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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.rotation;
18  
19  import java.util.function.UnaryOperator;
20  
21  import org.apache.commons.geometry.euclidean.threed.Vector3D;
22  
23  /**
24   * A collection of standard vector rotation operators implemented as
25   * {@link UnaryOperator}s. These can be used to test rotation algorithms.
26   */
27  public final class StandardRotations {
28  
29      /** The identity rotation; the input vector is returned unchanged. */
30      public static final UnaryOperator<Vector3D> IDENTITY = v -> v;
31  
32      /** Rotates {@code pi/2} around the {@code +x} axis */
33      public static final UnaryOperator<Vector3D> PLUS_X_HALF_PI = v -> Vector3D.of(v.getX(), -v.getZ(), v.getY());
34  
35      /** Rotates {@code pi/2} around the {@code -x} axis */
36      public static final UnaryOperator<Vector3D> MINUS_X_HALF_PI = v -> Vector3D.of(v.getX(), v.getZ(), -v.getY());
37  
38      /** Rotates {@code pi} around the {@code x} axis (+x and -x are the same) */
39      public static final UnaryOperator<Vector3D> X_PI = v -> Vector3D.of(v.getX(), -v.getY(), -v.getZ());
40  
41      /** Rotates {@code pi/2} around the {@code +y} axis */
42      public static final UnaryOperator<Vector3D> PLUS_Y_HALF_PI = v -> Vector3D.of(v.getZ(), v.getY(), -v.getX());
43  
44      /** Rotates {@code pi/2} around the {@code -y} axis */
45      public static final UnaryOperator<Vector3D> MINUS_Y_HALF_PI = v -> Vector3D.of(-v.getZ(), v.getY(), v.getX());
46  
47      /** Rotates {@code pi} around the {@code y} axis (+y and -y are the same) */
48      public static final UnaryOperator<Vector3D> Y_PI = v -> Vector3D.of(-v.getX(), v.getY(), -v.getZ());
49  
50      /** Rotates {@code pi/2} around the {@code -y} axis */
51      public static final UnaryOperator<Vector3D> PLUS_Z_HALF_PI = v -> Vector3D.of(-v.getY(), v.getX(), v.getZ());
52  
53      /** Rotates {@code pi/2} around the {@code -y} axis */
54      public static final UnaryOperator<Vector3D> MINUS_Z_HALF_PI = v -> Vector3D.of(v.getY(), -v.getX(), v.getZ());
55  
56      /** Rotates {@code pi} around the {@code y} axis (+y and -y are the same) */
57      public static final UnaryOperator<Vector3D> Z_PI = v -> Vector3D.of(-v.getX(), -v.getY(), v.getZ());
58  
59      /** Rotates {@code 2pi/3} around the {@code (1, 1, 1)} axis */
60      public static final UnaryOperator<Vector3D> PLUS_DIAGONAL_TWO_THIRDS_PI = v ->
61          Vector3D.of(v.getZ(), v.getX(), v.getY());
62  
63      /** Rotates {@code 2pi/3} around the {@code (-1, -1, -1)} axis */
64      public static final UnaryOperator<Vector3D> MINUS_DIAGONAL_TWO_THIRDS_PI = v ->
65          Vector3D.of(v.getY(), v.getZ(), v.getX());
66  
67      /** Private constructor. */
68      private StandardRotations() {}
69  }