@Override
    protected void doDisplayFrustumDebug(int shadowMapIndex) {
        ((Node) viewPort.getScenes().get(0)).attachChild(createFrustum(points, shadowMapIndex));
        ShadowUtil.updateFrustumPoints2(shadowCam, points);
        ((Node) viewPort.getScenes().get(0)).attachChild(createFrustum(points, shadowMapIndex));
    }
Sets the light to use to cast shadows
@param light a DirectionalLight
jme3-vr/src/main/java/com/jme3/shadow/DirectionalLightShadowRendererVR.java