every_pathfinder_operation_is_pinned built its stars with shapes::star,
which calls the platform's cos and sin. At the star angle
2.204350845268838, cos on macOS x86_64 (measured under Rosetta on
macOS 27.0.1) returns 0xbfe2f1c59f37cbf4, where the correctly rounded
value, which macOS aarch64 returns, is 0xbfe2f1c59f37cbf5. In the set
of five shapes with seed 7, this moves one star vertex by one ulp, and
the set's Unite hashes to 60181664961792917, where PINNED has
9388160212451732406. Under Rosetta, 21 of the 40 hashes differ.
The test now builds each star from a table of the correctly rounded
cosine and sine of the star's ten angles, written as f64 bit patterns,
with the arithmetic of shapes::star. PINNED is unchanged. With these
inputs, all 40 hashes equal PINNED on aarch64 and under Rosetta.
Trim, Merge and Crop walk the arrangement once per input shape, and every walk tested each edge
side with a coverage mask built from a winding vector with one slot per input. On 300 paths,
against main:
- Trim: 362 → 31 ms
- Merge: 366 → 31 ms
- Crop: 303 → 28 ms
- Unite, Intersect, Exclude, Minus Front and Minus Back: unchanged or a little faster
- Multi, the arrangement's winding, keeps only the non-zero windings as sorted (input, winding)
pairs, added in place. A face is covered by a few inputs, so a test reads a few entries
instead of one per input. The winding arithmetic is unchanged.
- Arrangement::covered lists the inputs that cover a face (the true entries of its coverage
mask). Trim, Merge, Crop, Minus Front, Minus Back, Intersect and Exclude test that list; each
test's old mask form is in a comment beside it. mask() still builds the same mask for the rest.
pathfinder_pinned hashes the output of all ten operations on 2, 5, 12 and 30 overlapping
ellipses, rectangles and stars (even-odd and non-zero, shared keys for Merge). The 40 hashes were
computed with main's dense windings, and the new code gives every one of them. A wrong Crop test
fails it. The pathops suite (103 tests) passes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VmMmc1J8XeNLxhRihWv9cc
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