Skybox (2D)

From Valve Developer Community

In Source, the skybox is a series of six images, joined together to make a cube. The cube is then locked to the player's viewpoint and acts as the most distant area of a map, usually the sky. Because the skybox is fixed to the player's viewport, it never changes perspective, allowing the cube to appear as a seamless whole.

Contents 1 Adding sky to a map 2 Changing the displayed skybox 3 Skybox Lighting 4 Creating a Custom 2D Skybox Texture 5 Creating a 2D skybox for Goldsource, using Source 6 See also

Adding sky to a map

Simply texture a world brush (not a brush entity) with the tools/toolsskybox material.

In-game, the skybox will be seen through each surface that toolsskybox is applied to.

toolsskybox Brushes do not need to be box-shaped.

Changing the displayed skybox

If you don't like the standard "sky_day01_01" sky, you can change it by setting the skybox name in Hammer's Map Properties dialog. With the correct map opened, follow these steps:

1. Go to the Map menu
2. Choose Map Properties... from the drop down list
3. In the Object Properties window, select the Skybox Texture Name field.
4. Replace the sky listed there with the name of the skybox you wish to display.

Skybox Lighting

Skyboxlight is projected into the World from every toolsskybox surface, and represents Direct Sunlight (or Moonlight) and the Diffuse light reflected from overhead cloud, etc.

These lighting settings - direction, colour, brightness, etc are fairly specific to the actual image used for the 2D skybox. The Sky List article suggests some settings for some of Valve's skyboxes. Note also that env_fog_controller settings will look wrong if they don't correspond to the particular skybox used.

Skybox Lighting enters the Map through every toolsskybox-textured Brush.

• Its basic properties are controlled by three Entities used in combination: light_environment defines (a) the color and intensity of the Diffuse Skylight and (b) the direction, color and intensity of the Direct Sunlight. It also creates (buggy, unconfigurable) Dynamic Shadows which can only be overridden/controlled by the shadow_control Entity. env_sun places a glow sprite in the skybox to represent the Sun's apparent position in the sky. To make sense of it all, just make sure you have only one of each of these entities in your map, and that the Pitch and Yaw <angles> are set the same for all three of them. (Pitch is equivalent to the Sun's Angle of Elevation from the ground, and Yaw is its Compass Bearing.)
• The Sky List article suggests some settings for some of Valve's skyboxes. The worldspawn Entity defines which skybox to use. Note also that env_fog_controller settings will look wrong if they don't correspond to the particular skybox in use.
  

Creating a Custom 2D Skybox Texture

These are instructions on how to create custom (i.e., not default) skybox textures.

1. Prepare your image files (i.e. skynameBK.tga, skynameFT.tga, skynameUP.tga, skynameDN.tga, skynameRT.tga, skynameLF.tga)
2. Convert them to VTF
3. Create a VMT's with the textures' desired names (which should be the same as the VTF's) containing:

"sky"
{
	
	"$hdrcompressedTexture" "skybox/<filename>"	
	"$nofog" "1"
	"$ignorez" "1"
	"$basetexture" "skybox/<filename>"
}

• Replace <filename> with the name of the file, and remember to append the appropriate suffix to the sky name (i.e. bk, ft, rt, lf, up, dn)
• Now go into your mod's materials folder and create the folder skybox.
• Copy your new VTF and VMT files into the skybox folder.
• In Hammer, go to Map > Map Properties > Skybox Texture Name and type in your skyname, without the side tags.

Creating a 2D skybox for Goldsource, using Source

It is possible to create an area of your map into a 2D Skybox to be used in Goldsource (the HL1-engine). Here's an simple example:

1. Create a large outdoor area with some displacement maps and treelines, and fog to hide the edges. Lets call it carrotjuice .
2. Load the map ingame and turn cheats on ( sv_cheats 1 ).
3. Activate the noclip-mode by simply opening the console and enter "noclip" and hit Enter.
4. Fly to the center of where you want the skybox.
5. Open up the console and type "mat_envmaptgasize 256", hit Enter.
6. Now type "envmap" and press Enter. Now, 6 TGA-files are now created and saved into a folder named "cubemap_screenshots" in your modfolder ( i.e. for HL2DM: Steam\SteamApps\youraccount\Half-Life 2 Deathmatch\hl2mp ).

Since the mapname was carrotjuice , the name of the 6 TGA-files are as following:

carrotjuicert.tga (Right)
carrotjuiceft.tga (Front)
carrotjuicelf.tga (Left)
carrotjuicebk.tga (Back)
carrotjuiceup.tga (Up)
carrotjuicedn.tga (Down)

You can now copy or move these to your HL1-mods gfx\env-folder, to use it as skybox in a level.

See also

• light_environment, env_sun and shadow_control entities define the skybox lighting settings, which are emitted from the toolsskybox texture into the map.
• Sky List

Environment articles:
Skies and environment maps	Skybox (2D) • Skybox (3D) • HDR Skies • Skybox with Terragen • Skybox with Terragen - Advanced • List of skies
Terrain and displacement mapping	Displacements • Holes in displacements • Digital Elevation Models