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Revert "Campaign V slice V4a" - it lost world multisampling

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This reverts ceec3bc4. Two independent reasons, either sufficient.

The rendering regression. The slice deleted TextRenderGlStateScope, which
saved GL_MULTISAMPLE and GL_SAMPLE_ALPHA_TO_COVERAGE on entry, disabled them
for the text pass, and restored them on exit (TextRenderGlStateScope.cs:111-112
and 153-154 at the parent commit). Its replacement bakes that state into the
text pipeline but nothing restores it, and GlGpuPassEncoder.Dispose does not
either. Every world renderer is still raw GL at this point in the campaign, so
from the first UI frame onward the world drew with multisampling disabled.

The offline pixel gate caught it: 1,791 of 563,200 compared pixels differed,
0.318% against a 0.001 threshold. The commit message attributed this to
wall-clock-driven ambient animation shifting phase, and committed through the
failure. That explanation does not survive its own control: capturing twice at
the reverted-to commit differs by 19 pixels and twice at the slice's own commit
by 8, while base-versus-head differs by 1,791 - a 224x gap that no shared-noise
source explains. An amplified difference image settles it visually: the changed
pixels are the silhouette edges of every tree, building and rock, with terrain
interiors, water and the entire UI untouched. That is the signature of losing
edge antialiasing, not of animated sprites.

This is the exact failure mode two existing memory notes already warn about -
a mid-frame renderer must set every GL state it uses rather than inherit it,
and issue #52's lesson that a rendering migration must audit per-pass GL state
before declaring itself done.

The scope. The brief was three small leaf renderers plus additive frame-
lifecycle wiring, roughly ten files. The commit changed 334 files with 3,665
insertions and 3,845 deletions, including 323 public-to-internal visibility
conversions across the App assembly, 55 test files, two retired conformance
tests, and a self-described temporary escape hatch for bridging raw-GL viewport
textures. Even without the regression, that is not separable into the part
worth keeping and the part worth dropping.

Reverting rather than patching because the good work here - the RHI frame
lifecycle wiring and a genuine render-state-cache staleness fix - is small
enough to redo cleanly against a tightened spec, while untangling it from 300+
files of unrelated churn is not.

Post-revert: Release build clean, App suite back to 3,843 passed / 3 skipped,
offline pixel gate passing at 19 differing pixels.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
Erik 2026-07-27 18:27:52 +02:00
parent ceec3bc440
commit 9aaf97e785
334 changed files with 3841 additions and 3661 deletions
Download patch file Download diff file Expand all files Collapse all files

