text: cam_pos      = [97.0865, 463.511, -291.864]';
  cam_dir      = [0.0160183, -0.399006, 0.916808]';
  cam_up       = [0.0382965, 0.916498, 0.398202]';
  cam_lookat   = [0, 0, 1]';
  cam_sky      = [0, 1, 0]';
  cam_right    = [1.32885, -0.0382136, -0.0398485]';
  cam_fpoint   = [0, 0, 10]';
  cam_angle    = 90;
  