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implement equals(), hashCode(), and isSimilar() for bounding volumes (#…
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…2252)

* implement equals() and hashCode() for BoundingBox

* implement equals() and hashCode() for BoundingSphere

* implement isSimilar() for BoundingBox

* implement isSimilar() for BoundingSphere

* BoundingSphere:  add comments to emphasize the treatment of checkPlane

* TestBoundingSphere:  test equals() and isSimilar()

* jme3-core tests:  add the TestBoundingBox class

* BoundingVolume:  add equals() and hashCode() methods

* utilize super.equals() and super.hashCode()

* refactor to utilize Objects.hash()
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stephengold authored and scenemax3d committed Jun 11, 2024
1 parent 9a11aa6 commit 954b3ae
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73 changes: 72 additions & 1 deletion jme3-core/src/main/java/com/jme3/bounding/BoundingBox.java
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2009-2021 jMonkeyEngine
* Copyright (c) 2009-2024 jMonkeyEngine
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
Expand Down Expand Up @@ -46,6 +46,7 @@
import java.io.IOException;
import java.nio.FloatBuffer;
//import com.jme.scene.TriMesh;
import java.util.Objects;

/**
* <code>BoundingBox</code> describes a bounding volume as an axis-aligned box.
Expand Down Expand Up @@ -587,6 +588,76 @@ public BoundingVolume clone(BoundingVolume store) {
return rVal;
}

/**
* Tests for exact equality with the argument, distinguishing -0 from 0. If
* {@code other} is null, false is returned. Either way, the current
* instance is unaffected.
*
* @param other the object to compare (may be null, unaffected)
* @return true if {@code this} and {@code other} have identical values,
* otherwise false
*/
@Override
public boolean equals(Object other) {
if (!(other instanceof BoundingBox)) {
return false;
}

if (this == other) {
return true;
}

BoundingBox otherBoundingBox = (BoundingBox) other;
if (Float.compare(xExtent, otherBoundingBox.xExtent) != 0) {
return false;
} else if (Float.compare(yExtent, otherBoundingBox.yExtent) != 0) {
return false;
} else if (Float.compare(zExtent, otherBoundingBox.zExtent) != 0) {
return false;
} else {
return super.equals(otherBoundingBox);
}
}

/**
* Returns a hash code. If two bounding boxes have identical values, they
* will have the same hash code. The current instance is unaffected.
*
* @return a 32-bit value for use in hashing
*/
@Override
public int hashCode() {
int hash = Objects.hash(xExtent, yExtent, zExtent);
hash = 59 * hash + super.hashCode();

return hash;
}

/**
* Tests for approximate equality with the specified bounding box, using the
* specified tolerance. If {@code other} is null, false is returned. Either
* way, the current instance is unaffected.
*
* @param aabb the bounding box to compare (unaffected) or null for none
* @param epsilon the tolerance for each component
* @return true if all components are within tolerance, otherwise false
*/
public boolean isSimilar(BoundingBox aabb, float epsilon) {
if (aabb == null) {
return false;
} else if (Float.compare(Math.abs(aabb.xExtent - xExtent), epsilon) > 0) {
return false;
} else if (Float.compare(Math.abs(aabb.yExtent - yExtent), epsilon) > 0) {
return false;
} else if (Float.compare(Math.abs(aabb.zExtent - zExtent), epsilon) > 0) {
return false;
} else if (!center.isSimilar(aabb.getCenter(), epsilon)) {
return false;
}
// The checkPlane field is ignored.
return true;
}

/**
* <code>toString</code> returns the string representation of this object.
* The form is: "[Center: vector xExtent: X.XX yExtent: Y.YY zExtent:
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65 changes: 64 additions & 1 deletion jme3-core/src/main/java/com/jme3/bounding/BoundingSphere.java
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2009-2021 jMonkeyEngine
* Copyright (c) 2009-2024 jMonkeyEngine
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
Expand Down Expand Up @@ -43,6 +43,7 @@
import com.jme3.util.TempVars;
import java.io.IOException;
import java.nio.FloatBuffer;
import java.util.Objects;
import java.util.logging.Level;
import java.util.logging.Logger;

Expand Down Expand Up @@ -651,6 +652,68 @@ public BoundingVolume clone(BoundingVolume store) {
return new BoundingSphere(radius, center.clone());
}

