📅  最后修改于: 2022-03-11 14:44:45.369000             🧑  作者: Mango
Check position of point M(X, Y) relative to vector AB with points A(Ax, Ay) and B(Bx, By):
position = sign((Bx - Ax) * (Y - Ay) - (By - Ay) * (X - Ax))
M is: +1 left,
-1 right,
0 on the vector AB