weatherLib

The shared WGSL of weatheringMaterials: hashing and noise (value noise, fbm, cellular, crack network), the object frame a weathering layer reads (position in metres, face normal, bounds from the per-instance lanes, curvature), the gathering masks (facing up, height above the object's foot, crevices from a screen-space occlusion probe over the scene depth, box edges and curvature, streaks down from top edges and bolts, rising plumes, low spots, noise), screen-space bump helpers, and the composite that wets a surface and lays a lit deposit over it in one premultiplied blend. Included by weatherOverlay, weatherSwatch, weatherToon and weatherSticker.