jpmschweitzerandClaude Opus 4.8
b73b4e6d92
Close the last D-234 piece — terrain water-direction extraction wired through to founding orientation and the quarter waterfront rule: - Layer 1: TerrainAnalysis::water_bearing — 8-octant integer bearing toward the nearest water from the water_dist gradient (D-010, no atan2). Stored on GeographicAttractor.water_bearing (360 = none). - #956 founding orientation: coastal/river settlements now get a real water-facing bearing (the anchoring attractor's), replacing the 0 stub. - #957 waterfront rule (D-234b): the water-facing quarter edge (from the settlement's Coastal founding orientation) drops its block setback to 0 so buildings present flush to the quay (dock-orthogonal). Typed Edge + coastal_edge + per-block gating. Golden + atlas_response fixture rebaked (additive water_bearing field only). 8 new tests. All integer-deterministic (D-010). Pending: the waterfront rule reads context.founding_orientation, which city_context_reader still stubs to Cardinal — real per-settlement orientation reaches quarter generation once the Layer-3 placement -> Layer-4 GenerateSkeleton dispatch is wired (the remaining cross-layer integration). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
786 lines
27 KiB
Rust
786 lines
27 KiB
Rust
//! Geographic feature tag extraction — Layer 1 (D-209).
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//!
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//! After D8 drainage analysis (D-208), this module extracts the 7
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//! `AttractorType` tags from the heightmap + river network. Each attractor has
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//! a pixel position and a `strength` (integer 0–100) derived from local terrain
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//! quality — computed in floating point, then quantized to an integer at the
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//! extraction boundary so all downstream decisions stay integer-deterministic
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//! (D-010).
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//!
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//! **D-209 / D-223 reconciliation:** D-209 reads ocean/lake polygons from
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//! `markers.json`, but D-223 reduced markers to a names-only pool — those
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//! polygons no longer exist. Coast and lake cells are therefore derived from
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//! the heightmap itself: ocean = the largest connected below-sea-level water
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//! body; lakes = smaller enclosed below-sea-level bodies.
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//!
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//! **Determinism (D-010 #4):** all collections iterate in sorted/row-major
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//! order; the final attractor list is sorted by `(attractor_type, row, col)`.
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//! No `HashMap`/`HashSet` iteration. `strength` (integer 0–100) is not part of
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//! that ordering here, so float quantization can't perturb the sort; consumers
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//! that rank by strength (e.g. `layer1::attach_feature_names`) do so on the
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//! integer value.
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use std::collections::{BTreeMap, VecDeque};
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use crate::atlas::drainage::DrainageResult;
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use crate::atlas::heightmap::BodyHeightmap;
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use crate::simulation::generator::AttractorType;
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/// 8-neighbor offsets (dr, dc). Columns wrap horizontally (equirectangular
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/// globe); rows are bounds-clamped at the poles. Matches `drainage::D8`.
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const NB8: [(i32, i32); 8] = [
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(-1, 0),
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(1, 0),
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(0, 1),
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(0, -1),
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(-1, 1),
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(-1, -1),
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(1, 1),
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(1, -1),
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];
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/// Minimum spacing (cells) between attractors of an areal type, so coastlines /
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/// valleys / plains yield a sparse, placement-friendly set rather than one
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/// attractor per pixel.
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const MIN_SPACING: i32 = 12;
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/// Hard cap on attractors per body (keeps the #955 matching tractable).
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const MAX_ATTRACTORS: usize = 256;
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/// A feature before sub-biome classification: position, type, strength.
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/// `layer1` enriches these into `GeographicAttractor`s.
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#[derive(Debug, Clone, Copy, PartialEq)]
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pub struct RawAttractor {
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pub row: u16,
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pub col: u16,
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pub attractor_type: AttractorType,
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/// Strength on a 0–100 integer scale (100 = strongest). Quantized here from
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/// the f32 flow-accumulation ratio — the single f32→integer boundary, after
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/// which every ranking/scoring decision is integer (D-010, #955).
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pub strength: i32,
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}
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/// Precomputed per-cell terrain fields, shared by feature extraction (D-209)
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/// and sub-biome classification (D-210) so neither recomputes them.
