Savegame bloating due to inefficient fog textures format
Currently we store a fog of war for every cell inside a savegame (FTEX subrecords). Such textures usually occupy about 20% of savegame data.
Every fog texture is just a black texture with alpha, so in theory the 1 byte per pixel is enough, but we store 4 bytes per pixel, where 75% of data are zeroes. It means that about 15% of savegame data (several megabytes of data depending on count of visited cells) is just wasted.
Also I was told that OSG just can not write grayscale images, so we have to use RGBA format.