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fix #180: port retail's stateful camera sought-position - the sweep target converges onto the wall contact

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The camera-collision sweep strobed the eye 0.27m every ~5-10 frames while
the compressed chase boom moved along corridor walls (pulledIn 0.27<->0.53
on ~1.4mm input drift): RetailChaseCamera re-demanded the FULL-length ideal
boom from scratch each frame, so the pivot->eye ray re-rolled the same
knife-edge r+-eps graze on the double-faced slabs every frame, and its two
first-contact solutions tear-interleaved at ~1700fps into the #176
"stripes/triangles".

Retail never re-rolls that ray. CameraManager::UpdateCamera (0x00456660)
interpolates FROM THE CURRENT SWEPT VIEWER toward the desired pose
(interpolate_origin/rotation, stiffness 0.45 x dt x 10, clamped) and the
result becomes viewer_sought_position (SmartBox::PlayerPhysicsUpdatedCallback
0x00452d60); update_viewer (0x00453ce0) sweeps pivot->SOUGHT. Pressed against
a wall the sweep ray extends one interpolation step past the contact
(sub-mm at high fps), so a bistable graze can move the eye by at most that
step - the strobe is structurally impossible. A 0.4mm/2e-4 dead-band parks
the sought exactly on the viewer when converged (0x00456fcd-0x00457035).

- RetailChaseCamera: _dampedEye -> _soughtEye + _publishedEye (retail's two
  Positions); lerp base = the published (swept) viewer; sweep targets the
  sought; total-fallback (ViewerCellId==0) resets the sought like
  set_viewer(player_pos, 1). The old "collision must NOT feed back into the
  damped state" comment had the coupling backwards - what stays clean is the
  transient desired pose, not the sought.
- SweepEye untouched (faithful update_viewer port, exonerated by the #180
  investigation).
- Tests: the old pin asserting instant full re-extension after a clamp
  (the divergence itself) replaced with four retail pins: gradual
  re-extension, sweep-target-converges-onto-contact, total-fallback
  re-extends from the player, wall-press glide stability.
- Pseudocode doc: docs/research/2026-07-06-camera-sought-position-pseudocode.md
  (UpdateCamera tail incl. the sought derivation + set_viewer reset semantics
  + Frame interpolate/close_rotation).
- Register: AD-37 (forward-vector nlerp vs quaternion slerp), AD-38
  (init-at-full-extension vs retail re-extend-from-player) - both
  pre-existing, identified during the decomp reading.

Suites green (Core 2599+2skip / App 729+2skip / UI 425 / Net 385).
Pending: autonomous visual verify + user gate (#180 + the #176 re-gate).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Erik 2026-07-06 16:49:01 +02:00
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8
docs/ISSUES.md
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@ -48,7 +48,13 @@ Copy this block when adding a new issue:
## #180 — Camera-collision sweep bistable at a compressed boom → per-frame eye strobe (the #176 "stripes")
**Status:** OPEN — mechanism PINNED numerically; fix = port retail's stateful sought-position
**Status:** 🟡 FIX SHIPPED 2026-07-06 (stateful sought-position ported per
`CameraManager::UpdateCamera` 0x00456660 — the interpolation base is the
CURRENT swept viewer and the sweep targets the converging sought, never the
full-length boom; pseudocode
`docs/research/2026-07-06-camera-sought-position-pseudocode.md`; register
AD-37/AD-38 filed for the two pre-existing adaptations found in the reading).
Awaiting autonomous visual verify + the user gate (with the #176 re-gate).
**Severity:** HIGH (the visible flicker/stripe artifact the #176 gate keeps failing on; corridor camera constantly rides walls)
**Filed:** 2026-07-06
**Component:** camera / physics (NOT render — every render suspect eliminated by isolation)

2
docs/architecture/retail-divergence-register.md
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@ -96,6 +96,8 @@ accepted-divergence entries (#96, #49, #50).
| AD-34 | Retail's intrusive `DLListBase`/`DLListData` lists are managed `LinkedList<T>`s; node identity via `LinkedListNode<>` references (Phase R1 anim list, 2026-07-02; extended R2-Q3 to `MotionTableManager.pending_animations`; extended R4-V2 to `MoveToManager.pending_actions` — whose node type, retail `MoveToManager::MovementNode`, is RENAMED `MoveToNode` to avoid colliding with R2's `Motion/MotionNode.cs` pending_motions node) | `src/AcDream.Core/Physics/Motion/CSequence.cs` (`_animList`); `src/AcDream.Core/Physics/Motion/MotionTableManager.cs` (`_pendingAnimations`); `src/AcDream.Core/Physics/Motion/MoveToManager.cs` (`_pendingActions`) + `MoveToNode.cs` | Same topology + cursor semantics (curr_anim/first_cyclic/tail-anchored scans are node references); unlink/delete becomes `Remove(node)`; conformance tests pin the surgery state tables | Any retail behavior depending on the −4 pointer adjustment or node memory reuse (none observed in the decomp) would diverge; a reader grepping for retail's `MovementNode` name must find it via this row | `acclient.h` DLListBase; `r1-csequence-decomp.md` §0; `r2-motiontable-decomp.md` §11; `r4-moveto-decomp.md` node factories §4a |
