Eg if a is the origin, and b is another point,
in degrees one would get 0 to -180 when b was above a.
-180 would be b in line with a.
Same for under a.
Providing a third point c gives the interior angle, where b is the middle point.
See also angleRadianCircle which returns coordinates on 0..Math.Pi*2
range. This avoids negative numbers.
Returns the angle in radians between
aandb.Eg if
ais the origin, andbis another point, in degrees one would get 0 to -180 whenbwas abovea. -180 would bebin line witha. Same for undera.Providing a third point
cgives the interior angle, wherebis the middle point.See also angleRadianCircle which returns coordinates on 0..Math.Pi*2 range. This avoids negative numbers.