feat(runtime): own SetPosition collision reports

src/AcDream.Core/Physics/PhysicsObjUpdate.cs

@@ -81,14 +81,53 @@ public static class PhysicsObjUpdate
         Action? leaveGround = null,
         Func<bool>? isCurrent = null,
         Func<bool>? isVelocityCurrent = null)
+    {
+        if (!CommitSetPositionContactTransition(
+                body,
+                inContact,
+                onWalkable,
+                previousOnWalkable,
+                hitGround,
+                leaveGround,
+                isCurrent))
+        {
+            return false;
+        }
+
+        // Position, Vector, and Movement are independently timestamped but
+        // can all install m_velocityVector. If a later one arrived from a
+        // callback above, retain its vector and finish the non-overlapping
+        // contact/pose commit without applying this older collision response.
+        if (isVelocityCurrent?.Invoke() == false)
+            return isCurrent?.Invoke() ?? true;
+
+        HandleAllCollisions(
+            body,
+            collisionNormalValid,
+            collisionNormal,
+            previousContact,
+            previousOnWalkable,
+            body.OnWalkable);
+        return isCurrent?.Invoke() ?? true;
+    }
+
+    /// <summary>
+    /// Commits retail's Contact/OnWalkable and HitGround/LeaveGround prefix,
+    /// stopping immediately before <c>handle_all_collisions</c>. Runtime uses
+    /// this seam to run the canonical collision-table reports without adding
+    /// another per-placement delegate allocation.
+    /// </summary>
+    public static bool CommitSetPositionContactTransition(
+        PhysicsBody body,
+        bool inContact,
+        bool onWalkable,
+        bool previousOnWalkable,
+        Action? hitGround = null,
+        Action? leaveGround = null,
+        Func<bool>? isCurrent = null)
     {
         ArgumentNullException.ThrowIfNull(body);
 
-        // SetPositionInternal replaces Contact first but retains the source
-        // OnWalkable bit through its first calc_acceleration call. A deferred
-        // teleport may have parked the live body with both bits cleared, so
-        // restore the captured source bit explicitly before reproducing that
-        // ordering.
         if (previousOnWalkable)
             body.TransientState |= TransientStateFlags.OnWalkable;
         else
@@ -106,10 +145,6 @@ public static class PhysicsObjUpdate
         else
             body.TransientState &= ~TransientStateFlags.OnWalkable;
 
-        // AP-10 (Campaign P Slice P4, 2026-07-30): mirror WATER_CONTACT_TS
-        // alongside CONTACT_TS/ON_WALKABLE_TS, same as ApplySetPositionContact.
-        // Callers (e.g. RemoteTeleportPlacement) already set body.ContactPlaneIsWater
-        // before invoking this commit.
         if (body.ContactPlaneIsWater)
             body.TransientState |= TransientStateFlags.WaterContact;
         else
@@ -128,21 +163,6 @@ public static class PhysicsObjUpdate
                 return false;
         }
         body.calc_acceleration();
-
-        // Position, Vector, and Movement are independently timestamped but
-        // can all install m_velocityVector. If a later one arrived from a
-        // callback above, retain its vector and finish the non-overlapping
-        // contact/pose commit without applying this older collision response.
-        if (isVelocityCurrent?.Invoke() == false)
-            return isCurrent?.Invoke() ?? true;
-
-        HandleAllCollisions(
-            body,
-            collisionNormalValid,
-            collisionNormal,
-            previousContact,
-            previousOnWalkable,
-            finalOnWalkable);
         return isCurrent?.Invoke() ?? true;
     }
 
@@ -179,14 +199,14 @@ public static class PhysicsObjUpdate
         // is now owned by the SetPositionInternal-derived contact flags, not a Velocity.Z<=0
         // gate). A grounded corridor wall-slide keeps its tangential velocity (should_reflect
         // false), exactly as retail.
-        bool sledding = body.State.HasFlag(PhysicsStateFlags.Sledding);
+        bool sledding = (body.State & PhysicsStateFlags.Sledding) != 0;
         bool shouldReflect = !(prevOnWalkable && nowOnWalkable && !sledding);
 
         if (body.FramesStationaryFall <= 1)
         {
             if (shouldReflect && collisionNormalValid)
             {
-                if (body.State.HasFlag(PhysicsStateFlags.Inelastic))
+                if ((body.State & PhysicsStateFlags.Inelastic) != 0)
                 {
                     body.Velocity = Vector3.Zero;                          // pc:282720-282722
                 }

src/AcDream.Core/Physics/ShadowObjectRegistry.cs

@@ -1563,6 +1563,32 @@ public sealed class ShadowObjectRegistry
     internal bool HasLogicalOwner(uint entityId) =>
         _entityReg.ContainsKey(entityId);
 
+    /// <summary>
+    /// Returns the exact collision identity consumed by retail
+    /// <c>CPhysicsObj::track_object_collision</c>.  Reporting must classify
+    /// an encountered object from the same retained shadow registration that
+    /// produced the collision; presence of an entity id alone is not enough
+    /// to infer either a static/environment collision or physics state.
+    /// </summary>
+    internal bool TryGetCollisionOwner(
+        uint entityId,
+        out uint physicsState,
+        out bool isStatic)
+    {
+        if (_entityReg.TryGetValue(
+                entityId,
+                out RegistrationRecord? registration))
+        {
+            physicsState = registration.State;
+            isStatic = registration.IsStatic;
+            return true;
+        }
+
+        physicsState = 0u;
+        isStatic = false;
+        return false;
+    }
+
     public int PrefixOwnerSlotCapacityForDiagnostics(uint landblockId) =>
         _prefixOwnerSlots.TryGetValue(
             landblockId & 0xFFFF0000u,