1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * https://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 /*
19 * This is not the original file distributed by the Apache Software Foundation
20 * It has been modified by the Hipparchus project
21 */
22 package org.hipparchus.geometry.euclidean.threed;
23
24 import java.util.ArrayList;
25 import java.util.List;
26
27 import org.hipparchus.exception.MathIllegalArgumentException;
28 import org.hipparchus.geometry.Point;
29 import org.hipparchus.geometry.euclidean.oned.Euclidean1D;
30 import org.hipparchus.geometry.euclidean.oned.Interval;
31 import org.hipparchus.geometry.euclidean.oned.IntervalsSet;
32 import org.hipparchus.geometry.euclidean.oned.Vector1D;
33 import org.hipparchus.geometry.partitioning.Region.Location;
34
35 /** This class represents a subset of a {@link Line}.
36 */
37 public class SubLine {
38
39 /** Underlying line. */
40 private final Line line;
41
42 /** Remaining region of the hyperplane. */
43 private final IntervalsSet remainingRegion;
44
45 /** Simple constructor.
46 * @param line underlying line
47 * @param remainingRegion remaining region of the line
48 */
49 public SubLine(final Line line, final IntervalsSet remainingRegion) {
50 this.line = line;
51 this.remainingRegion = remainingRegion;
52 }
53
54 /** Create a sub-line from two endpoints.
55 * @param start start point
56 * @param end end point
57 * @param tolerance tolerance below which points are considered identical
58 * @exception MathIllegalArgumentException if the points are equal
59 */
60 public SubLine(final Vector3D start, final Vector3D end, final double tolerance)
61 throws MathIllegalArgumentException {
62 this(new Line(start, end, tolerance), buildIntervalSet(start, end, tolerance));
63 }
64
65 /** Create a sub-line from a segment.
66 * @param segment single segment forming the sub-line
67 * @exception MathIllegalArgumentException if the segment endpoints are equal
68 */
69 public SubLine(final Segment segment) throws MathIllegalArgumentException {
70 this(segment.getLine(),
71 buildIntervalSet(segment.getStart(), segment.getEnd(), segment.getLine().getTolerance()));
72 }
73
74 /** Get the endpoints of the sub-line.
75 * <p>
76 * A subline may be any arbitrary number of disjoints segments, so the endpoints
77 * are provided as a list of endpoint pairs. Each element of the list represents
78 * one segment, and each segment contains a start point at index 0 and an end point
79 * at index 1. If the sub-line is unbounded in the negative infinity direction,
80 * the start point of the first segment will have infinite coordinates. If the
81 * sub-line is unbounded in the positive infinity direction, the end point of the
82 * last segment will have infinite coordinates. So a sub-line covering the whole
83 * line will contain just one row and both elements of this row will have infinite
84 * coordinates. If the sub-line is empty, the returned list will contain 0 segments.
85 * </p>
86 * @return list of segments endpoints
87 */
88 public List<Segment> getSegments() {
89
90 final List<Interval> list = remainingRegion.asList();
91 final List<Segment> segments = new ArrayList<>(list.size());
92
93 for (final Interval interval : list) {
94 final Vector3D start = line.toSpace((Point<Euclidean1D>) new Vector1D(interval.getInf()));
95 final Vector3D end = line.toSpace((Point<Euclidean1D>) new Vector1D(interval.getSup()));
96 segments.add(new Segment(start, end, line));
97 }
98
99 return segments;
100
101 }
102
103 /** Get the intersection of the instance and another sub-line.
104 * <p>
105 * This method is related to the {@link Line#intersection(Line)
106 * intersection} method in the {@link Line Line} class, but in addition
107 * to compute the point along infinite lines, it also checks the point
108 * lies on both sub-line ranges.
109 * </p>
110 * @param subLine other sub-line which may intersect instance
111 * @param includeEndPoints if true, endpoints are considered to belong to
112 * instance (i.e. they are closed sets) and may be returned, otherwise endpoints
113 * are considered to not belong to instance (i.e. they are open sets) and intersection
114 * occurring on endpoints lead to null being returned
115 * @return the intersection point if there is one, null if the sub-lines don't intersect
116 */
117 public Vector3D intersection(final SubLine subLine, final boolean includeEndPoints) {
118
119 // compute the intersection on infinite line
120 Vector3D v1D = line.intersection(subLine.line);
121 if (v1D == null) {
122 return null;
123 }
124
125 // check location of point with respect to first sub-line
126 Location loc1 = remainingRegion.checkPoint((Point<Euclidean1D>) line.toSubSpace((Point<Euclidean3D>) v1D));
127
128 // check location of point with respect to second sub-line
129 Location loc2 = subLine.remainingRegion.checkPoint((Point<Euclidean1D>) subLine.line.toSubSpace((Point<Euclidean3D>) v1D));
130
131 if (includeEndPoints) {
132 return ((loc1 != Location.OUTSIDE) && (loc2 != Location.OUTSIDE)) ? v1D : null;
133 } else {
134 return ((loc1 == Location.INSIDE) && (loc2 == Location.INSIDE)) ? v1D : null;
135 }
136
137 }
138
139 /** Build an interval set from two points.
140 * @param start start point
141 * @param end end point
142 * @return an interval set
143 * @param tolerance tolerance below which points are considered identical
144 * @exception MathIllegalArgumentException if the points are equal
145 */
146 private static IntervalsSet buildIntervalSet(final Vector3D start, final Vector3D end, final double tolerance)
147 throws MathIllegalArgumentException {
148 final Line line = new Line(start, end, tolerance);
149 return new IntervalsSet(line.toSubSpace((Point<Euclidean3D>) start).getX(),
150 line.toSubSpace((Point<Euclidean3D>) end).getX(),
151 tolerance);
152 }
153
154 }