Stolen from the shader half of Sebastian Lague's graphics-library video (the Voronoi farm-plot
trick), because it turns out to be an anatomy tool rather than a decoration: mucosa at SEM scale
IS a Voronoi diagram. Lane D's own oral prompt asks FLUX for a "cobblestone pavement of flat
polygonal squamous epithelial cells" — that is a Voronoi described in English, and generating it
in the fragment shader instead is free, never repeats, and can do the one thing a baked texture
never will: BREATHE. Membrane width rides vPulse, the same wave the vertex shader displaces
with, so the pavement compresses exactly where the muscle contracts.
- F2-F1 Voronoi (9-tap), multiplied into the detail LUMINANCE, never added — D's texture stays
the author of the look and this is structure underneath it. Applied to both the textured and
the assets-optional fallback path.
- Rides D's own tiling (duv * scale), so cells hold their physical size on a radius-7 hiatus and
a radius-70 sea — the upstream arc-length fix does that work for free.
- Compiled out with a define, not branched out on a uniform: a biome that wants no pavement pays
nothing for nine hashes a pixel.
Per-biome, because a pavement is a CLAIM ABOUT TISSUE and not a filter: oral 0.50 (squamous
epithelium is the strongest case in the body), appendix 0.48 and colon 0.42 (biofilm mats are
literally cells), stomach 0.38 (gastric pits), small intestine 0.20 and esophagus 0.18 (villi
are projections and folds are folds — there it is a whisper that only breaks the texture repeat).
Verified: per-biome values reach the material (esophagus 0.18, not the 0.35 default), the effect
reads on the wall at gameplay distance, and world.hash() is byte-identical (bea3807c) before and
after — this is pixels only, the determinism law is untouched.
Not measured: frame cost on real hardware. Nine hashes per wall pixel is not free and the budget
is 60fps on mid laptops; if it bites, the honest lever is dropping the low-gain biomes to 0
(which compiles it out entirely) rather than cheapening the shader.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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