74
src/AcDream.App/Rendering/ClipPlaneSet.cs
View file

@ -1,4 +1,4 @@
// ClipPlaneSet.cs
// ClipPlaneSet.cs
//
// Phase U.2c: turn a CellView (a cell's accumulated screen-space clip region,
// in NDC) into a small set of clip-space half-space planes for the GPU's
@ -6,18 +6,18 @@
// convex plane set.
//
// This is the bridge between PortalVisibilityBuilder's 2D NDC view polygons and
// the per-vertex clip the mesh/terrain shaders will perform (Phase U.2c → U.2e).
// the per-vertex clip the mesh/terrain shaders will perform (Phase U.2c → U.2e).
// Pure System.Numerics math; NO GL. The shader consumes each plane as
// d = nx*clip.x + ny*clip.y + 0*clip.z + dw*clip.w (>= 0 ⇒ keep)
// d = nx*clip.x + ny*clip.y + 0*clip.z + dw*clip.w (>= 0 ⇒ keep)
// where (nx, ny, dw) = the plane's (normal.xy, offset). z is always 0 because a
// screen-space (NDC) edge is a vertical slab in clip space — independent of depth.
// screen-space (NDC) edge is a vertical slab in clip space — independent of depth.
//
// === The convexity rule (read before touching this file) =====================
// gl_ClipDistance planes are a CONJUNCTION of half-spaces, i.e. exactly ONE
// convex region (their intersection). A CellView with MORE THAN ONE polygon is a
// UNION of convex regions, which is in general NOT convex and CANNOT be
// represented by one plane set. Emitting just the first/largest polygon's planes
// would clip away the others → a real visibility bug (under-inclusion).
// would clip away the others → a real visibility bug (under-inclusion).
//
// Therefore From() NEVER emits a single polygon's planes when the CellView holds
// several. Multi-polygon (and >8-edge) regions degrade to the UNION AABB scissor:
@ -27,13 +27,13 @@
//
// === The three Count==0 states (how a consumer tells them apart) =============
// Count == 0 can mean three different things; the consumer MUST distinguish:
// (a) Empty — IsNothingVisible == true, UseScissorFallback == false.
// The cell/region isn't visible at all → DRAW NOTHING. The
// (a) Empty — IsNothingVisible == true, UseScissorFallback == false.
// The cell/region isn't visible at all → DRAW NOTHING. The
// ScissorNdcAabb is a degenerate inverted box (min > max) so that a
// consumer which naively scissors on it still draws nothing.
// (b) Scissor — UseScissorFallback == true, IsNothingVisible == false.
// (b) Scissor — UseScissorFallback == true, IsNothingVisible == false.
// The convex-plane budget was exceeded (multi-polygon or >8 edges)
// → DRAW the ScissorNdcAabb box (a valid min<=max NDC rectangle).
// → DRAW the ScissorNdcAabb box (a valid min<=max NDC rectangle).
// There is no third Count==0 state produced by From(). (A separate "no-clip,
// pass-all" slot 0 is constructed by the consumer directly, not via From().)
// When Count > 0, Planes carries the convex gate and the scissor fields are unused.
@ -45,26 +45,26 @@ using System.Numerics;
namespace AcDream.App.Rendering;
/// <summary>
/// An NDC convex view region reduced to ≤8 clip-space gl_ClipDistance planes, or a
/// An NDC convex view region reduced to ≤8 clip-space gl_ClipDistance planes, or a
/// scissor AABB fallback. See the file header for the convexity rule and the three
/// Count==0 states.
/// </summary>
internal readonly struct ClipPlaneSet
public readonly struct ClipPlaneSet
{
// Max simultaneous hardware clip planes we target (GL guarantees >= 8).
private const int MaxPlanes = 8;
// Collinear-edge merge threshold. Two consecutive edge directions are treated as
// the same edge when the turn between them is below ~0.5° (retail copy_view does a
// ~1px screen-space dedup). |sin θ| for unit dirs = |cross|; sin(0.5°) ≈ 0.0087265.
// the same edge when the turn between them is below ~0.5° (retail copy_view does a
// ~1px screen-space dedup). |sin θ| for unit dirs = |cross|; sin(0.5°) ≈ 0.0087265.
private const float CollinearSinEps = 0.0087265f;
// Drop a vertex whose two incident edges are shorter than this (NDC) — a duplicate
// Drop a vertex whose two incident edges are shorter than this (NDC) — a duplicate
// or near-duplicate point that would otherwise yield a garbage normalized normal.
private const float DegenerateEdgeLen = 1e-6f;
// A polygon whose absolute signed area (full area, not 2x) falls below this is a line
// or point — zero screen coverage ⇒ nothing visible. A real portal opening has area far
// or point — zero screen coverage ⇒ nothing visible. A real portal opening has area far
// above this (e.g. the sliver-clip test region is 0.4); only an edge-on projection gets here.
private const float MinPolygonArea = 1e-7f;
private readonly Vector4[] _planes;
@ -77,7 +77,7 @@ internal readonly struct ClipPlaneSet
ScissorNdcAabb = scissorNdcAabb;
}
/// <summary>Number of active clip planes, 0..8. 0 ⇒ inspect <see cref="UseScissorFallback"/>
/// <summary>Number of active clip planes, 0..8. 0 ⇒ inspect <see cref="UseScissorFallback"/>
/// and <see cref="IsNothingVisible"/> to decide between "draw the AABB" and "draw nothing".</summary>
public int Count => _planes?.Length ?? 0;
@ -89,11 +89,11 @@ internal readonly struct ClipPlaneSet
// its frame-scoped slice instead of cloning every plane payload a second time.
internal Vector4[] PlaneArray => _planes ?? Array.Empty<Vector4>();
/// <summary>True ⇒ the convex-plane budget was exceeded; gate on <see cref="ScissorNdcAabb"/>
/// <summary>True ⇒ the convex-plane budget was exceeded; gate on <see cref="ScissorNdcAabb"/>
/// instead (draw the box). Always false when <see cref="Count"/> &gt; 0 or when the region is empty.</summary>
