This tutorial will cover how to convert normal maps to a format that Stalker can use. This will allow you to use custom normal maps in Stalker as well as converting existing Stalker normal maps to a normal one that other game engines can read. However, this tutorial will not cover the process of creating normal maps, there are tons of other tutorials about this topic.
- Photoshop or any other software that is capable of creating normal maps
- A working, updated Stalker installation
- A model & skin you want to create a normal map for
- When using Photoshop, the nVidia normal map plugin as well as the nVidia .dds Utilities will come in very handy
- First of all, we need to open the skin we want to edit in our picture-editing software, I will use Photoshop CS2 and the default MP5 texture for this tutorial.
- Prepare the normal map using the nVidia normal map filter. This tutorial will not cover how to create a good normal map, there are tons of other tutorials regarding this topic.
- Stalker will use the red channel of your new normal map as some kind of specular map; unfortunately I am not sure what this map is really used for. Still, it is obvious that the map is a toned down greyscaled version of the regular skin. Refer to screenshot B for an example of what your normal map could look like.
- Now the important part starts: change to the channels tab.
For making a normal map useable in Stalker, we need to swap the channels refering to the following table:
Channel of the normal map: Swap to channel: Red Blue Green Alpha 1 Blue Green Alpha 1 Red
- For doing so using Photoshop CS2, I duplicate every channel and rename them to their real names. After this, I delete the original channels, bring the new ones left into the right order (Red, Green, Blue, Alpha 1) and change the image format back to RGB. Refer to screenshot C, D and E as screens during the swapping process. Screenshot F shows a possible outcome of your swapped normal map.
- Save your new normal map in the .dds file format with the addition "_bump" at the end of the filename. In my case of the MP5 skin, the filename would be "wpn_mp5_bump.dds".
You're done. If you followed every step correctly you will finally have a working normal map in Stalker that matches your skin.