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#[derive(Debug, Clone)]
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pub struct TerrainAnalysis {
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pub w: usize,
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pub h: usize,
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/// `elev < sea_level` (any submerged cell).
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pub ocean_mask: Vec<bool>,
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/// Submerged cells not part of the largest water body (enclosed lakes/seas).
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pub lake_mask: Vec<bool>,
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/// Chebyshev distance (cells) to the nearest ocean cell or river mouth,
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/// capped at `WATER_DIST_CAP`. Moisture proxy for habitability/sub-biome.
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pub water_dist: Vec<u16>,
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/// Local slope proxy in degrees: `atan(max |Δelev| over 8 neighbors)`.
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/// Elevation is normalized [0,1]; this is a relative steepness measure.
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pub slope_deg: Vec<f32>,
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/// Elevation percentile [0,1] among land cells (ocean cells = 0.0).
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pub elev_pct: Vec<f32>,
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}
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const WATER_DIST_CAP: u16 = 255;
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#[inline]
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fn idx(r: usize, c: usize, w: usize) -> usize {
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r * w + c
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}
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#[inline]
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fn wrap_col(c: i32, w: i32) -> usize {
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c.rem_euclid(w) as usize
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}
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impl TerrainAnalysis {
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/// Compute all shared terrain fields for a body. O(w·h).
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pub fn analyze(hm: &BodyHeightmap, drainage: &DrainageResult) -> TerrainAnalysis {
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let w = hm.width as usize;
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let h = hm.height as usize;
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let n = w * h;
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let elev = &hm.data;
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let sea = hm.sea_level;
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let ocean_mask: Vec<bool> = (0..n).map(|i| elev[i] < sea).collect();
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let lake_mask = compute_lake_mask(&ocean_mask, w, h);
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let water_dist = compute_water_dist(&ocean_mask, &drainage.river_network.mouths, w, h);
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let slope_deg = compute_slope(elev, w, h);
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let elev_pct = compute_elev_percentile(elev, &ocean_mask, w, h);
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TerrainAnalysis {
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w,
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h,
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ocean_mask,
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lake_mask,
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water_dist,
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slope_deg,
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elev_pct,
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}
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}
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#[inline]
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pub fn is_ocean(&self, r: usize, c: usize) -> bool {
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self.ocean_mask[idx(r, c, self.w)]
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}
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/// Compass bearing toward the nearest water from cell `(r, c)`, quantized to
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/// 8 octants (0=N, 45=NE … 315=NW); `360` = "no water in range" (#957, D-234).
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///
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/// Reads the `water_dist` field's local gradient — the 8-neighbour with the
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/// smallest distance-to-water points toward water. Integer-only (no `atan2`)
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/// for D-010 determinism. Returns `360` when the cell is itself water or no
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/// neighbour is closer to water (flat/inland).
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pub fn water_bearing(&self, r: usize, c: usize) -> u16 {
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let here = self.water_dist[idx(r, c, self.w)];
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if here == 0 || here >= WATER_DIST_CAP {
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return NO_WATER_BEARING; // on water, or no water within range
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}
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let mut best = here;
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let mut bdir = (0i32, 0i32);
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for &(dr, dc) in &NB8 {
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let nr = r as i32 + dr;
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if nr < 0 || nr >= self.h as i32 {
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continue;
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}
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let nc = wrap_col(c as i32 + dc, self.w as i32);
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let nd = self.water_dist[idx(nr as usize, nc, self.w)];
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if nd < best {
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best = nd;
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bdir = (dr, dc);
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}
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}
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if bdir == (0, 0) {
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NO_WATER_BEARING
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} else {
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octant_bearing(bdir.0, bdir.1)
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}
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}
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}
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/// Sentinel for [`TerrainAnalysis::water_bearing`] meaning "no water direction".
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pub const NO_WATER_BEARING: u16 = 360;
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/// Quantize a (Δrow, Δcol) step to a compass octant bearing (0=N … 315=NW).
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/// `Δrow < 0` is north (rows increase downward). Integer-only (D-010).
