public void setSubPixelShift(float subPixelShift) {
        this.subPixelShift = subPixelShift;
        if (material != null) {
            material.setFloat("SubPixelShift", this.subPixelShift);
        }
    }
set to 0.0f for higher quality

@param subPixelShift the desired shift (default=0.25)
jme3-effects/src/main/java/com/jme3/post/filters/FXAAFilter.java