crown_eyewall

The mesocyclone's wall, lit from within. A self-shading surface shader: banded, differentially-rotating cloud that is exactly periodic around the ring (no seam), a fresnel rim that gives the wall volume against a black shaft, an amber bleed from the eye at the throat, and a hot pulse that runs up the wall while an attack is winding up. spin, charge, core_glow, tighten and flash are driven per-frame from the crown system, so the surface and the fight run on one number.