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 "wpnmp5_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.