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fix(research): A6.P3 slice 1 T1 — citation corrections + LKCP re-latch note

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Code-review feedback on commit 6b4be7f:
  - Section 1: strip stale [309NNN] inline annotations (off by 2-8
    lines from actual file content; the 0052c1xx address comments
    are the reliable anchor); address comments already present in the
    decomp output are now used as inline anchors instead
  - Section 2: validate_transition function header is at file line
    272547 (was: 272538, inside the preceding check_collisions
    function). Address 0050aa70 + LKCP-block range 272565-272583
    were already correct. References section updated to match.
  - Section 5: add note that SetContactPlane re-latches LKCP fields
    (no-op when LKCP is the source, but non-obvious side effect)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
Erik 2026-05-22 08:20:24 +02:00
parent 6b4be7f863
commit c6bc2b9980
1 changed files with 12 additions and 11 deletions
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23
docs/research/2026-05-21-a6-p3-slice1-retail-mech-b-research.md
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@ -16,25 +16,25 @@ Retail decomp at `acclient_2013_pseudo_c.txt` lines 309573–309593 (address
// 0052c130 enum TransitionState __thiscall CEnvCell::find_env_collisions(
// class CEnvCell const* this, class CTransition* arg2)
{
// [309573] Check entry restrictions (object ethereal? door closed? etc.)
// Check entry restrictions (object ethereal? door closed? etc.)
enum TransitionState result = CObjCell::check_entry_restrictions(this, arg2);
if (result == OK_TS) {
// [309575] Clear obstruction-ethereal so BSP collision is live.
// 0052c144 Clear obstruction-ethereal so BSP collision is live.
arg2->sphere_path.obstruction_ethereal = 0;
if (this->structure->physics_bsp != 0) {
// [309578] Project sphere into cell-local space.
// 0052c169 Project sphere into cell-local space.
SPHEREPATH::cache_localspace_sphere(&arg2->sphere_path, &this->pos, 1f);
// [309580] Run BSP: INITIAL_PLACEMENT → placement_insert path;
// 0052c175 Run BSP: INITIAL_PLACEMENT → placement_insert path;
// all other insert_types → find_collisions path.
if (arg2->sphere_path.insert_type != INITIAL_PLACEMENT_INSERT)
result = BSPTREE::find_collisions(this->structure->physics_bsp, arg2, 1f);
else
result = BSPTREE::placement_insert(this->structure->physics_bsp, arg2);
// [309585] On collision with environment (non-Contact objects only).
// 0052c1a5 On collision with environment (non-Contact objects only).
if (result != OK_TS && (arg2->object_info.state & 1) == 0)
arg2->collision_info.collided_with_environment = 1;
}
@ -55,11 +55,10 @@ synthesis path anywhere in this function.
**Function:** `CTransition::validate_transition`
**Retail address:** `0050aa70`
**Decomp line range:** `acclient_2013_pseudo_c.txt` lines 272540–272700
**Identified via:** The awk step above returned: `272530 CTransition::check_collisions`,
meaning the most recent function header before line 272540 was
`CTransition::check_collisions` at line 272530. The `validate_transition`
function header appears at line 272538 (`0050aa70`).
**Decomp line range:** `acclient_2013_pseudo_c.txt` lines 272547–272700
**Identified via:** The `validate_transition` function header appears at line
272547 (`0050aa70`). Line 272538 is inside the preceding
`CTransition::check_collisions` function.
The LKCP-restore block runs at lines 272565–272582 (addresses `0050aaed`–`0050ab4c`).
@ -189,6 +188,8 @@ else
oi.State &= ~ObjectInfoState.OnWalkable;
```
> **Note:** `SetContactPlane` also re-latches `LastKnownContactPlane`, `LastKnownContactPlaneCellId`, and `LastKnownContactPlaneIsWater` (TransitionTypes.cs:258-261). Passing LKCP as the source means the re-latch is a no-op on those fields — functionally safe, but worth knowing if you later decide to inline the writes instead of using `SetContactPlane`.
**Note on the LKCP-update strategy divergence (Gap 3):** Retail's `validate_transition`
at `0050acff` does `last_known_contact_plane_valid = contact_plane_valid`
unconditionally — this means when contact is invalid and stays invalid, LKCP is
@ -256,7 +257,7 @@ slice 1.
## References
- `acclient_2013_pseudo_c.txt` lines 309570–309595 (`CEnvCell::find_env_collisions`)
- `acclient_2013_pseudo_c.txt` lines 272538–272700 (`CTransition::validate_transition`)
- `acclient_2013_pseudo_c.txt` lines 272547–272700 (`CTransition::validate_transition`)
- `src/AcDream.Core/Physics/TransitionTypes.cs` lines 2751–2873 (`ValidateTransition`)
- `src/AcDream.Core/Physics/TransitionTypes.cs` lines 1514–1777 (`FindEnvCollisions`)
- `src/AcDream.Core/Physics/PhysicsEngine.cs` lines 640–692 (`RunTransitionResolve`)