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fn octant_bearing(drow: i32, dcol: i32) -> u16 {
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let (ar, ac) = (drow.abs(), dcol.abs());
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let north = drow < 0;
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let east = dcol > 0;
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if ar >= ac * 2 {
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if north {
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0
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} else {
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180
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}
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} else if ac >= ar * 2 {
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if east {
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90
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} else {
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270
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}
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} else {
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match (north, east) {
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(true, true) => 45,
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(true, false) => 315,
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(false, true) => 135,
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(false, false) => 225,
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}
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}
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}
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/// Largest connected below-sea-level component = ocean; all others = lakes.
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/// Deterministic: BFS seeds scanned row-major; ties broken by lowest cell index.
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fn compute_lake_mask(ocean_mask: &[bool], w: usize, h: usize) -> Vec<bool> {
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let n = w * h;
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let mut comp = vec![-1i32; n];
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let mut comp_sizes: Vec<usize> = Vec::new();
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let mut next_comp = 0i32;
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for start in 0..n {
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if !ocean_mask[start] || comp[start] >= 0 {
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continue;
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}
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// Flood fill this component (row-major BFS = deterministic).
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let mut size = 0usize;
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let mut q = VecDeque::new();
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comp[start] = next_comp;
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q.push_back(start);
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while let Some(cur) = q.pop_front() {
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size += 1;
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let (r, c) = (cur / w, cur % w);
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for &(dr, dc) in &NB8 {
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let nr = r as i32 + dr;
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if nr < 0 || nr >= h as i32 {
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continue;
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}
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let nc = wrap_col(c as i32 + dc, w as i32);
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let ni = idx(nr as usize, nc, w);
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if ocean_mask[ni] && comp[ni] < 0 {
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comp[ni] = next_comp;
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q.push_back(ni);
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}
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}
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}
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comp_sizes.push(size);
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next_comp += 1;
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}
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if comp_sizes.is_empty() {
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return vec![false; n]; // no water at all
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}
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// Largest component (tie → lowest comp id, which is the earliest row-major).
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let mut ocean_comp = 0i32;
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let mut best = 0usize;
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for (cid, &sz) in comp_sizes.iter().enumerate() {
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if sz > best {
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best = sz;
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ocean_comp = cid as i32;
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}
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}
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// Lakes = submerged cells in any non-ocean component.
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(0..n)
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.map(|i| comp[i] >= 0 && comp[i] != ocean_comp)
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.collect()
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}
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/// Multi-source BFS Chebyshev distance to nearest ocean cell or river mouth.
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fn compute_water_dist(ocean_mask: &[bool], mouths: &[(u16, u16)], w: usize, h: usize) -> Vec<u16> {
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let n = w * h;
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let mut dist = vec![WATER_DIST_CAP; n];
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let mut q = VecDeque::new();
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// Seeds in row-major order for determinism.
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for i in 0..n {
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if ocean_mask[i] {
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dist[i] = 0;
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q.push_back(i);
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}
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}
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for &(mr, mc) in mouths {
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let i = idx(mr as usize, mc as usize, w);
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if dist[i] != 0 {
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dist[i] = 0;
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q.push_back(i);
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}
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}
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while let Some(cur) = q.pop_front() {
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let d = dist[cur];
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if d >= WATER_DIST_CAP {
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continue;
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}
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let (r, c) = (cur / w, cur % w);
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for &(dr, dc) in &NB8 {
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let nr = r as i32 + dr;
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if nr < 0 || nr >= h as i32 {
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continue;
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}
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let nc = wrap_col(c as i32 + dc, w as i32);
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let ni = idx(nr as usize, nc, w);
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if dist[ni] > d + 1 {
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dist[ni] = d + 1;
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q.push_back(ni);
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}
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}
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}
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dist
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}
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/// Local slope proxy: `atan(max |Δelev| to 8 neighbors)` in degrees.
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fn compute_slope(elev: &[f32], w: usize, h: usize) -> Vec<f32> {
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let n = w * h;
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let mut slope = vec![0.0f32; n];
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for r in 0..h {
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for c in 0..w {
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let i = idx(r, c, w);
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let e = elev[i];
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let mut max_grad = 0.0f32;
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for &(dr, dc) in &NB8 {
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let nr = r as i32 + dr;
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if nr < 0 || nr >= h as i32 {
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continue;
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}
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let nc = wrap_col(c as i32 + dc, w as i32);
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let g = (e - elev[idx(nr as usize, nc, w)]).abs();
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if g > max_grad {
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max_grad = g;
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}
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}
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slope[i] = max_grad.atan().to_degrees();
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}
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}
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slope
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}
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/// Elevation percentile [0,1] among land cells; ocean cells get 0.0.
