Wire the existing attractor-matching engine (#919/#925) into the
generation cascade as Layer 3, and make the whole placement-scoring path
integer-deterministic.
Layer 3 (D-211):
- CascadeLayer::Settlement + Layer3Output (placements) on the snapshot;
BodyWorldState gains a `placements` field (the D-203 hot cache).
- run_layer3 runs the five-phase match_cities against Layer-1 attractors
via the authored D-195 compatibility matrix; pure function of
(attractors, cities) — no RNG. cities are passed in by the caller so the
cascade stays DB-free and testable. A `// cache seam` marks where a
persistent cache wraps it later (#1021).
- gen_queue passes &[] for now (Topography needs no cities); the runtime
settlement read (gen_queue/layer_proxy) is the #955 follow-on.
Integer determinism (D-010 / D-227 — D-195 amended):
- Wiring match_cities into the deterministic cascade made its f32 scoring
a live cross-platform divergence risk (a near-tie comparison or the
Hungarian's f32 reductions can round differently per platform → a
different world from the same seed). Converted the entire path to
integers: CompatibilityMatrix is a 0-100 affinity table; attractor
strength is 0-100 and terrain cost is a percent (100 = baseline),
quantized once at the Layer-1 feature boundary; cell_score, the
Hungarian, and CityPlacement.score are i64. No f32 in any placement or
ranking decision.
- Layer-1 golden fixture rebaked: confirmed selection/positions are
unchanged (same 256 attractors, 93 river cells) — only the strength/cost
representation changed.
Tests: lib green (1292); new settlement_layer_places_cities_deterministically
covers placement + determinism + propagation into BodyWorldState.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Pre-push surfaced fmt + clippy (-D warnings) failures in the new code:
- rustfmt the 6 new/changed atlas files + the bench example.
- features.rs: HashMap → BTreeMap (project bans HashMap for determinism via
clippy disallowed_types; the bucket map is lookup-only either way).
- attractor_matching.rs: drop now-redundant .clone() on AttractorType (it
became Copy in #953) — clippy clone_on_copy.
- drainage.rs tests: manual range → (1..=12).contains(&n).
- features.rs test: drop .clone() on Copy AttractorType.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
From the Hoshe/Tyre review:
- drainage: assert flow_accumulation/max_accumulation determinism + clamp ≥ 1
(the D-209 strength denominator); isolated-basin merge path (no panic).
- subbiome: each derivable variant reachable + Volcanic never emitted.
- planet_simulation: new test_sim_determinism.py — same body simulates to a
bit-identical elevation array at 1024×512 (the 271-body bake can't be cheaply
re-run, so a silent drift = full re-bake). Verified PASS.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Wire the empty-world topography cascade (D-208/209/210):
- generator.rs: add SubBiomeVariant (11 variants, D-210) + sub_biome and
terrain_modification_cost fields on GeographicAttractor; AttractorType
is now Copy.
- features.rs (new, D-209): extract the 7 attractor tags from heightmap +
drainage. Coast/lake derived from the heightmap (D-209/D-223
reconciliation — markers are names-only now, no polygons). Deterministic
(sorted seeds, integer keys, bucket-grid thinning); strength-capped at
MAX_ATTRACTORS preserving type diversity. Shared TerrainAnalysis
(masks/slope/moisture/percentile) feeds both extraction and sub-biome.
- subbiome.rs (new, D-210): classify sub-biome + terrain_modification_cost
from elevation/slope/moisture/latitude. Volcanic stays in the enum but
is not emitted (no heightmap signal).
- layer1.rs (new): run_layer1 orchestrator + attach_feature_names (D-223
pool names to largest rivers / Alpine peaks).
- attractor_matching constructors updated for the new fields.
76 atlas tests pass; run_layer1 determinism verified.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
jpmschweitzerandClaude Opus 4.8