Fr0zka
e479fcdf7d
STAGE C group 2. No operator, no parameter, no new stack: Underwater IS TunnelNetwork.
PREMISE VERIFIED BEFORE BUILDING ON IT (the lesson this refactor has paid for four times)
OPSTACK-DECOMPOSITION §8 claims there is no density difference at all. Both halves were re-read
rather than assumed:
- GetDensityAt already puts `case Underwater:` and `case TunnelNetwork:` in the SAME arm, both
calling GetDensityWithParams (VoxelGenerator.cpp, the production switch);
- a repo-wide search for WaterLevelRelative shows FStrateGenerationParams' copy is read only by
UVoxelStrateManager's water-level query (render side) and by the SurfaceWorld beach op through
a DIFFERENT struct. GetDensityWithParams never reads it.
So the wiring is one more `case` above the existing one, sharing CP_Tunnel.
ONE REAL DIFFERENCE FROM THE FIVE CASES ABOVE IT, stated in the code
No degenerate-strate guard. The other five archetypes have one because their density functions
early-out to `return 1.0f` on zero height and the stack has no such early-out by design.
GetDensityWithParams has no early-out at all -- read line by line, not assumed. Adding a guard here
would make the stack diverge from the switch on degenerate strates, in exactly the direction the
guard exists elsewhere to prevent.
TEST (same commit): new check 5 samples 2000 points in the Underwater SLOT, with the same room-op
pool attached to that definition before anything is evaluated. This is not tautological even
though both paths call the same function: the Underwater slot is a different strate, hence a
different StrateIndex, hence a different bake seed and a different entry in the strate-index memo.
It exercises what six chunks of slot 0 cannot -- that the stack follows the right room set when
two strates of the same archetype coexist in one world.
The failure message says explicitly that if the TunnelNetwork equivalence is green and only this
one fails, the finding is a real density difference between the two archetypes, which contradicts
§8 and is worth more written down than patched.
UsesOperatorStackForChunk still returns false for both. That is C3.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>