1) Shortening the anchor lines when touching another infill line
to avoid over extrusion.
2) Reduction of the Intersection structure complexity by referencing
the source lines.
1) Merging of collinear infill lines separated by a thin gap created
by trimming with the boundary polygon.
2) Sorting of the T-joints separately to the left / right of the common
line.
3) Trimming self intersections of the anchor lines.
4) Dropping of very short segments, not anchoring short segments.
limited anchors, while before a full perimeter segment was always
taken if possible.
2) Adapted the line infills (grid, stars, triangles, cubic) to 1).
This also solves a long standing issue of these infills producing
anchors for each sweep direction independently, thus possibly
overlapping and overextruding, which was quite detrimental
in narrow areas.
3) Refactored cubic adaptive infill anchroing algorithm
for performance and clarity.
Hooks are preferably generated in the direction of printed perimeters.
Small refactoring of the algorithm. Some parts of the algorithm are better documented.
1) Fixed a wrong offset when extracting infill lines from the octree.
2) Added a variant for testing triangle in a bounding sphere
when buildind the octree. Currently not used as the box test
is more tight.
3) "Bridging infill" regions are now triangulated and used to densify
the octree as well to support the bridging infill correctly.
1) Octree is built directly from the triangle mesh by checking
overlap of a triangle with an octree cell. This shall produce
a tighter octree with less dense cells.
2) The same method is used for both the adaptive / support cubic infill,
where for the support cubic infill the non-overhang triangles are
ignored.
The AABB tree is no more used.
3) Optimized extraction of continuous infill lines in O(1) instead of O(n^2)
1) All slicer's exceptions are now derived from Slic3r::Exception.
2) New exceptions are defined for slicing errors.
3) Exceptions are propagated to the Plater to show.
It remains to modify the slicing back-end to throw the new SlicingError
exceptions instead of std::runtime_error and to show the other exceptions
by a message dialog instead of a notification.
