protected final void setPostShadowMaterial(Material postShadowMat) {
        this.postshadowMat = postShadowMat;
        postshadowMat.setFloat("ShadowMapSize", shadowMapSize);
        for (int i = 0; i < nbShadowMaps; i++) {
            postshadowMat.setTexture(shadowMapStringCache[i], shadowMaps[i]);
        }
        setShadowCompareMode(shadowCompareMode);
        setEdgeFilteringMode(edgeFilteringMode);
        setShadowIntensity(shadowIntensity);
    }
set the post shadow material for this renderer

@param postShadowMat
jme3-vr/src/main/java/com/jme3/shadow/AbstractShadowRendererVR.java