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fn compute_elev_percentile(elev: &[f32], ocean_mask: &[bool], w: usize, h: usize) -> Vec<f32> {
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let n = w * h;
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// (scaled_elev, idx) for land cells; integer key for deterministic sort.
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let mut land: Vec<(i64, usize)> = (0..n)
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.filter(|&i| !ocean_mask[i])
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.map(|i| ((elev[i] as f64 * 1_000_000.0) as i64, i))
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.collect();
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land.sort_unstable_by(|a, b| a.0.cmp(&b.0).then(a.1.cmp(&b.1)));
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let mut pct = vec![0.0f32; n];
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let m = land.len();
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if m <= 1 {
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for &(_, i) in &land {
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pct[i] = 0.5;
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}
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return pct;
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}
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for (rank, &(_, i)) in land.iter().enumerate() {
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pct[i] = rank as f32 / (m - 1) as f32;
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}
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pct
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}
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/// Habitability score [0,1] from elevation band, flatness, and moisture.
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/// Used by `ValleyFloor`/`PlainCenter` strengths and the D-210 classifier.
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pub fn habitability(elev_pct: f32, slope_deg: f32, water_dist: u16) -> f32 {
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let elev_score = (1.0 - (elev_pct - 0.35).abs() / 0.65).clamp(0.0, 1.0);
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let flat_score = (1.0 - slope_deg / 15.0).clamp(0.0, 1.0);
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let water_score = (1.0 - water_dist as f32 / 40.0).clamp(0.0, 1.0);
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(0.4 * elev_score + 0.3 * flat_score + 0.3 * water_score).clamp(0.0, 1.0)
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}
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/// Extract the 7 D-209 attractor tags. Returns raw attractors (no sub-biome),
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/// sorted by `(attractor_type, row, col)` for determinism. Higher-priority
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/// types claim their cells first so a cell is tagged at most once.
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pub fn extract_attractors(
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hm: &BodyHeightmap,
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drainage: &DrainageResult,
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ta: &TerrainAnalysis,
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) -> Vec<RawAttractor> {
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let w = hm.width as usize;
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let h = hm.height as usize;
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let elev = &hm.data;
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let accum = &drainage.flow_accumulation;
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let max_accum = drainage.max_accumulation.max(1) as f32;
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let mut claimed = vec![false; w * h];
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let mut out: Vec<RawAttractor> = Vec::new();
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// O(1) river-cell membership (avoids a binary_search per valley candidate).
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let mut river_mask = vec![false; w * h];
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for &(r, c) in &drainage.river_network.river_cells {
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river_mask[idx(r as usize, c as usize, w)] = true;
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}
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let claim = |out: &mut Vec<RawAttractor>,
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claimed: &mut [bool],
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r: usize,
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c: usize,
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at: AttractorType,
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strength: f32| {
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let i = idx(r, c, w);
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if claimed[i] {
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return;
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}
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claimed[i] = true;
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out.push(RawAttractor {
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row: r as u16,
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col: c as u16,
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attractor_type: at,
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// The single f32→integer boundary: quantize the 0.0–1.0 ratio to 0–100.
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strength: (strength.clamp(0.0, 1.0) * 100.0).round() as i32,
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});
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};
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// 1. RiverMouth — strength = accum / max_accum.
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for &(r, c) in &drainage.river_network.mouths {
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let i = idx(r as usize, c as usize, w);
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let s = accum[i] as f32 / max_accum;
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claim(
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&mut out,
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&mut claimed,
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r as usize,
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c as usize,
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AttractorType::RiverMouth,
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s,
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);
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}
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// 2. RiverCrossing — confluences, strength = accum / max_accum * 0.7.
