public static void R_SetFrustum()
{
if (r_refdef.fov_x == 90)
{
// front side is visible
frustum[0].normal = vpn + vright;
frustum[1].normal = vpn - vright;
frustum[2].normal = vpn + vup;
frustum[3].normal = vpn - vup;
}
else
{
// rotate VPN right by FOV_X/2 degrees
Mathlib.RotatePointAroundVector(out frustum[0].normal, ref vup, ref vpn, -(90 - r_refdef.fov_x / 2));
// rotate VPN left by FOV_X/2 degrees
Mathlib.RotatePointAroundVector(out frustum[1].normal, ref vup, ref vpn, 90 - r_refdef.fov_x / 2);
// rotate VPN up by FOV_X/2 degrees
Mathlib.RotatePointAroundVector(out frustum[2].normal, ref vright, ref vpn, 90 - r_refdef.fov_y / 2);
// rotate VPN down by FOV_X/2 degrees
Mathlib.RotatePointAroundVector(out frustum[3].normal, ref vright, ref vpn, -(90 - r_refdef.fov_y / 2));
}
for (int i = 0; i < 4; i++)
{
frustum[i].type = q_shared.PLANE_ANYZ;
frustum[i].dist = Vector3.Dot(r_origin, frustum[i].normal);
frustum[i].signbits = (byte)SignbitsForPlane(frustum[i]);
}
}