public bool UseScissorFallback { get; }
/// <summary>True ⇒ the region is not visible at all; the consumer draws NOTHING.
/// <summary>True ⇒ the region is not visible at all; the consumer draws NOTHING.
/// Mutually exclusive with <see cref="UseScissorFallback"/>, and only meaningful when Count == 0.</summary>
public bool IsNothingVisible { get; }
@ -106,20 +106,20 @@ internal readonly struct ClipPlaneSet
public static ClipPlaneSet Empty { get; } =
new(Array.Empty<Vector4>(), useScissorFallback: false, isNothingVisible: true, scissorNdcAabb: DegenerateAabb);
// Inverted box (min > max) — any sane AABB intersection against it is empty.
// Inverted box (min > max) — any sane AABB intersection against it is empty.
private static Vector4 DegenerateAabb => new(1f, 1f, -1f, -1f);
/// <summary>
/// Reduce a CellView's NDC clip region to a ClipPlaneSet. One convex polygon (≤8 edges
/// after collinear-merge) → per-edge planes; multi-polygon or >8 edges → union-AABB scissor;
/// empty/degenerate → <see cref="Empty"/>. See the file header for the full rule.
/// Reduce a CellView's NDC clip region to a ClipPlaneSet. One convex polygon (≤8 edges
/// after collinear-merge) → per-edge planes; multi-polygon or >8 edges → union-AABB scissor;
/// empty/degenerate → <see cref="Empty"/>. See the file header for the full rule.
/// </summary>
public static ClipPlaneSet From(CellView region)
{
if (region is null || region.IsEmpty || region.Polygons.Count == 0)
return Empty;
// MORE THAN ONE polygon ⇒ union, not convex ⇒ never emit one polygon's planes.
// MORE THAN ONE polygon ⇒ union, not convex ⇒ never emit one polygon's planes.
// Over-include via the union AABB (safe). region.Min/Max already track the union.
if (region.Polygons.Count > 1)
return Scissor(region.MinX, region.MinY, region.MaxX, region.MaxY);
@ -152,15 +152,15 @@ internal readonly struct ClipPlaneSet
{
int count = NormalizeAndMerge(input, verts);
// Fewer than 3 distinct edges survive ⇒ a sliver/line with no area. There is no
// Fewer than 3 distinct edges survive ⇒ a sliver/line with no area. There is no
// meaningful AABB to over-include (a zero-area region), so treat it as nothing visible.
if (count < 3)
return Empty;
ReadOnlySpan<Vector2> normalized = verts[..count];
// A single convex polygon with too many edges to fit the hardware budget ⇒ scissor
// on ITS own AABB (still a superset of the polygon → over-include, safe).
// A single convex polygon with too many edges to fit the hardware budget ⇒ scissor
// on ITS own AABB (still a superset of the polygon → over-include, safe).
if (count > MaxPlanes)
return Scissor(normalized);
@ -173,10 +173,10 @@ internal readonly struct ClipPlaneSet
Vector2 q = normalized[(i + 1) % count];
Vector2 dir = q - p;
// Inward normal for CCW winding: perp(dir) = (-dir.y, dir.x) points to the polygon's
// interior (the "left" side of the directed edge p→q).
// interior (the "left" side of the directed edge p→q).
Vector2 n = Vector2.Normalize(new Vector2(-dir.Y, dir.X));
// Plane: n·x + d >= 0 inside, with d = -(n·p). In clip space with NDC x = clip.x/clip.w:
// dist = n.x*clip.x + n.y*clip.y + 0*clip.z + (-(n·p))*clip.w (>= 0 ⇒ keep)
// Plane: n·x + d >= 0 inside, with d = -(n·p). In clip space with NDC x = clip.x/clip.w:
// dist = n.x*clip.x + n.y*clip.y + 0*clip.z + (-(n·p))*clip.w (>= 0 ⇒ keep)
planes[i] = new Vector4(n.X, n.Y, 0f, -Vector2.Dot(n, p));
}
return new ClipPlaneSet(planes, useScissorFallback: false, isNothingVisible: false, scissorNdcAabb: DegenerateAabb);
@ -233,9 +233,9 @@ internal readonly struct ClipPlaneSet
if (SignedArea2(points[..count]) < 0f)
points[..count].Reverse();
// 3) Merge collinear edges: drop vertex i when edge (i-1→i) and edge (i→i+1) point the same
// way (turn angle < ~0.5°). Iterate until stable — removing one vertex can expose a new
// collinear triple. |cross(a,b)| of unit dirs = |sin θ|; dot>0 rules out a 180° reversal.
// 3) Merge collinear edges: drop vertex i when edge (i-1→i) and edge (i→i+1) point the same
// way (turn angle < ~0.5°). Iterate until stable — removing one vertex can expose a new
// collinear triple. |cross(a,b)| of unit dirs = |sin θ|; dot>0 rules out a 180° reversal.
bool changed = true;
while (changed && count >= 3)
{
@ -260,12 +260,12 @@ internal readonly struct ClipPlaneSet
d0 /= l0;
d1 /= l1;
float cross = d0.X * d1.Y - d0.Y * d1.X; // sin θ
float dot = d0.X * d1.X + d0.Y * d1.Y; // cos θ
float cross = d0.X * d1.Y - d0.Y * d1.X; // sin θ
float dot = d0.X * d1.X + d0.Y * d1.Y; // cos θ
if (dot > 0f && MathF.Abs(cross) < CollinearSinEps)
{
points[(i + 1)..count].CopyTo(points[i..]);
count--; // cur lies on the straight line prev→next
count--; // cur lies on the straight line prev→next
changed = true;
break;
}
@ -276,7 +276,7 @@ internal readonly struct ClipPlaneSet
return 0;
// Final degeneracy gate: a polygon with negligible area is a line/point even if it still
// has >= 3 distinct vertices (e.g. an edge-on portal, or a near-collinear triple the 0.5°
// has >= 3 distinct vertices (e.g. an edge-on portal, or a near-collinear triple the 0.5°
// merge didn't quite collapse). Emitting its planes would yield an empty half-space
// intersection that silently gates out everything; report it honestly as nothing-visible.
if (MathF.Abs(SignedArea2(points[..count])) * 0.5f < MinPolygonArea)
@ -285,7 +285,7 @@ internal readonly struct ClipPlaneSet
return count;
}
// Twice the signed area (the "shoelace" sum). > 0 ⇒ CCW, < 0 ⇒ CW.
// Twice the signed area (the "shoelace" sum). > 0 ⇒ CCW, < 0 ⇒ CW.
private static float SignedArea2(ReadOnlySpan<Vector2> poly)
{
float a = 0f;