Iridescent Soap Bubble — Thin-Film Color Shift & Wobble

Real soap bubbles get their shifting rainbow sheen from thin-film interference: light reflecting off the front and back of the microscopically thin liquid film interferes constructively and destructively depending on film thickness and viewing angle. This scene approximates that with a per-vertex color computed from a simulated thickness field and a fresnel (view-angle) term, on top of a wobbling sphere mesh mimicking surface-tension oscillation.