// whose accepted Position resolves to NoPositionOperation (retail's
// airborne no-op — writes nothing at all) or Interpolate (retail's
// near InterpolateTo queue — no direct body write here) never
// receives it. remotePlacementRequired guarantees the classifier's
// teleport (SetPosition) disposition never reaches here — that stays
// route 4b. The local player never reaches this generic-remote code
// path at all. Every classification 4a does NOT own — the >=96 m
// far snap, a cell-less remote, a rejected authority or payload, and
// "no classification at all" — falls through to the pre-existing
// legacy routing completely unchanged; 4b deletes that fallback.
RuntimeAuthoritativePositionRoute? earlyRemoteRoute =
update.Guid != _playerServerGuid && !remotePlacementRequired
? ClassifyRemoteAcceptedPosition(
update,
acceptedPositionCanonical,
timestampDisposition,
timestamps,
worldPos)
: null;
TryApplyGenericRemoteRenderPose(
entity,
earlyRemoteRoute,
worldPos,
p.LandblockId,
rot);
// The spatial bucket transaction runs for EVERY classification,
// including both 4a branches: it is the only site that moves an
// ordinary moving remote's draw bucket, commits its canonical
// FullCellId (which feeds back as the classifier's own
// CommittedCellId and as the ConstraintDistance cell key), and
// recovers a pending bucket promotion. Neither 4a branch performs a
// placement, so unlike route 2 there is no committed placement
// receipt that could project this in its stead.
if (!_liveEntities!.RebucketLiveEntity(update.Guid, p.LandblockId)
|| !_liveEntities.TryGetRecord(
update.Guid,
@ -1519,13 +1702,19 @@ internal sealed class LiveEntityNetworkUpdateController
// leash at zero displacement on a fresh accepted Position, matching
// retail's per-packet re-anchor.
// docs/research/2026-07-30-constraint-leash-constants.md §2/§3.2.
if (rmState.Host is { } remoteConstraintHost)
//
// C4 route 4a / D2: retail arms this AFTER the operation, only on
// a nonzero MoveOrTeleport return (@0x00454272, inside the
// `if (MoveOrTeleport(...) != 0)` at @0x00454254) — so this
// pre-operation, unconditional arming is now the LEGACY shape and
// runs only for the classifications 4a does not own. The two 4a
// classifications arm it after their own operation instead, or
// (the airborne no-op) not at all. 4b deletes this fallback.
if (!RuntimeRemoteSteadyStatePosition.OwnsSteadyState(earlyRemoteRoute)
&& rmState.Host is { } remoteConstraintHost)
{
AcDream.Core.Physics.Position anchor = remoteConstraintHost.Position;
remoteConstraintHost.PositionManager.ConstrainTo(
anchor,
AcDream.Core.Physics.Motion.ConstraintDistance.GetStartConstraintDistance(anchor.ObjCellId),
AcDream.Core.Physics.Motion.ConstraintDistance.GetMaxConstraintDistance(anchor.ObjCellId));
RuntimeRemoteSteadyStatePosition.ArmConstraintAfterOperation(
remoteConstraintHost);
}
// L.3 M2 (2026-05-05): retail-faithful MoveOrTeleport routing for
@ -1546,7 +1735,11 @@ internal sealed class LiveEntityNetworkUpdateController
// ResolveWithTransition gate (rm.CellId != 0); without this
// an airborne player remote falls through the floor because
// the sphere sweep is skipped. Note: enabling the sweep also
// exposes a pre-existing depenetration bug — see #42.
// exposes a pre-existing depenetration bug — see #42. This is
// acdream's OWN free-fall sweep bookkeeping, not a retail
// CPhysicsObj field, so the D1 "writes nothing" rule below
// deliberately does not reach it — register row AP-135, and
// the NPC arm keeps the identical pair for the same reason.
rmState.CellId = p.LandblockId;
// Diagnostic (ACDREAM_REMOTE_VEL_DIAG=1): roll the previous
@ -1581,19 +1774,33 @@ internal sealed class LiveEntityNetworkUpdateController
rmState.LastServerPosTime = nowSecDiag;
}
// ── AIRBORNE NO-OP ────────────────────────────────────────────
// Mirrors retail CPhysicsObj::MoveOrTeleport (acclient @ 0x00516330):
// when has_contact==0, return false (don't touch body, don't queue).
