cam_pos      = [0.18312, 1.68674, 0.840885]';
cam_dir      = [-0.971631, -0.201156, 0.124373]';
cam_up       = [-0.203177, 0.440825, -0.874296]';
cam_lookat   = [0, 0, 1]';
cam_sky      = [0, 1, 0]';
cam_right    = [-0.160987, 1.16343, 0.624021]';
cam_fpoint   = [0, 0, 1]';
cam_angle    = 90;