Fr0zka
f1fd1e0b05
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>