// body.Velocity (set once by OnLiveVectorUpdated at jump start) keeps
// integrating gravity via per-frame UpdatePhysicsInternal. Server is
// authoritative for the arc; we don't predict it locally.
// ── AIRBORNE NO-OP (C4 route 4a / D1+D2) ─────────────────────
// Retail CPhysicsObj::MoveOrTeleport (0x00516330): arg4 == 0
// (the wire has_contact bit) falls straight to `return 0`
// @0x0051636D and writes NOTHING — not the body, not the
// interpolation queue, not the render entity, and (because
// ConstrainTo sits inside `if (MoveOrTeleport(...) != 0)` at
// @0x00454254) not the ConstraintManager leash either. The
// classifier read the SAME wire bit this packet carries, so
// there is nothing left to undo: the generic render-pose
// write above was suppressed for this exact classification.
if (RuntimeRemoteSteadyStatePosition.IsAirborneNoOperation(
earlyRemoteRoute))
{
return;
}
if (!update.IsGrounded)
{
// Undo the unconditional entity hard-snap at the top of the
// function (entity.SetPosition(worldPos)): the body is mid-arc
// and TickAnimations will write entity = body next frame
// anyway. Setting entity = body now prevents a 1-frame
// LEGACY airborne no-op, unchanged, for the packets 4a
// does not own — a cell-less remote (route 4b's
// SetPosition), a rejected authority/payload, or no
// classification at all. Those DID take the generic
// render-pose write above, so this still undoes it: the
// body is mid-arc and TickAnimations will write
// entity = body next frame anyway, and setting
// entity = body now prevents a 1-frame
// teleport-to-server-then-yank-back rubber-band.
// 4b deletes this fallback.
entity.SetPosition(rmState.Body.Position);
return;
}
@ -1612,6 +1819,32 @@ internal sealed class LiveEntityNetworkUpdateController
rmState.Body.Position = worldPos;
rmState.Body.Orientation = rot;
// C4 route 4a / D2: a landing packet is a GROUNDED
// correction, so retail's MoveOrTeleport returns nonzero
// and SmartBox::HandleReceivedPosition does arm the leash
// (@0x00454272). This block returns before the grounded
// routing below, so it arms its own — post-move, matching
// the anchor retail reads. Only for a classification 4a
// owns: every other one already armed the legacy
// pre-operation call above.
RuntimeRemoteSteadyStatePosition.TryArmConstraintAfterOperation(
earlyRemoteRoute,
rmState);
// C4 route 4a: a landing packet classifies Interpolate, so
// the generic render-pose write was suppressed for it —
// this block must therefore commit the landing pose to the
// render entity itself, from the RESOLVED body, exactly as
// the two branch tails below do. Before route 4a the
// generic write had already put the entity at worldPos,
// which is the same value the snap above just installed;
// without this the rendered pose lags one frame until
// RemotePhysicsUpdater re-projects it. rmState.CellId is
// the server cell adopted at the top of this arm.
entity.SetPosition(rmState.Body.Position);
entity.ParentCellId = rmState.CellId;
entity.Rotation = rmState.Body.Orientation;
// #161: retail landing = MovementManager::HitGround
// (minterp → moveto, 0x00524300 — the R5-V5 facade
// relay) with the Gravity state bit STILL SET
@ -1650,56 +1883,72 @@ internal sealed class LiveEntityNetworkUpdateController
}
// ── GROUNDED ROUTING (CPhysicsObj::MoveOrTeleport) ────────────
const float MaxPhysicsDistance = 96f; // retail player_distance far-snap
const float BodySnapThreshold = 4f; // large correction / teleport / unplaced -> snap
var localPlayerPos = _playerController?.Position ?? System.Numerics.Vector3.Zero;
float dist = System.Numerics.Vector3.Distance(worldPos, localPlayerPos);
// #184 Slice 2b: the player UP routing gains the SAME placement-snap
// backstop the NPC routing got in Slice 1 (AP-87). Now that grounded
// PLAYER remotes run the sweep, an unplaced / stale-cell body — a
// UM-first RemoteMotion seeded to the spawn pos (:5176) then a first UP
// in a DIFFERENT cell, which the UP-creation seed (:5720) does NOT cover
// — would enqueue and the per-tick sweep would run from a cell that does
// not contain the body -> garbage resolved pos -> the digest's
// INVISIBLE/misplaced player. The 4 m bodyToTarget guard is the
// LOAD-BEARING backstop (AP-87; firstUp via LastServerPosTime is a poor
// signal for players — it is already set by the VEL_DIAG block above);
// !willBeDrTicked snaps a no-Sequencer player whose queue nothing would
// consume; dist>96 is retail's far-snap. Placed + near corrections still
// enqueue for the smooth catch-up.
