The router began as a port of FreeRouting and has grown its own engine
(negotiated congestion, tree nets, exact checks, axis escapes), and
'freeroute' was one letter from the project it no longer follows. The
package, module and command are now rpmroute; the freeroute command stays
as an alias, and the RPMROUTE / RPMROUTE_ORACLE_JAVA variables fall back
to the old FREEROUTE names. Version 2026.10.07. Routing is unchanged: a
PCBench board routes to a byte-identical session either way.
Ports geometry/planar/Polygon.java (corner de-duplication and collinear
removal, winding number) and PolygonShape.java, including the recursive
split_to_convex that decomposes a simple polygon into convex Simplex
tiles by dividing at concave corners along minimal axis-parallel lines.
Orientation and convexity tests are exact; the division-point search is
approximate (float line evaluation, split point rounded to an integer
corner) as upstream. The concave-corner search starts deterministically
at corner 0 rather than a seeded PRNG; this only affects which valid
decomposition is produced.
Supporting additions: Simplex.from_corners (convex polygon to simplex)
and Line.function_value_approx / function_in_y_value_approx.
Invariant tests over L, plus, staircase and square polygons: tile areas
sum to the polygon area (no gaps, no overlap), a point is in the polygon
iff in some tile, and no point is strictly inside more than one tile
(interiors disjoint). Also covers Polygon normalization and orientation.
rsp2k