# Pastebin 6tlVxIZE
public final void set(AxisAngle4f a)
    {
	float mag,amag;
	// Quat = cos(theta/2) + sin(theta/2)(roation_axis) 
	amag = (float)Math.sqrt( a.x*a.x + a.y*a.y + a.z*a.z);
	if (amag < EPS ) {
	    w = 0.0f;
	    x = 0.0f;
	    y = 0.0f;
	    z = 0.0f;
	} else {  
	    amag = 1.0f/amag; 
	    mag = (float)Math.sin(a.angle/2.0);
	    w = (float)Math.cos(a.angle/2.0);
	    x = a.x*amag*mag;
	    y = a.y*amag*mag;
	    z = a.z*amag*mag;
	}
    }