/**
* Tests for exact equality with the argument, distinguishing -0 from 0. If
* {@code other} is null, false is returned. Either way, the current
* instance is unaffected.
*
* @param other the object to compare (may be null, unaffected)
* @return true if {@code this} and {@code other} have identical values,
* otherwise false
*/
@Override
public boolean equals(Object other) {
if (!(other instanceof BoundingSphere)) {
return false;
}

if (this == other) {
return true;
}

BoundingSphere otherBoundingSphere = (BoundingSphere) other;
if (Float.compare(radius, otherBoundingSphere.getRadius()) != 0) {
return false;
} else {
return super.equals(otherBoundingSphere);
}
}

/**
* Returns a hash code. If two bounding boxes have identical values, they
* will have the same hash code. The current instance is unaffected.
*
* @return a 32-bit value for use in hashing
*/
@Override
public int hashCode() {
int hash = Objects.hash(radius);
hash = 59 * hash + super.hashCode();

return hash;
}

/**
* Tests for approximate equality with the specified bounding sphere, using
* the specified tolerance. If {@code other} is null, false is returned.
* Either way, the current instance is unaffected.
*
* @param sphere the bounding sphere to compare (unaffected) or null for none
* @param epsilon the tolerance for each component
* @return true if all components are within tolerance, otherwise false
*/
public boolean isSimilar(BoundingSphere sphere, float epsilon) {
if (sphere == null) {
return false;
} else if (Float.compare(Math.abs(sphere.getRadius() - radius), epsilon) > 0) {
return false;
} else if (!center.isSimilar(sphere.getCenter(), epsilon)) {
return false;
}
// The checkPlane field is ignored.
return true;
}

/**
* <code>toString</code> returns the string representation of this object.
* The form is: "Radius: RRR.SSSS Center: vector".
Expand Down
45 changes: 44 additions & 1 deletion jme3-core/src/main/java/com/jme3/bounding/BoundingVolume.java
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2009-2021 jMonkeyEngine
* Copyright (c) 2009-2024 jMonkeyEngine
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
Expand Down Expand Up @@ -40,6 +40,7 @@
import com.jme3.util.TempVars;
import java.io.IOException;
import java.nio.FloatBuffer;
import java.util.Objects;

/**
* <code>BoundingVolume</code> defines an interface for dealing with
Expand Down Expand Up @@ -180,6 +181,48 @@ public final BoundingVolume transform(Transform trans) {
*/
public abstract BoundingVolume clone(BoundingVolume store);

/**
* Tests for exact equality with the argument, distinguishing -0 from 0. If
* {@code other} is null, false is returned. Either way, the current
* instance is unaffected.
*
* @param other the object to compare (may be null, unaffected)
* @return true if {@code this} and {@code other} have identical values,
* otherwise false
*/
@Override
public boolean equals(Object other) {
if (!(other instanceof BoundingVolume)) {
return false;
}

if (this == other) {
return true;
}

BoundingVolume otherBoundingVolume = (BoundingVolume) other;
if (!center.equals(otherBoundingVolume.getCenter())) {
return false;
}
// The checkPlane field is ignored.

return true;
}

/**
* Returns a hash code. If two bounding volumes have identical values, they
* will have the same hash code. The current instance is unaffected.
*
* @return a 32-bit value for use in hashing
*/
@Override
public int hashCode() {
int hash = Objects.hash(center);
// The checkPlane field is ignored.

return hash;
}

public final Vector3f getCenter() {
return center;
}
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99 changes: 99 additions & 0 deletions jme3-core/src/test/java/com/jme3/bounding/TestBoundingBox.java
Original file line number Diff line number Diff line change
@@ -0,0 +1,99 @@
/*
* Copyright (c) 2024 jMonkeyEngine
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the name of 'jMonkeyEngine' nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.jme3.bounding;

import com.jme3.math.Vector3f;
import org.junit.Assert;
import org.junit.Test;

/**
* Test cases for the BoundingBox class.
*
* @author Stephen Gold
*/
public class TestBoundingBox {
/**
* Verify that equals() behaves as expected.
*/
@Test
public void testEquals() {
BoundingBox bb1 = new BoundingBox(new Vector3f(3f, 4f, 5f), 0f, 1f, 2f);
BoundingBox bb2
= new BoundingBox(new Vector3f(3f, 4f, 5f), -0f, 1f, 2f);

BoundingBox bb3 = new BoundingBox(new Vector3f(3f, 0f, 2f), 9f, 8f, 7f);
BoundingBox bb4
= new BoundingBox(new Vector3f(3f, -0f, 2f), 9f, 8f, 7f);

BoundingBox bb5 = new BoundingBox(new Vector3f(4f, 5f, 6f), 9f, 8f, 7f);
BoundingBox bb6 = (BoundingBox) bb5.clone();
bb6.setCheckPlane(1);

