@Override
    public void write(JmeExporter ex) throws IOException {
        super.write(ex);
        OutputCapsule oc = ex.getCapsule(this);
        oc.write(light, "light", null);
    }
sets the light to use for casting shadows with this processor

@param light the point light
jme3-core/src/main/java/com/jme3/shadow/PointLightShadowRenderer.java