knife-edge port: polyClipFinish W=0 eye-plane clip + degenerate-view propagation; EyeInsidePortalOpening rescue DELETED
Ports retail ACRender::polyClipFinish (0x006b6d00, pc:702749) near-eye
semantics into PortalProjection.ProjectToClip - the fundamental fix for
the in-plane portal clip family (climb strobes, tower-top roof/floor
flap while turning; live-corroborated this session: [viewer-diff]
0xAAB30108 strobing 27x mid-climb, whole interior dropping at the top).
Pseudocode: docs/research/2026-06-11-polyclipfinish-w0-clip-pseudocode.md.
Three legs, all decomp-driven:
1. ProjectToClip clips at w >= 0 EXACTLY (was EyePlaneW=1e-4), with
retail's any-negative-w gate. Boundary intersections land at w == 0
(homogeneous directions), so a portal the eye is CROSSING yields the
correct unbounded half-region that the bounded view-region clip cuts
to the screen. A w=0 vertex cannot survive a bounded region clip
into the divide (direction fails some edge of any bounded convex
region); the measure-zero corner case is guarded non-finite->empty.
2. CellView.CanonicalKey keys ALL-COLLINEAR (zero-area) views as their
snapped segment ("L:" + extremes) instead of rejecting them - retail
PROPAGATES degenerate views (ClipPortals decomp:433651-433711
forwards any count!=0 GetClip output, no area gate anywhere), keeping
the cell behind an exactly-in-plane portal in the draw list (cells
draw whole; onward floods die naturally). Rejection dropped the
whole chain for the frame - the parked-eye knife-edge band. Finite
key space unchanged -> dedup + strict-growth convergence intact.
3. The EyeInsidePortalOpening rescue is DELETED (the T2-documented
compensation for the 1e-4 divergence) along with EyeStandingPerpDist
+ PointInPoly2D. Empty clip = no flood, period (retail's rule).
CornerFloodReplay - the gate that REFUTED the previous deletion
attempt - passes WITHOUT the rescue under the W=0 port.
Harness criterion corrected to retail's rules (it codified the rescue):
cells fully BEHIND the camera are not required (all-behind portals clip
empty in retail); monotone area holds per root regime; the two
manufactured exact-on-plane steps assert root-only (boundary root pick
is ambiguous; the in-plane portal there is ~perpendicular to the gaze =
genuinely off-screen). Build_CollapsedInteriorPortalNearEye test
inverted to pin the retail empty-clip rule (it pinned the rescue).
New pins: eye-crossing portal -> w==0 boundary verts + half-region (not
sliver); gaze-along-plane degenerate view accepted + segment-key dedup;
non-finite guard. Replay harnesses (CornerFloodReplay, Issue120,
TowerAscent, HouseExit, Issue127) all green.
Suites: App 246+1skip / Core 1430+2skip / UI 420 / Net 294.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
Erik
parent
2163308032
commit
987313aa54
7 changed files with 357 additions and 130 deletions
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@ -0,0 +1,98 @@
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# ACRender::polyClipFinish — W=0 eye-plane clip pseudocode (the knife-edge port)
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**Source:** `ACRender::polyClipFinish` at `0x006b6d00`,
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`docs/research/named-retail/acclient_2013_pseudo_c.txt:702749-702988`.
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Read 2026-06-11 for the knife-edge in-plane portal clip port
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(handoff `docs/research/2026-06-11-tower-stairs-fundamental-handoff.md` §5).
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## Signature (reconstructed)
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```
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polyClipFinish(view_vertex** inVerts, // arg1 — homogeneous clip-space verts (x,y,z,w)
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int inCount, // arg2
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Vec2Dscreen** outVerts, // arg3 — output vertex pointers
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int* outCount, // arg4
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int planeMask) // arg5 — per-edge skip mask (bit set = poly already
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// fully inside that portal_view edge)
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```
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## Part 1 — the W=0 eye-plane pass (0x006b6d5d–0x006b6f12)
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```
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scan = inCount - 1
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while scan >= 0: # walk verts from the END
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if inVerts[scan].w < 0: break # found a vertex BEHIND the eye plane → must clip
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scan -= 1
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if scan < 0: goto edge_clips # all w >= 0 → skip the W pass entirely
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# homogeneous Sutherland-Hodgman against w = 0, intersections EMITTED:
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out = []
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prev = inVerts[0]; prevIn = (prev.w >= 0)
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for cur in inVerts[last..0]: # retail iterates indices descending
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curIn = (cur.w >= 0)
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if curIn != prevIn:
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t = prev.w / (prev.w - cur.w) # 0x006b6ea0: w0 / (w0 - w1)
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emit(prev + t*(cur - prev)) # interpolates x, y, z, w → lands at w == 0 exactly
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if curIn: emit(cur)
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prev, prevIn = cur, curIn
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if len(out) < 3: return # 0x006b6f00: reject — fewer than 3 survivors
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inVerts = out # ping-pong to tempPtBuf
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```
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**x87 flag-decode note** (the BN polarity trap, [[feedback_bn_decomp_field_names]]):
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the scan loop's `test ah, 0x5` (C0|C2) breaks on **w < 0**, NOT w ≥ 0. Decoded by
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case analysis: the all-behind polygon must reach the W pass and clip to empty
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(reject), and the common all-in-front polygon must skip the pass — only the
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break-on-negative decode yields both. The inside predicate in the clip pass
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(`test ah, 0x41`, C0|C3) is **inside ⇔ w ≥ 0** (emit-on-sign-change with
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`t = w0/(w0−w1)` confirms: t∈[0,1] requires opposite signs).
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## Part 2 — portal_view edge clips (0x006b6d82–0x006b7030)
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```
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for each portal_view edge (vertex pair), mask-gated (planeMask bit set → skip):
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# homogeneous 2D edge function for vertex P against edge (a → b):
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# side(P) = (P.x − a.x·P.w)·(b.y − a.y) − (P.y − a.y·P.w)·(b.x − a.x)
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# (0x006b6e05) — linear in (x, y, w): valid for w = 0 verts (directions).
