1## Copyright (C) 2021 David Legland
2## All rights reserved.
3##
4## Redistribution and use in source and binary forms, with or without
5## modification, are permitted provided that the following conditions are met:
6##
7##     1 Redistributions of source code must retain the above copyright notice,
8##       this list of conditions and the following disclaimer.
9##     2 Redistributions in binary form must reproduce the above copyright
10##       notice, this list of conditions and the following disclaimer in the
11##       documentation and/or other materials provided with the distribution.
12##
13## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ''AS IS''
14## AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15## IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16## ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
17## ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18## DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
19## SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
20## CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
21## OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
22## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23##
24## The views and conclusions contained in the software and documentation are
25## those of the authors and should not be interpreted as representing official
26## policies, either expressed or implied, of the copyright holders.
27
28function clipped = clipEdge3d(edge, box)
29%CLIPEDGE3D Clip a 3D edge with a cuboid box.
30%
31%   CLIPPED = clipEdge3d(EDGE, BOX)
32%
33%   Example
34%   clipEdge3d
35%
36%   See also
37%     lines3d, edges3d, clipLine3d
38
39% ------
40% Author: David Legland
41% e-mail: david.legland@inra.fr
42% Created: 2018-04-12,    using Matlab 9.3.0.713579 (R2017b)
43% Copyright 2018 INRA - Cepia Software Platform.
44
45% compute supporting line of edge
46line = [edge(:, 1:3) edge(:,4:6)-edge(:,1:3)];
47
48% clip supporting line
49clipped = clipLine3d(line, box);
50
51% for each clipped line, check that extremities are contained in edge
52nEdges = size(edge, 1);
53for i = 1:nEdges
54    % if supporting line does not intersect the box, the edge is totally
55    % clipped.
56    if isnan(clipped(i,1))
57        continue;
58    end
59
60    % position of intersection points on the current supporting line
61    pos1 = linePosition3d(clipped(i,1:3), line(i,:));
62    pos2 = linePosition3d(clipped(i,4:6), line(i,:));
63
64    if pos1 > 1 || pos2 < 0
65        % case of an edge totally clipped
66        clipped(i,:) = NaN;
67    elseif pos1 > 0 && pos2 < 1
68        % case of an edge already contained within the bounding box
69        % -> nothin to do...
70        continue;
71    else
72        % otherwise, need to adjust bounds of the clipped edge
73        pos1 = max(pos1, 0);
74        pos2 = min(pos2, 1);
75        p1 = line(i,1:3) + pos1 * line(i,4:6);
76        p2 = line(i,1:3) + pos2 * line(i,4:6);
77        clipped(i,:) = [p1 p2];
78    end
79end
80