| AD-35 | `MotionTableManager.PerformMovement`'s unhandled-type default case returns the named sentinel `0xFFFFFFFF` (`MotionTableManagerError.NotHandled`); retail's compiled code leaks the `CSequence*` pointer reinterpreted as the return code (BN-confirmed artifact, dead/unreachable — callers gate on type first) (R2-Q3, 2026-07-02) | `src/AcDream.Core/Physics/Motion/MotionTableManager.cs` (`PerformMovement` default case) | No retail caller consults the return value for unhandled types (RawCommand/StopRawCommand/MoveTo\*/TurnTo\* route elsewhere); returning a stable non-zero sentinel preserves the only observable contract (non-zero = not success) without fabricating a pointer-shaped number | If a future port wires a caller that passes unhandled types AND branches on the exact return value, it would see `0xFFFFFFFF` where retail saw an arbitrary pointer — flag at that port | `PerformMovement` 0x0051c0b0 (`r2-motiontable-decomp.md` §11 default-case note) |
| AD-36 | `IMotionDoneSink.MotionDone` consumed for CREATURE-class entities only: R3-W2 binds the seam to the entity's `MotionInterpreter.MotionDone` (player via `PlayerMovementController.Motion`, remotes via `RemoteMotion.Motion`, resolved at fire time); interp-less entities (statics that never receive a UM/UP and so never get a `RemoteMotion`) keep a diagnostic-recorder-only target — retail gives every CPhysicsObj a MovementManager/CMotionInterp (R2-Q4 seam, narrowed R3-W2, 2026-07-02; R5-V5 gave every `RemoteMotion`/player ONE literal `MovementManager` facade, so the residue is only the no-RemoteMotion class) | `src/AcDream.App/Rendering/GameWindow.cs` (TickAnimations MotionDoneTarget bind) | Motion for entities without a `RemoteMotion` (never UM/UP-touched) completes via the manager queue alone; nothing consumes their MotionDone until every sequencer-owning entity gets a host/`RemoteMotion` (doors DO have one since the R4-V5 door fix — first UM creates it) | An entity behavior depending on pending_motions bookkeeping in that no-RemoteMotion class (none known) would silently no-op | `CPhysicsObj::MotionDone` 0x0050fdb0; retire when every sequencer-owning entity constructs a `RemoteMotion`/host (post-M1.5 entity-class unification; R5-V5 closed the facade half) |
| AD-37 | Camera rotation state is a forward VECTOR (nlerp + normalize; roll always 0, up = world Z); retail's sought carries a full Frame and slerps quaternions (`Frame::interpolate_rotation` shortest-path slerp with 2e-4 nlerp fallback). The dead-band compares forward-vector distance against the same 2e-4 epsilon retail applies per quaternion component | `src/AcDream.App/Rendering/RetailChaseCamera.cs` (`_dampedForward`, `ApplyConvergenceSnap`) | The chase camera never rolls (heading frames are Z-up by construction), so a forward vector spans the reachable rotation space; identified (not introduced) during the #180 UpdateCamera tail reading | If a future camera mode needs roll (death cam, cutscene) the vector state can't represent it; large-angle per-frame turns nlerp (chord) vs slerp (arc) — imperceptible at 0.45-stiffness step sizes | `Frame::interpolate_rotation` 0x00535390, `Frame::close_rotation` 0x00455d70; pseudocode doc 2026-07-06-camera-sought-position |
| AD-38 | First camera frame seats sought = viewer = the full-length target eye (starts converged); retail hard resets both to the PLAYER's position (`set_viewer(pos, reset_sought=1)`) at login/teleport/cell-loss, so the retail camera visibly re-extends outward from the head over ~1 s | `src/AcDream.App/Rendering/RetailChaseCamera.cs` (`_initialised` branch) | acdream teleports don't reset the camera object today; the pivot-anchored sweep self-heals in one convergence, and the login zoom-out is cosmetic. Identified (not introduced) during the #180 reading | Login/teleport first frames show a fully-extended boom where retail shows a zoom-out; if a teleport lands the stale sought behind distant geometry the first sweeps clip until convergence (sub-second) | `SmartBox::set_viewer` 0x00452c40 (reset_sought=1 sites pc:92775, pc:92886); retire by wiring teleport → sought reset |
---

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docs/research/2026-07-06-camera-sought-position-pseudocode.md Normal file
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@ -0,0 +1,268 @@
# Retail camera sought-position derivation — pseudocode (#180 fix)
Source: `docs/research/named-retail/acclient_2013_pseudo_c.txt` (Sept 2013 EoR
build, PDB-named Binary Ninja decomp). Read 2026-07-06 for #180 (the
camera-sweep eye strobe = the #176 "stripes").
Functions covered (address = retail VA, line = pseudo-C line):
| Function | VA | pseudo-C line |
|---|---|---|
| `CameraManager::UpdateCamera` | `0x00456660` | 95505 |
| `SmartBox::PlayerPhysicsUpdatedCallback` | `0x00452d60` | 91836 |
| `SmartBox::set_viewer` | `0x00452c40` | 91780 |
| `SmartBox::update_viewer` (consumption; already ported) | `0x00453ce0` | 92761 |
| `CameraManager::QueryPivotPosition` | `0x004564f0` | 95448 |
| `Frame::interpolate_origin` | `0x005352f0` | 319607 |
| `Frame::interpolate_rotation` | `0x00535390` | 319618 |
| `Frame::close_rotation` | `0x00455d70` | 94838 |
| `CameraManager::CameraManager` (ctor defaults) | `0x00457090` | 95957 |
## 1. The state machine — three Positions, one loop
`SmartBox` holds **two viewer Positions**; `CameraManager` computes a third
(the desired pose) transiently each frame:
- **`viewer`** — the PUBLISHED camera pose. What the renderer/sound/sky use.
Written only by `set_viewer` (the swept result each frame).
- **`viewer_sought_position`** — the STATEFUL sweep target. Persisted across
frames. Converges from the current `viewer` toward the desired pose.
- **desired pose** (transient inside `UpdateCamera`) — pivot + heading-rotated
`viewer_offset`, the full-length ideal boom. Never swept directly.
