angle static method
(en)Computes and returns the angle between vectorA and the vectorB. The unit of the return value is radians.
(ja)このベクトルaとベクトルbとの間の角度を計算して返します。 戻り値の単位はラジアンです。
a
: vector a.b
: vector b.origin
: the origin.
Implementation
static double angle(Sp3dV2D a, Sp3dV2D b,
{Sp3dV2D origin = const Sp3dV2D(0, 0)}) {
double v1 = (a.x - origin.x) * (b.y - origin.y) -
(a.y - origin.y) * (b.x - origin.x);
double v2 = (a.x - origin.x) * (b.x - origin.x) +
(a.y - origin.y) * (b.y - origin.y);
return atan2(v1, v2);
}