cam_pos      = [-0.616586, 0.914186, -0.137893]';
cam_dir      = [-0.375833, 0.0803881, -0.923194]';
cam_up       = [0.926492, 0.0530868, -0.372552]';
cam_lookat   = [0, 0, 1]';
cam_sky      = [0, 1, 0]';
cam_right    = [-0.0253507, 1.32381, 0.125593]';
cam_fpoint   = [0, 0, 1]';
cam_angle    = 90;