- remove edge scaling, instead avoid checking intersections with connected edges.
- replace local line intersection functions with BLI_math
- center the projection for more precise calculation.
D1988 by @wisaac, with own edits and improvements.
This improves on existing tangent calculation functions too.
- BM_face_calc_tangent_auto: Chooses method based on number of sides, used by manipulator (not exposed to Python).
- BM_face_calc_tangent_edge: from longest edge.
- BM_face_calc_tangent_edge_pair: from longest edge-pair (most useful with quads).
- BM_face_calc_tangent_edge_diagonal: edge farthest from any vertex.
- BM_face_calc_tangent_vert_diagonal: vert farthest from any vertex.
Also optimize BM_vert_tri_calc_tangent_edge* functions to avoid sqrt.
Issues was again the ugly hack of swapping last generated tri with original face
we use in BMesh triangulate code - here it could lead in some rare case to have
invalid face pointer in doubles list.
Triangulate with beautify caused a bug when there were existing edges
could make the bmesh-operator return an invalid face-map.
Now the beauty is calculated on the 2d-tri's resulting from polyfill,
its simpler and faster.
- selecting a boundary edge would randomly point in/outside the face (now point away).
- selecting 3 verts would use the first selected edge as the tangent (now use longest).
- selecting 1 vert betweem edges, uses the edges to define the tangent.
Turned out there was still quite a few cases were indices were set dirty,
but elem_index_dirty was not tagged accordingly (mostly for BM_LOOP,
but a few others as well). So probably this crash was not the only one
hidden here.
Hopefully all possible cases were catched this time!
We need to support cutting degenerate ngons, see: T39418
This commit disallows cuts across faces where the same vertices can create better cuts on different faces.
