pub fn apply_smoothing(samples: &mut [f32], smoothing: f32)Expand description
Apply a single-pole IIR low-pass to a buffer of waveform samples,
matching MD2’s f_wave_smoothing. smoothing ∈ [0, 1]:
0 = no smoothing, 0.9 ≈ heavy attenuation. Mutates in place.
The pole α is mapped from smoothing so that the perceptual range
matches MilkDrop’s slider: a smoothing of 0.75 → α ≈ 0.625, which
is the MD2 sweet spot for visible spike rejection without making the
waveform look like a flat line.