Per-frame loop (order matters):
```
CPhysics::UseTime (0x00509900 loop, line 271640):
for each physics obj: CPhysicsObj::update_object(obj)
if obj == player:
SmartBox::PlayerPhysicsUpdatedCallback(smartbox) // 0x005099f2
→ sought = CameraManager::UpdateCamera(mgr, &viewer) // ← CURRENT swept viewer in
...later in the frame...
SmartBox::UseTime → SmartBox::update_viewer (called at 0x00454c34)
→ sweep viewer_sphere: pivot → sought
→ set_viewer(swept_result, reset_sought=0) // viewer = swept; sought UNTOUCHED
```
So each frame's sweep target derives from the PREVIOUS frame's collided
position. **The full-length ideal boom ray is never re-rolled per frame** —
that is the #180 fix: after a wall contact the sought sits at (or a small step
past) the contact, and re-extends toward the ideal pose gradually.
## 2. `SmartBox::set_viewer(pos, reset_sought)` — 0x00452c40
```
set_viewer(this, pos, reset_sought):
this->viewer = pos // objcell_id + frame
if reset_sought != 0:
this->viewer_sought_position = pos // HARD RESET of the sought
this->viewer_cell = null
... (viewer light, sound listener, sky position, SceneTool::SetupCamera)
```
`reset_sought=1` call sites: teleport/hard resets, the `player->cell == 0`
bail in `update_viewer` (:92775), and the total sweep-failure fallback
(:92886). This is why retail's camera re-extends outward from your head after
a portal: sought = viewer = player position, then converges back out to the
boom.
## 3. `SmartBox::PlayerPhysicsUpdatedCallback` — 0x00452d60
```
PlayerPhysicsUpdatedCallback(this):
Position ret = CameraManager::UpdateCamera(this->camera_manager, &this->viewer)
this->viewer_sought_position = ret // objcell_id (0x00452d84) + frame (0x00452d87)
```
The argument is `&this->viewer` — the **current swept** viewer, not the
previous sought. The return becomes the new sought.
## 4. `CameraManager::UpdateCamera(this, ret, viewer)` — 0x00456660
Head (previously read): disabled bail, dt bookkeeping, manual offset-key
integration, pivot query. Tail (read this session): the desired pose + the
stateful interpolation. Full shape:
```
UpdateCamera(this, ret, viewer): // viewer = SmartBox::viewer (swept)
if !m_bEnabled: return viewer // 0x00456672 — pass-through
dt = Timer::cur_time - last_update_time // real seconds, float64
last_update_time = Timer::cur_time
// Manual camera-adjust keys integrate into the offsets (held-key rates):
if m_dwCameraOffsetMovement: viewer_offset += FlagsToVector(flags) * dt // 0x004566ca
if m_dwPivotOffsetMovement: pivot_offset += FlagsToVector(flags) * dt // 0x00456718
pivot_obj = CPhysicsObj::GetObjectA(pivot_object_id)
ok = pivot_obj != null && QueryPivotPosition(&pivotPos) // 0x004567f1
if !ok: return viewer // 0x00457050 tail — pass-through
// ── Everything below happens in the VIEWER's coordinate space ──
p = Position::localtoglobal(viewer, pivotPos) // pivot origin in viewer space (0x00456815)
look = (0,0,0) // the look-direction accumulator
if target_status & 2: // LOOK_AT_OBJECT (0x0045684a)
target = GetObjectA(target_object_id) // + optional part anchor
t = localtoglobal(viewer, targetPos, target_offset)
d = t - p
if normalize(d) ok: look += d
if m_bAlignCameraToSlope && (target_status & 0x10): // ALIGN_WITH_PLANE (0x00456928)
avgVel = 5-slot ring average of pivot velocity // 0x00456944..0x00456a5f
if normalize(avgVel) ok:
if |avgVel.x| < 2e-4 && |avgVel.y| < 2e-4: // near-vertical motion only
n = (transient_state & CONTACT) ? contact_plane.N
: (heading-of-avgVel or (0,0,1)) // 0x00456ab1
fwd = pivot's local +Y in world // localtoglobalvec (0x00456b90)
slopeFwd = fwd - n * dot(fwd, n) // project facing onto the plane
if normalize(slopeFwd) ok:
if target_status & 1: look += headingFrame(slopeFwd).rotate(direction)
else: look += slopeFwd
else if target_status & 1: look += pivot.rotate(direction)
else: // not moving →
if target_status & 1: // LOOK_IN_DIRECTION (0x00456dfa)
look += pivot.rotate(direction) // player facing ⊗ this->direction
if normalize(look) failed: // 0x00456ca4 — degenerate accumulator
look = pivot.rotate(direction) // fall back to the facing direction
// ── Desired pose: boom offset in the heading frame ──
Frame headingFrame // var_40
headingFrame.origin = p // pivot, viewer-space (0x00456cd7-0x00456cf1)
headingFrame.set_vector_heading(look) // 0x00456cf8
desiredEye = headingFrame.localtoglobal(viewer_offset) // pivot + R(look)·offset (0x00456d0d)
if target_status & 4: // LOOK_AT_PIVOT (0x00456d33)
look = p - desiredEye // re-aim from the DESIRED eye at the pivot
if normalize(look) failed: look = (0,0,0)
if normalize(look) failed: // 0x00456e59
look = pivot.rotate(direction)
Frame desired // var_c8
desired.origin = desiredEye
desired.set_vector_heading(look) // 0x00456e8c
// ── Stiffness → per-frame interpolation factors ──
tSnap = t_stiffness >= 1.0 - 2e-4 // 0x00456e9e
t = tSnap ? 1.0 : min(t_stiffness * dt * 10, 1.0) // 0x00456ec2
rSnap = r_stiffness >= 1.0 - 2e-4 // 0x00456ee1
r = rSnap ? 1.0 : min(r_stiffness * dt * 10, 1.0) // 0x00456f04
// ── THE STATEFUL STEP: interpolate FROM THE SWEPT VIEWER ──
Frame f // var_150
f.interpolate_origin(viewer.frame, desired, t) // lerp origins (0x00456fae)
f.interpolate_rotation(viewer.frame, desired, r) // slerp quaternions (0x00456fc8)
// ── Dead-band: park the sought ON the viewer when converged ──
if !tSnap: // 0x00456fe6
if distance(f.origin, viewer) < 4e-4 // 2 × 2e-4 m (0x00456fe1, 0x00456fed)
&& !rSnap
&& Frame::close_rotation(f, viewer.frame, 2e-4):
return viewer // EXACT copy — sought parks on the viewer
return Position{ objcell_id: viewer.objcell_id, frame: f } // 0x00457038-0x00457071
```
Ctor defaults (0x00457090): `t_stiffness = r_stiffness = 0.45`,
`viewer_offset = (0,-3,0)`, `direction = (0,1,0)`,
`target_status = LOOK_IN_DIRECTION`, `m_bAlignCameraToSlope = 1`,
`m_rCameraAdjustmentSpeed = 40`.