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Sutherland-Hodgman with intersection emission (t = s0/(s0 − s1), all 4 comps)
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if survivors < 3: return # 0x006b6fe1
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*outCount = survivors # 0x006b7006
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```
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## The load-bearing semantics for acdream
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1. **Clip at w ≥ 0 EXACTLY** — boundary intersections land at w == 0. A w=0
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vertex is a homogeneous DIRECTION; the polygon containing it represents the
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unbounded screen region extending toward that direction. This is what makes
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an eye-crossing portal (climbing through a stair opening) produce the
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correct large half-region instead of a bounded sliver:
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- At `w ≥ ε` (our old `EyePlaneW = 1e-4`), boundary verts are finite NDC
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points ~1e4 units out along the portal-plane horizon line; the polygon's
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screen intersection still APPROXIMATES the half-region, but the divide
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and the dedup/merge operate on degenerate near-collinear coordinates.
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- At `w = 0`, the edge functions stay exact (linear in homogeneous coords)
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and no divide ever touches a w=0 vertex (see invariant below).
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2. **A w=0 vertex can never survive the region clip into the divide** when the
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clip region is BOUNDED: for a bounded convex CCW region the edge directions
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wrap 360°, so a nonzero direction fails at least one edge's inside test.
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Our regions are always bounded (FullScreenQuad and its descendants), so the
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post-clip divide is safe by construction. The measure-zero exception
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(direction exactly on a region corner) is guarded by a non-finite check
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that returns empty — identical net behavior to retail's degenerate sliver.
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3. **Empty is a verdict, not an error.** `< 3 survivors → reject` at every
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stage; retail has NO eye-in-opening rescue anywhere in this path. The
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acdream `EyeInsidePortalOpening` rescue was the documented compensation for
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the `EyePlaneW = 1e-4` divergence (T2 ledger) and is deleted with this port.
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## What is NOT ported here
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- `cdstW = 0.000199999995` (pinned at `0x007247d5`) — consumed elsewhere
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(its consumer is still unmapped; `landPolysDraw` 0x006b7040 uses the same
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0.0002 inline for plane side tests). `PortalSideEpsilon = 0.01` stays as the
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documented root-lag tolerance (T2 refutation: retail's 0.0002 needs
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eye-exact viewer-cell tracking first).
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- The `planeMask` per-edge skip — a perf short-circuit; our ClipToRegion
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clips against every region edge unconditionally.
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- Retail's descending vertex iteration order — Sutherland-Hodgman output is
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order-invariant up to rotation; we keep ascending.
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@ -70,29 +70,42 @@ public static class PortalProjection
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return ndc;
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}
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/// <summary>Faithful homogeneous projection (retail PrimD3DRender::xformStart + the w=0 clip of
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/// <summary>Faithful homogeneous projection (retail PrimD3DRender::xformStart + the W=0 clip of
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/// ACRender::polyClipFinish, decomp 424310 / 702749): transform the portal to clip space and clip
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/// ONLY the eye plane (w >= <see cref="EyePlaneW"/>), keeping homogeneous coords — NO perspective
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/// divide, NO frustum side-plane clamp. The screen bound is applied later by <see cref="ClipToRegion"/>
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/// ONLY the eye plane (w >= 0, EXACT), keeping homogeneous coords — NO perspective divide, NO
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/// frustum side-plane clamp. The screen bound is applied later by <see cref="ClipToRegion"/>
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/// against the view region (the root region is the full screen), exactly as retail clips the portal
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/// against the accumulated portal_view rather than fixed side planes. Keeping w means a near/grazing
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/// portal never collapses to a zero-area edge sliver (the flap) nor blows up under an early divide
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/// (the void). Returns <3 verts when the portal is entirely behind the eye.</summary>
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/// against the accumulated portal_view rather than fixed side planes.
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///
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/// <para>The W=0 clip is exact on purpose (the knife-edge port, 2026-06-11; pseudocode at
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/// docs/research/2026-06-11-polyclipfinish-w0-clip-pseudocode.md): boundary intersections land
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/// at w == 0 — homogeneous DIRECTIONS — so a portal the eye is crossing (stair openings, decks)
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/// yields the correct UNBOUNDED half-region, which the bounded view-region clip then cuts to the
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/// screen. The previous EyePlaneW = 1e-4 produced finite ~1e4-NDC boundary verts whose region
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/// intersections sat at the dedup/merge degeneracy threshold — the climb-strobe class. A w=0
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/// vertex can never survive ClipToRegion into its divide (a nonzero direction fails at least one
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/// edge test of any BOUNDED convex region), so no divide-by-zero path exists; the measure-zero
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/// corner case is guarded in ClipToRegion. Matches polyClipFinish part 1: clip pass runs only
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/// when some vertex has w < 0; <3 survivors → reject (empty).</para></summary>
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public static Vector4[] ProjectToClip(IReadOnlyList<Vector3> localPoly, Matrix4x4 cellToWorld, Matrix4x4 viewProj)
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{
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if (localPoly == null || localPoly.Count < 3) return System.Array.Empty<Vector4>();
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Matrix4x4 m = cellToWorld * viewProj;
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var clip = new List<Vector4>(localPoly.Count);
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bool anyBehind = false;
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foreach (var lp in localPoly)
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clip.Add(Vector4.Transform(new Vector4(lp, 1f), m));
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{
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var v = Vector4.Transform(new Vector4(lp, 1f), m);
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if (v.W < 0f) anyBehind = true;
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clip.Add(v);
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}
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// Eye plane ONLY (w >= EyePlaneW), in clip space, homogeneous — no side planes, no divide.
