pub fn lod_color(level: u8) -> [f32; 3]Expand description
Distinct linear-RGB colour per LOD level. Same hue spin (level * 0.137) and
HSV→RGB construction as the existing terrain_surface layer_color, so the
debug palette matches the rest of the project. Returns plain [f32;3] (no
engine-backed Color) so it is testable headlessly.