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 * http://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 package org.apache.commons.geometry.euclidean.threed;
18
19 import java.util.Arrays;
20 import java.util.List;
21
22 import org.apache.commons.geometry.core.Transform;
23
24 /** Simple implementation of {@link Triangle3D}.
25 *
26 * <p>Instances of this class are guaranteed to be immutable.</p>
27 */
28 final class SimpleTriangle3D extends AbstractConvexPolygon3D implements Triangle3D {
29
30 /** First point in the triangle. */
31 private final Vector3D p1;
32
33 /** Second point in the triangle. */
34 private final Vector3D p2;
35
36 /** Third point in the triangle. */
37 private final Vector3D p3;
38
39 /** Construct a new instance from a plane and 3 points. Callers are responsible for ensuring that
40 * the points lie on the plane and define a triangle. No validation is performed.
41 * @param plane the plane containing the triangle
42 * @param p1 first point in the triangle
43 * @param p2 second point in the triangle
44 * @param p3 third point in the triangle
45 */
46 SimpleTriangle3D(final Plane plane, final Vector3D p1, final Vector3D p2, final Vector3D p3) {
47 super(plane);
48
49 this.p1 = p1;
50 this.p2 = p2;
51 this.p3 = p3;
52 }
53
54 /** {@inheritDoc} */
55 @Override
56 public Vector3D getPoint1() {
57 return p1;
58 }
59
60 /** {@inheritDoc} */
61 @Override
62 public Vector3D getPoint2() {
63 return p2;
64 }
65
66 /** {@inheritDoc} */
67 @Override
68 public Vector3D getPoint3() {
69 return p3;
70 }
71
72 /** {@inheritDoc} */
73 @Override
74 public List<Vector3D> getVertices() {
75 return Arrays.asList(p1, p2, p3);
76 }
77
78 /** {@inheritDoc} */
79 @Override
80 public double getSize() {
81 final Vector3D v1 = p1.vectorTo(p2);
82 final Vector3D v2 = p1.vectorTo(p3);
83 return 0.5 * v1.cross(v2).norm();
84 }
85
86 /** {@inheritDoc} */
87 @Override
88 public Vector3D getCentroid() {
89 return Vector3D.centroid(p1, p2, p3);
90 }
91
92 /** {@inheritDoc} */
93 @Override
94 public SimpleTriangle3D reverse() {
95 final Plane rPlane = getPlane().reverse();
96
97 return new SimpleTriangle3D(rPlane, p1, p3, p2); // reverse point ordering
98 }
99
100 /** {@inheritDoc} */
101 @Override
102 public SimpleTriangle3D transform(final Transform<Vector3D> transform) {
103 final Plane tPlane = getPlane().transform(transform);
104 final Vector3D t1 = transform.apply(p1);
105 final Vector3D t2 = transform.apply(p2);
106 final Vector3D t3 = transform.apply(p3);
107
108 return new SimpleTriangle3D(tPlane, t1, t2, t3);
109 }
110 }