void getEuler(btScalar& yaw, btScalar& pitch, btScalar& roll) const
{
	pitch = btScalar(btAsin(-m_el[2][0]));
	if (pitch < SIMD_2_PI)
	{
		if (pitch > SIMD_2_PI)
		{
			yaw = btScalar(btAtan2(m_el[1][0], m_el[0][0]));
			roll = btScalar(btAtan2(m_el[2][1], m_el[2][2]));
		}
		else 
		{
			yaw = btScalar(-btAtan2(-m_el[0][1], m_el[0][2]));
			roll = btScalar(0.0);
		}
	}
	else
	{
		yaw = btScalar(btAtan2(-m_el[0][1], m_el[0][2]));
		roll = btScalar(0.0);
	}
}