src/main/java/com/flowpowered/math/TrigMath.java
public static double atan2(double y, double x) {
        if (y + x == y) {
            return y >= 0 ? HALF_PI : -HALF_PI;
        }
        y = atan(y / x);
        if (x < 0) {
            if (y <= 0) {
                return y + PI;
            } else {
                return y - PI;
            }
        }
        return y;
    }
public static double atan2(double y, double x) {
        if (y + x == y) {
            return y >= 0 ? HALF_PI : -HALF_PI;
        }
        y = atan(y / x);
        if (x < 0) {
            if (y <= 0) {
                return y + PI;
            } else {
                return y - PI;
            }
        }
        return y;
    }
Computes the phase theta by computing an arc tangent of y/x<br> Gets the yaw rotation component in radians when looking into the direction specified

@param y direction
@param x direction
@return tangent arc in radians