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for &(r, c) in &drainage.river_network.confluences {
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let i = idx(r as usize, c as usize, w);
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let s = accum[i] as f32 / max_accum * 0.7;
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claim(
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&mut out,
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&mut claimed,
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r as usize,
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c as usize,
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AttractorType::RiverCrossing,
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s,
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);
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}
|
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|
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// 3. CoastalAccess — land within 3 cells of ocean, thinned by spacing.
|
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// strength = 0.6 + coast-density bonus (capped).
|
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let mut coastal: Vec<(usize, usize, f32)> = Vec::new();
|
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for r in 0..h {
|
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for c in 0..w {
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let i = idx(r, c, w);
|
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// water_dist (precomputed) is a cheap pre-filter: only cells within
|
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// 3 of water can be coastal, so skip the 49-cell scan for inland.
|
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if ta.ocean_mask[i] || claimed[i] || ta.water_dist[i] > 3 {
|
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continue;
|
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}
|
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let near = ocean_cells_within(ta, r, c, 3);
|
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if near > 0 {
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let bonus = (near as f32 / 24.0).min(0.3);
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coastal.push((r, c, 0.6 + bonus));
|
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}
|
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}
|
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}
|
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for (r, c, s) in thin_by_spacing(coastal, &claimed, w) {
|
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claim(
|
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&mut out,
|
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&mut claimed,
|
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r,
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c,
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AttractorType::CoastalAccess,
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s,
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||
);
|
||
}
|
||
|
||
// 4. ValleyFloor — gentle slope, mid elevation, positive habitability.
|
||
let mut valleys: Vec<(usize, usize, f32)> = Vec::new();
|
||
for r in 0..h {
|
||
for c in 0..w {
|
||
let i = idx(r, c, w);
|
||
if ta.ocean_mask[i] || claimed[i] {
|
||
continue;
|
||
}
|
||
if river_mask[i] || ta.slope_deg[i] >= 5.0 {
|
||
continue;
|
||
}
|
||
if ta.elev_pct[i] < 0.10 || ta.elev_pct[i] > 0.60 {
|
||
continue;
|
||
}
|
||
let hab = habitability(ta.elev_pct[i], ta.slope_deg[i], ta.water_dist[i]);
|
||
if hab > 0.0 {
|
||
valleys.push((r, c, hab));
|
||
}
|
||
}
|
||
}
|
||
for (r, c, s) in thin_by_spacing(valleys, &claimed, w) {
|
||
claim(&mut out, &mut claimed, r, c, AttractorType::ValleyFloor, s);
|
||
}
|
||
|
||
// 5. PassEntrance — morphological saddles in higher terrain.
|
||
// strength = 1 - elev_pct (lower passes score higher).
|
||
let mut passes: Vec<(usize, usize, f32)> = Vec::new();
|
||
for r in 1..h.saturating_sub(1) {
|
||
for c in 0..w {
|
||
let i = idx(r, c, w);
|
||
if ta.ocean_mask[i] || claimed[i] || ta.elev_pct[i] < 0.5 {
|
||
continue;
|
||
}
|
||
if is_saddle(elev, r, c, w, h) {
|
||
passes.push((r, c, 1.0 - ta.elev_pct[i]));
|
||
}
|
||
}
|
||
}
|
||
for (r, c, s) in thin_by_spacing(passes, &claimed, w) {
|
||
claim(&mut out, &mut claimed, r, c, AttractorType::PassEntrance, s);
|
||
}
|
||
|
||
// 6. LakeShore — land adjacent to an enclosed lake. strength = 0.5.
|
||
let mut shores: Vec<(usize, usize, f32)> = Vec::new();
|
||
for r in 0..h {
|
||
for c in 0..w {
|
||
let i = idx(r, c, w);
|
||
if ta.ocean_mask[i] || ta.lake_mask[i] || claimed[i] {
|
||
continue;
|
||
}
|
||
if adjacent_to_lake(ta, r, c) {
|
||
shores.push((r, c, 0.5));
|
||
}
|
||
}
|
||
}
|
||
for (r, c, s) in thin_by_spacing(shores, &claimed, w) {
|
||
claim(&mut out, &mut claimed, r, c, AttractorType::LakeShore, s);
|
||
}
|
||
|
||
// 7. PlainCenter — very flat, away from everything. strength = hab * 0.4.
