%--------------------------
 % @Author: Jingqiao Hu
 % @Date: 2021-12-27 20:26:33
 % @LastEditTime: 2021-12-30 18:12:48
%--------------------------
function conn_list = dt_connection(seeds)

    DT = delaunayTriangulation(seeds);
    tri_mesh = DT.ConnectivityList;
   
    npnts = size(seeds, 1);
    conn_list = cell(npnts, 1);

%     figure; triplot(DT); hold on;
    parfor i = 1 : npnts
        [r, ~] = find(tri_mesh == i);
        idx1 = tri_mesh(r, :);
        idx2 = unique(idx1(:));

        % remove i 
        conn_list{i} = idx2(idx2 ~= i);
        
%         figure(1); clf; triplot(DT); hold on;
%         voronoi(seeds(:,1), seeds(:,2)); hold on;
%         scatter(seeds(i,1), seeds(i,2), 'filled'); hold on;
%         scatter(seeds(conn_list{i},1), seeds(conn_list{i},2)); hold on;
%         bp = [];
%         poly_local = c_polys([conn_list{i}; i]);
%         for testi = 1:size(poly_local, 1)
%             bp = [bp; polyshape(poly_local{testi})];
%         end
%         hold on; plot(bp);
    end
end

function [area] = tri_area(x, y)
    area = 0.5 * ((x(:,1).* y(:,2) - x(:,2).*y(:,1)) + ...
                  (x(:,2).* y(:,3) - x(:,3).*y(:,2)) + ...
                  (x(:,3).* y(:,1) - x(:,1).*y(:,3)));
    area = abs(area); % important!
end