public static final float smoothstep(final float a, final float b, final float x) {
        if (x < a) {
            return 0;
        } else if (x > b) {
            return 1;
        }
        float xx = (x - a) / (b - a);
        return xx * xx * (3 - 2 * xx);
    }
A private constructor to inhibit instantiation of this class.
jme3-terrain/src/main/java/com/jme3/terrain/noise/ShaderUtils.java