Returns -1, 0, or +1 according to whether the normal of edge A has
negative, zero, or positive dot product with the normal of edge B. This
essentially measures whether the edges A and B are closer to proceeding in
the same direction or in opposite directions around the sphere.
This method returns an exact result, i.e. the result is zero if and only if
the two edges are exactly perpendicular or at least one edge is degenerate.
(i.e., both edge endpoints project to the same point on the sphere).
CAVEAT: This method does not use symbolic perturbations. Therefore it can
return zero even when A0 != A1 and B0 != B1, e.g. if (A0 == C * A1) exactly
for some constant C > 0 (which is possible even when both points are
considered "normalized").
REQUIRES: Neither edge can consist of antipodal points (e.g., A0 == -A1)
(see comments in CompareEdgeDistance).
Returns -1, 0, or +1 according to whether the normal of edge A has negative, zero, or positive dot product with the normal of edge B. This essentially measures whether the edges A and B are closer to proceeding in the same direction or in opposite directions around the sphere.
This method returns an exact result, i.e. the result is zero if and only if the two edges are exactly perpendicular or at least one edge is degenerate. (i.e., both edge endpoints project to the same point on the sphere).
CAVEAT: This method does not use symbolic perturbations. Therefore it can return zero even when A0 != A1 and B0 != B1, e.g. if (A0 == C * A1) exactly for some constant C > 0 (which is possible even when both points are considered "normalized").
REQUIRES: Neither edge can consist of antipodal points (e.g., A0 == -A1) (see comments in CompareEdgeDistance).