Author: http://www.cnblogs.com/open-coder/p/3898159.html

The light mapping effects between PC and Mobile become very incosistant just as following:

With the same light maps, the left one is the Android Platform, and the right one is the PC Platform. But the right one is much brigher than the left one.
Why? ????????????
Let check the Unity3D light map decode function:

The reason is that the light map encode use High dynamic range encode. The range on the PC is [0, 8], but the range on the Mobile will only in [0, 2].
That means the when you switch the platform from PC to Android, the light map color range will clamp to [0, 2] no matter what value it is.
And the best way to keep light map consistant on PC and Android is keep the light map color range in [0, 2].
Sometimes, we would like to multiply the light map color with a factor. I strongly suggest that please make sure this factor larger than 1.0 (Only bright is instead of darker it).