Skybox Last edited 1 month ago2024-03-02 23:44:39 UTC

In GoldSrc, a skybox is a set of 6 textures that wraps around an inverted box. In game, wherever you place SKY texture will be rendered in its place a skybox, which is static relative to the player i.e. moving around the map doesn't shift the perspective of the skybox textures in any way.

The files for skyboxes for Half-Life and mods can be found by looking in the gfx/env/ folder relative to the game/mod folder. For legacy WON installations, you could find them inside the pak#.pak files (where # is a number) which you can open with any software that is capable of reading Quake PAKs files like PAKScape. As each skybox is composed of 6 textures, the files are appropriately suffixed with the respective sides: ft - front, bk - back, rt - right, lf - left, up - up, dn - down.

The actual texture shown in game is controlled by the Map Properties setting Environment Map (cl_skyname). The name should be same as one of the texture sets in the gfx/env/ without the suffixes (any underscore between the name and the suffix can be omitted too.) The default is desert.

Custom skies can be added by adding the file set to the gfx/env/ folder and then selected in the map properties before compiling. Each file in the set should be in 24-bit TGA file format and 256×256px in size. While BMP files are also supported they are of the lower fidelity 8-bit kind to support older video cards of the 1990s, and thus no longer relevant in the 2020s.

To have part of the map render the skybox, texture the brushes with the SKY texture as mentioned earlier.

3D Skybox

The term 3D skybox can mean two things:

1. A regular skybox whose textures are generated using a 3D terrain generation software, or
2. Another projection layer in which a miniature landscape (usually 1:16 the size) placed in an unreachable, far away corner of the level, gets projected into the playable areas of the level, similar to SKY but the projection shifts appropriately to match the player's position in the level.

The latter is a feature in the Source engine. Some GoldSrc mods like Spirit of Half-Life also supports but they usually require a particular set of configurations.

See also

• Pages on Half-Life Skies on 69th Vlatitude and RUST archives
• Tutorial: Custom Skyboxes for Goldsource