final public void setShadowIntensity(float shadowIntensity) {
        this.shadowIntensity = shadowIntensity;
        postshadowMat.setFloat("ShadowIntensity", shadowIntensity);
    }
Set the shadowIntensity. The value should be between 0 and 1. A 0 value
gives a bright and invisible shadow, a 1 value gives a pitch black
shadow. The default is 0.7

@param shadowIntensity the darkness of the shadow
jme3-core/src/main/java/com/jme3/shadow/AbstractShadowRenderer.java