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| author | Dan Goodliffe <dan@randomdan.homeip.net> | 2023-11-05 14:21:14 +0000 |
|---|---|---|
| committer | Dan Goodliffe <dan@randomdan.homeip.net> | 2023-11-05 14:21:14 +0000 |
| commit | eb5dea3d035c61327543d7ab527d897ef3768570 (patch) | |
| tree | 15add79eb14e68c895729487d24583bd4f2b1b0a /game | |
| parent | Add methods to walk the boundary of the terrain mesh (diff) | |
| download | ilt-eb5dea3d035c61327543d7ab527d897ef3768570.tar.bz2 ilt-eb5dea3d035c61327543d7ab527d897ef3768570.tar.xz ilt-eb5dea3d035c61327543d7ab527d897ef3768570.zip | |
Fix and split linesCross
Previous tested they crossed in a specific direction, which is wrong but useful. Adds
linesCrossLtR for this use case.
Diffstat (limited to 'game')
| -rw-r--r-- | game/geoData.cpp | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/game/geoData.cpp b/game/geoData.cpp index f9c11bf..78f753f 100644 --- a/game/geoData.cpp +++ b/game/geoData.cpp @@ -129,11 +129,22 @@ namespace { [[nodiscard]] constexpr inline bool linesCross(const glm::vec2 a1, const glm::vec2 a2, const glm::vec2 b1, const glm::vec2 b2) { + return (pointLeftOfLine(a2, b1, b2) == pointLeftOfLine(a1, b2, b1)) + && (pointLeftOfLine(b1, a1, a2) == pointLeftOfLine(b2, a2, a1)); + } + + static_assert(linesCross({1, 1}, {2, 2}, {1, 2}, {2, 1})); + static_assert(linesCross({2, 2}, {1, 1}, {1, 2}, {2, 1})); + + [[nodiscard]] constexpr inline bool + linesCrossLtR(const glm::vec2 a1, const glm::vec2 a2, const glm::vec2 b1, const glm::vec2 b2) + { return pointLeftOfLine(a2, b1, b2) && pointLeftOfLine(a1, b2, b1) && pointLeftOfLine(b1, a1, a2) && pointLeftOfLine(b2, a2, a1); } - static_assert(linesCross({1, 1}, {2, 2}, {1, 2}, {2, 1})); + static_assert(linesCrossLtR({1, 1}, {2, 2}, {1, 2}, {2, 1})); + static_assert(!linesCrossLtR({2, 2}, {1, 1}, {1, 2}, {2, 1})); } OpenMesh::FaceHandle @@ -208,7 +219,7 @@ GeoData::walkUntil(const PointFace & from, const glm::vec2 to, const std::functi if (f.is_valid() && f != previousFace) { const auto e1 = point(to_vertex_handle(*next)); const auto e2 = point(to_vertex_handle(opposite_halfedge_handle(*next))); - if (linesCross(from.point, to, e1, e2)) { + if (linesCrossLtR(from.point, to, e1, e2)) { previousFace = f; break; } |