001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.math3.geometry.partitioning;
018
019 import org.apache.commons.math3.geometry.Vector;
020 import org.apache.commons.math3.geometry.Space;
021
022 /** This interface represents an hyperplane of a space.
023
024 * <p>The most prominent place where hyperplane appears in space
025 * partitioning is as cutters. Each partitioning node in a {@link
026 * BSPTree BSP tree} has a cut {@link SubHyperplane sub-hyperplane}
027 * which is either an hyperplane or a part of an hyperplane. In an
028 * n-dimensions euclidean space, an hyperplane is an (n-1)-dimensions
029 * hyperplane (for example a traditional plane in the 3D euclidean
030 * space). They can be more exotic objects in specific fields, for
031 * example a circle on the surface of the unit sphere.</p>
032
033 * @param <S> Type of the space.
034
035 * @version $Id: Hyperplane.java 1416643 2012-12-03 19:37:14Z tn $
036 * @since 3.0
037 */
038 public interface Hyperplane<S extends Space> {
039
040 /** Copy the instance.
041 * <p>The instance created is completely independant of the original
042 * one. A deep copy is used, none of the underlying objects are
043 * shared (except for immutable objects).</p>
044 * @return a new hyperplane, copy of the instance
045 */
046 Hyperplane<S> copySelf();
047
048 /** Get the offset (oriented distance) of a point.
049 * <p>The offset is 0 if the point is on the underlying hyperplane,
050 * it is positive if the point is on one particular side of the
051 * hyperplane, and it is negative if the point is on the other side,
052 * according to the hyperplane natural orientation.</p>
053 * @param point point to check
054 * @return offset of the point
055 */
056 double getOffset(Vector<S> point);
057
058 /** Check if the instance has the same orientation as another hyperplane.
059 * <p>This method is expected to be called on parallel hyperplanes. The
060 * method should <em>not</em> re-check for parallelism, only for
061 * orientation, typically by testing something like the sign of the
062 * dot-products of normals.</p>
063 * @param other other hyperplane to check against the instance
064 * @return true if the instance and the other hyperplane have
065 * the same orientation
066 */
067 boolean sameOrientationAs(Hyperplane<S> other);
068
069 /** Build a sub-hyperplane covering the whole hyperplane.
070 * @return a sub-hyperplane covering the whole hyperplane
071 */
072 SubHyperplane<S> wholeHyperplane();
073
074 /** Build a region covering the whole space.
075 * @return a region containing the instance
076 */
077 Region<S> wholeSpace();
078
079 }