float bodyToTarget = System.Numerics.Vector3.Distance(
rmState.Body.Position, worldPos);
bool willBeDrTicked = WillAdvanceRemoteMotion(
update.Guid,
rmState);
if (dist > MaxPhysicsDistance || !willBeDrTicked
|| bodyToTarget > BodySnapThreshold)
// C4 route 4a: the near (Interpolate) decision — including the
// AP-87 placement-snap backstop — now lives in
// RuntimeRemoteSteadyStatePosition.ApplyInterpolate, shared
// with the NPC branch below. Every OTHER classification (the
// >=96 m far snap, a cell-less remote, a rejection, or none at
// all) keeps the pre-existing legacy near/far routing below,
// unchanged, until route 4b — "not Interpolate" is NOT "far".
bool willBeDrTicked = WillAdvanceRemoteMotion(update.Guid, rmState);
if (RuntimeRemoteSteadyStatePosition.IsNearInterpolate(
earlyRemoteRoute))
{
// Beyond view bubble / large correction / unplaced body:
// SetPositionSimple slide-snap. Clear queue.
rmState.Interp.Clear();
rmState.Body.Position = worldPos;
rmState.Body.Orientation = rot;
}
else
{
// Within view bubble, placed + near: enqueue waypoint for
// adjust_offset to walk to. The per-frame TickAnimations player-
// remote path drives the actual body advancement via
// InterpolationManager.AdjustOffset. Pass body's current position so
// the InterpolationManager can detect a far-distance enqueue (>100 m
// from body) and pre-arm an immediate blip.
System.Numerics.Quaternion? immediateOrientation =
rmState.Interp.Enqueue(
RuntimeRemoteSteadyStatePosition.ApplyInterpolate(
rmState,
worldPos,
rot,
isMovingTo: rmState.Movement.IsMovingTo(),
currentBodyPosition: rmState.Body.Position,
currentBodyOrientation: rmState.Body.Orientation);
if (immediateOrientation is { } closeOrientation)
rmState.Body.Orientation = closeOrientation;
willBeDrTicked);
// D2: ConstrainTo arms strictly AFTER the operation,
// anchored post-move — retail arms it only once
// MoveOrTeleport returns nonzero (@0x00454254/@0x00454272).
RuntimeRemoteSteadyStatePosition.TryArmConstraintAfterOperation(
earlyRemoteRoute,
rmState);
}
else
{
// LEGACY near/far routing, unchanged. Its leash was
// already armed by the legacy pre-operation call above.
const float MaxPhysicsDistance = 96f; // retail player_distance far-snap
const float BodySnapThreshold = 4f; // large correction / teleport / unplaced -> snap
var localPlayerPos = _playerController?.Position ?? System.Numerics.Vector3.Zero;
float dist = System.Numerics.Vector3.Distance(worldPos, localPlayerPos);
// #184 Slice 2b: the player UP routing gains the SAME placement-snap
// backstop the NPC routing got in Slice 1 (AP-87). The 4 m
// bodyToTarget guard is the LOAD-BEARING backstop;
// !willBeDrTicked snaps a no-Sequencer player whose queue nothing
// would consume; dist>96 is retail's far-snap.
float bodyToTarget = System.Numerics.Vector3.Distance(
rmState.Body.Position, worldPos);
if (dist > MaxPhysicsDistance || !willBeDrTicked
|| bodyToTarget > BodySnapThreshold)
{
// Beyond view bubble / large correction / unplaced body:
// SetPositionSimple slide-snap. Clear queue.
rmState.Interp.Clear();
rmState.Body.Position = worldPos;
rmState.Body.Orientation = rot;
}
else
{
// Within view bubble, placed + near: enqueue waypoint for
// adjust_offset to walk to.