|
||
let mut plains: Vec<(usize, usize, f32)> = Vec::new();
|
||
for r in 0..h {
|
||
for c in 0..w {
|
||
let i = idx(r, c, w);
|
||
if ta.ocean_mask[i] || claimed[i] || ta.slope_deg[i] >= 2.0 {
|
||
continue;
|
||
}
|
||
let hab = habitability(ta.elev_pct[i], ta.slope_deg[i], ta.water_dist[i]);
|
||
plains.push((r, c, hab * 0.4));
|
||
}
|
||
}
|
||
for (r, c, s) in thin_by_spacing(plains, &claimed, w) {
|
||
claim(&mut out, &mut claimed, r, c, AttractorType::PlainCenter, s);
|
||
}
|
||
|
||
// Cap to MAX_ATTRACTORS while preserving type diversity. D-209 calls
|
||
// RiverMouth "always high-value", but its *normalized* strength
|
||
// (accum / max_accum) is tiny for all but the largest river, so a pure
|
||
// global-strength cap lets abundant ValleyFloor/CoastalAccess crowd every
|
||
// RiverMouth out. Instead: group by type, sort each group strongest-first,
|
||
// then round-robin across types so every present type keeps representation.
|
||
// Deterministic (BTreeMap type order, integer strength key, fixed rotation).
|
||
if out.len() > MAX_ATTRACTORS {
|
||
let mut by_type: std::collections::BTreeMap<u8, Vec<RawAttractor>> =
|
||
std::collections::BTreeMap::new();
|
||
for a in out.drain(..) {
|
||
by_type.entry(a.attractor_type as u8).or_default().push(a);
|
||
}
|
||
for group in by_type.values_mut() {
|
||
group.sort_by(|a, b| {
|
||
// strength is integer now — rank by it directly (descending).
|
||
b.strength
|
||
.cmp(&a.strength)
|
||
.then(a.row.cmp(&b.row))
|
||
.then(a.col.cmp(&b.col))
|
||
});
|
||
}
|
||
let mut kept: Vec<RawAttractor> = Vec::with_capacity(MAX_ATTRACTORS);
|
||
let mut depth = 0usize;
|
||
'fill: loop {
|
||
let mut progressed = false;
|
||
for group in by_type.values() {
|
||
if let Some(a) = group.get(depth) {
|
||
kept.push(*a);
|
||
progressed = true;
|
||
if kept.len() >= MAX_ATTRACTORS {
|
||
break 'fill;
|
||
}
|
||
}
|
||
}
|
||
if !progressed {
|
||
break;
|
||
}
|
||
depth += 1;
|
||
}
|
||
out = kept;
|
||
}
|
||
out.sort_by(|a, b| {
|
||
(a.attractor_type as u8, a.row, a.col).cmp(&(b.attractor_type as u8, b.row, b.col))
|
||
});
|
||
out
|
||
}
|
||
|
||
fn ocean_cells_within(ta: &TerrainAnalysis, r: usize, c: usize, radius: i32) -> usize {
|
||
let mut count = 0;
|
||
for dr in -radius..=radius {
|
||
let nr = r as i32 + dr;
|
||
if nr < 0 || nr >= ta.h as i32 {
|
||
continue;
|
||
}
|
||
for dc in -radius..=radius {
|
||
let nc = wrap_col(c as i32 + dc, ta.w as i32);
|
||
if ta.ocean_mask[idx(nr as usize, nc, ta.w)] {
|
||
count += 1;
|
||
}
|
||
}
|
||
}
|
||
count
|
||
}
|
||
|
||
fn adjacent_to_lake(ta: &TerrainAnalysis, r: usize, c: usize) -> bool {
|
||
for &(dr, dc) in &NB8 {
|
||
let nr = r as i32 + dr;
|
||
if nr < 0 || nr >= ta.h as i32 {
|
||
continue;
|
||
}
|
||
let nc = wrap_col(c as i32 + dc, ta.w as i32);
|
||
if ta.lake_mask[idx(nr as usize, nc, ta.w)] {
|
||
return true;
|
||
}
|
||
}
|
||
false
|
||
}
|
||
|
||
/// Morphological saddle: walking the 8-neighbor ring, the sign of
|
||
/// `(neighbor - cell)` alternates at least 4 times (≥2 higher sectors
|
||
/// separated by ≥2 lower sectors).
|
||
fn is_saddle(elev: &[f32], r: usize, c: usize, w: usize, h: usize) -> bool {
|
||
// Ring order (clockwise) so transitions are meaningful.
