nx_gradient_blend.nx

nx_gradient_blend.nx -- smooth zone-to-zone transition primitive. Sixth demonstration of the kind-specific-generator cardinal `feedback-kind-specific-generators-not-broad-noise`. Solves the "biome edges are sharp cliffs" problem: when two zones (biomes, elevation bands, climate regions, kind-generators) meet, they SHOULDN'T abruptly snap from one to the other. Real-world biome transitions are gradients over kilometres of varying ecological pressure. This primitive ships the interpolation kernels. Caller pattern: blended = nx_gradient_blend_q14(value_a, value_b, progress, curve) where progress in [0, Q] (0 = pure A, Q = pure B). Sealed-enum easing curves give different aesthetic options: LINEAR -- straight line, equal-weight blend SMOOTHSTEP -- cubic Hermite, smooth at both ends (Perlin's classic fade curve) EASE_IN_OUT -- slow start + slow end (s-curve) SHARP -- nearly-step but with thin transition band CRENULATE -- alternating pattern (used for forest/grassland transitions that look "fingery" rather than a smooth line) V2 follow-ups (queued): - 2D progress (perpendicular + along the transition line) - Noise-perturbed transition for organic edges (composes nx_perlin or nx_worley_noise to roughen the transition line) - Catmull-Rom and bezier easing for N-way blends - Multi-zone blending (3+ neighbours) - "Fingery" forest edge via L-system extension Loss audit: Q14 integer arithmetic; cubic and s-curve evaluation uses 64-bit intermediates to avoid overflow. Clamping at boundary values to keep output bounded. CRENULATE relies on hash for determinism. genealogy_id: perlin_2002_improving_noise + ken_perlin_smoothstep + whittaker_1975_community_ecology lineage_id: nx_gradient_blend_5curve_q14_v1