@Override
    protected void initFilter(AssetManager assetManager, RenderManager renderManager,
            ViewPort viewPort, int width, int height) {
        material = new Material(assetManager, "Common/MatDefs/Post/ContrastAdjustment.j3md");

        //different channels exp for different transfer functions
        setExponents(redExponent, greenExponent, blueExponent);

        //input range
        setInputRange(lowerLimit, upperLimit);

        //final pass scales
        setScales(redScale, greenScale, blueScale);
    }
Initializes the Filter when it is added to a FilterPostProcessor.

@param assetManager for loading assets (not null)
@param renderManager unused
@param viewPort unused
@param width unused
@param height unused
jme3-effects/src/main/java/com/jme3/post/filters/ContrastAdjustmentFilter.java