|
||
const RING: [(i32, i32); 8] = [
|
||
(-1, 0),
|
||
(-1, 1),
|
||
(0, 1),
|
||
(1, 1),
|
||
(1, 0),
|
||
(1, -1),
|
||
(0, -1),
|
||
(-1, -1),
|
||
];
|
||
let e = elev[idx(r, c, w)];
|
||
let mut signs = [0i8; 8];
|
||
for (k, &(dr, dc)) in RING.iter().enumerate() {
|
||
let nr = r as i32 + dr;
|
||
if nr < 0 || nr >= h as i32 {
|
||
return false; // poles can't be saddles in this scheme
|
||
}
|
||
let nc = wrap_col(c as i32 + dc, w as i32);
|
||
signs[k] = if elev[idx(nr as usize, nc, w)] > e {
|
||
1
|
||
} else {
|
||
-1
|
||
};
|
||
}
|
||
let mut transitions = 0;
|
||
for k in 0..8 {
|
||
if signs[k] != signs[(k + 1) % 8] {
|
||
transitions += 1;
|
||
}
|
||
}
|
||
transitions >= 4
|
||
}
|
||
|
||
/// Greedy spatial thinning: sort candidates by descending strength (ties by
|
||
/// row, col), keep one per `MIN_SPACING` Chebyshev neighborhood.
|
||
///
|
||
/// Uses a bucket grid (cell size = `MIN_SPACING`) so each candidate only checks
|
||
/// the 3×3 neighboring buckets — O(k) amortized rather than O(k²). The kept
|
||
/// order is fully determined by the sorted candidate iteration; the bucket map
|
||
/// is `BTreeMap` (the project bans `HashMap` for determinism) and is lookup-only
|
||
/// regardless.
|
||
fn thin_by_spacing(
|
||
mut cands: Vec<(usize, usize, f32)>,
|
||
_claimed: &[bool],
|
||
_w: usize,
|
||
) -> Vec<(usize, usize, f32)> {
|
||
// Deterministic order: strength desc, then row, col asc.
|
||
cands.sort_by(|a, b| {
|
||
let sa = (a.2 * 1e6) as i64;
|
||
let sb = (b.2 * 1e6) as i64;
|
||
sb.cmp(&sa).then(a.0.cmp(&b.0)).then(a.1.cmp(&b.1))
|
||
});
|
||
let sp = MIN_SPACING.max(1) as usize;
|
||
let mut buckets: BTreeMap<(usize, usize), Vec<(usize, usize)>> = BTreeMap::new();
|
||
let mut kept: Vec<(usize, usize, f32)> = Vec::new();
|
||
for (r, c, s) in cands {
|
||
let (br, bc) = (r / sp, c / sp);
|
||
let mut ok = true;
|
||
'scan: for nbr in br.saturating_sub(1)..=br + 1 {
|
||
for nbc in bc.saturating_sub(1)..=bc + 1 {
|
||
if let Some(pts) = buckets.get(&(nbr, nbc)) {
|
||
for &(kr, kc) in pts {
|
||
let dr = (kr as i32 - r as i32).abs();
|
||
let dc = (kc as i32 - c as i32).abs();
|
||
if dr.max(dc) < MIN_SPACING {
|
||
ok = false;
|
||
break 'scan;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
if ok {
|
||
buckets.entry((br, bc)).or_default().push((r, c));
|
||
kept.push((r, c, s));
|
||
}
|
||
}
|
||
kept
|
||
}
|
||
|
||
#[cfg(test)]
|
||
mod tests {
|
||
use super::*;
|
||
use crate::atlas::drainage;
|
||
|
||
fn slope_grid(w: u32, h: u32) -> Vec<f32> {
|
||
let n = (w * h) as usize;
|
||
(0..n)
|
||
.map(|i| {
|
||
let r = i / w as usize;
|
||
let c = i % w as usize;
|
||
1.0 - (r as f32 / h as f32 * 0.5 + c as f32 / w as f32 * 0.5)
|
||
})
|
||
.collect()
|
||
}
|
||
|
||
fn hm(data: Vec<f32>, w: u32, h: u32, sea: f32) -> BodyHeightmap {
|
||
BodyHeightmap {
|
||
