cam_pos      = [-0.616586, 0.914186, -0.137893]';
cam_dir      = [-0.309393, 0.101605, -0.945491]';
cam_up       = [0.950871, 0.0445069, -0.30637]';
cam_lookat   = [0, 0, 1]';
cam_sky      = [0, 1, 0]';
cam_right    = [-0.0145662, 1.32179, 0.146811]';
cam_fpoint   = [0, 0, 1]';
cam_angle    = 90;