inOutStatus - Class: DelaunayTri

Status of triangles in 2-D constrained Delaunay triangulation

Syntax

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

Output Arguments

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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