public boolean testSphere(Vector3fc center, float radius) {
        return testSphere(center.x(), center.y(), center.z(), radius);
    }
public boolean testSphere ( Vector3fc center , float radius ) { return testSphere ( center . x ( ) , center . y ( ) , center . z ( ) , radius ) ; }
Test whether the given sphere is partly or completely within or outside of the frustum defined by <code>this</code> frustum culler.
<p>
The algorithm implemented by this method is conservative. This means that in certain circumstances a <i>false positive</i>
can occur, when the method returns <code>true</code> for spheres that are actually not visible.
See <a href="http://iquilezles.org/www/articles/frustumcorrect/frustumcorrect.htm">iquilezles.org</a> for an examination of this problem.

@param center
the sphere's center
@param radius
the sphere's radius
@return <code>true</code> if the given sphere is partly or completely inside the frustum;
<code>false</code> otherwise