Expand description
Generate an alpha-mask RenderTexture from a MaskShape
(M-DYN.1 / AUT-43).
The output texture stores coverage as (m, m, m, m): same value
in RGB and alpha so consumers can either alpha-multiply (sample
.a) or display as a grayscale silhouette. The mask is decoupled
from foreground sampling — composition happens in a downstream
pipeline.
Architectural rationale (AUT-43): this primitive owns only
coverage. Privacy blur, redaction, and spotlight will compose with
these textures via separate paths. The cache (AUT-44) layers on
top to avoid regenerating identical masks every frame.