nx_mountain_chain.nx

nx_mountain_chain.nx -- specialized mountain-chain generator. Eleventh kind-specific generator per feedback-kind-specific-generators-not-broad-noise. A mountain chain is NOT FBM noise -- it has a primary RIDGE polyline, height envelope along the ridge, perpendicular falloff to neighbouring valleys, and tributary ridges branching off the main spine. Generator architecture: - Main ridge polyline: hash-deterministic meandering line with mild perturbation, similar to nx_river_carve but no downhill bias (mountains follow tectonic stress, not drainage). - Per-segment height: bell curve along the ridge length; peak at mid-ridge, taper toward both ends. - Perpendicular falloff: smoothstep over ridge_width on either side. - Tributary ridges: N branches at hash-determined indices along the main spine, each at a hash-determined angle off-perpendicular. Record layout (variable-length; first 8 i64 are header): rec[0] = n_main_points number of main-ridge polyline points rec[1] = n_tributaries count of branch ridges rec[2] = peak_height_q14_m max height of main spine rec[3] = ridge_width_q14_m perpendicular falloff distance rec[4] = peak_at_index which main point has the global max rec[5] = seed Park-Miller LCG seed rec[6] = reserved rec[7] = reserved rec[8..] = main_points 2 i64 per point (x, z) rec[...] = tributary records 4 i64 per tributary: start_idx, n_tributary_pts, height_factor_q14, reserved rec[...] = tributary points 2 i64 per tributary point (x, z) genealogy_id: anderson_2003_tectonic_geomorphology + himalaya_orogeny_canon + ridge_field_canon lineage_id: nx_mountain_chain_polyline_tributary_v1 nx_safety_envelope: intended_use: "Polyline mountain-chain generator with