How to understand this part of code?

[wangx1996]

in livox_feature_extractor.cpp 497 colum

` // TODO: handle this case.
screen_out << "First point should be normal!!!" << std::endl;

                pt_info->pt_2d_img << 0.01, 0.01;
                pt_info->polar_dis_sq2 = 0.0001;
                add_mask_of_point( pt_info, e_pt_000 );
                //return 0;`

and column 588

if ( m_pts_info_vec[ split_idx[ val_index + 1 ] ].polar_dis_sq2 > 10000 ) { pt_angle_index = split_idx[ val_index + 1 ] - ( int ) ( internal_size * 0.20 ); scan_angle = atan2( m_pts_info_vec[ pt_angle_index ].pt_2d_img( 1 ), m_pts_info_vec[ pt_angle_index ].pt_2d_img( 0 ) ) * 57.3; scan_angle = scan_angle + 180.0; } else { pt_angle_index = split_idx[ val_index + 1 ] - ( int ) ( internal_size * 0.80 ); scan_angle = atan2( m_pts_info_vec[ pt_angle_index ].pt_2d_img( 1 ), m_pts_info_vec[ pt_angle_index ].pt_2d_img( 0 ) ) * 57.3; scan_angle = scan_angle + 180.0; }

[Fellowflyingsky]

in livox_feature_extractor.cpp 497 colum

` // TODO: handle this case. screen_out << "First point should be normal!!!" << std::endl;

                pt_info->pt_2d_img << 0.01, 0.01;
                pt_info->polar_dis_sq2 = 0.0001;
                add_mask_of_point( pt_info, e_pt_000 );
                //return 0;`

and column 588

if ( m_pts_info_vec[ split_idx[ val_index + 1 ] ].polar_dis_sq2 > 10000 ) { pt_angle_index = split_idx[ val_index + 1 ] - ( int ) ( internal_size * 0.20 ); scan_angle = atan2( m_pts_info_vec[ pt_angle_index ].pt_2d_img( 1 ), m_pts_info_vec[ pt_angle_index ].pt_2d_img( 0 ) ) * 57.3; scan_angle = scan_angle + 180.0; } else { pt_angle_index = split_idx[ val_index + 1 ] - ( int ) ( internal_size * 0.80 ); scan_angle = atan2( m_pts_info_vec[ pt_angle_index ].pt_2d_img( 1 ), m_pts_info_vec[ pt_angle_index ].pt_2d_img( 0 ) ) * 57.3; scan_angle = scan_angle + 180.0; }

将拐点之间的点分为内外两类，分别求得点的极坐标