body_id: "T".into(),
|
||
width: w,
|
||
height: h,
|
||
data,
|
||
sea_level: sea,
|
||
}
|
||
}
|
||
|
||
#[test]
|
||
fn deterministic_extraction() {
|
||
let h = hm(slope_grid(64, 32), 64, 32, 0.3);
|
||
let dr = drainage::analyze(&h.data, 64, 32, 0.3);
|
||
let ta = TerrainAnalysis::analyze(&h, &dr);
|
||
let a1 = extract_attractors(&h, &dr, &ta);
|
||
let a2 = extract_attractors(&h, &dr, &ta);
|
||
assert_eq!(a1, a2, "attractor extraction must be deterministic");
|
||
}
|
||
|
||
#[test]
|
||
fn attractors_sorted_and_bounded() {
|
||
let h = hm(slope_grid(128, 64), 128, 64, 0.3);
|
||
let dr = drainage::analyze(&h.data, 128, 64, 0.3);
|
||
let ta = TerrainAnalysis::analyze(&h, &dr);
|
||
let a = extract_attractors(&h, &dr, &ta);
|
||
assert!(a.len() <= MAX_ATTRACTORS);
|
||
// Sorted by (type as u8, row, col).
|
||
for win in a.windows(2) {
|
||
let ka = (win[0].attractor_type as u8, win[0].row, win[0].col);
|
||
let kb = (win[1].attractor_type as u8, win[1].row, win[1].col);
|
||
assert!(ka <= kb, "attractors must be sorted");
|
||
}
|
||
}
|
||
|
||
#[test]
|
||
fn percentile_in_range() {
|
||
let h = hm(slope_grid(32, 16), 32, 16, 0.3);
|
||
let dr = drainage::analyze(&h.data, 32, 16, 0.3);
|
||
let ta = TerrainAnalysis::analyze(&h, &dr);
|
||
assert!(ta.elev_pct.iter().all(|&p| (0.0..=1.0).contains(&p)));
|
||
assert_eq!(ta.slope_deg.len(), 32 * 16);
|
||
}
|
||
|
||
/// Multi-octave sine terrain (continents + many small coastal streams) —
|
||
/// produces > MAX_ATTRACTORS candidates with plenty of river mouths.
|
||
fn sine_grid(w: u32, h: u32) -> Vec<f32> {
|
||
use std::f32::consts::{PI, TAU};
|
||
(0..(w * h))
|
||
.map(|i| {
|
||
let r = (i / w) as f32;
|
||
let c = (i % w) as f32;
|
||
let x = c / w as f32 * TAU;
|
||
let y = r / h as f32 * PI;
|
||
(0.5 + 0.25 * (x * 3.0).sin() * (y * 2.0).sin()
|
||
+ 0.15 * (x * 7.0).cos() * (y * 5.0).sin()
|
||
+ 0.08 * (x * 13.0).sin() * (y * 11.0).cos()
|
||
+ 0.05 * (x * 23.0).cos() * (y * 19.0).sin())
|
||
.clamp(0.0, 1.0)
|
||
})
|
||
.collect()
|
||
}
|
||
|
||
#[test]
|
||
fn river_mouths_survive_cap() {
|
||
// D-209 + the type-aware cap: even though RiverMouth normalized strength
|
||
// is tiny, a body full of mouths must still keep RiverMouth attractors
|
||
// (a global-strength cap would drop all of them — the bug Hoshe caught).
|
||
let h = hm(sine_grid(512, 256), 512, 256, 0.40);
|
||
let dr = drainage::analyze(&h.data, 512, 256, 0.40);
|
||
assert!(
|
||
!dr.river_network.mouths.is_empty(),
|
||
"fixture must have mouths"
|
||
);
|
||
let ta = TerrainAnalysis::analyze(&h, &dr);
|
||
let a = extract_attractors(&h, &dr, &ta);
|
||
assert!(a.len() <= MAX_ATTRACTORS);
|
||
assert!(
|
||
a.iter()
|
||
.any(|x| x.attractor_type == AttractorType::RiverMouth),
|
||
"RiverMouth attractors must survive the cap when mouths exist"
|
||
);
|
||
}
|
||
}
|