cam_pos      = [-0.616586, 0.914186, -0.137893]';
cam_dir      = [-0.151747, 0.0894451, -0.984364]';
cam_up       = [0.988252, 0.0320373, -0.149436]';
cam_lookat   = [0, 0, 1]';
cam_sky      = [0, 1, 0]';
cam_right    = [-0.0241661, 1.32398, 0.12403]';
cam_fpoint   = [0, 0, 1]';
cam_angle    = 90;