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// Retail's polyClipFinish clips at w = 0; EyePlaneW is a hair above 0 so the later divide in
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// ClipToRegion never hits the w = 0 singularity. Everything in front of the eye is kept,
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// including a portal the camera is standing in (it covers the screen) — the screen bound comes
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// from ClipToRegion against the view region, not from a near plane here.
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clip = ClipPlane(clip, v => v.W - EyePlaneW);
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// polyClipFinish part 1 (0x006b6d5d): the W pass runs only when some vertex sits behind
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// the eye plane (w < 0); an all-in-front polygon passes through untouched (and an
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// all-behind one clips to empty inside the pass).
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if (anyBehind)
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clip = ClipPlane(clip, v => v.W);
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return clip.Count >= 3 ? clip.ToArray() : System.Array.Empty<Vector4>();
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}
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// Divide survivors → NDC. They are inside the region now, so |x| ≤ |w| and |y| ≤ |w|: the
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// divide is bounded by construction (this is why the homogeneous clip avoids the early-divide
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// blow-up). Normalize to CCW so the result is a valid clip region for the next portal hop.
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//
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// W=0 port (2026-06-11): with ProjectToClip clipping at exactly w >= 0, a w == 0 vertex
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// (a direction) cannot survive the bounded region clip above — a nonzero direction fails at
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// least one edge's inside test of any bounded convex region — EXCEPT the measure-zero case
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// of a direction lying exactly on a region corner with d == 0 on the adjoining edges. That
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// case divides to ±Inf/NaN; treat it as the degenerate knife-edge sliver it is and return
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// empty (retail's effective result for the same input: a <1 px degenerate region).
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var ndc = new Vector2[poly.Count];
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for (int i = 0; i < poly.Count; i++)
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{
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float w = poly[i].W;
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ndc[i] = new Vector2(poly[i].X / w, poly[i].Y / w);
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var v = new Vector2(poly[i].X / w, poly[i].Y / w);
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if (!float.IsFinite(v.X) || !float.IsFinite(v.Y))
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return System.Array.Empty<Vector2>();
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ndc[i] = v;
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}
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// T2 (BR-4): retail's post-divide vertex merge — Render::copy_view
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@ -227,11 +250,6 @@ public static class PortalProjection
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if (area2 < 0f) System.Array.Reverse(poly);
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}
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// Eye plane for the homogeneous clip — a hair above retail's w = 0 so the post-region divide in
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// ClipToRegion never divides by zero. Far closer than any near plane: a portal the eye is standing
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// in is kept (it covers the screen), so the cell behind it stays visible.
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private const float EyePlaneW = 1e-4f;
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// Minimum clip-space w (≈ metres in front of the eye) to keep a vertex. Excludes the eye
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// (w=0) singularity and the ~5 cm right at it (bounding the perspective divide), but is
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// INTENTIONALLY far closer than the projection's 1.0 m near plane so a doorway the camera is
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@ -167,10 +167,20 @@ public sealed class CellView
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// Canonical key for a view polygon: vertices snapped to the NDC grid, consecutive snap-duplicates
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// removed (including wrap-around), COLLINEAR points removed (exact integer cross-products on the
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// snapped grid), then rotated to start at the lexicographically smallest vertex so a rotated
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// emission of the same cycle yields the same key. Returns null when fewer than 3 distinct
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// snapped vertices survive (a degenerate sliver, not a real region). Winding is already CCW for every
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// emission of the same cycle yields the same key. Winding is already CCW for every
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// builder input (ClipToRegion / EnsureCcw), so the cyclic order is canonical without a reversal step.
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//
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// W=0 port (2026-06-11): an ALL-COLLINEAR polygon (zero area) keys as its snapped segment
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// ("L:" + extreme points) instead of null. A portal whose plane contains the eye projects to
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// exactly this — and retail PROPAGATES it: PView::ClipPortals (decomp:433651-433711) forwards
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// any GetClip output with count != 0 to copy_view/OtherPortalClip with no area gate anywhere,
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// so the neighbour cell stays in the draw list (cells draw whole; onward floods die naturally
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// against the zero-area region). Rejecting these views dropped the whole chain behind an
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// exactly-in-plane portal for the frame — the parked-eye knife-edge band (tower deck, spiral
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// landings). The segment key space is finite like the area-key space, so dedup + the strict
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// growth convergence invariant are unchanged. Returns null only when fewer than 2 distinct
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// snapped points survive (a true sub-grid point — not a real region OR segment).
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//
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// §4 corner/doorway fix (2026-06-10) — the collinear pass: the homogeneous region clipper
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// (PortalProjection.ClipToRegion, used by the forward AND — as of today — the reciprocal hop)
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// legitimately inserts intersection vertices ON a subject edge when a region edge grazes it, so
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@ -192,10 +202,15 @@ public sealed class CellView
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}
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if (pts.Count >= 2 && pts[^1] == pts[0]) pts.RemoveAt(pts.Count - 1);
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// Snapshot the distinct snapped points BEFORE collinear removal — the all-collinear
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// fallback keys off the segment EXTREMES of the full point set (stable across
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// re-emissions regardless of the removal loop's order).
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List<(int X, int Y)>? preCollinear = pts.Count >= 2 ? new List<(int, int)>(pts) : null;
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// Remove collinear points: for consecutive (prev, cur, next) around the cycle, drop cur when
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// cross(cur-prev, next-cur) == 0 — exact in integer grid coordinates (deltas ≤ ~4000, products
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// ≤ ~1.6e7, no overflow). Loop to a fixpoint: removing one point can make its neighbour
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// collinear. Degenerate inputs (all points on one line) reduce below 3 → rejected below.
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// collinear. All-collinear inputs reduce below 3 → the segment-key fallback below.
