SSMF%3A_Normal_Map - beyond-all-reason/springrts_engine_wiki_mirror GitHub Wiki
Normal Map
Normal maps (in this case) are used to add "fake" 3d detail to a flat 2d image. It is a technique of manipulating lighting to give the appearance of looking at a 3d object, when actually it is just 2D.
This is what a normal map looks like: