Width (in uvContent units) over which the threshold input fades
to zero past the element boundary.
Additive gain on the bloom.
Extra pad around the element in CSS (logical) px so the glow has
room to spread. "fullscreen" reaches the viewport edges.
Halo spread, 0..1. Linear in octaves of reach: each step of
1/(depth−1) activates one more pyramid level. Intensity is
normalised by active depth so brightness stays roughly
scatter-independent.
Soft-knee width, 0..1. COD:AW-style quadratic knee of half-width
threshold × softness centred on the cutoff. softness=0 → hard
threshold; 1 → knee stretches down to zero.
Luminance cutoff in [0,1].
Dither amount 0..1. Non-zero injects ±0.5-LSB interleaved-gradient
noise at composite time to mask 8-bit banding.