@Override
    protected GeometryList getOccludersToRender(int shadowMapIndex, GeometryList shadowMapOccluders) {
        for (Spatial scene : viewPort.getScenes()) {
            ShadowUtil.getGeometriesInCamFrustum(scene, shadowCam, RenderQueue.ShadowMode.Cast, shadowMapOccluders);
        }
        return shadowMapOccluders;
    }
Sets the light to use to cast shadows

@param light a SpotLight
jme3-core/src/main/java/com/jme3/shadow/SpotLightShadowRenderer.java