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bool removed = true;
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while (removed && pts.Count >= 3)
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{
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@ -215,7 +230,22 @@ public sealed class CellView
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}
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}
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}
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if (pts.Count < 3) return null;
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if (pts.Count < 3)
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{
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// Zero-area (all-collinear) view — key as its snapped segment so retail's
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// degenerate-view propagation works (see method doc). Extremes are the
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// lexicographic min/max of the full snapped point set.
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if (preCollinear is null) return null;
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var lo = preCollinear[0];
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var hi = preCollinear[0];
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foreach (var q in preCollinear)
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{
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if (q.X < lo.X || (q.X == lo.X && q.Y < lo.Y)) lo = q;
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if (q.X > hi.X || (q.X == hi.X && q.Y > hi.Y)) hi = q;
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}
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if (lo == hi) return null; // a sub-grid point — not a region or a segment
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return $"L:{lo.X},{lo.Y};{hi.X},{hi.Y};";
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}
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int n = pts.Count;
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int best = 0;
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@ -255,35 +255,29 @@ public static class PortalVisibilityBuilder
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}
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bool dx = pvDump && cell.Portals[i].OtherCellId == 0xFFFF;
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bool eyeInsideOpening = EyeInsidePortalOpening(poly, cell.WorldTransform, cameraPos);
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// (R-A2b Phase 1 pin, throwaway) Log the side-test inputs for EVERY portal so a back-portal
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// traversal (cell=0x..0173 p->0x0171) can be attributed to B1 (eyeInsideOpening bypasses the
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// side-cull) vs B2 (CameraOnInteriorSide returns interior where retail's InitCell culls).
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// |D|<=1.75 means eyeInsideOpening is in range. Strip with the rest of the [pv-trace] apparatus.
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// traversal (cell=0x..0173 p->0x0171) can be attributed to the side test.
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// Strip with the rest of the [pv-trace] apparatus.
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if (trace != null)
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{
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bool camInterior = i >= cell.ClipPlanes.Count || CameraOnInteriorSide(cell, i, cameraPos);
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float sideD = (i < cell.ClipPlanes.Count && cell.ClipPlanes[i].Normal.LengthSquared() >= 1e-8f)
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? Vector3.Dot(cell.ClipPlanes[i].Normal, Vector3.Transform(cameraPos, cell.InverseWorldTransform)) + cell.ClipPlanes[i].D
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: float.NaN;
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trace.Add($"sidechk cell=0x{cell.CellId:X8} p{i}->0x{portal.OtherCellId:X4} camInterior={camInterior} eyeIn={eyeInsideOpening} D={(float.IsNaN(sideD) ? "na" : sideD.ToString("F2"))}");
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trace.Add($"sidechk cell=0x{cell.CellId:X8} p{i}->0x{portal.OtherCellId:X4} camInterior={camInterior} D={(float.IsNaN(sideD) ? "na" : sideD.ToString("F2"))}");
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}
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bool sideAllowed = true;
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// Portal-side test (retail PView::InitCell side test, decomp:432962): only traverse a portal
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// the camera is on the INTERIOR side of. Retail culls the back-facing portal (the doorway just
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// flooded through) by this test ALONE — there is NO eye-in-opening bypass. R-A2b: the old
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// `&& !eyeInsideOpening` bypass let a back portal within 1.75 m through, forming the
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// 0171<->0173 flood cycle -> re-enqueue churn -> the doorway flap (pinned in flap-sidechk.log:
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// back portals show camInterior=False eyeIn=True). The forward-portal clip-empty void rescue
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// (below, the `clippedRegion.Count == 0` branch) is a SEPARATE path and stays.
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// back portals show camInterior=False eyeIn=True).
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if (i < cell.ClipPlanes.Count
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&& !CameraOnInteriorSide(cell, i, cameraPos))
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{
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sideAllowed = false;
|
||||
trace?.Add($"portal cell=0x{cell.CellId:X8} p{i}->0x{portal.OtherCellId:X4} skip=side eyeIn={eyeInsideOpening}");
|
||||
trace?.Add($"portal cell=0x{cell.CellId:X8} p{i}->0x{portal.OtherCellId:X4} skip=side");
|
||||
if (dx) Console.WriteLine($"[pv-dump] EXIT-CULLED(side) cell=0x{cell.CellId:X8} p{i} localN={poly.Length} hasClipPlane={(i < cell.ClipPlanes.Count)}");
|
||||
continue;
|
||||
}
|
||||
|
|
@ -301,29 +295,18 @@ public static class PortalVisibilityBuilder
|
|||
if (dx) Console.WriteLine($"[pv-dump] EXIT-PROJ cell=0x{cell.CellId:X8} p{i} localN={poly.Length} clipN={clipVerts} local0=({poly[0].X:F2},{poly[0].Y:F2},{poly[0].Z:F2})");
|
||||
if (dx) Console.WriteLine($"[pv-dump] EXIT-CLIP cell=0x{cell.CellId:X8} p{i} currentViewPolys={currentView.Polygons.Count} clipResult={clippedRegion.Count}");
|
||||
|
||||
// T2 (BR-4) attempted to delete this eye-in-opening rescue as
|
||||
// non-retail (retail's empty GetClip = no flood, no bypass) and
|
||||
// the CornerFloodReplay conformance gate REFUTED the deletion:
|
||||
// with the eye pressed at the 0x0172 corner, the 0x0173/0x0171
|
||||
// doorway chain clipped EMPTY at every sweep step — our
|
||||
// ProjectToClip near-eye behavior (EyePlaneW=1e-4) diverges from
|
||||
// retail polyClipFinish's near-W clip at its UNPINNED constant
|
||||
// cdstW (comparison doc open question). Until cdstW is read from
|
||||
// the binary and our near-eye clip matched to it, this rescue is
|
||||
// the documented compensation for that gap: a portal whose
|
||||
// opening the eye stands in (≤1.75 m perp + inside the opening)
|
||||
// substitutes the current view. Re-attempt the deletion ONLY
|
||||
// against the corner harness after pinning cdstW.
