Module grain 

Film grain overlay — per-pixel random brightness noise, mimicking analog film emulsion.

The grain pattern is spatially uncorrelated (white noise) and temporally randomized each frame (driven by a seed uniform). Grain can be scaled by luma to avoid brightening dark pixels too much (luma-weighted grain).

Structs

GrainCurve

Maps a time value to a grain intensity, useful for animated grain during hit events.

GrainParams

Film grain pass parameters.