private void setupViewPortFrameBuffer() {
        if (renderFrameBufferMS != null) {
            viewPort.setOutputFrameBuffer(renderFrameBufferMS);
        } else {
            viewPort.setOutputFrameBuffer(renderFrameBuffer);
        }
    }
returns an unmodifiable version of the filter list.
@return the filters list
jme3-core/src/main/java/com/jme3/post/FilterPostProcessor.java