A slightly more efficient version of Project() where the cross product of
the two endpoints has been precomputed. The cross product does not need to
be normalized, but should be computed using S2::RobustCrossProd() for the
most accurate results. Requires that x, a, and b have unit length.
A slightly more efficient version of Project() where the cross product of the two endpoints has been precomputed. The cross product does not need to be normalized, but should be computed using S2::RobustCrossProd() for the most accurate results. Requires that x, a, and b have unit length.