atan2
float atan2(float y, float x)
Returns the principal value of the inverse tangent of y/x, using the signs of the two arguments to determine the quadrant of the result. The return value is in the range -π to π.
float atan2(float y, float x)
Returns the principal value of the inverse tangent of y/x, using the signs of the two arguments to determine the quadrant of the result. The return value is in the range -π to π.