scalar_t m4_determinant(mat4_t m)
{
	scalar_t det11 =	(m[1][1] * (m[2][2] * m[3][3] - m[3][2] * m[2][3])) -
						(m[1][2] * (m[2][1] * m[3][3] - m[3][1] * m[2][3])) +
						(m[1][3] * (m[2][1] * m[3][2] - m[3][1] * m[2][2]));

	scalar_t det12 =	(m[1][0] * (m[2][2] * m[3][3] - m[3][2] * m[2][3])) -
						(m[1][2] * (m[2][0] * m[3][3] - m[3][0] * m[2][3])) +
						(m[1][3] * (m[2][0] * m[3][2] - m[3][0] * m[2][2]));

	scalar_t det13 =	(m[1][0] * (m[2][1] * m[3][3] - m[3][1] * m[2][3])) -
						(m[1][1] * (m[2][0] * m[3][3] - m[3][0] * m[2][3])) +
						(m[1][3] * (m[2][0] * m[3][1] - m[3][0] * m[2][1]));

	scalar_t det14 =	(m[1][0] * (m[2][1] * m[3][2] - m[3][1] * m[2][2])) -
						(m[1][1] * (m[2][0] * m[3][2] - m[3][0] * m[2][2])) +
						(m[1][2] * (m[2][0] * m[3][1] - m[3][0] * m[2][1]));

	return m[0][0] * det11 - m[0][1] * det12 + m[0][2] * det13 - m[0][3] * det14;
}