function [x,y] = bsp04g(bs,s)
% Eckart Gekeler, Universitaet Stuttgart, Release 8.4.05
% backfacing step, Geometriedaten
% NE=bsp03g gives the number of boundary segment
% D=bsp03g(bs) gives a matrix with one column for each
% boundary segment specified in BS.
% Row 1 contains the start parameter value.
% Row 2 contains the end parameter value.
% Row 3 contains the number of the left hand region.
% Row 4 contains the number of the right hand region.
% [X,Y]=bsp03g(BS,S) gives coordinates of boundary points.
% BS specifies the boundary segments and S the
% corresponding parameter values. BS may be a scalar.
% -- number of boundary segments ---------
nbs=45;
if nargin == 0,x = nbs; return, end
% d = [start par. value; end par. value;
% left hand region; right hand region]
d1 = [...
% 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1;
1 1 1 1 2 2 2 3 3 3 4 4 4 5 5 6 6 6 7 7 8 8 8 9 9;
3 4 0 2 0 0 0 0 0 5 5 6 0 0 7 7 8 0 0 9 9 10 0 0 11];
d2 = [...
% 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0;
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1;
10 10 10 11 11 12 12 12 13 13 14 14 14 15 15 16 16 16 17 17;
11 12 0 0 13 13 14 0 0 15 15 16 0 0 17 17 0 0 0 0];
d = [d1,d2];
% -- Randsegmente ----------------
bs1 = bs(:)';
if find(bs1<1 | bs1>nbs),
error('Non existent boundary segment number'), end
if nargin == 1, x = d(:,bs1); return, end
x = zeros(size(s)); y = zeros(size(s));
[m,n] = size(bs);
if m == 1 & n == 1,
bs = bs*ones(size(s)); % expand bs
elseif m ~= size(s,1) | n ~= size(s,2),
error('bs must be scalar or of same size as s');
end
if ~isempty(s)
for K = 1:nbs
ii = find(bs == K); % boundary segment K
if length(ii)
[X,Y,P] = bsp04f(K);
x(ii) = interp1(P,X,s(ii),'linear');
y(ii) = interp1(P,Y,s(ii),'linear');
end
end
end
function [X,Y,P] = bsp04f(segnr)
% backfacing step, Randsegmente
% A = [X-Werte; Y-Werte];
switch segnr
case 1, A = [0.04, 0.08; 0.02, 0.02];
case 2, A = [0.08, 0.08; 0.02, 0.056];
case 3, A = [0.08, 0.04; 0.056, 0.056];
case 4, A = [0.04, 0.04; 0.056, 0.02];
case 5, A = [0.04, 0; 0.056, 0.056];
case 6, A = [0, 0; 0.056, 0.02];
case 7, A = [0, 0.04; 0.02, 0.02];
case 8, A = [0.04, 0.04; 0.02, 0];
case 9, A = [0.04, 0.08; 0, 0];
case 10, A = [0.08, 0.08; 0, 0.02];
case 11, A = [0.08, 0.12; 0.02, 0.02];
case 12, A = [0.12, 0.12; 0.02, 0.056];
case 13, A = [0.12, 0.08; 0.056, 0.056];
case 14, A = [0.08, 0.12; 0, 0];
case 15, A = [0.12, 0.12; 0, 0.02];
case 16, A = [0.12, 0.16; 0.02, 0.02];
case 17, A = [0.16, 0.16; 0.02, 0.056];
case 18, A = [0.16, 0.12; 0.056, 0.056];
case 19, A = [0.12, 0.16; 0, 0];
case 20, A = [0.16, 0.16; 0, 0.02];
case 21, A = [0.16, 0.20; 0.02, 0.02];
case 22, A = [0.20, 0.20; 0.02, 0.056];
case 23, A = [0.20, 0.16; 0.056, 0.056];
case 24, A = [0.16, 0.20; 0, 0];
case 25, A = [0.20, 0.20; 0, 0.02];
case 26, A = [0.20, 0.24; 0.02, 0.02];
case 27, A = [0.24, 0.24; 0.02, 0.056];
case 28, A = [0.24, 0.20; 0.056, 0.056];
case 29, A = [0.20, 0.24; 0, 0];
case 30, A = [0.24, 0.24; 0, 0.02];
case 31, A = [0.24, 0.28; 0.02, 0.02];
case 32, A = [0.28, 0.28; 0.02, 0.056];
case 33, A = [0.28, 0.24; 0.056, 0.056];
case 34, A = [0.24, 0.28; 0, 0];
case 35, A = [0.28, 0.28; 0, 0.02];
case 36, A = [0.28, 0.32; 0.02, 0.02];
case 37, A = [0.32, 0.32; 0.02, 0.056];
case 38, A = [0.32, 0.28; 0.056, 0.056];
case 39, A = [0.28, 0.32; 0, 0];
case 40, A = [0.32, 0.32; 0, 0.02];
case 41, A = [0.32, 0.36; 0.02, 0.02];
case 42, A = [0.36, 0.36; 0.02, 0.056];
case 43, A = [0.36, 0.32; 0.056, 0.056];
case 44, A = [0.32, 0.36; 0, 0];
case 45, A = [0.36, 0.36; 0, 0.02];
end
N = size(A,2); L = 0; AUX = zeros(1,N); P = AUX;
for I = 1:N-1
% ungefaehre Laenge der Segmente
AUX(I) = sqrt((A(1,I+1) - A(1,I))^2 + (A(2,I+1) - A(2,I))^2);
end
L = sum(AUX); AUX = AUX/L;
for I = 2:N, P(I) = P(I-1) + AUX(I-1); end
X = A(1,:); Y = A(2,:);
