inOutStatus

Class: DelaunayTri

(Will be removed) Status of triangles in 2-D constrained Delaunay triangulation

Syntax

IN = inOutStatus(DT)

Description

IN = inOutStatus(DT) returns the in/out status of the triangles in a 2-D constrained Delaunay triangulation of a geometric domain. Given a Delaunay triangulation that has a set of constrained edges that define a bounded geometric domain. The i'th triangle in the triangulation is classified as inside the domain if IN(i) = 1 and outside otherwise.

    Note:   inOutStatus is only relevant for 2-D constrained Delaunay triangulations where the imposed edge constraints bound a closed geometric domain.

Input Arguments

DTDelaunay triangulation.

Output Arguments

INLogical array of length equal to the number of triangles in the triangulation. The constrained edges in the triangulation define the boundaries of a valid geometric domain.

Examples

Create a geometric domain that consists of a square with a square hole:

outerprofile = [-5 -5; -3 -5; -1 -5; 1 -5; 3 -5; ...
 5 -5; 5 -3; 5 -1; 5 1; 5 3;...
 5 5; 3 5; 1 5; -1 5; -3 5; ...
 -5 5; -5 3; -5 1; -5 -1; -5 -3; ];
innerprofile = outerprofile.*0.5;
profile = [outerprofile; innerprofile];
outercons = [(1:19)' (2:20)'; 20 1;];
innercons = [(21:39)' (22:40)'; 40 21];
edgeconstraints = [outercons; innercons];

Create a constrained Delaunay triangulation of the domain:

dt = DelaunayTri(profile, edgeconstraints)
subplot(1,2,1);
triplot(dt);
hold on; 
plot(dt.X(outercons',1), dt.X(outercons',2), ...
     '-r', 'LineWidth', 2); 
plot(dt.X(innercons',1), dt.X(innercons',2), ...
     '-r', 'LineWidth', 2);
axis equal;
% Plot showing interior and exterior
% triangles with respect to the domain.
hold off;
subplot(1,2,2);
inside = inOutStatus(dt);
triplot(dt(inside, :), dt.X(:,1), dt.X(:,2));
hold on;
plot(dt.X(outercons',1), dt.X(outercons',2), ...
     '-r', 'LineWidth', 2); 
plot(dt.X(innercons',1), dt.X(innercons',2), ...
     '-r', 'LineWidth', 2);
axis equal;
% Plot showing interior triangles only
hold off;

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