### Units & feel
`t = 0.45 · dt · 10 = 4.5·dt` → an exponential approach with rate constant
4.5/s (time constant ≈ 0.22 s: the sought covers ~63% of the remaining gap
every 0.22 s, frame-rate independently). The dead-band (0.4 mm translation +
2e-4 quaternion-component rotation) turns the asymptote into an exact fixed
point.
## 5. Consumption: `SmartBox::update_viewer` — 0x00453ce0 (already ported)
Already faithfully ported by `PhysicsCameraCollisionProbe.SweepEye`
(exonerated in the #180 investigation — see the handoff's DO-NOT-RETRY). For
completeness, the sought's role:
```
update_viewer(this):
if player.cell == null: set_viewer(player.pos, reset_sought=1); return // :92775
pivot = player/part frame origin + R·pivot_offset // :92815
startCell = indoor ? AdjustPosition-seat at pivot : player.cell // :92832
sweep viewer_sphere (r=0.3): pivot → viewer_sought_position, flags 0x5c // :92860-92868
if find_valid_position ok: set_viewer(swept.curr_pos, 0); viewer_cell = swept.curr_cell
else if AdjustPosition(sought) ok: set_viewer(sought_seated, 0)
else: set_viewer(player.pos, reset_sought=1); viewer_cell = null // :92886
```
Note both `reset_sought=1` sites map to acdream's
`CameraSweepResult.ViewerCellId == 0` returns in `SweepEye` (the cell-0 bail
and Fallback 2) — a clean 1:1 seam for the port.
## 6. Frame helpers
```
Frame::interpolate_origin(this, a, b, t): // 0x005352f0
this.origin = (1-t)·a.origin + t·b.origin // plain lerp
Frame::interpolate_rotation(this, a, b, t): // 0x00535390
d = dot(a.q, b.q)
if d < 0: b.q = -b.q; d = -d // shortest-path sign flip
if 1-d < 2e-4: w = (1-t, t) // near-identical → nlerp weights
else: θ = acos(d); w = (sin((1-t)θ), sin(tθ)) / sin θ // slerp
this.q = w₀·a.q + w₁·b.q // (+ re-cache)
Frame::close_rotation(a, b, eps): // 0x00455d70
return |a.qw-b.qw| ≤ eps && |a.qx-b.qx| ≤ eps
&& |a.qy-b.qy| ≤ eps && |a.qz-b.qz| ≤ eps // component-wise, all four
```
## 7. Why this kills the #180 strobe (mechanism)
The probed failure: with the compressed boom moving along a wall, the
full-length pivot→ideal-eye ray grazes the corridor's double-faced slabs at
r±ε and has TWO first-contact solutions 0.27 m apart; mm-scale input drift
flips between them every few frames (`pulledIn` 0.27 ↔ 0.53).
With the retail sought: the target sits a single interpolation step past the
current contact — `α·|desired−viewer|` ≈ 0.7 mm at 1700 fps, ≈ 2 cm at 60 fps
(for the 0.27 m compression). The sweep ray extends only that far past the
wall, so even a bistable contact solution can only move the eye by the step
size, not 0.27 m. The strobe amplitude collapses from 0.27 m to sub-mm; the
eye glides along the wall following the player's drift. No damping of the
SWEPT result is involved — the published eye still hard-follows the sweep
every frame, exactly like retail.
## 8. Port mapping → `RetailChaseCamera`
| Retail | acdream |
|---|---|
| `viewer` (swept, published) | `_publishedEye` (+ `Position` property) |
| `viewer_sought_position` | `_soughtEye` (was `_dampedEye` — which wrongly lerped from ITSELF) |
| desired pose (transient) | `targetEye`/`targetForward` (existing boom math — unchanged) |
| `interpolate_origin(viewer→desired, t)` | `Vector3.Lerp(_publishedEye, targetEye, tAlpha)` |
| `interpolate_rotation(viewer→desired, r)` | forward-vector lerp (adaptation — register AD-37) |
| dead-band `return viewer` | `ApplyConvergenceSnap(_publishedEye, …)` parks sought on the viewer |
| `set_viewer(pos, 1)` resets sought | `swept.ViewerCellId == 0` → `_soughtEye = swept.Eye` |
| sweep pivot→sought | `SweepEye(pivotWorld, _soughtEye, …)` (was `_dampedEye` = full boom) |
Intentional adaptations (register rows added with the port commit):
- **AD-37** — rotation state is a forward VECTOR (nlerp + normalize, roll
always 0, up = world Z) instead of retail's quaternion slerp
(`interpolate_rotation` 0x00535390). Pre-existing shape of
`RetailChaseCamera`; the close_rotation dead-band test compares forward
vectors against the same 2e-4 epsilon.
