Generating signed distance field for L-shape

Signed distance field describe the closest distance to a shape from any point in the domain. For example, the code below will generate a signed distance field for a rectangular domain with holes. Can someone please help me to modify this code or write another code that can generate signed distance field for an L-shape in the attached picture. Thank you so much.

The code:

DomainWidth=2;
DomainHight=1;
ENPC=40;
ENPR=80;

EW = DomainWidth / ENPR;       %  The width of each finite element.
EH = DomainHight / ENPC;        %   The hight of each finite element.
M = [ ENPC + 1 , ENPR + 1 ];


[ x ,y ] = meshgrid( EW * [0: ENPR] , EH * [ 0 : ENPC]);
LS.x = x(:); LS.y = y(:);                           % The coordinates of each Level Set grid


cx = DomainWidth / 200 * [ 0   0    0   33.33   33.33    33.33   66.67   66.67   66.67   100   100   100  133.33    133.33   133.33    166.67     166.67    166.67   200   200    200];
cy = DomainHight / 100 * [ 25  50   75   25      50       75      25      50       75     25    50    75   25         50       75         25         50       75      25   50     75];

for i = 1 : length( cx )
    tmpPhi( :, i ) = - sqrt ( ( LS . x - cx ( i ) ) .^2 + ( LS . y  - cy ( i ) ) .^2 ) + DomainHight/15;
end

Phi1 =  -(max(tmpPhi.')).';

Phi = Phi1;
save('Phi1.mat','Phi1')

LS.Phi = griddata( LS.x, LS.y, Phi, LS.x, LS.y, 'cubic');

figure(11)
load('Phi1.mat');
LS.Phi1 = Phi1;

figure(11)
subplot(2,1,1)
contourf( reshape( LS.x, M), reshape(LS.y , M), reshape(LS.Phi, M));axis equal;grid on;title('initialization');
subplot(2,1,2)
contourf( reshape( LS.x, M), reshape(LS.y , M), reshape(LS.Phi1, M), [0 0]);axis equal;grid on;title('initialization');hold on;