float u;
float v;

	if(v.z>0.0)
	{
		
		u = (v.x / (2.0*(1.0 + v.z))) + 0.5;
		v = (v.y / (2.0*(1.0 + v.z))) + 0.5;

	}
	else
	{
		u = (v.x / (2.0*(1.0 - v.z))) + 0.5;
		v = (v.y / (2.0*(1.0 - v.z))) + 0.5;
	}