cam_pos      = [0.560964, 1.56252, 0.255714]';
cam_dir      = [-0.875665, -0.409099, -0.25661]';
cam_up       = [-0.257222, 0.84484, -0.469129]';
cam_lookat   = [0, 0, 1]';
cam_sky      = [0, 1, 0]';
cam_right    = [-0.543591, 0.458576, 1.12388]';
cam_fpoint   = [0, 0, 1]';
cam_angle    = 90;