System.Numerics.Quaternion? immediateOrientation =
rmState.Interp.Enqueue(
worldPos,
rot,
isMovingTo: rmState.Movement.IsMovingTo(),
currentBodyPosition: rmState.Body.Position,
currentBodyOrientation: rmState.Body.Orientation);
if (immediateOrientation is { } closeOrientation)
rmState.Body.Orientation = closeOrientation;
}
}
// Track the UP-derived synth velocity for diagnostics
// ([VEL_DIAG] pace comparison). L.2g S5 (2026-07-02): the
// #39-era cycle-refinement call that used to live here is
@ -1754,6 +2003,35 @@ internal sealed class LiveEntityNetworkUpdateController
}
double nowSec = (now - System.DateTime.UnixEpoch).TotalSeconds;
// ── AIRBORNE NO-OP (C4 route 4a / D1) ────────────────────────────
// The exact mirror of the player-remote arm above. Retail's
// MoveOrTeleport makes no `this == player` distinction: arg4 == 0
// returns 0 @0x0051636D and writes nothing, so an NPC remote's
// wire not-in-contact packet must no longer hard-snap the body,
// decide an animation cycle from a synthesized arc velocity, sync
// the render entity, or publish a collision shadow. This branch
// is now driven by the WIRE has_contact bit through the
// classifier, not by the client-tracked rmState.Airborne flag
// (which is what D1 was).
//
// Two acdream-only per-packet bookkeeping writes are deliberately
// KEPT here, exactly as the player arm has always kept them (see
// register row AP-135): the server cell id, which acdream's own
// per-tick free-fall ResolveWithTransition sweep gates on
// (rm.CellId != 0) and without which an airborne remote falls
// through the floor, and the last-server-position sample, without
// which the first grounded packet after the arc would synthesize
// its velocity across the whole jump.
if (RuntimeRemoteSteadyStatePosition.IsAirborneNoOperation(
earlyRemoteRoute))
{
rmState.CellId = p.LandblockId;
rmState.LastServerPos = worldPos;
rmState.LastServerPosTime = nowSec;
return;
}
System.Numerics.Vector3? serverVelocity = update.Velocity;
if (serverVelocity is null
&& !IsPlayerGuid(update.Guid)
@ -1801,28 +2079,44 @@ internal sealed class LiveEntityNetworkUpdateController
}
if (!snapSuppressedByStick)
{
// #184 (2026-07-07): retail CPhysicsObj::MoveOrTeleport (0x00516330)
// for grounded NPC remotes. The body is PLACED (hard-snapped) whenever
// it is not already tracking NEAR the server position — the first UP,
// a large correction / teleport, an out-of-view creature (>96 m from
// the local player), or an entity the DR loop won't tick — otherwise the
// server point is a GENTLE dead-reckoning TARGET the per-tick interp
// catch-up walks to, and the KEPT sweep de-overlaps that movement.
// C4 route 4a: the near (Interpolate) decision — including the
// AP-87 placement-snap backstop — is now the SAME Runtime
// owner the player-remote branch above calls; retail's
// MoveOrTeleport (0x00516330) makes no `this == player`
// distinction, so the two per-kind copies became one. TS-44's
// sticky suppression stays an NPC-only CALLER gate (this
// `if`), which is what its register row describes and what
// the player arm has never had.