- **AD-38** — first-frame init seats sought = viewer = the full-length target
eye; retail initializes via `set_viewer(player_pos, 1)` so the camera
re-extends from the player's head at login/teleport. acdream's teleports
don't reset the camera today; the pivot-anchored sweep self-heals within
one convergence (~1 s).
The previous in-code comment ("the collision must NOT feed back into the
damped state — retail keeps viewer_sought_position separate from viewer")
was WRONG about the direction of the coupling: retail's sought is derived
FROM the swept viewer every frame (0x00452d75); what stays clean is the
*desired pose*, which is recomputed transiently and never swept directly.
The old shape (lerp sought→ideal from itself + sweep the full boom) is what
made the knife-edge re-roll — and the #180 strobe — possible.

105
src/AcDream.App/Rendering/RetailChaseCamera.cs
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@ -8,8 +8,12 @@ namespace AcDream.App.Rendering;
/// Retail-faithful chase camera. Ports the chase-cam behavior from the
/// 2013 acclient (<c>CameraManager</c> + <c>CameraSet</c>, decomp at
/// <c>docs/research/named-retail/acclient_2013_pseudo_c.txt:95505</c>):
/// exponential damping toward a target pose, 5-frame velocity-averaged
/// slope-aligned heading frame, mouse-input low-pass filter.
/// a STATEFUL sought position that converges from the current swept
/// viewer toward the desired boom pose (<c>CameraManager::UpdateCamera</c>
/// 0x00456660 → <c>viewer_sought_position</c>, the #180 fix), 5-frame
/// velocity-averaged slope-aligned heading frame, mouse-input low-pass
/// filter. Pseudocode:
/// <c>docs/research/2026-07-06-camera-sought-position-pseudocode.md</c>.
///
/// <para>
/// Sits behind <see cref="CameraDiagnostics.UseRetailChaseCamera"/>
@ -97,11 +101,23 @@ public sealed class RetailChaseCamera : ICamera
private const float SnapEpsilon = 0.000199999995f * 2f;
private const float RotCloseEpsilon = 0.000199999995f;
// ── Damped state ────────────────────────────────────────────────
// ── Stateful camera state (retail SmartBox's two Positions) ─────
//
// _soughtEye = retail viewer_sought_position — the persisted sweep
// TARGET, re-derived each frame from the current swept
// viewer (NOT from itself).
// _publishedEye = retail viewer — the swept, published eye; the base
// of next frame's interpolation (SmartBox::
// PlayerPhysicsUpdatedCallback passes &this->viewer
// into UpdateCamera, 0x00452d75).
// _dampedForward = the sought's look direction. Sweeps translate but
// never rotate, so the viewer's rotation is always the
// previous sought rotation — one field serves both.
private readonly Vector3[] _velocityRing = new Vector3[5];
private int _velocityCount;
private Vector3 _dampedEye;
private Vector3 _soughtEye;
private Vector3 _publishedEye;
private Vector3 _dampedForward = new(1f, 0f, 0f);
private bool _initialised;
@ -155,10 +171,18 @@ public sealed class RetailChaseCamera : ICamera
Vector3 targetEye = pivotWorld + forward * (-horizontal) + up * vertical;
Vector3 targetForward = Vector3.Normalize(pivotWorld - targetEye);
// 5. Exponential damping (independent translation + rotation rates).
// 5. Stateful sought position (#180). Retail CameraManager::UpdateCamera
// (0x00456660) interpolates FROM THE CURRENT SWEPT VIEWER toward the
// desired pose and assigns the result to viewer_sought_position
// (SmartBox::PlayerPhysicsUpdatedCallback 0x00452d60) — the sweep
// target converges onto whatever the collision produced last frame
// and re-extends gradually. The full-length ideal boom is never swept
// directly. Pseudocode:
// docs/research/2026-07-06-camera-sought-position-pseudocode.md.
if (!_initialised)
{
_dampedEye = targetEye;
_soughtEye = targetEye;
_publishedEye = targetEye; // start converged (AD-38: retail re-extends from the player)
_dampedForward = targetForward;
_initialised = true;
}
@ -166,36 +190,48 @@ public sealed class RetailChaseCamera : ICamera
{
float tAlpha = ComputeDampingAlpha(CameraDiagnostics.TranslationStiffness, dt);
float rAlpha = ComputeDampingAlpha(CameraDiagnostics.RotationStiffness, dt);
Vector3 candidateEye = Vector3.Lerp(_dampedEye, targetEye, tAlpha);
// interpolate_origin(viewer.frame → desired, t) — the lerp base is the
// VIEWER (0x00456fae), not the previous sought. The forward base is the
// viewer's rotation ≡ the previous sought forward (sweeps never rotate).
Vector3 candidateEye = Vector3.Lerp(_publishedEye, targetEye, tAlpha);
Vector3 candidateForward = Vector3.Normalize(Vector3.Lerp(_dampedForward, targetForward, rAlpha));
// Retail UpdateCamera convergence snap (0x00456fcd): freeze at an exact fixed
// point once the lerp step is sub-epsilon, instead of dithering forever. This is
// the at-rest flicker fix — see ApplyConvergenceSnap + SnapEpsilon.
(_dampedEye, _dampedForward, _) =
ApplyConvergenceSnap(_dampedEye, _dampedForward, candidateEye, candidateForward);
// Retail UpdateCamera dead-band (0x00456fcd–0x00457035): once the step
// off the viewer is sub-epsilon in translation AND rotation, the sought
// parks EXACTLY ON the viewer — an exact fixed point instead of an
// asymptote. Kills the at-rest drift AND the residual micro-jitter when
// pressed against a wall. See ApplyConvergenceSnap + SnapEpsilon.
