cam_pos      = [-0.488703, 1.00932, 1.68889]';
cam_dir      = [0.907736, 0.407135, -0.101278]';
cam_up       = [-0.371981, 0.892668, 0.254508]';
cam_lookat   = [0, 0, 1]';
cam_sky      = [0, 1, 0]';
cam_right    = [-0.258055, 0.257158, -1.27913]';
cam_fpoint   = [0, 0, 1]';
cam_angle    = 90;