triangulate_pareBySideLength(XYZ, v, maxSideLength)

% v = triangulate_pareBySideLength(XYZ, v, maxSideLength)
%
% pare results of triangulate by length of sides of
% triangles generated. this is useful because if the
% original vertices were on a regular grid, erroneous
% triangles completing the convex shape enclosing all the
% vertices will have at least one long side and can be pared
% easily.

function v = triangulate_pareBySideLength(XYZ, v, maxSideLength)

N = size(v,2);

tris = cat(3, XYZ(:,v(1,:)), XYZ(:,v(2,:)), XYZ(:,v(3,:)));
tris = permute(tris, [1 3 2]);

tris = tris(1:2,:,:); % ignore Z

accepted = zeros(N,1);

maxSideLengthSq = maxSideLength^2;

for n=1:N
	tri = tris(:,:,n);
	A = tri(:,1) - tri(:,2);
	B = tri(:,2) - tri(:,3);
	C = tri(:,3) - tri(:,1);
	a = sum(A.^2);
	b = sum(B.^2);
	c = sum(C.^2);
	maxSideSq = max([a b c]);
	if maxSideSq <= maxSideLengthSq accepted(n)=1; end
end

v = v(:,find(accepted));