(_soughtEye, _dampedForward, _) =
ApplyConvergenceSnap(_publishedEye, _dampedForward, candidateEye, candidateForward);
}
// 5b. Spring-arm collision (A8.F). Retail SmartBox::update_viewer
// (0x00453ce0) keeps TWO states: viewer_sought_position (the damped
// desired eye) and viewer (the published eye = set_viewer(curr_pos)).
// The collision produces the PUBLISHED eye each frame but must NOT
// feed back into the damped state — writing the clamped result into
// _dampedEye makes next frame's lerp start from the wall and fight
// the clamp, which shows up as visible oscillation/vibration when the
// eye is pressed against a wall. So collide into a separate local and
// leave _dampedEye as the clean, uncollided sought position.
Vector3 publishedEye = _dampedEye;
// 5b. Spring-arm collision (A8.F / #180). Retail SmartBox::update_viewer
// (0x00453ce0) sweeps the viewer_sphere pivot → viewer_sought_position
// and publishes the swept result as the viewer (set_viewer(curr_pos, 0)
// — the sought is NOT reset on success). Pressed against a wall, the
// sweep ray extends only one interpolation step past the contact, so a
// knife-edge r±ε graze can move the eye by at most that step (sub-mm at
// high fps) instead of re-solving the full-length boom with its 0.27 m
// bistable contact pair — the #180 strobe fix.
Vector3 publishedEye = _soughtEye;
// The viewer cell defaults to the player cell (collision off / null probe); the sweep
// overwrites it with the swept cell (retail viewer_cell). Always set so GameWindow has a
// robust per-frame "which cell is the camera in?" answer.
ViewerCellId = cellId;
if (CameraDiagnostics.CollideCamera && CollisionProbe is not null)
{
var swept = CollisionProbe.SweepEye(pivotWorld, _dampedEye, cellId, selfEntityId, playerPosition);
var swept = CollisionProbe.SweepEye(pivotWorld, _soughtEye, cellId, selfEntityId, playerPosition);
publishedEye = swept.Eye;
ViewerCellId = swept.ViewerCellId;
// Total-failure fallback = retail set_viewer(player_pos, reset_sought=1)
// (update_viewer :92886 and the cell==0 bail :92775 — both surface here as
// ViewerCellId == 0): the sought resets to the returned position and
// re-extends from there.
if (swept.ViewerCellId == 0)
_soughtEye = swept.Eye;
}
// Retail viewer — the base of next frame's interpolation (step 5).
_publishedEye = publishedEye;
// 6. Publish renderer surface (from the collided eye; rotation stays the
// smoothly-damped look direction toward the pivot).
@ -396,22 +432,23 @@ public sealed class RetailChaseCamera : ICamera
}
/// <summary>
/// Retail <c>CameraManager::UpdateCamera</c> convergence snap (decomp 0x00456fcd).
/// After the per-frame lerp, if the translation step from <paramref name="dampedEye"/>
/// to <paramref name="candidateEye"/> is below <see cref="SnapEpsilon"/> AND the
/// rotation step is below <see cref="RotCloseEpsilon"/>, retail returns the input
/// position unchanged — an exact fixed point. Returns <c>frozen=true</c> with the
/// current state in that case; otherwise <c>frozen=false</c> with the candidate.
/// Both conditions are required (retail couples origin + rotation in the snap test),
/// Retail <c>CameraManager::UpdateCamera</c> dead-band (decomp 0x00456fcd–0x00457035).
/// After the per-frame lerp, if the translation step from <paramref name="viewerEye"/>
/// (the interpolation base = the current swept viewer) to <paramref name="candidateEye"/>
/// is below <see cref="SnapEpsilon"/> AND the rotation step is below
/// <see cref="RotCloseEpsilon"/>, retail returns the VIEWER unchanged — the sought
/// parks exactly on it (<c>return viewer</c>, 0x00457025). Returns <c>frozen=true</c>
/// with the viewer state in that case; otherwise <c>frozen=false</c> with the candidate.
/// Both conditions are required (retail couples origin + rotation in the test),
/// so the boom keeps converging while the heading is still turning.
/// </summary>
internal static (Vector3 eye, Vector3 forward, bool frozen) ApplyConvergenceSnap(
Vector3 dampedEye, Vector3 dampedForward, Vector3 candidateEye, Vector3 candidateForward)
Vector3 viewerEye, Vector3 viewerForward, Vector3 candidateEye, Vector3 candidateForward)
{
bool translationConverged = Vector3.Distance(candidateEye, dampedEye) < SnapEpsilon;
bool rotationConverged = Vector3.Distance(candidateForward, dampedForward) < RotCloseEpsilon;
bool translationConverged = Vector3.Distance(candidateEye, viewerEye) < SnapEpsilon;
bool rotationConverged = Vector3.Distance(candidateForward, viewerForward) < RotCloseEpsilon;
if (translationConverged && rotationConverged)
return (dampedEye, dampedForward, true); // freeze: exact fixed point
return (viewerEye, viewerForward, true); // park: exact fixed point on the viewer
return (candidateEye, candidateForward, false);
}

244
tests/AcDream.App.Tests/Rendering/RetailChaseCameraTests.cs
View file

@ -579,31 +579,233 @@ public class RetailChaseCameraTests
}
[Fact]
public void Update_CollisionDoesNotCorruptDampedState()
public void Update_AfterClampReleases_EyeReExtendsGradually()
{
// Regression for the wall-press vibration: the sweep must NOT write its
// clamped result back into the damped "sought" eye (retail keeps
// viewer_sought_position separate from viewer). Frame 1 clamps the eye
// near the pivot; frame 2 releases. With the damp state kept clean, the
// published eye returns straight to the (constant) target on frame 2; if
// it were corrupted, frame 2 would only lerp ~7.5% back from the clamp
// and stay pinned near it.
