BoundingVolume: add equals() and hashCode() methods

jme3-core/src/main/java/com/jme3/bounding/BoundingVolume.java

@@ -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
@@ -180,6 +180,49 @@ 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 = 3;
+        hash = 59 * hash + center.hashCode();
+        // The checkPlane field is ignored.
+
+        return hash;
+    }
+
     public final Vector3f getCenter() {
         return center;
     }