$lightwarptexture
$lightwarptexture
(DX9+ SM3) is a material shader parameter for the VertexLitGeneric shader available in all Source games since Source 2006. It tints texels depending on their brightness. It can be thought of as localized color correction.
Caveats
$lightwarptexture
must be specified after all other textures, otherwise it will overwrite them.$lightwarptexture
on VertexLitGeneric requires a $bumpmap. If not specified, a default one will be used instead! It will be as if a $bumpmap is in the VMT!
$lightwarptexture
.
- $detailblendmode 5-9 won't work - 5 & 6 will work when $phong is used.
- $envmapmask won't work, except in Mapbase.
- $selfillum_envmapmask_alpha doesn't work in any branch.
$lightwarptexture
does not seem to exist at all for LightmappedGeneric in CS:GO engine branch.Lightwarp textures
A lightwarp texture is a one-dimensional strip of pixels. Dark texels will be tinted with the colour on the left-hand side, and bright texels with the colour on the right. 50% gray means no tint.
$lightwarptexture
on a brush or displacement will appear as if lightwarp were not present, whereas the same $lightwarptexture
on a model with no phong would result in the model being lit uniformly (like GoldSrc flatshade texture mode.VTF parameters
A lightwarp texture should use uncompressed BGR888 format to avoid undesired color banding on lighting gradients[1], and should be UV clamped.
If using VTEX, use these compile parameters:
nocompress 1 // disable texture compression, to prevent undesired color banding nomip 1 // disable mipmaps, which are unnecessary in this instance nolod 1 // always use the full resolution version of this texture (due to being low-resolution to begin with) clamps 1 // prevent tints at lighting extremes from blending together clampt 1 // optional? stripalphachannel 1 // remove unnecessary alpha channel, if present
Examples
ground/snow_warp.vtf
()- This is the lightwarp texture used in the Day of Defeat: Source screen above. It is designed to add a subtle bluish tint to darker snow without affecting brighter regions.
models/player/pyro/pyro_lightwarp.vtf
()- This is applied to all Team Fortress 2 characters, not just the Pyro. It creates the high-contrast shadows with red-tinged terminators typical of the illustrative art the game apes.
- Posterized (custom)
- This custom warp texture creates a posterized "line art" style. Enabling lightwarp alone isn't enough however: ambient lighting must be at 0 to make unlit areas black, and world lighting must become viewer-dependent to ensure that shadows are always cast.
- Cel Shading (custom)
- Cel shading can make objects look more cartoony by replacing the smooth lighting gradient with sharp steps.
Other possible uses of $lightwarptexture
include contrast enhancement, tweaking vertex lighting shadow transitions, highlight softening, and more.