@Override
    public void write(JmeExporter exporter) throws IOException {
        super.write(exporter);
        OutputCapsule capsule = exporter.getCapsule(this);

        capsule.write(gamma, "gamma", 0.6f);
        capsule.write(numColors, "numColors", 8);
        capsule.write(strength, "strength", 1f);
    }
Save properties when the filter is serialized, for example when saving to
a J3O file.

@param exporter the exporter to use (not null)
@throws IOException from the exporter
jme3-effects/src/main/java/com/jme3/post/filters/PosterizationFilter.java