CameraDiagnostics.CollideCamera = true;
var probe = new ClampThenReleaseProbe { ClampEye = new Vector3(0f, 0f, 2f) };
var cam = new RetailChaseCamera { CollisionProbe = probe };
// #180: retail's sought position is STATEFUL — CameraManager::UpdateCamera
// (0x00456660) interpolates from the CURRENT SWEPT VIEWER toward the desired
// pose, so after an obstruction clears the eye re-extends at the stiffness
// rate (τ ≈ 0.22 s), NOT in one jump. (The previous pin here asserted the
// instant full re-extension — the exact divergence that re-rolled the
// full-length knife-edge boom ray per frame and produced the strobe.)
bool savedColl = CameraDiagnostics.CollideCamera;
float savedT = CameraDiagnostics.TranslationStiffness;
float savedR = CameraDiagnostics.RotationStiffness;
try
{
CameraDiagnostics.CollideCamera = true;
CameraDiagnostics.TranslationStiffness = 0.45f;
CameraDiagnostics.RotationStiffness = 0.45f;
void Step() => cam.Update(
playerPosition: Vector3.Zero, playerYaw: 0f, playerVelocity: Vector3.Zero,
isOnGround: true, contactPlaneNormal: Vector3.UnitZ, dt: 1f / 60f,
cellId: 0x100, selfEntityId: 0x5);
var probe = new ClampThenReleaseProbe { ClampEye = new Vector3(0f, 0f, 2f) };
var cam = new RetailChaseCamera { CollisionProbe = probe };
Step(); // frame 1: clamps to (0,0,2)
Step(); // frame 2: releases
void Step() => cam.Update(
playerPosition: Vector3.Zero, playerYaw: 0f, playerVelocity: Vector3.Zero,
isOnGround: true, contactPlaneNormal: Vector3.UnitZ, dt: 1f / 60f,
cellId: 0x100, selfEntityId: 0x5);
// Constant pose → target eye ≈ (-2.5, 0, 2.25). Full recovery means
// Position.X is near the target (< -2), not pinned near the clamp (X≈0).
Assert.True(cam.Position.X < -2f,
$"published eye should fully recover to the target after release, got {cam.Position}");
Step(); // frame 1: clamps to (0,0,2) — the viewer sits at the clamp
Step(); // frame 2: releases
// Constant pose → target eye ≈ (-2.5, 0, 2.25). Frame 2's eye is one
// 7.5% lerp step off the clamp (X ≈ -0.19) — near the clamp, NOT the
// full target.
Assert.True(cam.Position.X > -0.5f,
$"eye must re-extend gradually from the contact, got {cam.Position}");
// ...and converges onto the target over the following seconds.
for (int i = 0; i < 200; i++) Step();
Assert.True(cam.Position.X < -2.4f,
$"eye should converge to the target after release, got {cam.Position}");
}
finally
{
CameraDiagnostics.CollideCamera = savedColl;
CameraDiagnostics.TranslationStiffness = savedT;
CameraDiagnostics.RotationStiffness = savedR;
}
}
// Probe that records every requested sweep target and clamps the eye to a
// fixed contact point (a wall the boom is pressed into).
private sealed class RecordingClampProbe : ICameraCollisionProbe
{
public readonly System.Collections.Generic.List<Vector3> Requests = new();
public Vector3 ClampEye;
public CameraSweepResult SweepEye(Vector3 pivot, Vector3 desiredEye, uint cellId, uint selfEntityId, Vector3 playerPos)
{
Requests.Add(desiredEye);
return new CameraSweepResult(ClampEye, cellId);
}
}
[Fact]
public void Update_SweepTargetConvergesOntoContact_NotTheFullBoom()
{
// THE #180 structural pin. Retail sweeps pivot → viewer_sought_position
// (SmartBox::update_viewer 0x00453ce0), and the sought derives from the
// swept viewer — so while pressed against a wall the requested sweep
// target sits ONE interpolation step past the contact. acdream's old shape
// re-requested the full-length ideal boom every frame; with mm input drift
// that full ray grazed distant geometry at r±ε and flipped its first-contact
// solution 0.27 m along the boom every few frames (the #176 stripes).
bool savedColl = CameraDiagnostics.CollideCamera;
float savedT = CameraDiagnostics.TranslationStiffness;
float savedR = CameraDiagnostics.RotationStiffness;
try
{
CameraDiagnostics.CollideCamera = true;
CameraDiagnostics.TranslationStiffness = 0.45f;
CameraDiagnostics.RotationStiffness = 0.45f;
var wall = new Vector3(0f, 0f, 2f);
var probe = new RecordingClampProbe { ClampEye = wall };
var cam = new RetailChaseCamera { CollisionProbe = probe };
void Step() => cam.Update(
playerPosition: Vector3.Zero, playerYaw: 0f, playerVelocity: Vector3.Zero,
isOnGround: true, contactPlaneNormal: Vector3.UnitZ, dt: 1f / 60f,
cellId: 0x100, selfEntityId: 0x5);
Step(); // frame 1: init requests the full boom (AD-38), eye clamps to the wall
Step(); // frame 2: the request must now derive from the CLAMPED viewer
// Frame 1 documents the contrast: the init request is the full-length
// target, ~2.5 m from the contact.
