.RES File Extension

RES files became prevalent in 1998 with the release of Half-Life, which was the first title from Valve Software. The files were used to store locations of resources instead of the resources themselves to reduce download times. When playing a game, such as Half-Life, the RES file is referenced by the game if the player is playing a custom map then downloads the resources, making them playable within the game.

But as download speeds have increased, new resource formats have been released, and the game engine evolved, actual RES files have become less common. Now, RES files are typically embedded into the map files they are associated with, using BSPZIP, a command-line tool. However, if a map with embedded resource lists cannot be accepted, the RES file can be used.

If the BSP map is incorrectly loaded by the game, it is most likely due to a typo in one or more of the resource paths. You can use a text editor to view and edit the RES file.

NOTE: In order for a RES file to be recognized by a game, it must be placed in the \​maps folder with the BSP map it is associated with and must also bear the same name as the BSP map.

The Microsoft Resource Compiler is a tool that developers use to compile and package various program resources, such as icons, cursors, menus, and dialog boxes. Developers can then link the compiled resources into their program's executable file using their chosen C++ linker. This allows the program to access and load those resources.

To compile resources with Microsoft Resource Compiler, developers first create an RC file. This file is a plain text script that defines the resources the associated program uses. Typically, RC files contain references to several resource files, such as .CUR cursor files and .ICO icon files. (RC files may also contain resources defined entirely within the files themselves, using plain text.)

Developers then use Microsoft Resource Compiler to compile their RC file to a RES file. The resulting RES file contains not only a compiled version of the RC file, but also a compiled version of all the resources the RC file references. Developers can also use Microsoft Resource Compiler to link their RES file to their application's EXE file.

NOTE: Microsoft Resource Compiler is included as part of Microsoft Visual Studio and the Microsoft Windows Software Development Kit (SDK).

In most cases, RES files are not meant to be opened. However, you can use Resource Hacker (Windows) to decompile a RES file, allowing you to view and edit the resources it contains.

In Godot Engine, RES resource files are the binary version of .TRES resource files, which are saved in plain text. The TRES format allows developers to more easily control resource versions. When a developer exports the game, Godot Engine converts the TRES files to RES binary files to reduce their size and increase the efficiency of the game package.