erik/acdream
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions 1

feat(physics): A4 — Transition.CheckOtherCells + ApplyOtherCellResult

Browse source 
Port of retail's CTransition::check_other_cells at
acclient_2013_pseudo_c.txt:272717-272798. Iterates every non-primary
cell in a candidate set, runs BSPQuery.FindCollisions per cell with
that cell's WorldTransform-derived rotation + origin, halts on first
Collided/Adjusted/Slid.

ApplyOtherCellResult is the combine-semantics helper extracted for
unit testability — it pins the retail switch:
  - Collided/Adjusted → CollidedWithEnvironment = true (gated on
    !Contact), halt.
  - Slid              → ContactPlaneValid + ContactPlaneIsWater = false,
                        halt.
  - OK                → continue.

Not yet wired into FindEnvCollisions — see next commit. Probe gated
on PhysicsDiagnostics.ProbeIndoorBspEnabled (ACDREAM_PROBE_INDOOR_BSP).

Six new unit tests: five against the pure combine helper for each halt
case + one direct CheckOtherCells call exercising the null-BSP guard.

Spec: docs/superpowers/specs/2026-05-20-phase-a4-multi-cell-bsp-design.md
Plan: docs/superpowers/plans/2026-05-20-phase-a4-multi-cell-bsp.md

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
Erik 2026-05-20 16:14:05 +02:00
parent e6369e266f
commit 493c5e5ff6
2 changed files with 257 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

115
src/AcDream.Core/Physics/TransitionTypes.cs
View file

@ -1387,6 +1387,121 @@ public sealed class Transition
/// Ported from pseudocode section 4 (LandCell.FindEnvCollisions + ValidateWalkable).
/// ACE: LandCell.FindEnvCollisions / ObjectInfo.ValidateWalkable.
/// </summary>
/// <summary>
/// Phase A4 (2026-05-20). Port of retail's
/// <c>CTransition::check_other_cells</c> at
/// <c>acclient_2013_pseudo_c.txt:272717-272798</c>.
///
/// <para>
/// After the primary cell's BSP collision returns OK, iterate every
/// other cell in the sphere's overlap set and run BSP collision
/// against each. Halt on the first Collided/Adjusted/Slid; OK
/// continues. Mirrors retail's behaviour exactly — no save/restore
/// of <see cref="Transition"/> state between cells.
/// </para>
/// </summary>
internal TransitionState CheckOtherCells(
PhysicsEngine engine,
Vector3 footCenter,
float sphereRadius,
System.Collections.Generic.IReadOnlyCollection<uint> cellSet)
{
if (engine.DataCache is null) return TransitionState.OK;
var sp = SpherePath;
// Deterministic order for greppable probe logs. Skip the primary
// cell — caller has already run its BSP.
var ordered = new System.Collections.Generic.List<uint>(cellSet);
ordered.Sort();
foreach (uint cellId in ordered)
{
if (cellId == sp.CheckCellId) continue;
var cell = engine.DataCache.GetCellStruct(cellId);
// R2 guard: stale CellPhysics loaded for render but not physics.
if (cell?.BSP?.Root is null) continue;
// Transform sphere into THIS cell's local space. Mirrors the
// primary-cell pattern at TransitionTypes.cs (FindEnvCollisions,
// ~line 1413) AND the Bug B world-origin fix that decomposes
// WorldTransform per cell so BSP Path-3 + Path-4 land write
// world-space ContactPlanes.
var localCenter = Vector3.Transform(footCenter, cell.InverseWorldTransform);
var localCurrCenter = Vector3.Transform(sp.GlobalCurrCenter[0].Origin, cell.InverseWorldTransform);
var localSphere = new DatReaderWriter.Types.Sphere
{
Origin = localCenter,
Radius = sphereRadius,
};
DatReaderWriter.Types.Sphere? localSphere1 = null;
if (sp.NumSphere > 1)
{
localSphere1 = new DatReaderWriter.Types.Sphere
{
Origin = Vector3.Transform(sp.GlobalSphere[1].Origin, cell.InverseWorldTransform),
Radius = sp.GlobalSphere[1].Radius,
};
}
System.Numerics.Quaternion cellRotation;
Vector3 cellOrigin;
if (!System.Numerics.Matrix4x4.Decompose(cell.WorldTransform, out _,
out cellRotation, out cellOrigin))
{
Console.WriteLine(System.FormattableString.Invariant(
$"[other-cells] WARN cell 0x{cellId:X8} WorldTransform did not decompose — falling back to identity rotation"));
cellRotation = System.Numerics.Quaternion.Identity;
cellOrigin = cell.WorldTransform.Translation;
}
var result = BSPQuery.FindCollisions(
cell.BSP.Root, cell.Resolved, this,
localSphere, localSphere1, localCurrCenter,
Vector3.UnitZ, 1.0f, cellRotation, engine,
worldOrigin: cellOrigin);
if (PhysicsDiagnostics.ProbeIndoorBspEnabled)
{
Console.WriteLine(System.FormattableString.Invariant(
$"[other-cells] primary=0x{sp.CheckCellId:X8} iter=0x{cellId:X8} result={result}"));
}
if (ApplyOtherCellResult(result, out var halted))
return halted;
}
return TransitionState.OK;
}
/// <summary>
/// Phase A4 (2026-05-20). Combine helper for
/// <see cref="CheckOtherCells"/>. Mirrors retail's switch at
/// <c>acclient_2013_pseudo_c.txt:272739-272752</c>:
/// Collided/Adjusted halt with <c>CollidedWithEnvironment</c>; Slid
/// halts AND clears the contact-plane fields; OK continues.
/// </summary>
internal bool ApplyOtherCellResult(TransitionState result, out TransitionState finalState)
{
finalState = result;
switch (result)
{
case TransitionState.Collided:
case TransitionState.Adjusted:
if (!ObjectInfo.State.HasFlag(ObjectInfoState.Contact))
CollisionInfo.CollidedWithEnvironment = true;
return true;
case TransitionState.Slid:
CollisionInfo.ContactPlaneValid = false;
CollisionInfo.ContactPlaneIsWater = false;
return true;
default:
return false;
}
}
private TransitionState FindEnvCollisions(PhysicsEngine engine)
{
var sp = SpherePath;