Build a real-time WebGPU soft-body "jelly" study of a halved passion fruit, same engine and editorial page style as my Melon / Avocado / Peach jelly slices. Geometry from SDFs: a slightly squashed sphere cut flat at the top, a thin wrinkled purple skin, a ~0.15 R white pith wall, and a hollow filled with lumpy translucent orange pulp sitting a little below the rim. Sim: CPU XPBD co-rotational shape matching + volume constraints on a 5-tet hex lattice, 10 substeps at 60 Hz, with per-tet regions — a firm, leathery rind cup and a very soft pulp whose volume constraints are compliant, so grabbing the pulp makes it neck and stretch like goo and slump back instead of lifting the whole fruit. Render a surface-nets mesh skinned to the lattice: refraction, Beer–Lambert absorption, subsurface scattering, Fresnel studio reflections, GGX, shadow map, contact AO, PBR Neutral tone mapping. Shader regions from rest-space SDFs: rounded wrinkle bump on the skin (faded at grazing angles and distance), pale pith, a thin yellow membrane lining the hollow, soft Voronoi juice-sac cells in the pulp; ~100 dark flat teardrop seeds and a few bubbles embedded in the pulp so they ride the wobble. Varieties: Purple, Golden, Granadilla. Controls: firmness, internal damping, nudge, reset, ¼ speed, show mesh, pause; mass/volume/kinetic readouts; "Inside the experiment" notes. English UI, mobile-friendly.