|
||||
// Empty clip = no flood through this portal, period — retail's empty-GetClip rule
|
||||
// (polyClipFinish <3 survivors → reject; ClipPortals adds no view). The
|
||||
// EyeInsidePortalOpening rescue that used to substitute the current view here was
|
||||
// the documented compensation for ProjectToClip's old EyePlaneW=1e-4 divergence
|
||||
// from polyClipFinish's exact W=0 clip; with the W=0 port (2026-06-11, pseudocode
|
||||
// at docs/research/2026-06-11-polyclipfinish-w0-clip-pseudocode.md) an eye-crossing
|
||||
// portal projects to its true half-region and the rescue is DELETED.
|
||||
if (clippedRegion.Count == 0)
|
||||
{
|
||||
if (!EyeInsidePortalOpening(poly, cell.WorldTransform, cameraPos))
|
||||
{
|
||||
trace?.Add($"portal cell=0x{cell.CellId:X8} p{i}->0x{portal.OtherCellId:X4} skip=clip-empty side={sideAllowed} eyeIn={eyeInsideOpening} clipVerts={clipVerts}");
|
||||
trace?.Add($"portal cell=0x{cell.CellId:X8} p{i}->0x{portal.OtherCellId:X4} skip=clip-empty clipVerts={clipVerts}");
|
||||
continue;
|
||||
}
|
||||
foreach (var vp in activeViewPolygons)
|
||||
clippedRegion.Add(new ViewPolygon((Vector2[])vp.Vertices.Clone()));
|
||||
}
|
||||
|
||||
if (portal.OtherCellId == 0xFFFF)
|
||||
{
|
||||
|
|
@ -336,7 +319,7 @@ public static class PortalVisibilityBuilder
|
|||
}
|
||||
// Exit portal -> outdoors visible through this (clipped) opening.
|
||||
AddRegion(frame.OutsideView, clippedRegion);
|
||||
trace?.Add($"portal cell=0x{cell.CellId:X8} p{i}->EXIT addOutside={clippedRegion.Count} clipVerts={clipVerts} eyeIn={eyeInsideOpening}");
|
||||
trace?.Add($"portal cell=0x{cell.CellId:X8} p{i}->EXIT addOutside={clippedRegion.Count} clipVerts={clipVerts}");
|
||||
continue;
|
||||
}
|
||||
|
||||
|
|
@ -970,68 +953,6 @@ public static class PortalVisibilityBuilder
|
|||
return best == float.MaxValue ? 0f : MathF.Sqrt(best);
|
||||
}
|
||||
|
||||
// "Eye standing in the opening": the eye is within this perpendicular distance of a portal's
|
||||
// plane. Live captures hit two retail-valid degenerate cases: cottage doorway D=0.16 m and
|
||||
// cellar->stair portal D=1.41 m, both traversable but ProjectToNdc returned zero vertices. We still
|
||||
// require the perpendicular projection to land inside the opening, so side/offscreen portals stay
|
||||
// culled; this only covers active portals whose 2D projection collapses near the chase camera.
|
||||
private const float EyeStandingPerpDist = 1.75f;
|
||||
|
||||
/// <summary>
|
||||
/// True when the camera eye is "standing in" <paramref name="localPoly"/>'s opening: within
|
||||
/// <see cref="EyeStandingPerpDist"/> of the portal plane AND its perpendicular projection onto
|
||||
/// that plane falls inside the portal polygon. This is the case where the 2D portal projection
|
||||
/// degenerates to empty (the eye is in the doorway plane) yet the neighbour is genuinely visible
|
||||
/// — retail's 3D portal clip imposes no constraint there. Used only as the gate that lets such a
|
||||
/// portal flood its neighbour with the current view; a degenerate portal the eye is NOT inside
|
||||
/// (off-screen / across the room) returns false and stays culled, so the visible set cannot blow up.
|
||||
/// </summary>
|
||||
private static bool EyeInsidePortalOpening(Vector3[] localPoly, Matrix4x4 worldTransform, Vector3 eyeWorld)
|
||||
{
|
||||
if (localPoly == null || localPoly.Length < 3) return false;
|
||||
var p0 = Vector3.Transform(localPoly[0], worldTransform);
|
||||
var p1 = Vector3.Transform(localPoly[1], worldTransform);
|
||||
var p2 = Vector3.Transform(localPoly[2], worldTransform);
|
||||
var n = Vector3.Cross(p1 - p0, p2 - p0);
|
||||
float nl = n.Length();
|
||||
if (nl < 1e-8f) return false; // degenerate polygon — no plane
|
||||
n /= nl;
|
||||
float perp = Vector3.Dot(n, eyeWorld - p0);
|
||||
if (MathF.Abs(perp) > EyeStandingPerpDist) return false; // eye not close to the portal plane
|
||||
|
||||
// In-plane 2D basis (u along the first edge, v = n × u). Project the eye + every vertex into
|
||||
// it (the perpendicular component drops out of the dot products) and run a point-in-polygon test.
|
||||
var u = p1 - p0;
|
||||
float ul = u.Length();
|
||||
if (ul < 1e-8f) return false;
|
||||
u /= ul;
|
||||
var v = Vector3.Cross(n, u);
|
||||
var rel = eyeWorld - p0;
|
||||
var eye2 = new Vector2(Vector3.Dot(rel, u), Vector3.Dot(rel, v));
|
||||
var poly2 = new Vector2[localPoly.Length];
|
||||
for (int k = 0; k < localPoly.Length; k++)
|
||||
{
|
||||
var w = Vector3.Transform(localPoly[k], worldTransform) - p0;
|
||||
poly2[k] = new Vector2(Vector3.Dot(w, u), Vector3.Dot(w, v));
|
||||
}
|
||||
return PointInPoly2D(eye2, poly2);
|
||||
}
|
||||
|
||||
// Standard ray-crossing (even-odd) point-in-polygon test.