//
// The placement-snap is LOAD-BEARING: the earlier attempt (reverted)
// enqueued EVERYTHING, so an unplaced body (origin, first UP) blipped
// over a huge distance into the sweep -> a resolve started in a cell that
// did not contain the body -> garbage resolved pos -> INVISIBLE monster
// while its shadow (synced to server truth) stayed put -> player stuck on
// nothing. Airborne keeps the authoritative hard-snap (arc integrates
// locally, K-fix15). Physics digest 2026-07-07 banner.
if (rmState.Airborne)
{
rmState.Body.Position = worldPos;
rmState.Body.Orientation = rot;
}
else
// Every OTHER classification (the >=96 m far snap, a
// cell-less remote, a rejection, or none at all) keeps the
// pre-existing legacy routing below, unchanged, until route
// 4b — "not Interpolate" is NOT "far".
// #184 (2026-07-07): an AIRBORNE body keeps its authoritative
// hard-snap (the arc integrates locally, K-fix15), and that
// decision is taken FIRST — a landing packet classifies
// Interpolate, so letting route 4a's branch see it before the
// airborne test would enqueue a body that must plant, and a
// creature knocked off a ledge would glide down over a packet
// interval. Physics digest 2026-07-07 banner.
if (ApplyRemoteContactRouting(
rmState,
earlyRemoteRoute,
worldPos,
rot,
WillAdvanceRemoteMotion(update.Guid, rmState))
is RemoteContactArm.Legacy)
{
// LEGACY NPC near/far routing, unchanged. Its leash was
// already armed by the legacy pre-operation call above.
// The body is PLACED (hard-snapped) whenever it is not
// already tracking NEAR the server position — the first
// UP, a large correction / teleport, an out-of-view
// creature (>96 m from the local player), or an entity the
// DR loop won't tick — otherwise the server point is a
// GENTLE dead-reckoning TARGET the per-tick interp
// catch-up walks to, and the KEPT sweep de-overlaps that
// movement.
const float MaxPhysicsDistanceNpc = 96f; // retail player_distance far-snap
const float BodySnapThresholdNpc = 4f; // large correction / teleport -> snap
var localPlayerPosNpc = _playerController?.Position
@ -1830,18 +2124,7 @@ internal sealed class LiveEntityNetworkUpdateController
float distNpc = System.Numerics.Vector3.Distance(worldPos, localPlayerPosNpc);
float bodyToTargetNpc = System.Numerics.Vector3.Distance(
rmState.Body.Position, worldPos);
// The 4 m bodyToTargetNpc guard is the LOAD-BEARING placement backstop:
// it snaps any body not already near the target (an unplaced first-UP
// body sits at the origin / spawn pos, far from worldPos). firstUpNpc is
// a belt-and-suspenders hint only — it is NOT a reliable "never placed"
// signal because a UM that enters a locomotion cycle can stamp
// LastServerPosTime before the first UP (~:5340). Don't tune the 4 m
// threshold down without re-checking the unplaced-body case.
bool firstUpNpc = rmState.LastServerPosTime <= 0.0;
// Enqueue only if the canonical ordinary-object workset
// will consume the queue. Animation is optional in retail;
// LiveEntityAnimationScheduler advances a spatial
// RemoteMotion even when no LiveEntityAnimationState exists.
bool willBeDrTickedNpc = WillAdvanceRemoteMotion(
update.Guid,
rmState);
@ -1871,6 +2154,21 @@ internal sealed class LiveEntityNetworkUpdateController
}
}
}
// D2: ConstrainTo arms strictly AFTER the operation above,
// anchored post-move (@0x00454272, inside the
// `if (MoveOrTeleport(...) != 0)` at @0x00454254), and only for a
// classification route 4a owns — every other one already armed
// the legacy pre-operation call above, exactly as before. Retail's
// ConstraintManager leash is independent of the acdream-only TS-44
// sticky suppression (which only concerns the enqueue/snap above),
// so this deliberately sits OUTSIDE the snapSuppressedByStick
// gate: a stuck NPC's leash still re-arms every accepted Position
// exactly as it did before this route split the single call into a
// per-branch pair.
RuntimeRemoteSteadyStatePosition.TryArmConstraintAfterOperation(
earlyRemoteRoute,
rmState);
// K-fix15 (2026-04-26): DON'T auto-clear airborne on UP.
// ACE broadcasts UPs during the arc (peak / mid-fall / land)
// at ~5-10 Hz. The previous K-fix9 logic cleared Airborne on