Expand description
Story: arc + annular sector SDF primitives (M-VEC.20 / AUT-224).
Six samples in a 3×2 grid:
- filled disc (full angular span,
r_inner = 0), - pie slice (90° wedge),
- full donut (
r_inner > 0, full angular span), - annular sector (partial donut),
- thin stroked arc via
draw_arc(chart gauge needle / tick), - semicircular gauge-style arc with thicker stroke.