protected boolean isRequiresBilinear() {
        return false;
    }
Override this method and return true if you want the scene (input) texture
to use bilinear filtering or false to use nearest filtering.

Typically, filters that perform samples <em>in between</em> pixels
should enable bilinear filtering.

@return true to use linear filtering, false to use nearest filtering.
jme3-core/src/main/java/com/jme3/post/Filter.java