STAGE B group 2 of 5. The stack is now 11 ops:
ConstantRock -> RoomGraph -> SdfCarve -> CaveRoughness -> Terrace -> LayerLines -> Ribbing
-> Worms -> [structural x3]
Still NOT wired: UsesOperatorStackForChunk returns false for TunnelNetwork.
STRUCTURAL CHANGE THIS GROUP FORCED
FRoomGraphSource's thread_local SDF cache moved out of Eval into a `static FState& State()`
accessor, because terracing re-queries the cache at Z+-1 and (from B4 on) columns walk it and the
room-relative ops need NearestRoomIdx. Kept `static`, i.e. SHARED BETWEEN INSTANCES, on purpose:
that is what the original does, and the test's stale-cache check (check 3) rests on two stacks
sharing this cache while the params CRC in the key keeps them from serving each other's rooms.
Making it a member would have turned that check green for the wrong reason.
This is the established pattern in this file, not a new one: FOverhangShelfMod reads
FSurfaceColumnSource, FShaftLedgeMod reads FShaftFieldSource, both via a non-owning pointer
handed over at build time. Terrace now reads FRoomGraphSource the same way.
TRANSCRIBED
- FCaveTerraceMod: the Z-only SDF gradient orientation gate, the optional noise displacement of Z
before the staircase, the Edge = lerp(0.45, 0.02, Hardness) stair profile, the quadratic fade.
- FLayerLineMod: sine along Z, half-wave rectified, CUBED, subtracted.
- FRibbingMod: same sine shifted by PI/2, rectified, SQUARED, added.
THINGS THAT LOOK WRONG AND WERE PORTED AS-IS
- Terrace's two gradient probes use UNWARPED X/Y and RAW Z, while the field they probe was
evaluated at WARPED coords and effective Z, and they exclude pits/chimneys. So the probe does
not sample exactly the field whose slope it measures. Real, in the original, load-bearing for
the look; noted in OPSTACK-PROGRESS rather than fixed.
- Terrace/LayerLines/Ribbing use raw WorldZ while roughness uses EffectiveZ. Deliberate in the
original (geology stays horizontal whatever the strate's vertical scale).
- `&& CaveSDF < FLT_MAX` is redundant under the bNearCaveSurface gate; kept.
- NearestRoom is now reset to -1 unconditionally, which the original does not do (its thread_local
keeps the previous voxel's value when RoomDensity <= 0). Unobservable there because no consumer
runs; here the consumers are separate objects, and a stale value crossing an operator boundary
is not something you find later.
Ribbing and LayerLines are FillOnly / CarveOnly rather than Both -- two detail modifiers that keep
a usable direction for the fold, which is more than the roughness or the terrace can say.
TEST (same commit): op count 8 -> 11; the three params move from DisableStageBModifiers into
EnableTunnelFeatures with spacings deliberately small against the sample window; three MORE
coverage probes, one per operator rather than one per group -- a single "B2" probe would stay
green while two of the three were wrong.
IF THIS GROUP IS WRONG: diffs cluster where |SDF| < spacing*1.5 near horizontal surfaces
(terrace) or in thin Z bands (lines/ribs). If instead the whole equivalence collapses everywhere,
suspect the FState hoist, not the three new ops.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Fr0zka
ab1a996cc5