Making Your Portal Mod

This article will discuss how to create a Portal content mod, from scratch. Part of the reason for creating the mod from scratch is that Valve does not provide a specific SDK or mod template for Portal. Another reason is that creating the mod from scratch is not difficult and is of general interest to Source SDK developers that would like to learn more about how everything works. So, let's get started.

Note: Portal modification is different from some of the other Source based games in that source code to build the client.dll and server.dll files is not provided by Valve. However, a modder can still modify anything that isn't built directly into the game, which includes scenes, scripts, sounds, textures, and models, to name a few.

Prerequisites

To follow along with this article, you will need a copy of Portal and the Source SDK, installed on Steam.

The article uses a command shell to describe simple file manipulations. The commands used are:

Command	Description
cd	Change directory
mkdir	Create a directory
new-item	Create an empty file (roughly)

Creating the Mod

Creating the mod consists of creating a game folder and filling it with configuration files and mod-related content. Let's assume we are creating a mod named "My Portal Mod". Further, let [Steam Root] be Steam's installed path on your machine. (e.g. C:\Program Files (x86)\Steam)

Create the Game Folder

Navigate to your SourceMods directory and create a folder named "MyPortalMod".

   $> cd "[Steam Root]\steamapps\SourceMods"
   $> mkdir MyPortalMod

In this new directory, create a file called GameInfo.txt.

   $> new-item GameInfo.txt -type file

Edit the contents of GameInfo.txt so that they look similar to the following snippet. For details about the structure of this file, see Gameinfo.txt.

"GameInfo"
{
    game   "My Portal Mod"
    title  "My Portal Mod"
    type   singleplayer_only
    icon   "myportalmod"  // Assumes myportalmod.tga is in the same directory as GameInfo.txt

    nodifficulty  1
    hasportals    1

    FileSystem
    {
        SteamAppId  400
        ToolsAppId  211      

        SearchPaths
        {
            Game  |gameinfo_path|.
            Game  portal
            Game  hl2
        }
    }
}

Restarting Steam at this point will create an entry in the game Library for the mod. Deleting the game folder we created or removing the GameInfo.txt file will remove the entry.

Configure the Mod

Initial Setup

Let's add some standard folders to the game directory that will hold our mod's configuration files and content. Add the following folders to your game directory:

• cfg
• resource
• maps.

While we're at it, let's add the following optional folders, for custom content like models and sounds:

• materials
• models
• scenes
• scripts
• sound

   $> cd "[Steam Root]\steamapps\SourceMods\MyPortalMod"
   $> mkdir cfg
   $> mkdir resource
   $> mkdir maps
   $> mkdir materials
   $> mkdir models
   $> mkdir scenes
   $> mkdir scripts
   $> mkdir sound

Create a Map List

In your game directory, create a file called maplist.txt. In it, we will list all of the mod's map names (excluding the .bsp extension). This file allows the game to pre-cache the first .125 milliseconds of sound for a map, which is enough time to load the remainder. ^[confirm]

   $> cd "[Steam Root]\steamapps\SourceMods\MyPortalMod"
   $> new-item maplist.txt -type file

The following is a sample maplist.txt for a mod with two maps, named myportalmod_map_00.bsp and myportalmod_map_01.bsp.

myportalmod_map_00
myportalmod_map_01

Create Chapter Configuration Files

Change to your mod's cfg directory. Create configuration files for each chapter of your mod, starting with chapter1.cfg and continuing on to chapter2.cfg, etc. For example:

   $> cd "[Steam Root]\steamapps\SourceMods\MyPortalMod\cfg"
   $> new-item chapter1.cfg -type file
   $> new-item chapter2.cfg -type file

In these files, you will issue whatever commands you want to be executed by the developer console when the chapter is first loaded. Typically, a command to load the chapter's corresponding map is used.

The following is a chapter1.cfg example:

echo "==== /cfg/chapter1.cfg: Execution Started"

map myportalmod_map_00

echo "==== /cfg/chapter1.cfg: Execution Ended"

Create a Localization File

Create a localization file, called MyPortalMod_english.txt, in your game directory's resource folder.

   $> cd "[Steam Root]\steamapps\SourceMods\MyPortalMod\resource"
   $> new-item MyPortalMod_english.txt -type file

Modify the contents of MyPortalMod_english.txt so that it is similar to the following:

"lang"
{
    "Language" "english"
    "Tokens"
    {
        "MyPortalMod_chapter1"  "The First Chapter"
        "MyPortalMod_chapter2"  "The Second Chapter"
    }
}

In this case, MyPortalMod is used because it is the name of the mod's game directory. "The First Chapter" is an english title for the mod's first chapter. Add any additional chapters for your mod by following the pattern in "Tokens".

Warning: This file must be saved in a Unicode format.

Confirm: Which unicode formats are acceptable? The author used UTF-8.

Setting Up Hammer

Note: If you have not yet created a mod from the 'Source SDK' tool (creating a 'Source code only' mod doesn't count), then you will need to first create one. Otherwise, you will not be allowed to add a game configuration file for MyPortalMod. This configuration file is required to save Hammer settings specific for the MyPortalMod mod. See Create a Mod for details on this process. Do not create a 'Source code only' mod.

Launch the 'Source SDK' from your Steam Library 'Tools' section. Make sure that the 'Engine Version' pull-down has "Source Engine 2009" selected. Select 'Edit Game Configurations'. From the pop-up menu, select 'Add'. A second pop-up will appear, asking for a name and a directory. Enter the name that you want your mod to be listed as (with respect to the 'Source SDK' tool) and enter the path to your game directory ([Steam Root]\steamapps\SourceMods\MyPortalMod). Then select 'OK' for the second and first pop-ups. Assume we named our game configuration "My Portal Mod".

A screenshot showing configuration settings.

Restart the 'Source SDK' tool. Set 'Engine Version' and 'Current Game' to 'Source Engine 2009' and 'My Portal Mod', respectively. Now, select 'Hammer Editor'. In the editor, select Tools > Options. A 'Configure Hammer' pop-up should appear. Select the 'Game Configurations' tab and then hit the 'Add' button for 'Game Data Files'. Select the file portal.fgd and accept the changes. These configurations will be saved and restored the next time you open Hammer from the 'Source SDK' tool with your mod name selected.

See Also

• Portal mod template