Custom Decals
To add a custom decal to your game. First you need to locate the ModsData folder of EAI, once you find it you can create a folder in it and name it CustomDecals. You can now create a new folder, this folder is the category of your decal.
This category folder can have one of these names : Alphabet, Beach, Graffiti, Ground, Industry, Leaf, Misc, Numbers, Parking, Puddles, RoadAssets, RoadMarkings, Stains, Trash and WallDecor.
In the category folder you just create, create a new folder and name it with the name of your decal and in this folder you need to at least have _BaseColorMap.png, the other file : _MaskMap.png, _NormalMap.png, icon.png & decal.json (this one is highly recommended) are optional.
You can find an example of decal.json here or in any mod that add custom decals.
I recommend you to use texture of 512×512 to 1024x1024.
Note
The mod automatically resize the icon to 128x128 and if there is no icon.png in the folder, the mod create one using the _BaseColorMap.png.
The base colour map, is the texture of the surface, here is some example of _BaseColorMap
The normal map, is the texture that add shadow to the surface, to create a 3D effect. It usually looks blue, but for the game it's pink.
Unity already made a wiki on that here.
For an unknown reason, you need to linear invert the colour of the red channel of this texture to make it work properly.
Here is some example of _NormalMap :
This texture is a combination of multiple one, Unity made a good wiki for that here
Here is some example of _MaskMap:
