Procedural jelly kitten knight in a grassy field

Build "Knight Kitten": a single self-contained HTML file, native WebGPU, fully procedural (no models, no textures, no libraries). The scene: a tiny jelly kitten knight sitting in a grassy field. - The kitten wears a little suit of armour and a bow. - It holds a sword far too big for it, and a cape is sewn to its back. - The kitten, the armour, the bow and the sword are all one signed distance field filled with a single lattice, so no part can come loose. Material regions are painted in rest space: jelly, armour, blade, grip, guard and pommel, bow. - Candy-bright glossy eyes; tabby stripes and a cream muzzle, chest and toes inside the jelly. Physics (XPBD): - The body is a soft lattice: co-rotational shape matching on hexahedral cells plus tetrahedral volume constraints, a fixed 60 Hz step with substeps, edge damping and sleeping. - The armour is firmer than the jelly. - The sword is steel that bends: overlapping shape-matching clusters along it, with the hilt held in the kitten's grip in the torso's best-fit frame. - The seat keeps its footing on the grass and the toy rights itself after a wobble. - A drag stretches the kitten. "Lift" mode picks the whole kitten up so it dangles and jiggles, then lands and finds its footing again. - The cape is an XPBD cloth (stretch, shear and bend constraints from a flat pattern) sewn to points embedded in the lattice. - Spheres riding the body keep the cape off it, and it rests on the grass. - Per-triangle aerodynamic wind acts on it. - The cape can be grabbed; a hard pull tugs the kitten along. Rendering: - The jelly is a refractive volume: front depth plus the nearest back face, absorption by thickness, a glowing deep colour, gloss and the environment refracted through it. - The kitten is skinned on the GPU from the lattice nodes and their deformation gradients. - The sun shadow map also stores the coloured light the jelly lets through; a top-down height map gives contact shading under the kitten. - An instanced grass field around it sways in the same wind formula as the physics. Weather presets, each with its own sun, sky and wind: - Mist (soft hazy light); - Wind (gusts that lean on the toy and blow the cape); - Rain (falling streaks and splashes on the ground); - Storm (dark sky, heavy rain, lightning flashes). Make all four look unmistakably different. Interaction: - Drag the kitten to stretch it; drag the background to orbit; zoom. - Grab the cape. - A Lift toggle to carry the kitten. UI: - A minimal glassy UI: weather buttons (keys 1–4), jelly palettes Honey, Rose and Icy blue, Softness and Wind sliders, Pause (Space) and Reset (R). - Responsive on phones; adaptive quality. - NaN-safe WGSL: clamp every pow and smoothstep input and clamp the HDR result, so no black specks appear on real GPUs.