surf_cloud

Reactive cloud-sea surface for the cloudsurf part. The grid mesh stays put while the noise field scrolls past via scroll(t) = scroll0 + speed * (game_t - t0); touch points tp0..tp23 carve a healing wake in field space, and dye_color/hue_shift tint the churned fluff. The height field layers a base roll, cumulus mounds, and Worley billow lobes; the fragment re-samples the lobe field for bump + crevice shading, silver-lining rim, and sun backscatter.