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## Copyright (C) 2024 David Legland
## All rights reserved.
##
## Redistribution and use in source and binary forms, with or without
## modification, are permitted provided that the following conditions are met:
##
## 1 Redistributions of source code must retain the above copyright notice,
## this list of conditions and the following disclaimer.
## 2 Redistributions in binary form must reproduce the above copyright
## notice, this list of conditions and the following disclaimer in the
## documentation and/or other materials provided with the distribution.
##
## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ''AS IS''
## AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
## IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
## ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
## ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
## DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
## SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
## CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
## OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
##
## The views and conclusions contained in the software and documentation are
## those of the authors and should not be interpreted as representing official
## policies, either expressed or implied, of the copyright holders.
function [intersects, inds] = intersectEdgePolygon(edge, poly, varargin)
%INTERSECTEDGEPOLYGON Intersection point of an edge with a polygon.
%
% INTER = intersectEdgePolygon(EDGE, POLY)
% Computes intersection(s) point(s) between the edge EDGE and the polygon
% POLY. EDGE is given by [x1 y1 x2 y2]. POLY is a N-by-2 array of vertex
% coordinates.
% INTER is a M-by-2 array containing coordinates of intersection(s). It
% can be empty if no intersection is found.
%
% [INTER, INDS] = intersectEdgePolygon(EDGE, POLY)
% Also returns index/indices of edge(s) involved in intersections.
%
% Example
% % Intersection of an edge with a square
% poly = [0 0;10 0;10 10;0 10];
% edge = [9 2 9+3*1 2+3*2];
% exp = [10 4];
% inter = intersectEdgePolygon(edge, poly)
% ans =
% 10 4
%
% See also
% edges2d, polygons2d, intersectLinePolygon, intersectRayPolygon
%
% ------
% Author: David Legland
% E-mail: david.legland@inrae.fr
% Created: 2012-02-24, using Matlab 7.9.0.529 (R2009b)
% Copyright 2012-2023 INRA - Cepia Software Platform
% get computation tolerance
tol = 1e-14;
if ~isempty(varargin)
tol = varargin{1};
end
% get supporting line of edge
line = edgeToLine(edge);
% compute all intersections of supporting line with polygon
[intersects, inds, pos] = intersectLinePolygon(line, poly, tol);
% keep only intersection points located on the edge
if ~isempty(intersects)
keep = pos >= -tol & pos <= (1+tol);
intersects = intersects(keep, :);
inds = inds(keep);
end
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