MotionPath: implement JmeCloneable and test

Author: stephengold

jme3-core/src/main/java/com/jme3/cinematic/MotionPath.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009-2021 jMonkeyEngine
+ * Copyright (c) 2009-2025 jMonkeyEngine
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -45,6 +45,8 @@
 import com.jme3.scene.shape.Box;
 import com.jme3.scene.shape.Curve;
 import com.jme3.util.TempVars;
+import com.jme3.util.clone.Cloner;
+import com.jme3.util.clone.JmeCloneable;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Iterator;
@@ -54,7 +56,7 @@
  * Motion path is used to create a path between way points.
  * @author Nehon
  */
-public class MotionPath implements Savable {
+public class MotionPath implements JmeCloneable, Savable {
 
     private Node debugNode;
     private AssetManager assetManager;
@@ -177,6 +179,40 @@ public void read(JmeImporter im) throws IOException {
         spline = (Spline) in.readSavable("spline", null);
     }
 
+    /**
+     * Callback from {@link com.jme3.util.clone.Cloner} to convert this
+     * shallow-cloned MotionPath into a deep-cloned one, using the specified
+     * cloner and original to resolve copied fields.
+     *
+     * @param cloner the cloner that's cloning this MotionPath (not null)
+     * @param original the object from which this MotionPath was shallow-cloned
+     * (not null, unaffected)
+     */
+    @Override
+    public void cloneFields(Cloner cloner, Object original) {
+        this.debugNode = cloner.clone(debugNode);
+        this.spline = cloner.clone(spline);
+        /*
+         * The clone will share both the asset manager and the list of listeners
+         * of the original MotionPath.
+         */
+    }
+
+    /**
+     * Creates a shallow clone for the JME cloner.
+     *
+     * @return a new object
+     */
+    @Override
+    public MotionPath jmeClone() {
+        try {
+            MotionPath clone = (MotionPath) clone();
+            return clone;
+        } catch (CloneNotSupportedException exception) {
+            throw new RuntimeException(exception);
+        }
+    }
+
     /**
      * compute the index of the waypoint and the interpolation value according to a distance
      * returns a vector 2 containing the index in the x field and the interpolation value in the y field

jme3-core/src/test/java/com/jme3/cinematic/MotionPathTest.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2025 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.cinematic;
+
+import com.jme3.math.Vector3f;
+import com.jme3.util.clone.Cloner;
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * Verifies that the {@link MotionPath} class works.
+ *
+ * @author Stephen Gold
+ */
+public class MotionPathTest {
+
+    /**
+     * Verifies that MotionPath cloning works.
+     */
+    @Test
+    public void cloneMotionPath() {
+        MotionPath original = new MotionPath();
+        original.setCycle(true);
+        original.addWayPoint(new Vector3f(20, 3, 0));
+        original.addWayPoint(new Vector3f(0, 3, 20));
+        original.addWayPoint(new Vector3f(-20, 3, 0));
+        original.addWayPoint(new Vector3f(0, 3, -20));
+        original.setCurveTension(0.83f);
+
+        MotionPath clone = Cloner.deepClone(original);
+
+        // Verify that the clone is non-null and distinct from the original:
+        Assert.assertNotNull(clone);
+        Assert.assertTrue(clone != original);
+
+        // Compare the return values of various getters:
+        Assert.assertEquals(
+                clone.getCurveTension(), original.getCurveTension(), 0f);
+        Assert.assertEquals(clone.getLength(), original.getLength(), 0f);
+        Assert.assertEquals(clone.getNbWayPoints(), original.getNbWayPoints());
+        Assert.assertEquals(
+                clone.getPathSplineType(), original.getPathSplineType());
+        Assert.assertEquals(clone.getWayPoint(0), original.getWayPoint(0));
+        Assert.assertEquals(clone.isCycle(), original.isCycle());
+    }
+}