public MaterialExtensionSet getMaterialExtensionSet() {
        return matExts;
    }
Returns the {@link MaterialExtensionSet} previously set using
{@link OgreMaterialKey#setMaterialExtensionSet(com.jme3.scene.plugins.ogre.matext.MaterialExtensionSet)
} method.

@return the {@link MaterialExtensionSet}
jme3-plugins/src/ogre/java/com/jme3/scene/plugins/ogre/matext/OgreMaterialKey.java