// Clones are equal to their base instances:
Assert.assertEquals(bb1, bb1.clone());
Assert.assertEquals(bb2, bb2.clone());
Assert.assertEquals(bb3, bb3.clone());
Assert.assertEquals(bb4, bb4.clone());
Assert.assertEquals(bb5, bb5.clone());
Assert.assertEquals(bb6, bb6.clone());

Assert.assertNotEquals(bb1, bb2); // because their extents differ
Assert.assertNotEquals(bb3, bb4); // because their centers differ
Assert.assertEquals(bb5, bb6); // because check planes are ignored
}

/**
* Verify that isSimilar() behaves as expected.
*/
@Test
public void testIsSimilar() {
BoundingBox bb1 = new BoundingBox(new Vector3f(3f, 4f, 5f), 0f, 1f, 2f);
BoundingBox bb2
= new BoundingBox(new Vector3f(3f, 4f, 5f), 0f, 1.1f, 2f);

BoundingBox bb3 = new BoundingBox(new Vector3f(3f, 4f, 2f), 9f, 8f, 7f);
BoundingBox bb4
= new BoundingBox(new Vector3f(3f, 3.9f, 2f), 9f, 8f, 7f);

BoundingBox bb5 = new BoundingBox(new Vector3f(4f, 5f, 6f), 9f, 8f, 7f);
BoundingBox bb6 = (BoundingBox) bb5.clone();
bb6.setCheckPlane(1);

Assert.assertFalse(bb1.isSimilar(bb2, 0.09999f));
Assert.assertTrue(bb1.isSimilar(bb2, 0.10001f));

Assert.assertFalse(bb3.isSimilar(bb4, 0.09999f));
Assert.assertTrue(bb3.isSimilar(bb4, 0.10001f));

Assert.assertTrue(bb5.isSimilar(bb6, 0f)); // check planes are ignored
}
}
51 changes: 51 additions & 0 deletions jme3-core/src/test/java/com/jme3/bounding/TestBoundingSphere.java
Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,57 @@
* @author Stephen Gold
*/
public class TestBoundingSphere {
/**
* Verify that equals() behaves as expected.
*/
@Test
public void testEquals() {
BoundingSphere bs1 = new BoundingSphere(0f, new Vector3f(3f, 4f, 5f));
BoundingSphere bs2 = new BoundingSphere(-0f, new Vector3f(3f, 4f, 5f));

BoundingSphere bs3 = new BoundingSphere(1f, new Vector3f(3f, 0f, 2f));
BoundingSphere bs4 = new BoundingSphere(1f, new Vector3f(3f, -0f, 2f));

BoundingSphere bs5 = new BoundingSphere(2f, new Vector3f(4f, 5f, 6f));
BoundingSphere bs6 = (BoundingSphere) bs5.clone();
bs6.setCheckPlane(1);

// Clones are equal to their base instances:
Assert.assertEquals(bs1, bs1.clone());
Assert.assertEquals(bs2, bs2.clone());
Assert.assertEquals(bs3, bs3.clone());
Assert.assertEquals(bs4, bs4.clone());
Assert.assertEquals(bs5, bs5.clone());
Assert.assertEquals(bs6, bs6.clone());

Assert.assertNotEquals(bs1, bs2); // because their radii differ
Assert.assertNotEquals(bs3, bs4); // because their centers differ
Assert.assertEquals(bs5, bs6); // because check planes are ignored
}

/**
* Verify that isSimilar() behaves as expected.
*/
@Test
public void testIsSimilar() {
BoundingSphere bs1 = new BoundingSphere(0f, new Vector3f(3f, 4f, 5f));
BoundingSphere bs2 = new BoundingSphere(0.1f, new Vector3f(3f, 4f, 5f));

BoundingSphere bs3 = new BoundingSphere(1f, new Vector3f(3f, 4f, 2f));
BoundingSphere bs4 = new BoundingSphere(1f, new Vector3f(3f, 3.9f, 2f));

BoundingSphere bs5 = new BoundingSphere(2f, new Vector3f(4f, 5f, 6f));
BoundingSphere bs6 = (BoundingSphere) bs5.clone();
bs6.setCheckPlane(1);

Assert.assertFalse(bs1.isSimilar(bs2, 0.09999f));
Assert.assertTrue(bs1.isSimilar(bs2, 0.10001f));

Assert.assertFalse(bs3.isSimilar(bs4, 0.09999f));
Assert.assertTrue(bs3.isSimilar(bs4, 0.10001f));

Assert.assertTrue(bs5.isSimilar(bs6, 0f)); // check planes are ignored
}

/**
* Verify that an infinite bounding sphere can be merged with a very
Expand Down

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