fix GImpact scaling in jme3-bullet (native Bullet)

jme3-bullet-native/src/native/cpp/com_jme3_bullet_collision_shapes_GImpactCollisionShape.cpp

@@ -55,6 +55,18 @@ extern "C" {
         return reinterpret_cast<jlong>(shape);
     }
 
+    /*
+     * Class:     com_jme3_bullet_collision_shapes_GImpactCollisionShape
+     * Method:    recalcAabb
+     * Signature: (J)V
+     */
+    JNIEXPORT void JNICALL Java_com_jme3_bullet_collision_shapes_GImpactCollisionShape_recalcAabb
+    (JNIEnv *env, jobject object, jlong shapeId) {
+        btGImpactMeshShape *pShape
+                = reinterpret_cast<btGImpactMeshShape *> (shapeId);
+        pShape->updateBound();
+    }
+
     /*
      * Class:     com_jme3_bullet_collision_shapes_GImpactCollisionShape
      * Method:    finalizeNative

jme3-bullet/src/main/java/com/jme3/bullet/collision/shapes/GImpactCollisionShape.java

@@ -36,6 +36,7 @@ import com.jme3.export.InputCapsule;
 import com.jme3.export.JmeExporter;
 import com.jme3.export.JmeImporter;
 import com.jme3.export.OutputCapsule;
+import com.jme3.math.Vector3f;
 import com.jme3.scene.Mesh;
 import com.jme3.scene.VertexBuffer.Type;
 import com.jme3.scene.mesh.IndexBuffer;
@@ -154,6 +155,23 @@ public class GImpactCollisionShape extends CollisionShape {
         createShape();
     }
     
+    /**
+     * Alter the scaling factors of this shape.
+     * <p>
+     * Note that if the shape is shared (between collision objects and/or
+     * compound shapes) changes can have unintended consequences.
+     *
+     * @param scale the desired scaling factor for each local axis (not null, no
+     * negative component, unaffected, default=(1,1,1))
+     */
+    @Override
+    public void setScale(Vector3f scale) {
+        super.setScale(scale);
+        recalcAabb(objectId);
+    }
+
+    native private void recalcAabb(long shapeId);
+
     /**
      * Instantiate the configured shape in Bullet.
      */