Reference:http://forum.gamer.com.tw/C.php?bsn=11177&snA=3061&last=1#down
Wiki
Reference:https://en.wikipedia.org/wiki/Ordered_dithering
Reference:https://en.wikipedia.org/wiki/Dither
Complete Description
Reference:http://bisqwit.iki.fi/story/howto/dither/jy/
Asset store :
Simple: https://www.assetstore.unity3d.com/en/#!/content/6774
Middle: https://www.assetstore.unity3d.com/en/#!/content/47180
Professional: https://www.assetstore.unity3d.com/en/#!/content/20329
