What is the exact function of a "Normal Map" node?
I'm wondering what is the exact function of a "Normal Map" node? The normal map is a color texture with three values for each pixel and the normal vector is also also defined by three values for the direction. But I suppose that it's not only the texture space that has to be specified directly in this node but also internally the mapping of each color component to a specific axis and whether it points into the positive or negative direction on that axis: In Blender it's R for X+, G for Y+ and B for Z+. This last mentioned mapping is called the "Swizzle" which differs from software to software as you can see here at the end of the page. I'm still confused about which normal map color space has which benefits. The normal map baking is partly also a mystery for me since most tutorials on Youtube are rather like cooking instruction and lack of background information on how this works behind the scenes.