588f9e0294feeb9e5f74bbd6b417ab699ea700d9
12 Commits
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 Fr0zka
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b426cfcb0d |
docs(audit): C2 is FULLY closed -- the live-edit half was fixed too
Was about to spec a Codex fix for OC_Chunk / BM_Chunk / FChunkBiomeCache, which three docs still list as open. Checked the sites first. All of them already carry a layout-version guard: CP_Chunk -> CP_Version OC_Chunk -> OC_Version BM_Chunk -> BM_Version TC_BiomeCache -> TC_SeenVersion FChunkBiomeCache::Invalidate() exists precisely because the validity box says nothing about the FBiomeContext its cells were classified against, and all four thread_local instances call it on a version change. The only other two instances in the tree (VoxelContentManager ~445, the height-stack test) are function-local, constructed per task, so staleness is impossible there. Seventh time in this project a confident premise reversed on reading. It cost a doc edit instead of a Codex run and a build cycle. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> |
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Fr0zka
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03ddcde334 |
feat(opstack): FRoomGraphSource::EffectOverBox answers spatially -- and AUDIT C2 is fixed
The chain no longer dies at the room source. The criterion is the per-voxel cull
lifted from point to box, which can fail for exactly one reason: Eval starts at
MinSDF = FLT_MAX and only lowers it through a primitive that survives its own
cull, so if no cached primitive survives its cull anywhere in the box, Sdf stays
FLT_MAX across the whole box.
FSdfConvertOp already returned Identity ("la source a repondu pour la paire") and
the twelve detail modifiers already inherited through VF_NoCaveOverBox. One
function learned to answer and fourteen operators became provable -- what the C1
wiring was built for.
Three deliberate choices, all erring toward CPU rather than toward a hole:
- |Perlin3D| <= 2, derived from GradDot + the convex hull of a trilinear lerp,
instead of the header's observed "~[-1,1]". A verdict resting on an observation
is the hole this file spends its life avoiding.
- the op pool is passed to BuildChunkCache, not nullptr: the bake reads OpParams
to place pits and chimneys, so nullptr would under-bound the cache and could
return Identity over a real pit.
- the search box is wider than Eval's, giving a superset of primitives.
The verdict is memoised per box (all twelve modifiers ask the same question), and
the cache is a SECOND per-worker cache so classification cannot disturb a live
generation's hot cache.
AUDIT C2, confirmed 2026-07-28, is fixed on the switch path in the same breath:
GetDensityWithParams now takes required ParamsFingerprint + LayoutVersion. The
alternative this audit section used to recommend -- add chunk Z to the key -- is
insufficient (Interleaved makes Alpha depend on chunk XY too) and destructive
(chunk XY is deliberately absent so gradient probes don't thrash the box, ARCH
8.10). The CRC is taken once per chunk where the params memo already lives, so
the per-voxel cost is two integer compares. The three test call sites pass it
too, so the oracle stops sharing the defect it tests.
Check 4 of the tunnel test no longer asserts "0 proved" -- that assertion would
now forbid the gain. It brute-forces every proved tile voxel by voxel instead and
reports the count, because a false verdict leaves no geometry and no collision
behind it.
The second debt (per-room ops can raise a modifier's amplitude above the strate
params a box bound reads) turned out to be DORMANT, not live: where the source
proves Identity the modifiers' gate never opens, and where it answers Both it
supplies no MaxCarveOverBox so nothing is provable anyway. It goes live the day
the source gains one. Written at the site.
Unbuilt.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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Fr0zka
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64d0e11821 |
docs(audit C2): the within-strate stale-room suspicion is CONFIRMED by reading -- and it is the default config
No code changed. AUDIT-2026-07.md only: §C2's "SUSPECTED, NOT PROVEN" sub-item becomes "CONFIRMED BY READING", with the four links of the chain and where each one is in the source. THE CHAIN, checked instead of believed 1. GetGenerationParams' Gradient arms compute Alpha = 1 - DistFromBottom / EffectiveBlend, where DistFromBottom = ChunkCoord.Z - Slot.BottomChunkZ. Alpha is therefore a function of chunk Z WITHIN the slot -- so two chunk Zs in the same strate really do get different params. The top boundary mirrors it. 2. They differ in exactly the fields that place rooms: Lerp expands VF_STRATE_PARAM_FIELDS, which lists RoomSpacing, RoomDensity, MinRoomRadius, MaxRoomRadius, RoomHeightRatio, RoomShapeVariety, SDFBlendRadius, CaveWarpStrength and the tunnel fields -- every input BuildChunkCache reads. 3. It is the DEFAULT: TransitionType = Gradient, TransitionBlendChunks = 2. Two chunk-Z layers with distinct params at each end of every strate, out of the box. 4. StrateIndex cannot save it: the memo resolves the SLOT index from the band centre, identical for every chunk Z in the slot, and the cache key's XY box does not change as a worker walks down a column. No rebuild happens. So a worker that builds (X,Y,Z1) then (X,Y,Z2) in one strate evaluates the second chunk against the room list baked from the first chunk's params. WHY IT MATTERS MORE THAN A SEAM The result depends on which chunk that worker happened to build first. That is a window-invariance break (ARCHITECTURE 8.4), not a cosmetic one, and in multiplayer two peers can generate different geometry for the same chunk from the same seed -- a direct 2.6.1 violation on the ORIGINAL path. WHY NOTHING CAUGHT IT The test fixture sets TransitionType = Hard on every strate deliberately, so that "which archetype owns this chunk" stays unambiguous. That switches the blend off entirely. The one configuration the tests never build is the default one. NOT FIXED HERE, deliberately: this is the switch path, and the fix (fold a params CRC + LayoutVersion into the SDF cache key, exactly as FRoomGraphSource already does) is a behaviour change to live generation that Jahni should land with a build in front of him. The operator stack does not inherit the bug. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> |
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Fr0zka
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ef5bda3d8a |
feat: TunnelNetwork stage A — the SDF spine, wrapping BuildChunkCache
The last archetype is ~1080 lines with 13 detail modifiers, a two-region cache and a per-room op override. Porting it whole before anything can be verified is ~600 unverified lines on top of ~200 — the pattern this refactor has dodged six times. So: three stages. Stage A = vertical scale, base rock, cave warp, room graph (+ pits and chimneys), carve, worms, structural post. 6 ops. It is verifiable NOW because every detail modifier is amplitude-gated and FStrateGenerationParams already defaults them all to zero — zeroing SurfaceRoughness sends the ORIGINAL down exactly the path stage A ported. TunnelNetwork stays OFF in UsesOperatorStackForChunk until stage C. The decision that matters: FRoomGraphSource CALLS BuildChunkCache and EvaluateSDFCached rather than transcribing them. That is where §8.4's two-region window-invariance discipline lives; a transcription would fork it, and the fork would be "validated" by a test comparing it to the original. Only the ~60 lines of glue are transcribed. FRAME ops are retired. All three candidates are now ported and none needed one: CaveWarp's scope is exactly one operator (pits/chimneys read unwarped coords), VerticalScale is a one-line pure function, and the island warp was already local. Not missing infrastructure — one idea seen three times from a distance. Also: check 3 was going to compare two interleaved param sets against the original, which would have FAILED — the original's SDF cache key has no params, so it serves B the rooms it built for A. Comparing there measures its bug, not the port. Rewritten against each stack evaluated alone. The same reasoning suggests a live production staleness across Gradient transitions; filed in AUDIT §C2 as SUSPECTED with the check that would confirm it, since it rests on a premise I have not verified. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> |
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Fr0zka
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96e75abe57 |
feat: port FloatingIslands — the stack that runs backwards
6 of 8 archetypes ported. This one starts from VOID and FILLS where the other four start from ROCK and CARVE, which is what it was worth doing: neither end of the pile needed a new operator, only the opposite sign. FConstantRockSource -> FConstantFieldSource(+/-Base) AllSolid <-> AllAir FSdfCarveOp -> FSdfConvertOp(Sign = +/-1) carve <-> fill FSdfRoughnessMod 4th archetype, unchanged Only the island blob source is new. Multiplying by +/-1 is exact in IEEE-754, so the three already-green ports are bit-for-bit untouched. ClassifyBox can return AllAir for the first time in the plugin, and an island strate is by construction mostly empty — the test counts AllSolid and AllAir separately so an aggregate cannot hide whether that fired. Two bounds that would have been holes if assumed rather than derived: the island bound is one-sided (a hairline thread of matter hangs below each island down its axis, so only the TOP may reject), and the domain warp displaces X and Y independently, so the pad needs WarpAmp*sqrt(2). Also: AUDIT C1 was NOT closed. The 2026-07-27 sweep matched `SeedF * K` and this archetype's warp spells it `(float)S * K`, so one site survived — at seed 2e9 the warp flattens and every island snaps back to a perfect circle. Fixed in both paths in one pass so the equivalence test stays a valid oracle. Expect island silhouettes to change at large seeds. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> |
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Fr0zka
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353c023dfd |
test: C9 is only half fixed — the libm half survives FPSemantics
All 9 tests green. LargeSeedSurvives proves C1 fixed by property rather than by comparison: seed 2e9 (what FMath::Rand produces) now yields 400 distinct heights over 400 samples where it previously gave a constant field. The three equivalence tests stayed green through an 85-site rewrite. The digest's NearIso warning fired at 2/115000 and its text blamed the /fp:fast vs precise split, which is fixed. First instinct was "stale warning, soften it". Checked instead, and the risk is real by a different mechanism: sinf/cosf are not specified by IEEE-754. FPSemantics = Precise makes MSVC and Clang agree on expression evaluation and says nothing about the math library; MSVC's CRT and glibc's libm may differ by ~1 ULP. FMath::Sin/Cos are used throughout the density path — layer lines, ribs, room placement, rotations. So C9's compiler half is closed by construction and its library half is not, and no build flag can close it. The measurement was also over-stating by ~100x: a single 1e-4 band is far too wide for a libm-scale delta (~1e-6 absolute at densities of magnitude ~10). Replaced with a three-band profile; only the tight band warns. UNVERIFIED: the reworded test. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> |
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Fr0zka
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921a9fb666 |
feat: height-space operator family — SurfaceWorld step 1, and C10 is solved
Maze and Slab now report BIT-IDENTICAL: FPSemantics = Precise, set for cross-platform play, dissolved the ULP residue. Hypothesis 3 had the right mechanism all along — under /fp:fast the compiler transforms by surrounding context with no isolable axis, which is exactly why five one-variable experiments all came back negative. Removing the permission removed the difference. Nobody solved C10; C9 got fixed for an unrelated reason and C10 fell out of it. SurfaceWorld step 1 forced an architectural decision. DECOMPOSITION section 5 notes the height ops operate on Z values rather than density, then lists them as children of FHeightfieldSource. Writing them made the consequence unavoidable: they do not fit IVoxelDensityOp. No input Z (they produce one), XY-pure per column rather than per voxel, and they write neither channel. Forcing them in would need a per-voxel channel for a column property, or one opaque op — section 2.5's failure mode. So height space gets its own contract: VoxelHeightOp.h (FVoxelHeightSample with Height + Relief, IVoxelHeightOp, FVoxelHeightStack) and five ops. Relief is the original's M — produced by the structural source, consumed by the terrace gate. Section 0.1 found density needed a second channel; this found terrain needs a second space. The type system now forbids for free what AUDIT 6.3 warns about: a height stack cannot hold Z-dependent data because there is no Z in the signature. Deliberately staged — this touches nothing on the density path. If height space had not decomposed cleanly, it shows up here for one test rather than after building the adapter, the column cache integration and the dispatch on top. The test runs twice; the second pass is load-bearing because the F20 terrain ops are off by default, so a defaults-only run leaves all four modifiers untested. It also brute-forces MaxDisplacement, since a false bound would later be a hole. ComputeSurfaceTerrainZ moved private -> public for the test, same justification as GetSlabDensity. Old declaration removed. UNVERIFIED: not compiled. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> |