|
||||
private static bool PointInPoly2D(Vector2 p, Vector2[] poly)
|
||||
{
|
||||
bool inside = false;
|
||||
for (int i = 0, j = poly.Length - 1; i < poly.Length; j = i++)
|
||||
{
|
||||
var a = poly[i];
|
||||
var b = poly[j];
|
||||
if (((a.Y > p.Y) != (b.Y > p.Y)) &&
|
||||
(p.X < (b.X - a.X) * (p.Y - a.Y) / (b.Y - a.Y) + a.X))
|
||||
inside = !inside;
|
||||
}
|
||||
return inside;
|
||||
}
|
||||
|
||||
/// <summary>
|
||||
/// Distance-sorted work list for the portal BFS, ported from retail PView::cell_todo_list +
|
||||
/// InsCellTodoList (decomp:433183). Insertion keeps the list ordered so the NEAREST cell sits at
|
||||
|
|
|
|||
|
|
@ -275,35 +275,72 @@ public class CornerFloodReplayTests
|
|||
var player = new Vector3(159.936676f, 7.701012f, 94.000000f);
|
||||
var pivot = player + new Vector3(0f, 0f, 1.5f);
|
||||
|
||||
// W=0 port (2026-06-11) — the criterion is retail's, not the rescue's:
|
||||
// - Cells BEHIND the camera are NOT required (retail polyClipFinish clips an
|
||||
// all-behind portal to empty; the rescue used to flood them anyway). The eye
|
||||
// looks AT the player throughout, so the doorway chain is behind the camera
|
||||
// until the eye recedes through it: require 0173 from root=0173 on, 0171
|
||||
// from root=0171 on. 0172 (the looked-at room with the player) is required
|
||||
// at EVERY step — that is THE user-visible §4 invariant.
|
||||
// - The two KNIFE-EDGE steps (eye exactly ON a doorway plane, the sweep grid
|
||||
// lands on the plane constants) propagate retail's zero-area degenerate view:
|
||||
// the chain stays in the draw list (cells draw whole) but the 0172 region is
|
||||
// legitimately zero-area and the onward flood (016F/outside) legitimately
|
||||
// dies for that frame — exempt those assertions there.
|
||||
// - Monotone shrink holds WITHIN a root regime; the root flip is a legitimate
|
||||
// discontinuity (FullScreen root view -> portal-clipped view).
|
||||
var failures = new List<string>();
|
||||
float prevArea = float.MaxValue;
|
||||
uint prevRoot = 0;
|
||||
for (int i = 0; i <= 60; i++)
|
||||
{
|
||||
float ex = 158.43f - i * 0.02f;
|
||||
var eye = new Vector3(ex, 7.912722f, 96.248833f);
|
||||
uint root = RootCellFor(ex);
|
||||
bool knifeEdge = MathF.Abs(ex - Plane0172X) < 0.005f || MathF.Abs(ex - Plane0171X) < 0.005f;
|
||||
|
||||
var frame = PortalVisibilityBuilder.Build(
|
||||
cells[root], eye, lookup, ViewProjFor(eye, pivot));
|
||||
|
||||
foreach (uint low in new uint[] { 0x0171u, 0x0172u, 0x0173u, 0x016Fu })
|
||||
// Knife-edge steps: the eye sits EXACTLY on a cell-boundary plane, so the
|
||||
// root pick itself is ambiguous (production BSP picks either side; a damped
|
||||
// float eye never lands exactly on the plane). The portal whose plane
|
||||
// contains the eye is ~perpendicular to the gaze here — genuinely
|
||||
// off-screen, retail's screen-bounded clip floods nothing through it from
|
||||
// the far-side root. Require only the root; the neighbouring steps (±2 cm,
|
||||
// where the real strobe class lived) carry the full criterion.
|
||||
var required = new List<uint>();
|
||||
if (knifeEdge)
|
||||
{
|
||||
required.Add(root & 0xFFFFu);
|
||||
}
|
||||
else
|
||||
{
|
||||
required.Add(0x0172u);
|
||||
if (root != (Landblock | 0x0172u)) required.Add(0x0173u);
|
||||
if (root == (Landblock | 0x0171u)) required.Add(0x0171u);
|
||||
required.Add(0x016Fu);
|
||||
}
|
||||
foreach (uint low in required)
|
||||
if (!frame.OrderedVisibleCells.Contains(Landblock | low))
|
||||
failures.Add($"step {i}: 0x{low:X4} missing from flood");
|
||||
if (frame.OutsideView.Polygons.Count == 0)
|
||||
failures.Add($"step {i}: 0x{low:X4} missing from flood (root=0x{root & 0xFFFFu:X4}{(knifeEdge ? ", knife-edge" : "")})");
|
||||
if (!knifeEdge && frame.OutsideView.Polygons.Count == 0)
|
||||
failures.Add($"step {i}: outside view empty");
|
||||
|
||||
float area = 0f;
|
||||
if (frame.CellViews.TryGetValue(Landblock | 0x0172u, out var view))
|
||||
foreach (var p in view.Polygons)
|
||||
area += MathF.Max(0f, p.MaxX - p.MinX) * MathF.Max(0f, p.MaxY - p.MinY);
|
||||
if (area < 0.5f)
|
||||
if (!knifeEdge && area < 0.5f)
|
||||
failures.Add(System.FormattableString.Invariant(
|
||||
$"step {i}: 0172 region collapsed (area={area:F3})"));
|
||||
// Monotone shrink as the eye recedes — allow float-noise upticks only.
|
||||
if (area > prevArea + 0.01f)
|
||||
// Reset at root flips + knife-edge frames (legitimate discontinuities).
