pub fn mask_combine_definition(count: usize) -> EffectDefExpand description
The pass combining count masks (1 to MAX_SHAPE_MASKS) into its source’s coverage.
Mask i is input m{i} (coverage in alpha), inverted when invert{i} is set, and combined
by mode{i}: coverage starts empty when the first mask adds and full otherwise; add is
c + m - c m, subtract c (1 - m), intersect c m. The source is multiplied by the result.
§Panics
When count is zero or more than MAX_SHAPE_MASKS.