The coverage mask from 94fe300 evaluated the f64 warp for every output
pixel. coverage_mask now asks Warp::block_coverage for each 32 x 16 block
(the shared warp formulas evaluated with outward-rounded intervals, no
edge margin) and evaluates only undecided blocks near the edge per pixel
with Warp::covers; the bits are unchanged
(coverage_mask_matches_per_pixel_decision, incl. partial words and
padding bits; coverage_mask_with_the_horizon_in_view, a perspective
denominator exactly 0 inside the image, so the clamp and
undecided-division paths go through block_coverage and the mask).
Measured (release, synthetic source, embedded lens warp + CA +
perspective as in embedded_lens_perspective_edges_match):
6000x4000 ~30 ms -> 2.7 ms (32 threads, 11x), ~580 ms -> 24.5 ms
(1 thread, 24x); 2048x1365 3.6 ms -> 1.0 ms (3.5x), 67.5 ms -> ~5 ms
(12-14x). Rotate270 the same.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
1237e198d5