private void clearMatParams(){
        for (Material mat : matCache) {

            //clearing only necessary params, the others may be set by other
            //renderers
            //Note that j start at 1 because other shadow renderers will have
            //at least 1 shadow map and will set it on each frame anyway.
            for (int j = 1; j < nbShadowMaps; j++) {
                mat.clearParam(lightViewStringCache[j]);
            }
            for (int j = 1; j < nbShadowMaps; j++) {
                mat.clearParam(shadowMapStringCache[j]);
            }
            mat.clearParam("FadeInfo");
            clearMaterialParameters(mat);
        }
        //No need to clear the postShadowMat params as the instance is locale to each renderer
    }
This method is called once per frame and is responsible for clearing any
material parameters that subclasses may need to clear on the post material.

@param material the material that was used for the post shadow pass
jme3-core/src/main/java/com/jme3/shadow/AbstractShadowRenderer.java