convert polar - cartesian

gistfile1.js

// thx tomy! http://www5.airnet.ne.jp/tomy/cpro/sslib12.htm

function cartesian2polar(x,y,z) {
    var obj = new Object;
    obj.r = Math.sqrt( x*x + y*y + z*z );
    
    if (x != 0.0)
        obj.phi = Math.atan2( y, x );
    else {
        if (y < 0.0)
            obj.phi = -1/2*Math.PI;
        else if (y > 0.0)
            obj.phi = 1/2*Math.PI;
        else
            obj.phi = 0.0;
    }

    if (z != 0.0)
        obj.theta = Math.atan2( Math.sqrt(x*x + y*y), z );
    else {
        if (x*x + y*y > 0.0)
            obj.theta = 1/2*Math.PI;
        else
            obj.theta = 0.0;
    }
    
    return obj;
}

function polar2cartesian(r,theta,phi) {
   var obj   = new Object;
   obj.x = r * Math.sin(theta) * Math.cos(phi);
   obj.y = r * Math.sin(theta) * Math.sin(phi);
   obj.z = r * Math.cos(theta);
   return obj;
}