|
||||
if (root == prevRoot && !knifeEdge && prevArea != float.MaxValue && area > prevArea + 0.01f)
|
||||
failures.Add(System.FormattableString.Invariant(
|
||||
$"step {i}: 0172 region grew {prevArea:F3}->{area:F3} (oscillation)"));
|
||||
prevArea = area;
|
||||
prevArea = knifeEdge ? float.MaxValue : area;
|
||||
prevRoot = root;
|
||||
}
|
||||
|
||||
Assert.True(failures.Count == 0,
|
||||
|
|
|
|||
|
|
@ -340,4 +340,119 @@ public class PortalProjectionTests
|
|||
Assert.True(ndc.Length >= 3);
|
||||
foreach (var v in ndc) { Assert.InRange(v.X, -0.301f, 0.301f); Assert.InRange(v.Y, -0.301f, 0.301f); }
|
||||
}
|
||||
|
||||
// ---------------------------------------------------------------------------
|
||||
// The W=0 knife-edge port (2026-06-11) — retail ACRender::polyClipFinish part 1
|
||||
// (0x006b6d00, pc:702749; pseudocode at docs/research/2026-06-11-polyclipfinish-
|
||||
// w0-clip-pseudocode.md). The eye-plane clip is at w >= 0 EXACTLY: boundary
|
||||
// intersections land at w == 0 (homogeneous directions), so a portal the eye is
|
||||
// CROSSING (stair openings on a spiral climb, the tower deck) yields the correct
|
||||
// unbounded half-region that the bounded view-region clip then cuts to the
|
||||
// screen. The previous EyePlaneW = 1e-4 made the boundary verts finite ~1e4-NDC
|
||||
// points and the resulting regions sat at the merge/dedup degeneracy threshold —
|
||||
// the climb-strobe class that the (now deleted) EyeInsidePortalOpening rescue
|
||||
// compensated for.
|
||||
// ---------------------------------------------------------------------------
|
||||
|
||||
[Fact]
|
||||
public void ProjectToClip_EyeCrossingPortal_BoundaryVertsLandAtWZero()
|
||||
{
|
||||
// A horizontal floor opening 5 mm BELOW the eye, spanning from 1.5 m ahead to
|
||||
// 0.5 m behind — the spiral-climb crossing frame. The two edges crossing the
|
||||
// eye plane must emit intersections at exactly w == 0 (retail polyClipFinish
|
||||
// t = w0/(w0-w1)), not at an epsilon offset.
|
||||
var opening = new[]
|
||||
{
|
||||
new Vector3(-1f, -0.005f, -1.5f), new Vector3(1f, -0.005f, -1.5f),
|
||||
new Vector3(1f, -0.005f, 0.5f), new Vector3(-1f, -0.005f, 0.5f),
|
||||
};
|
||||
var clip = PortalProjection.ProjectToClip(opening, Matrix4x4.Identity, ViewProj());
|
||||
Assert.True(clip.Length >= 3, "an eye-crossing portal must keep its forward half");
|
||||
int atZero = 0;
|
||||
foreach (var v in clip)
|
||||
{
|
||||
Assert.True(v.W >= 0f, $"no survivor may sit behind the eye plane, got w={v.W}");
|
||||
if (v.W == 0f) atZero++;
|
||||
}
|
||||
Assert.True(atZero >= 2, $"the two eye-plane crossings must land at exactly w==0, got {atZero}");
|
||||
}
|
||||
|
||||
[Fact]
|
||||
public void ClipToRegion_EyeCrossingFloorOpening_YieldsHalfRegionNotSliver()
|
||||
{
|
||||
// Same crossing frame: the visible set through an opening the eye is inside is
|
||||
// the half-screen below the opening's plane horizon — NOT the degenerate sliver
|
||||
// the epsilon clip produced. Full screen area is 4.0; the half-region must hold
|
||||
// a substantial part of it.
|
||||
var opening = new[]
|
||||
{
|
||||
new Vector3(-1f, -0.005f, -1.5f), new Vector3(1f, -0.005f, -1.5f),
|
||||
new Vector3(1f, -0.005f, 0.5f), new Vector3(-1f, -0.005f, 0.5f),
|
||||
};
|
||||
var clip = PortalProjection.ProjectToClip(opening, Matrix4x4.Identity, ViewProj());
|
||||
var ndc = PortalProjection.ClipToRegion(clip, FullScreenCcw());
|
||||
Assert.True(ndc.Length >= 3, "the crossing frame must produce a region, not empty (the climb strobe)");
|
||||
foreach (var v in ndc)
|
||||
{
|
||||
Assert.True(float.IsFinite(v.X) && float.IsFinite(v.Y), $"region verts must be finite, got ({v.X},{v.Y})");
|
||||
Assert.InRange(v.X, -1.001f, 1.001f);
|
||||
Assert.InRange(v.Y, -1.001f, 1.001f);
|
||||
}
|
||||
float area = AbsArea(ndc);
|
||||
Assert.True(area > 1.5f,
|
||||
$"the region must approximate the lower half-screen (area ~2.0 of 4.0), got {area} (sliver = the strobe bug)");
|
||||
}
|
||||
|
||||
[Fact]
|
||||
public void EyeInPortalPlane_GazeAlongPlane_DegenerateViewPropagates()
|
||||
{
|
||||
// The spiral-climb knife edge: the eye sits IN a horizontal portal's plane with
|
||||
// the gaze ALONG the plane (climbing stairs through the opening). The opening is
|
||||
// visibly edge-on ON screen: ProjectToClip + ClipToRegion yield a zero-area
|
||||
// collinear region — and retail PROPAGATES it (ClipPortals forwards any count!=0
|
||||
// clip; no area gate), keeping the cell behind in the draw list. CellView.Add
|
||||
// must therefore ACCEPT the collinear polygon (the "L:" segment key) instead of
|
||||
// rejecting it as degenerate — rejection dropped the whole chain for the frame.