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Fr0zka
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f1fd1e0b05 |
docs: new acceptance bar (peer agreement, not fidelity) — and C1's documented fix is wrong
Jahni: "I do not need your work to be identical or near identical to what I had before, only having it 99.99% at worst reproducible if two people share the same seed, since everyone rebuilds it on multiplayer." Recorded as OPSTACK-PLAN 2.6.1, superseding 2.6's "recognisably the same place". Consequences, each recorded where it will be found: - C10 closed permanently rather than parked: it measures old-path vs new-path agreement and the two never coexist in a shipped world. - The equivalence tests keep their value as PORT-CORRECTNESS checks, not fidelity checks. Isosurface hard-fail stays; ULP grading is diagnostic only. - C9 promoted to top open risk. "Two people share a seed" is exactly what /fp:fast weakens across toolchains, and a Linux dedicated server against Windows clients compiles the density path under opposite float models. FPSemantics = Precise is the fix and the IWYU debt now blocks something that matters. - C1 unblocked: it was deferred only because it re-rolls the world's noise. Then, doing C1's arithmetic before applying its documented one-liner: THE FIX IS WRONG. It bounds SeedF but keeps the * 97.7 multiplier, so the coordinate term still reaches 1.6e6 where the ULP is 0.19 — 9.5x the ~0.02/voxel step. It would have left the bug live for mid-range seeds while closing the ticket. The real fix deletes the multipliers: they only decorrelate the ~40 noise sites, which is a hashing job. VoxelHash::SeedOffset(Seed, Site) gives a site-salted, bounded, final-units offset. Bounding SeedF alone would also funnel every seed through 16384 offsets shared by all sites; per-site salting requires a collision at all ~40 sites instead. The op stack has already inherited the bug via FSlabVoidSource, so it must land in both paths at once — and every further port copies it again. Docs only; the C1 fix is not written. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> |
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Fr0zka
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34f06dfea7 |
docs: park the ULP residue as AUDIT C10; strip the diagnostic scaffolding
Jahni's call to pin it and move on, and the right one -- six builds spent and the information stopped being worth the cost. The final run closed it as far as it can be: SDFs identical everywhere (counted unconditionally, 0 differ), yet two character-identical carve implementations in the SAME translation unit fed a provably identical input differ by 1 ULP on 126/5000. That is only possible if they compile to different instruction sequences, which /fp:fast permits based on surrounding context with no single isolable axis. Hypothesis 3 was right about the mechanism and wrong about every clean variable proposed for it, which is why four well-designed isolation tests came back negative. AUDIT C10 records the observation, what is proven (SDF bit-exact 126/126, zero isosurface crossings), the five refuted hypotheses in a table so nobody repeats them at a build each, why the settling experiment is blocked (shared-PCH / IWYU debt), and the rule that actually matters: never run both density paths in one world and never compare them for equality. That is NOT a client-desync risk -- within a binary the field is proven bit-pure and every peer runs the same path -- the cross-platform concern is C9, which stands on its own. Corrected OPSTACK-PLAN 2.6 and C9: my earlier "/fp:fast across translation units" explanation was measurably wrong and is removed rather than softened. MazeEquivalence keeps the permanent value (equivalence with ULP grading, window-invariance, box-verdict brute force) and drops the verbatim copy, three-way, bisect, inlining and constness experiments. Phase 1 closed: Maze decomposes into 7 ops, SDF bit-exact, 0 isosurface crossings, window-invariant, and 23 of 60 tiles proved uniform where ClassifyTile proves zero. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> |
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Fr0zka
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0379d59c1c |
docs: AUDIT C9 — the FP default differs BY TOOLCHAIN, not just "fast is allowed to drift"
Jahni asked the right question: does the same seed produce identical results
across OS builds today? Checking the other toolchain made the answer sharper and
worse than what C9 originally said.
