Returns the inward-facing normal of the great circle passing through the
edge from vertex k to vertex k+1 (mod 4). The normals returned by
GetEdgeRaw are not necessarily unit length. For convenience, the
argument is reduced modulo 4 to the range [0..3].
Returns the inward-facing normal of the great circle passing through the edge from vertex k to vertex k+1 (mod 4). The normals returned by GetEdgeRaw are not necessarily unit length. For convenience, the argument is reduced modulo 4 to the range [0..3].