cam_pos      = [-0.616586, 0.914185, -0.137893]';
cam_dir      = [-0.34483, 0.0812509, -0.935142]';
cam_up       = [0.938451, 0.0511391, -0.341606]';
cam_lookat   = [0, 0, 1]';
cam_sky      = [0, 1, 0]';
cam_right    = [-0.0266884, 1.32386, 0.124866]';
cam_fpoint   = [0, 0, 1]';
cam_angle    = 90;