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Possible bug in compareEdges

Open Beginner friendly
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#56 1 comment 1 reaction 0 assignees View on GitHub

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
62/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Quiet
Tech stack
cpp, java
Domain
computer-graphics

Research direction

Start with compareEdges in library/src/com/google/common/geometry/S2EdgeUtil.java around line 3101, then compare it with src/s2/s2edge_crossings.h around line 63 in the referenced C++ implementation. Trace the surrounding arguments and existing tests to determine which comparison is intended; done means the Java behavior matches the verified implementation and tests pass.

Written by the indexing model from the issue text.

Description

The C++ and Java versions of compareEdges don't match as the C++ compare a1 and b1, while the Java compare b0 and b1.
I guess the C++ version is the correct one?

https://github.com/google/s2geometry/blob/fde443b85c018d2991b7459630932add72ef6f76/src/s2/s2edge_crossings.h#L63

Image

https://github.com/google/s2-geometry-library-java/blob/57151fc0f7fe543b75e9f743bf897e81928d5c3f/library/src/com/google/common/geometry/S2EdgeUtil.java#L3101

Dominant language
Java
Stars
587
Forks
232
No merged PRs in 30d

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