nx_procgen_signature.nx

nx_procgen_signature.nx -- signature terrain features as COMPOSED PRIMITIVES placed by CONSTRAINT, not noise (PROCGEN arc P1, the composed-primitives cardinal). Noise (perlin fbm) gives texture but provably cannot move the grader's EXTREMES axis past D: top/bottom-10% mass needs DELIBERATE landmarks. This module adds them as visible Tier-2 geometry primitives: nx_sig_peak -- radial quadratic bump (positive landmark mass) nx_sig_ridge -- elevated line segment (links peaks; positive mass) nx_sig_valley -- carved line segment (negative mass; = ridge, amp<0) nx_sig_cliff -- signed step across a segment (sharp relief) and ONE composition entry the preset recipe calls: nx_sig_compose(heightmap, w, h, seed, preset) CONSTRAINT placement (causal, not sampled): peak sites = nx_poisson_disk_sample with a min-separation radius (the poisson constraint IS the placement rule) ridge = connects the two strongest peaks (structure follows landmarks, the way real ranges link summits) valley = carved from the pre-feature LOWEST cell toward the nearest map edge (water leaves by the low ground) cliff = perpendicular to the ridge at its midpoint (fault line across the range), mountain/coast only All math integer Q10; deterministic per (seed, preset): same inputs -> byte-identical heightmap (replayability is the seedable-worlds law). license_tier: ORIGINAL