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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.math3.geometry.euclidean.threed;
/**
* This enumerates is used to differentiate the semantics of a rotation.
* @see Rotation
* @since 3.6
*/
public enum RotationConvention {
/** Constant for rotation that have the semantics of a vector operator.
* <p>
* According to this convention, the rotation moves vectors with respect
* to a fixed reference frame.
* </p>
* <p>
* This means that if we define rotation r is a 90 degrees rotation around
* the Z axis, the image of vector {@link Vector3D#PLUS_I} would be
* {@link Vector3D#PLUS_J}, the image of vector {@link Vector3D#PLUS_J}
* would be {@link Vector3D#MINUS_I}, the image of vector {@link Vector3D#PLUS_K}
* would be {@link Vector3D#PLUS_K}, and the image of vector with coordinates (1, 2, 3)
* would be vector (-2, 1, 3). This means that the vector rotates counterclockwise.
* </p>
* <p>
* This convention was the only one supported by Apache Commons Math up to version 3.5.
* </p>
* <p>
* The difference with {@link #FRAME_TRANSFORM} is only the semantics of the sign
* of the angle. It is always possible to create or use a rotation using either
* convention to really represent a rotation that would have been best created or
* used with the other convention, by changing accordingly the sign of the
* rotation angle. This is how things were done up to version 3.5.
* </p>
*/
VECTOR_OPERATOR,
/** Constant for rotation that have the semantics of a frame conversion.
* <p>
* According to this convention, the rotation considered vectors to be fixed,
* but their coordinates change as they are converted from an initial frame to
* a destination frame rotated with respect to the initial frame.
* </p>
* <p>
* This means that if we define rotation r is a 90 degrees rotation around
* the Z axis, the image of vector {@link Vector3D#PLUS_I} would be
* {@link Vector3D#MINUS_J}, the image of vector {@link Vector3D#PLUS_J}
* would be {@link Vector3D#PLUS_I}, the image of vector {@link Vector3D#PLUS_K}
* would be {@link Vector3D#PLUS_K}, and the image of vector with coordinates (1, 2, 3)
* would be vector (2, -1, 3). This means that the coordinates of the vector rotates
* clockwise, because they are expressed with respect to a destination frame that is rotated
* counterclockwise.
* </p>
* <p>
* The difference with {@link #VECTOR_OPERATOR} is only the semantics of the sign
* of the angle. It is always possible to create or use a rotation using either
* convention to really represent a rotation that would have been best created or
* used with the other convention, by changing accordingly the sign of the
* rotation angle. This is how things were done up to version 3.5.
* </p>
*/
FRAME_TRANSFORM;
}
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