Assert.True(Vector3.Distance(probe.Requests[0], wall) > 2f,
$"frame-1 init request should be the full boom, got {probe.Requests[0]}");
// Frame 2's request = one 7.5% lerp step off the wall (~0.19 m) — the
// knife-edge full-length ray is never re-rolled.
float reach = Vector3.Distance(probe.Requests[1], wall);
Assert.True(reach < 0.3f,
$"frame-2 sweep target must sit one step past the contact, got {reach:F3} m past it");
}
finally
{
CameraDiagnostics.CollideCamera = savedColl;
CameraDiagnostics.TranslationStiffness = savedT;
CameraDiagnostics.RotationStiffness = savedR;
}
}
// Probe that fails entirely on the FIRST call (retail set_viewer(player_pos, 1):
// eye = player, viewer_cell = 0), then releases; records requests.
private sealed class FallbackThenReleaseProbe : ICameraCollisionProbe
{
public readonly System.Collections.Generic.List<Vector3> Requests = new();
public int Calls;
public CameraSweepResult SweepEye(Vector3 pivot, Vector3 desiredEye, uint cellId, uint selfEntityId, Vector3 playerPos)
{
Calls++;
Requests.Add(desiredEye);
return Calls == 1
? new CameraSweepResult(playerPos, 0u) // total fallback (pc:92886)
: new CameraSweepResult(desiredEye, cellId);
}
}
[Fact]
public void Update_TotalFallback_ReExtendsFromThePlayer()
{
// After the total sweep failure retail resets viewer AND sought to the
// player's position (set_viewer(player_pos, reset_sought=1)) — the camera
// re-extends outward from the head, so the next sweep target is NEAR THE
// PLAYER, not the full-length boom.
bool savedColl = CameraDiagnostics.CollideCamera;
float savedT = CameraDiagnostics.TranslationStiffness;
float savedR = CameraDiagnostics.RotationStiffness;
try
{
CameraDiagnostics.CollideCamera = true;
CameraDiagnostics.TranslationStiffness = 0.45f;
CameraDiagnostics.RotationStiffness = 0.45f;
var probe = new FallbackThenReleaseProbe();
var cam = new RetailChaseCamera { CollisionProbe = probe };
void Step() => cam.Update(
playerPosition: Vector3.Zero, playerYaw: 0f, playerVelocity: Vector3.Zero,
isOnGround: true, contactPlaneNormal: Vector3.UnitZ, dt: 1f / 60f,
cellId: 0x100, selfEntityId: 0x5);
Step(); // frame 1: total fallback — viewer snaps to the player, cell 0
Assert.Equal(Vector3.Zero, cam.Position);
Assert.Equal(0u, cam.ViewerCellId);
Step(); // frame 2: the sweep target re-extends FROM the player
float reach = Vector3.Distance(probe.Requests[1], Vector3.Zero);
Assert.True(reach < 0.3f,
$"post-fallback sweep target must re-extend from the player, got {reach:F3} m out");
}
finally
{
CameraDiagnostics.CollideCamera = savedColl;
CameraDiagnostics.TranslationStiffness = savedT;
CameraDiagnostics.RotationStiffness = savedR;
}
}
// First-contact model of an infinite wall plane at X = WallX: requests whose
// ray from the pivot crosses the plane stop AT the plane; others pass through.
private sealed class WallPlaneProbe : ICameraCollisionProbe
{
public float WallX = -1f;
public CameraSweepResult SweepEye(Vector3 pivot, Vector3 desiredEye, uint cellId, uint selfEntityId, Vector3 playerPos)
{
if (desiredEye.X >= WallX || desiredEye.X - pivot.X >= -1e-6f)
return new CameraSweepResult(desiredEye, cellId);
float t = (WallX - pivot.X) / (desiredEye.X - pivot.X);
return new CameraSweepResult(pivot + (desiredEye - pivot) * t, cellId);
}
}
[Fact]
public void Update_PressedAgainstWall_EyeGlidesStably()
{
// The wall-press equilibrium: the sought parks one step past the contact,
// the sweep clips it back, and the published eye stays glued to the wall
// with no oscillation — retail's glide. (This was the fear behind the old
// "must not feed back" comment; the retail shape is stable by construction
// because the sweep target converges instead of fighting the full boom.)
bool savedColl = CameraDiagnostics.CollideCamera;
float savedT = CameraDiagnostics.TranslationStiffness;
float savedR = CameraDiagnostics.RotationStiffness;
try
{
CameraDiagnostics.CollideCamera = true;
CameraDiagnostics.TranslationStiffness = 0.45f;
CameraDiagnostics.RotationStiffness = 0.45f;
var cam = new RetailChaseCamera { CollisionProbe = new WallPlaneProbe { WallX = -1f } };
void Step() => cam.Update(
playerPosition: Vector3.Zero, playerYaw: 0f, playerVelocity: Vector3.Zero,
isOnGround: true, contactPlaneNormal: Vector3.UnitZ, dt: 1f / 60f,
cellId: 0x100, selfEntityId: 0x5);
// Settle a few frames, then watch 30 frames for per-frame jumps.
for (int i = 0; i < 5; i++) Step();
Vector3 prev = cam.Position;
float maxDelta = 0f;
for (int i = 0; i < 30; i++)
{
Step();
maxDelta = MathF.Max(maxDelta, Vector3.Distance(cam.Position, prev));
prev = cam.Position;
}
Assert.True(MathF.Abs(cam.Position.X - (-1f)) < 1e-3f,
$"eye should sit on the wall plane, got {cam.Position}");
Assert.True(maxDelta < 1e-3f,
$"pressed against a wall the eye must not jump frame-to-frame, max delta {maxDelta:F5} m");
}
finally
{
CameraDiagnostics.CollideCamera = savedColl;
CameraDiagnostics.TranslationStiffness = savedT;
CameraDiagnostics.RotationStiffness = savedR;
}
}
// ── Convergence snap (Part 1: kills the at-rest boom drift) ────────