ClangToolChain.cs (Linux, Mac, Windows-with-Clang):
case FPSemanticsMode.Default: // Default to precise FP semantics.
case FPSemanticsMode.Precise: Arguments.Add("-ffp-contract=off");
and VCToolChain forces Precise when Windows uses Clang. So the same
FPSemanticsMode.Default resolves to OPPOSITE float models per toolchain, and
Windows/MSVC is the only imprecise configuration in the engine's defaults. Two
builds of identical source are not merely permitted to diverge -- they are
compiled under different rules.
Also added, so the entry does not over-fear itself:
- Calibration: 0 of 20000 samples crossed the isosurface under a 1-ULP
perturbation, so divergence means occasional single-voxel surface differences,
not different terrain. The case that bites is topological (a cave pinch-point
connecting on one build and not the other), which is rare and unreproducible --
the expensive kind.
- Precise everywhere still would not guarantee cross-platform bit-identity:
FMath::Sin/Cos route to platform libm, which is not bit-standardised. It closes
the large gap, not every gap.
- The knob would ALIGN Windows with every other platform rather than being a
one-sided cost -- but still must not be turned speculatively.
- The claim is inferred, not measured. The cheap decisive test is one Windows
build with FPSemantics = Precise: if MazeEquivalence's 454-sample residue
vanishes, the FP model is confirmed as the sole cause.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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Fr0zka
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af5f2103b3 |
test: the Maze residue is /fp:fast, not port drift — encode the real bar
The bisect settled it. The difference survives every stage removal down to
"corridors + carve ONLY", which is character-for-character transcribed code, so
it is not in anything the decomposition added.
Cause, read out of the engine rather than assumed (VCToolChain.cs):
case FPSemanticsMode.Default: // Default is imprecise FP semantics.
case FPSemanticsMode.Imprecise: Arguments.Add("/fp:fast"); break;
with UBT's own doc: "the compiler is allowed to transform math expressions in
ways that might result in differently rounded results". Identical source in two
translation units may reassociate differently, worth ~1 ULP. It shows up on
exactly the ~2% of samples inside the SDF blend shell, where Blend - Sdf
catastrophically cancels; outside it Carve is exactly 0 or 1 and both agree.
So MazeEquivalence now grades what it can actually assert:
- hard fail : any isosurface crossing (geometry moves)
- info : differences at ULP scale (the unavoidable floor)
- warn : anything larger, which IS port drift, and runs the bisect
A test that warns on every port would get ignored by the port that matters.
Recorded in OPSTACK-PLAN 2.6, and as AUDIT C9 for the part that outlives this
refactor: ARCHITECTURE 9.1's "every peer regenerates identically" holds only
between bit-identical binaries under /fp:fast. Fine for one build on one
platform; a real desync source for a Linux server plus Windows clients both
regenerating authoritative geometry. The FPSemantics::Precise knob exists but
must not be turned speculatively -- it blocks the vectorisation T2.a was chasing,
on the hot loop, for an unmeasured cost.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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Fr0zka
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3128852d4e |
chore: track the design docs in git (.gitignore !*.md)
AUDIT P1: every markdown design doc except CODEMAP.md was untracked, so ARCHITECTURE / AUDIT / OPSTACK-PLAN / fable-idea / REVIEW_FINDINGS lived only on disk. Replaces the single !CODEMAP.md exception with !*.md. Also makes OPSTACK-PROGRESS.md commits actually record something, which the unattended crash-safety discipline depends on. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> |