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Shader Modding

Docs about shaders inside of Titanfall 2's rpak system

Prerequisites

Note

These docs are not going to teach you how to write shaders, or any basic HLSL. Refer to the many online resources for thoose topics to learn them.

The Basics

Note

In RSX make sure that the export for Shaders and Shadersets are both set to .msw

In rpak's there are two type of assets related to shaders, Shadersets [shds] and Shaders [shdr].

A Shader asset is comprised of multiple (mostly 1-15) individual compiled shader files, alone they do nothing and are useless inside an rpak. A Shaderset asset is a pretty small definition of, well, a set of two Shader assets, a Vertex and a Pixel Shader. This is what a Material references so the game knows what combination of Vertex and Pixel shader to use for said Material.

So, to figure out what shader you want to modify, or what shader you want to use as a base you need to find the shaderset used in a Material u want to replicate, then find the individual Shaders, this is pretty easy via RSX.

If after unpacking the exported shader you are unsure which compiled .fxc file to modify try the first one first, most of the time its 0.fxc.

Unpacking your Shader

Once you found a shader you will need to unpack the .msw file. Do so using the MSWUnpacker with the commandline.

.\MSWUnPacker.exe unpack <your msw file>

The unpacked shader files will now be in a newly created folder named after your .msw file.

Repacking your Shader

Once you have done your modifications to the Shader's .fxc files you'll want to pack it back into a .msw to use in repak Do so using the MSWUnpacker with the commandline.

.\MSWUnPacker.exe pack <your shader folder>

There should be an packed .msw file next to the unpacked shader folder.

Decompiling your Shader

To decompile the compiled .fxc file to a readable, and recompilable file use the HLSLDecompiler Do so using the commandline

.\cmd_Decompiler.exe -D <your fxc file>

Note

Make sure to use a capital D, a lowercase d will not decompile but instead disassemble.

Compiling your Shader

You can compile your modified .hlsl file using the Effect Compiler Tool mentioned in the Prerequisites.

Firstly you need to know which shader model you are compiling to.

If you are compiling a pixel shader its propably gonna be ps_5_0 If you are compiling a vertex shader its propably gonna be vs_5_0

Should you be unsure of which model your shader is supposed to be disassemble your original .fxc file using the -d option and you will see the model as the first line underneath the commented signatures.

To compile your .hlsl file do so using the commandline.

./fxc.exe /T <shadermodel> /Fo <output fxc filename> <input hlsl filename>

This will attempt to compile your .hlsl source file, if it fails it will show you warnings and errors for you to track down issues.

Making a new Shaderset

Its quite important to make a new Shaderset for your modified Shader if its supposed to only appear on a single Material of your choice instead of overwriting the original Shader and Shaderset.

Next we make sure that both our vertex shader and pixel shader have unique names. Usually we wanna name them in a way that makes them recognizable, in my example i would name them something like uberCustomShaderEM4Vtestshader_vs.msw and uberCustomShaderEM4Vtestshader_ps.msw. Note the Sufix's of _vs and _ps for vertex and pixel shader respectivly. From here on out do not change their names again as these are quite important from here on out to properly link everything later on in the .rpak file.

Lets get the GUID's of the shaders now, for this open a Commandline next to repak and execute the following, replacing with the name of your shader without its file extension:

.\RePak.exe -pakguid shader/<yourshader>.rpak

Do this for both your vertex and pixel shader.

Now get your base Shaderset .msw file and put it next to the MSW Shaderset Modifier python script.

Execute the script in a Commandline using the base .msw file as an argument. The script will now ask you for the GUID's of the shaders, enter the output given from repak and then enter a new name for your shaderset when prompted. A new .msw file will now have been generated.

Packing the .rpak

In order to pack the shaders and shaderset into an .rpak first prepare the following folder structure somewhere, with the json having whatever name you want:

Main Folder
├── RePak.exe
├── <mapname>.json
└── assets
    ├── shader
    └── shaderset

Now open the .json file and copy in the following example repak map:

{
  "keepDevOnly": true,
  "version": 7,
  "name": "example_map",
  "streamFileMandatory": "example_map.starpak",
  "assetsDir": "assets",
  "outputDir": "out/",
  "compressLevel": 0,
  "compressWorkers": 16,
  "files": [
    {
      "_type": "shdr",
      "_path": "shader/<shadername_ps>.rpak"
    },
    {
      "_type": "shdr",
      "_path": "shader/<shadername_vs>.rpak"
    },
    {
      "_type": "shds",
      "_path": "shaderset/<shadersetname>.rpak"
    }
    ]
}

Replace the <> names with your file names without the .msw extension.

Now open a Commandline and execute

./RePak.exe <mapname>.json

Repak should now spit out an .rpak file with the Shaderset and Shaders packed which you can now use in your mod.