parseLiDARStruct.m

%{
 * Copyright (C) 2013-2025, The Regents of The University of Michigan.
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 * AUTHOR: Bruce JK Huang (bjhuang[at]umich.edu)
 * WEBSITE: https://www.brucerobot.com/
%}

function [ring, ordered_ring] = parseLiDARStruct(LiDAR_structure, prefix, num_beam)
    num_beam_from_struct = numel(fieldnames(LiDAR_structure.elevation_struct));
    
    if num_beam ~= num_beam_from_struct
        error("Inconsistent beam number: \n -- In structure: %i; user specified: %i", ...
               num_beam_from_struct, num_beam);
    end
    
    ring(num_beam).angle = struct();
    
    for i = 0:num_beam-1
        key = convertCharsToStrings(prefix) + num2str(i);
        ring(i+1).angle = LiDAR_structure.elevation_struct.(key);
%         ring(i+1).height = i * 0.01; % each emitter is 1 cm higher than last one
        ring(i+1).height = LiDAR_structure.height.(key);
        ring(i+1).ring = num2str(i);
    end
    
    [~, idx] = sort([ring.angle]);
    ordered_ring = ring(idx);
end