pub fn band_coord(t: f32, steps: f32) -> f32Expand description
Quantize a palette coordinate onto steps hard bands — the canonical
definition every LUT sample site in the engine mirrors (module docs).
t' = (floor(t·N) + 0.5)/N lands on each band’s centre, so the colour a band
takes is the one the smooth ramp had in the middle of it rather than at its
edge. Below MIN_ACTIVE_STEPS (tested as < 1.5, since band_steps has
already rounded) the coordinate passes through untouched — the exact
identity, which is what keeps every shipped preset and every golden baseline
byte-identical.
Negative and above-1 coordinates are fine and are the common case: the LUT is
repeat-addressed, so a color_span above 1 wraps it, and floor keeps the
quantization aligned across every wrap.