Implements THE WORLD CONTRACT (TECH.md) in web/js/world/; drop-in for the stub.
boot.js now runs this on C's L2_esophagus (3600u, hash cefc4f83), zero console errors.
- spline.js: centreline + arclength LUTs + parallel-transport frames + radius law +
peristalsis phase + project() + hash(). No three.js import, so qa can run its
14-assertion selfcheck headless.
- curviness is solved from a curvature budget, not authored as an amplitude: the pinch
guard caught the tube folding through itself on a wide+curvy join (turn radius 9.9 vs
tube radius 17.2). C can no longer author a pinch.
- peristalsis: global OMEGA, k(s) = OMEGA/flow(s), phase K(s) = integral k ds. A crest
therefore travels at exactly the local flow speed, so "surf the crest" == "ride the
current". Esophagus wave amp 0.9 -> 1.4 (measured): moves wallRho for Lane B.
- tube.js: chunked streaming, seams aligned to biome joins, arenas own their s-span.
- arena.js: displaced icosphere shells v0 (three's polyhedron detail is 20*(detail+1)^2,
not 20*4^detail — 720 tris was far too coarse); fog sized to the room, since biome fog
tuned for 100u corridors renders C's 360u acid sea as a black rectangle.
- index.js: prefers assets.texture() over get() (get returns raw JSON a shader can't eat),
plus an explicit slug map — D's wall_smallint_a vs biome id small_intestine would miss
silently forever under the assets-optional law.
Measured (C's real L2 + D's real pack, 1920x1080, renderer.info): 8 draws worst frame
(budget 150), 74k tris (500k), no geometry leak across a full sweep, <120ms load,
pinch ratio 3.32. fps not claimed — the screenshot pane runs tabs hidden, pausing rAF.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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