jme3-core: add 2 getters for frame interpolators (#2152)

jme3-core/src/main/java/com/jme3/anim/MorphTrack.java

@@ -228,6 +228,15 @@ public class MorphTrack implements AnimTrack<float[]> {
         fi.interpolateWeights(blend, startFrame, weights, nbMorphTargets, store);
     }
 
+    /**
+     * Access the FrameInterpolator.
+     *
+     * @return the pre-existing instance or null
+     */
+    public FrameInterpolator getFrameInterpolator() {
+        return interpolator;
+    }
+
     /**
      * Replace the FrameInterpolator.
      *

jme3-core/src/main/java/com/jme3/anim/TransformTrack.java

@@ -301,6 +301,15 @@ public class TransformTrack implements AnimTrack<Transform> {
         }
     }
 
+    /**
+     * Access the FrameInterpolator.
+     *
+     * @return the pre-existing instance or null
+     */
+    public FrameInterpolator getFrameInterpolator() {
+        return interpolator;
+    }
+
     /**
      * Replaces the frame interpolator.
      *