for(int i = 0; i < 8; i++ )
{
	bool cornerIn = true;
	for(int j = 0; j < 6; j++ )
	{
		if(box.corner(i).x * frustum_planes[j].a + box.corner(i).y * frustum_planes[j].b + box.corner(i).z * frustum_planes[j].c + frustum_planes[j].d <= 0)
		{
			cornerIn = false;
		}
	}
	if(cornerIn)
	{
		return true;
	}
}