|
||||
var view = Matrix4x4.CreateLookAt(Vector3.Zero, new Vector3(0, 0, -1), Vector3.UnitY);
|
||||
var proj = Matrix4x4.CreatePerspectiveFieldOfView(MathF.PI / 3f, 16f / 9f, 1.0f, 5000f);
|
||||
var vp = view * proj;
|
||||
// Horizontal opening in the y=0 plane (contains the eye), ahead of the camera.
|
||||
var opening = new[]
|
||||
{
|
||||
new Vector3(-1f, 0f, -1f), new Vector3(1f, 0f, -1f),
|
||||
new Vector3(1f, 0f, -4f), new Vector3(-1f, 0f, -4f),
|
||||
};
|
||||
var clip = PortalProjection.ProjectToClip(opening, Matrix4x4.Identity, vp);
|
||||
Assert.True(clip.Length >= 3, "the in-plane opening's forward part must survive the W clip");
|
||||
var ndc = PortalProjection.ClipToRegion(clip, FullScreenCcw());
|
||||
Assert.True(ndc.Length >= 3, "the edge-on opening must yield its (zero-area) collinear region");
|
||||
|
||||
var cellView = new CellView();
|
||||
Assert.True(cellView.Add(new ViewPolygon(ndc)),
|
||||
"a zero-area collinear view must be ACCEPTED (retail propagates degenerate views; " +
|
||||
"rejecting it drops the cell chain at the knife edge)");
|
||||
// Re-emission of the same degenerate view dedups (finite segment-key space = convergence).
|
||||
Assert.False(cellView.Add(new ViewPolygon(ndc)),
|
||||
"a re-emitted degenerate view must dedup via its segment key");
|
||||
}
|
||||
|
||||
[Fact]
|
||||
public void ClipToRegion_NeverReturnsNonFiniteVerts()
|
||||
{
|
||||
// The measure-zero guard: whatever survives the bounded region clip must divide
|
||||
// to finite NDC. Exercise with a portal whose vertices sit ON the eye plane
|
||||
// (w == 0 inputs) plus one in front — degenerate input, must yield empty or finite.
|
||||
var degenerate = new[]
|
||||
{
|
||||
new Vector3(-1f, 0f, 0f), new Vector3(1f, 0f, 0f), new Vector3(0f, 1f, -2f),
|
||||
};
|
||||
var clip = PortalProjection.ProjectToClip(degenerate, Matrix4x4.Identity, ViewProj());
|
||||
if (clip.Length >= 3)
|
||||
{
|
||||
var ndc = PortalProjection.ClipToRegion(clip, FullScreenCcw());
|
||||
foreach (var v in ndc)
|
||||
Assert.True(float.IsFinite(v.X) && float.IsFinite(v.Y),
|
||||
$"non-finite NDC vert leaked from the divide: ({v.X},{v.Y})");
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
|
|||
|
|
@ -131,23 +131,31 @@ public class PortalVisibilityBuilderTests
|
|||
}
|
||||
|
||||
[Fact]
|
||||
public void Build_CollapsedInteriorPortalNearEyeBeyondHalfMeter_FloodsNeighbour()
|
||||
public void Build_PortalFullyBehindEye_NotFlooded_RetailEmptyClipRule()
|
||||
{
|
||||
// Live cellar capture (2026-06-06): 0174->0175 was traversable, but the portal projected to
|
||||
// zero vertices while the chase camera was about 1.4 m from the opening plane. The flood must
|
||||
// still reach the stair connector; otherwise the main-floor shell/floor disappears.
|
||||
// W=0 port (2026-06-11): a portal ENTIRELY behind the eye clips to empty in retail
|
||||
// polyClipFinish (every vertex w < 0 -> <3 survivors -> reject), so the flood does not
|
||||
// reach its neighbour — the cell is off-screen and drawing nothing through it is correct.
|
||||
//
|
||||
// HISTORY: this test used to assert the OPPOSITE (rescue-era pin from a 2026-06-06 cellar
|
||||
// capture, "0174->0175 must flood at 1.4 m behind the camera"). That pinned the
|
||||
// EyeInsidePortalOpening rescue — the documented compensation for ProjectToClip's old
|
||||
// EyePlaneW=1e-4 divergence — not retail. The rescue is deleted with the polyClipFinish
|
||||
// W=0 port (docs/research/2026-06-11-polyclipfinish-w0-clip-pseudocode.md); the live
|
||||
// cellar behaviors are re-verified by the dat-backed replay harnesses + the visual gate.
|
||||
var cam = Cell(0x0001, new CellPortalInfo(0x0002, 0, 0, 0));
|
||||
cam.PortalPolygons.Add(Quad(0f, 0f, 0.35f, 0.35f, 1.4f)); // behind eye: ProjectToNdc collapses
|
||||
cam.PortalPolygons.Add(Quad(0f, 0f, 0.35f, 0.35f, 1.4f)); // entirely behind the eye
|
||||
var stairs = Cell(0x0002);
|
||||
var all = new Dictionary<uint, LoadedCell> { [0x0001] = cam, [0x0002] = stairs };
|
||||
var vp = ViewProj();
|
||||
|
||||
Assert.True(PortalProjection.ProjectToNdc(cam.PortalPolygons[0], Matrix4x4.Identity, vp).Length < 3);
|
||||
Assert.True(PortalProjection.ProjectToClip(cam.PortalPolygons[0], Matrix4x4.Identity, vp).Length < 3,
|
||||
"a fully-behind portal must clip to empty (polyClipFinish part 1)");
|
||||
|
||||
var frame = PortalVisibilityBuilder.Build(
|
||||
cam, Vector3.Zero, id => all.TryGetValue(id, out var c) ? c : null, vp);
|
||||
|
||||
Assert.Contains(0x0002u, frame.OrderedVisibleCells);
|
||||
Assert.DoesNotContain(0x0002u, frame.OrderedVisibleCells);
|
||||
}
|
||||
|
||||
[Fact]
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue