Doom Eternal - Legacy Modding

Information about modding Doom Eternal with the Legacy Eternal Mod Injector. ALL CONTENT IN THIS BOOK IS DEPRECATED

assetsinfo JSON

The "assetsinfo" JSON can be used to add entirely new assets to the game.

assetsinfo JSON

Format Overview

The assetsinfo JSON format allows for advanced control over mod injector behavior.

The most common uses of assetsinfo JSON include:

Format Overview

{
	// experimental - used to add new map layers
    "layers":[
        {
            "name":""
        }
    ],
    
    // experimental - used to add new maps
    "maps":[
        {
            "name":"" 
        }
    ],
    
    // used for adding, removing, or re-ordering of .resources files
    "resources":[
        {
            "name":"",
            "remove":,
            "placeFirst":,
            "placeBefore":,
            "placeByName":""    
        }
    ],
    
    // used for adding, removing, or re-ordering of game assets
    "assets":[
        {
            "name":"",
            "mapResourceType":"",
            "resourceType":"",
            "streamDbHash":,
            "version":,
            "remove":,
            "placeBefore":,
            "placeByName":"",
            "placeByType":"",
            "specialByte1":,
            "specialByte2":,
            "specialByte3":
        }
    ]
}

"Layers" array

The first part of the assetsinfo JSON format is the layers array. This can be used to add additional layers to a map, which can then be referenced via .entities. 

Each item in this array contains an object that has the name property. This field is required for each entry. In there you can set the name of the layer you want to create. It's that simple.

Here is an example usage that adds three custom layers:

{
    "layers":[
        {
            "name":"game/sp/custom/my_custom_layer"
        },
        {
            "name":"game/sp/custom/my_custom_layer_2"
        },
        {
            "name":"game/sp/custom/my_custom_layer_3"
        }
    ]
}

Note: It is unclear what effect this has on gameplay, since it is possible to add new layers to the game without this step, and all existing layers in the game can already be used in any level without additional steps anyway.

"Maps" array

The second part of the assetsinfo JSON format is the maps array.

As with the layers array, each item contains an object that has the name property. In there you can set the name of the map you want to create. This feature is currently of limited use, since we can't create new maps anyway. 

Here is an example usage that adds two custom maps:

{
    "maps":[
        {
            "name":"maps/game/sp/custom/my_custom_map" 
        },
       	{
            "name":"maps/game/sp/custom/my_custom_map_2" 
        }
    ]
}

"Resources" array

The third part of the assetsinfo JSON format is the resources array. This one is a bit more complicated, so let's begin by explaining what this is actually for.

In DOOM Eternal, each map has a list of .resources and .streamdb files that will be loaded in the map itself. With this feature, you can tell the game to load additional .resources and/or .streamdb files in maps. In other words, you can load files that aren't normally loaded, giving you access to game assets and entities that normally aren't available. You can also tell the game to stop loading .resources or .streamdb files that are loaded by default in maps.

This feature is what allows us to load things like spirits and other DLC-specific enemies into the base campaign.

Below is an example usage. This would add the e5m1_spear.resources file, as well as several .streamdb files, to a map that it is not normally loaded in. Don't worry if you don't understand this - it is explained in more detail on the Reference: "resources" array page of the guide.

{
    "resources":[
        {
            "name":"e5m1_spear.resources"
        },
        {
            "name":"gameresources_6_1.streamdb",
            "placeBefore":true,
            "placeByName":"gameresources_0_4.streamdb"
        },
        {
            "name":"gameresources_0_6.streamdb",
            "placeBefore":true,
            "placeByName":"gameresources_0_4.streamdb"
        },
        {
            "name":"gameresources_1_8.streamdb",
            "placeBefore":true,
            "placeByName":"gameresources_0_4.streamdb"
        },
        {
            "name":"gameresources_2_2.streamdb",
            "placeBefore":true,
            "placeByName":"gameresources_0_4.streamdb"
        },
        {
            "name":"gameresources_3_2.streamdb",
            "placeBefore":true,
            "placeByName":"gameresources_0_4.streamdb"
        },
        {
            "name":"gameresources_4_3.streamdb",
            "placeBefore":true,
            "placeByName":"gameresources_0_4.streamdb"
        },
        {
            "name":"gameresources_5_3.streamdb",
            "placeBefore":true,
            "placeByName":"gameresources_0_4.streamdb"
        }
    ]
}

"Assets" array

The last feature in the assetsinfo JSON is the assets array. This is the most complicated one to understand as it has a lot of fields. In most cases, you will only need to use a few of them.

The main purpose of this section is to add entirely new assets to the game. (Most mods work by replacing another asset that already exists, rather than adding something new). For more details, refer to the Reference: "assets" array page of the guide.

An example usage is below. This would add a new image file to the game:

{
    "assets":[
        {
            "resourceType":"image",
            "version":21,
            "name":"custom_textures/custom_emissive_texture.tga$bc1$streamed$mtlkind=bloommask",
            "mapResourceType":"image"
        }
    ]
}

See Also

assetsinfo JSON

Reference: "resources" Array

In DOOM Eternal, each map has a list of .resources and .streamdb files that will be loaded in the map itself. With this feature, you can tell the game to load other .resources and/or .streamdb files in maps. You can also tell the game to stop loading .resources or .streamdb files that are loaded by default in maps.

Structure

The basic structure of the "resources" array is below:

{
	"resources":[
		{
			"name":"",
			"remove":,
			"placeFirst":,
			"placeBefore":,
			"placeByName":""    
		}
	]
}

If neither placeBefore nor placeByName are set, then the asset will be loaded last, with the lowest priority.

Example Usage

The most common use of this feature is to give custom map/level creators access to assets that aren't normally available in a map. For example, you can tell the game to load e5m1_spear.resources (and the required .streamdb files) within another level, such as e1m1_intro.

By doing this, a person modifying the e1m1_intro map can then freely access files/entities from e5m1_spear.resources, the same as if they existed in e1m1_intro already. This would allow you to use DLC AI such as spirits (and many other things) in e1m1_intro, where they normally can't be used.

Below is a sample .json snippet that loads the e5m1_spear.resources and .streamdb files.

{
    "resources":[
        {
            "name":"e5m1_spear.resources"
        },
        {
            "name":"gameresources_6_1.streamdb",
            "placeBefore":true,
            "placeByName":"gameresources_0_4.streamdb"
        },
        {
            "name":"gameresources_0_6.streamdb",
            "placeBefore":true,
            "placeByName":"gameresources_0_4.streamdb"
        },
        {
            "name":"gameresources_1_8.streamdb",
            "placeBefore":true,
            "placeByName":"gameresources_0_4.streamdb"
        },
        {
            "name":"gameresources_2_2.streamdb",
            "placeBefore":true,
            "placeByName":"gameresources_0_4.streamdb"
        },
        {
            "name":"gameresources_3_2.streamdb",
            "placeBefore":true,
            "placeByName":"gameresources_0_4.streamdb"
        },
        {
            "name":"gameresources_4_3.streamdb",
            "placeBefore":true,
            "placeByName":"gameresources_0_4.streamdb"
        },
        {
            "name":"gameresources_5_3.streamdb",
            "placeBefore":true,
            "placeByName":"gameresources_0_4.streamdb"
        }
    ]
}

How Do I Know Which Files to Add?

First, take a look at this spreadsheet (note: there are multiple tabs at the bottom): https://docs.google.com/spreadsheets/d/10R5fWKGyqPuCPdueqKeCYycHETSHg0QeFOCbWIQZUCY/

This spreadsheet contains the list of the default .resources and .streamdb files that are loaded in all the game's maps. So, let's say that we want to have access to all the assets in e5m1_spear.resources in e1m1_intro.resources. The first thing we need to do is find the "e5m1_spear" map name in the spreadsheet, using the "map name" column.

You will see that the map name appears multiple times. This is because the map loads multiple .resources and .streamdb files. In the "file name" column you will see the names of the files that are loaded in the map. The order of the files matters. It actually goes from bottom to up, so the files at the bottom are loaded first during the map loading process, and the files at the top are loaded last. This means that the files at the top override the others (if they share files in common). This is what we refer to as load priority.

 

EternalMod JSON

This .json file allows mod makers to define information about their mods, such as mod name, author(s), description and version number.

This feature is only available for zipped mods. You can not place an EternalMod JSON file at the root of your ~/Mods/ directory; it will be ignored.

How to Use:

Using the EternalMod.json file is simple:

  1. Create a file named "EternalMod.json"
  2. Place the EternalMod.json file at the root of your zipped mod, outside of the container folders. Example: ~/Mods/My_Amazing_Mod.zip/EternalMod.json
  3. Use a text editor such as Notepad++ to edit the file as needed.

Format:

This is the format of this JSON file (all fields are optional):

{
    "name":"",
    "author":"",
    "description":"",
    "version":"",
    "loadPriority":,
    "requiredVersion":
}

Example File:

Here's an example of an EternalMod.json file with all the fields filled in:

{
    "name":"Enemy Randomizer",
    "author":"proteh",
    "description":"This mod randomizes every enemy encounter in the base game and the DLCs.",
    "version":"3.0",
    "loadPriority":100,
    "requiredVersion":6
}

 

Legacy String Modding

Legacy String Modding

Extracting Strings

See Extracting Resources before proceeding. You must have gameresources.resources extracted.

A string is a sequence of characters (text) that appears literally.

Extracting Tools

BlangJsonGeneratorUI by PowerBall253 - Download
Modifies BLANG files and exports the changes as JSON.

BlangJsonGenerator by PowerBall253 - Download
Exports BLANG files into JSON, a format that can be edited with raw text editor, such as Notepad++.

BlangParser by proteh - Download
Directly modifies BLANG files with a simple GUI.

Currently, there are no released packages for BlangParser.
You will either need to find a compiled version in the 2016+ Modding Discord server
or compile it with a C# compiler.

Each BLANG file usually range from 1.5 MB to 2 MB of storage.

Finding BLANG files

Extraction Instructions ( BlangJsonGenerator )

The output folder must end with .json

List of Resources

Resource Name Information
english.blang Contains strings for the English language
french.blang Contains strings for the French language
german.blang Contains strings for the German language
italian.blang Contains strings for the Italian language
japanese.blang Contains strings for the Japanese language
latin_spanish.blang Contains strings for the Latin American Spanish language
polish.blang Contains strings for the Polish language
portuguese.blang Contains strings for the Portuguese language
russian.blang Contains strings for the Russian language
simplified_chinese.blang Contains strings for the Simplified Chinese language
spanish.blang Contains strings for the European Spanish language
traditional_chinese.blang Contains strings for the Traditional Chinese language

 

Legacy String Modding

Creating String Mods

See Extracting Strings before proceeding.

Make sure to backup the unmodified BLANG file.

Strings can be added to BLANG files, but you must reference them with decls files.

String Editing ( BlangJsonGeneratorUI )

screenshot.png

gameresources_patch1\EternalMod\strings

String Editing ( BlangJsonGenerator )

Any unused string can be deleted, so it can be compatible with other mods that affect other strings.

image-1631218573399.png

1) image-1631217604007.PNG
"identifier":
"name":

The "Replace with : " box is empty for screenshot 2.

2) image-1631217614687.PNG
"modified": 0

The "Replace with : " box is empty for screenshot 3.

3) image-1631217622425.PNG
^(?:[\t ]*(?:\r?\n|\r))+

image-1631218052834.png

gameresources_patch1\EternalMod\strings

The commas "," at the end of each string name and text are unnecessary and can be deleted.
However, they do not impact the syntax in any way.

Since JSON files can be edited with raw text editors,
you can execute scripts or regular expressions to edit strings more efficiently.

String Editing ( BlangParser )

The entire BLANG file will be modified, which means it will be incompatible with other string mods.

image-1631220049230.PNG

gameresources_patch1\strings

It is not recommended to delete existing string lines because DOOM Eternal will fail to recognize them.

Legacy String Modding

String File Extensions

These are the string file types you will be interacting with.

.blang

String files that CANNOT be read by a raw text editor.
BLANG files CAN be re-injected into DOOM Eternal.
Example:
english.blang

.json

Extracted string files that CAN be read by a raw text editor.
JSON files CANNOT be re-injected into DOOM Eternal.
Example:
english.json