Sky (Source 1 shader)

Source Engine

Source 2

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Sky is a shader for materials in Source meant for 2D skyboxes. The old method of making skyboxes before Source 2007 involved using the UnlitGeneric shader with $ignorez 1. This shader expands the amount of usable parameters and also allows for HDR skyboxes.

Tip:(in all games since ) $basetexture is not necessary for games that are HDR-only, as only the $hdrbasetexture or $hdrcompressedtexture will be used.

Note:This shader always ignores fog. Skyboxes with UnlitGeneric (and without $nofog 1 are affected by fog.

Warning:The Counter-Strike 2 import script doesn't like $hdrcompressedtexture; change it to $basetexture, then decompress to  EXR with no_vtf and use that instead^[Clarify].

Warning:While rare, mat_fullbright set to 1 might sometimes break the rendering of this shader.

With an uncompressed HDR skybox texture

If the skybox texture uses uncompressed BGRA16f16f16f16f, then the VMT should look something like this:

sky
{
	$basetexture skybox/sky_wasteland_00up // Sky texture to use for LDR
	$hdrbasetexture skybox/sky_wasteland_00_hdrup // Uncompressed HDR Sky texture to use for HDR-enabled maps
	$nofog 1
	$ignorez 1
	$nomip 1
}

With a compressed HDR skybox texture

If the skybox has been compressed using BGRA8888, then $hdrcompressedtexture should be used instead:

sky
{
	$basetexture skybox/sky_wasteland_00up // Sky texture to use for LDR
	$hdrcompressedtexture skybox/sky_wasteland_00_hdrup // Compressed HDR Sky texture to use for HDR-enabled maps
	$nofog 1
	$ignorez 1
	$nomip 1
}

Todo: Figure out what the "HDR compression method B" mentioned in sky_hdr_dx9.cpp does differently, as it asks for $hdrcompressedtexture0, $hdrcompressedtexture1, and $hdrcompressedtexture2 instead of a single $hdrcompressedtexture.

Without an HDR skybox texture

If an HDR version of the skybox texture is not available, $hdrbasetexture can use the same VTF as $basetexture:

sky
{
	$basetexture skybox/sky_wasteland_00up // Sky texture to use for LDR
	$hdrbasetexture skybox/sky_wasteland_00up // Sky texture to use for HDR, if the texture has NOT been specifically compiled for HDR
	$nofog 1
	$ignorez 1
	$nomip 1
}

Issues

This article or section needs to be cleaned up to conform to a higher standard of quality because:

See HDR Skybox Creation for better explanation of when $basetexturetransform may be necessary.

For help, see the VDC Editing Help and Wikipedia cleanup process. Also, remember to check for any notes left by the tagger at this article's talk page.

You might find that skyboxes sometimes fit the entire projection area of a level. To re-scale the material to fit, use $basetexturetransform or add the following line:

	$basetexturetransform "center 0 0 scale 1 2 rotate 0 translate 0 0" // For cutting off the bottom halves of the skybox

The scale 1 2 segment will maintain the fill-sizing of the X-axis, while locking the texture to the center line of the Y-axis (i.e. the absolute horizon line).