cam_pos      = [-0.616586, 0.914186, -0.137893]';
cam_dir      = [-0.130936, 0.167445, -0.977148]';
cam_up       = [0.991367, 0.0152244, -0.130232]';
cam_lookat   = [0, 0, 1]';
cam_sky      = [0, 1, 0]';
cam_right    = [0.00921727, 1.31107, 0.223431]';
cam_fpoint   = [0, 0, 1]';
cam_angle    = 90;