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 */
017package org.apache.commons.geometry.euclidean.threed;
018
019import java.util.Arrays;
020import java.util.Collections;
021import java.util.List;
022import java.util.stream.Stream;
023
024import org.apache.commons.geometry.core.Transform;
025import org.apache.commons.geometry.core.partitioning.AbstractConvexHyperplaneBoundedRegion;
026import org.apache.commons.geometry.core.partitioning.Hyperplane;
027import org.apache.commons.geometry.core.partitioning.HyperplaneConvexSubset;
028import org.apache.commons.geometry.core.partitioning.Split;
029
030/** Class representing a finite or infinite convex volume in Euclidean 3D space.
031 * The boundaries of this area, if any, are composed of plane convex subsets.
032 */
033public class ConvexVolume extends AbstractConvexHyperplaneBoundedRegion<Vector3D, PlaneConvexSubset>
034    implements BoundarySource3D {
035
036    /** Instance representing the full 3D volume. */
037    private static final ConvexVolume FULL = new ConvexVolume(Collections.emptyList());
038
039    /** Simple constructor. Callers are responsible for ensuring that the given path
040     * represents the boundary of a convex area. No validation is performed.
041     * @param boundaries the boundaries of the convex area
042     */
043    protected ConvexVolume(final List<PlaneConvexSubset> boundaries) {
044        super(boundaries);
045    }
046
047    /** {@inheritDoc} */
048    @Override
049    public Stream<PlaneConvexSubset> boundaryStream() {
050        return getBoundaries().stream();
051    }
052
053    /** {@inheritDoc} */
054    @Override
055    public double getSize() {
056        if (isFull()) {
057            return Double.POSITIVE_INFINITY;
058        }
059
060        double volumeSum = 0.0;
061
062        for (final PlaneConvexSubset boundary : getBoundaries()) {
063            if (boundary.isInfinite()) {
064                return Double.POSITIVE_INFINITY;
065            }
066
067            final Plane boundaryPlane = boundary.getPlane();
068            final double boundaryArea = boundary.getSize();
069            final Vector3D boundaryCentroid = boundary.getCentroid();
070
071            volumeSum += boundaryArea * boundaryCentroid.dot(boundaryPlane.getNormal());
072        }
073
074        return volumeSum / 3.0;
075    }
076
077    /** {@inheritDoc} */
078    @Override
079    public Vector3D getCentroid() {
080        double volumeSum = 0.0;
081
082        double sumX = 0.0;
083        double sumY = 0.0;
084        double sumZ = 0.0;
085
086        for (final PlaneConvexSubset boundary : getBoundaries()) {
087            if (boundary.isInfinite()) {
088                return null;
089            }
090
091            final Plane boundaryPlane = boundary.getPlane();
092            final double boundaryArea = boundary.getSize();
093            final Vector3D boundaryCentroid = boundary.getCentroid();
094
095            final double scaledVolume = boundaryArea * boundaryCentroid.dot(boundaryPlane.getNormal());
096
097            volumeSum += scaledVolume;
098
099            sumX += scaledVolume * boundaryCentroid.getX();
100            sumY += scaledVolume * boundaryCentroid.getY();
101            sumZ += scaledVolume * boundaryCentroid.getZ();
102        }
103
104        if (volumeSum > 0) {
105            final double size = volumeSum / 3.0;
106
107            // Since the volume we used when adding together the boundary contributions
108            // was 3x the actual pyramid size, we'll multiply by 1/4 here instead
109            // of 3/4 to adjust for the actual centroid position in each pyramid.
110            final double centroidScale = 1.0 / (4 * size);
111            return Vector3D.of(
112                    sumX * centroidScale,
113                    sumY * centroidScale,
114                    sumZ * centroidScale);
115        }
116
117        return null;
118    }
119
120    /** {@inheritDoc} */
121    @Override
122    public Split<ConvexVolume> split(final Hyperplane<Vector3D> splitter) {
123        return splitInternal(splitter, this, PlaneConvexSubset.class, ConvexVolume::new);
124    }
125
126    /** {@inheritDoc} */
127    @Override
128    public RegionBSPTree3D toTree() {
129        return RegionBSPTree3D.from(getBoundaries(), true);
130    }
131
132    /** {@inheritDoc} */
133    @Override
134    public PlaneConvexSubset trim(final HyperplaneConvexSubset<Vector3D> convexSubset) {
135        return (PlaneConvexSubset) super.trim(convexSubset);
136    }
137
138    /** Return a new instance transformed by the argument.
139     * @param transform transform to apply
140     * @return a new instance transformed by the argument
141     */
142    public ConvexVolume transform(final Transform<Vector3D> transform) {
143        return transformInternal(transform, this, PlaneConvexSubset.class, ConvexVolume::new);
144    }
145
146    /** Return an instance representing the full 3D volume.
147     * @return an instance representing the full 3D volume.
148     */
149    public static ConvexVolume full() {
150        return FULL;
151    }
152
153    /** Create a convex volume formed by the intersection of the negative half-spaces of the
154     * given bounding planes. The returned instance represents the volume that is on the
155     * minus side of all of the given plane. Note that this method does not support volumes
156     * of zero size (ie, infinitely thin volumes or points.)
157     * @param planes planes used to define the convex area
158     * @return a new convex volume instance representing the volume on the minus side of all
159     *      of the bounding plane or an instance representing the full space if the collection
160     *      is empty
161     * @throws IllegalArgumentException if the given set of bounding planes do not form a convex volume,
162     *      meaning that there is no region that is on the minus side of all of the bounding planes.
163     */
164    public static ConvexVolume fromBounds(final Plane... planes) {
165        return fromBounds(Arrays.asList(planes));
166    }
167
168    /** Create a convex volume formed by the intersection of the negative half-spaces of the
169     * given bounding planes. The returned instance represents the volume that is on the
170     * minus side of all of the given plane. Note that this method does not support volumes
171     * of zero size (ie, infinitely thin volumes or points.)
172     * @param boundingPlanes planes used to define the convex area
173     * @return a new convex volume instance representing the volume on the minus side of all
174     *      of the bounding plane or an instance representing the full space if the collection
175     *      is empty
176     * @throws IllegalArgumentException if the given set of bounding planes do not form a convex volume,
177     *      meaning that there is no region that is on the minus side of all of the bounding planes.
178     */
179    public static ConvexVolume fromBounds(final Iterable<? extends Plane> boundingPlanes) {
180        final List<PlaneConvexSubset> facets = new ConvexRegionBoundaryBuilder<>(PlaneConvexSubset.class)
181                .build(boundingPlanes);
182        return facets.isEmpty() ? full() : new ConvexVolume(facets);
183    }
184}