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Diffstat (limited to 'src/main/java/org/apache/commons/math3/geometry/euclidean/threed/RotationConvention.java')
-rw-r--r-- | src/main/java/org/apache/commons/math3/geometry/euclidean/threed/RotationConvention.java | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math3/geometry/euclidean/threed/RotationConvention.java b/src/main/java/org/apache/commons/math3/geometry/euclidean/threed/RotationConvention.java new file mode 100644 index 0000000..6111ac3 --- /dev/null +++ b/src/main/java/org/apache/commons/math3/geometry/euclidean/threed/RotationConvention.java @@ -0,0 +1,79 @@ +/* + * 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; + +} |