private static void flipDXT3Block(byte[] block, int h){
        if (h == 1)
            return;

        // first row
        byte tmp0 = block[0];
        byte tmp1 = block[1];

        if (h == 2){
            block[0] = block[2];
            block[1] = block[3];

            block[2] = tmp0;
            block[3] = tmp1;
        }else{
            // write last row to first row
            block[0] = block[6];
            block[1] = block[7];

            // write first row to last row
            block[6] = tmp0;
            block[7] = tmp1;

            // 2nd row
            tmp0 = block[2];
            tmp1 = block[3];

            // write 3rd row to 2nd
            block[2] = block[4];
            block[3] = block[5];

            // write 2nd row to 3rd
            block[4] = tmp0;
            block[5] = tmp1;
        }
    }
A private constructor to inhibit instantiation of this class.
jme3-core/src/plugins/java/com/jme3/texture/plugins/DXTFlipper.java