+Mat4 calc_projection_matrix(float f, float n, float aspect, float fov)
+{
+ float tmp;
+ tmp = 1 / tan(fov / 2.0);
+
+ Mat4 pmat = Mat4(
+ -tmp/aspect, 0, 0, 0,
+ 0, tmp, 0, 0,
+ 0, 0, (f + n) / (n - f), (2 * f * n) / (n - f),
+ 0, 0, -1, 0
+ );
+
+ return pmat;
+}
\ No newline at end of file