Lightmapped 4WayBlend
Lightmapped_4WayBlend is the shader used to blend the vertices of a displacement surface between four different materials. It handles four at once by using mirrored sets of parameters with "2", "3", or "4" in their name.
The pattern of the blend is defined by Hammer's sculpt window blend tool (shown in the picture on the right). The texture preview in Hammer requires you to set up additional VMT files for each texture to show up in the dialog. Those are not used by the shader itself. Some of the features of this dialog are disabled when using 4WayBlend, they are used by the Multiblend material.
The blend can be tuned between being a linear gradient and a more realistic look using the luminance of each basetexture adjusted by parameters.
Note:This shader only works on displacements.Note:This shader is only available in 
Counter-Strike: Global Offensive as of January 2014. Example
Lightmapped_4WayBlend
{
"$basetexture" "de_cbble/stone_alt/brick_a"
"$bumpmap" "de_cbble/stone_alt/brick_a_normal"
"$basetexture2" "de_cbble/stone_alt/brick_a_damaged"
"$bumpmap2" "de_cbble/stone_alt/brick_a_damaged_normals"
"$texture2_uvscale" "[1.0 1.0]"
"$texture2_lumstart" "0.0"
"$texture2_lumend" "0.8"
"$texture2_blendstart" "0.8"
"$texture2_blendend" "0.9"
"$basetexture3" "de_cbble/stone_alt/brick_a_bottom_grime"
"$texture3_blendmode" "0"
"$texture3_uvscale" "[2.0 2.0]"
"$texture3_lumstart" "0.005"
"$texture3_lumend" "0.05"
"$texture3_blendstart" "0.8"
"$texture3_blendend" "1.0"
"$basetexture4" "de_cbble/stone_alt/brick_a_top_grime"
"$texture4_blendmode" "0"
"$texture4_uvscale" "[2.0 2.0]"
"$texture4_lumstart" "0.0"
"$texture4_lumend" "0.2"
"$texture4_blendstart" "0.90"
"$texture4_blendend" "0.99"
"$detail" "detail\noise_detail_01"
"$detailscale" "[ 20 20 ]"
"$detailblendfactor" ".7"
"$detailblendfactor2" ".4"
"$detailblendfactor3" ".2"
"$detailblendfactor4" ".2"
}
Supported effects
The effects supported by LightmappedGeneric plus:
$basetexture2$texture2_uvscale$texture2_lumstart$texture2_lumend$texture2_blendstart$texture2_blendend
$basetexture3$texture3_blendmode$texture3_uvscale$texture3_lumstart$texture3_lumend$texture3_blendstart$texture3_blendend
$basetexture4$texture4_blendmode$texture4_uvscale$texture4_lumstart$texture4_lumend$texture4_blendstart$texture4_blendend