A box's own pixels had to be opaque, but the high-pass that measures its
grain reads 3 px around it, and a transparent pixel there is black once
unpremultiplied. A blur earlier in the stack pads the layer with
transparent pixels, so boxes along that border measured the edge as
strong, smooth colour grain, and Match Grain drew 12 px colour cells
from a clean source on the frames that picked them. Boxes now need their
3 px surround opaque too (a summed-area table keeps the check O(1) per
candidate). Remove Grain picks its boxes the same way.
The sample-box search rescanned every candidate box and the grain statistics
blurred the whole image three times per layer, although Match Grain only reads
the 80 sample boxes (~6.5k pixels). On a 4K frame that analysis was ~90 % of
the effect.
- measure the statistics from small crops around each box (3 px halo, the
Gaussian's support), deduplicating overlapping boxes so the sums match the
previous masked version;
- search the candidate box rows in parallel (the sort is a total order, so the
chosen boxes are unchanged);
- compute the "own" boxes and stats only when Compensate for Existing Noise is
on, and clone the frame for Preview composition only in Preview mode;
- run Plane::transpose/map_rows on the calling thread for small planes: the
rayon dispatch dominated per-box crops (240 blurs of ~15x15).
Release, Ryzen Threadripper 1920X, noisy source / flat target, defaults, best
of 4 (1080p / 4K):
- grain statistics: 151/463 ms -> 1.2/2.8 ms
- sample boxes (source): 43/179 ms -> 16/71 ms
- end to end: 266/1416 ms -> 99/465 ms (Compensate 50 %: 392/1830 -> 104/482)
Tests: the boxed statistics match the masked ones (overlapping and corner
boxes, alpha holes), plus the existing Match Grain/Remove Grain suites.
Kernels in fx_generate.wgsl mirror the CPU effects; wipe edges use f64
per-column/per-row terms uploaded as (hi, lo) pairs. CPU helpers shared
with the GPU are now public (camera_lens_spans, gen_mode, pattern_kind,
GrainLook, place_layer). GPU tests in tests_fx_generate.rs.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Adds 105 effects in new modules (keying, matte, channel, blur2, color2, stylize2, noise, generate2, distort2, perspective, transition, utility) plus shared plane/morphology/guided-filter helpers in util.rs, with 96 new unit tests.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
JonRC