Great, thanks for sharing!
You should probably add it to wiki.
I'll share my notepad++ configuration:
Code:
<NotepadPlus>
<UserLang name="Horde3D" ext="vert frag geom tesc tese v f g shader" udlVersion="2.1">
<Settings>
<Global caseIgnored="no" allowFoldOfComments="yes" foldCompact="no" forcePureLC="0" decimalSeparator="0" />
<Prefix Keywords1="no" Keywords2="no" Keywords3="no" Keywords4="yes" Keywords5="no" Keywords6="no" Keywords7="no" Keywords8="no" />
</Settings>
<KeywordLists>
<Keywords name="Comments">00// 01 02 03/* 04*/</Keywords>
<Keywords name="Numbers, prefix1"></Keywords>
<Keywords name="Numbers, prefix2"></Keywords>
<Keywords name="Numbers, extras1"></Keywords>
<Keywords name="Numbers, extras2"></Keywords>
<Keywords name="Numbers, suffix1"></Keywords>
<Keywords name="Numbers, suffix2"></Keywords>
<Keywords name="Numbers, range"></Keywords>
<Keywords name="Operators1">- ! ( ) , . ; [ ] + < = ></Keywords>
<Keywords name="Operators2"></Keywords>
<Keywords name="Folders in code1, open">{</Keywords>
<Keywords name="Folders in code1, middle"></Keywords>
<Keywords name="Folders in code1, close">}; }</Keywords>
<Keywords name="Folders in code2, open"></Keywords>
<Keywords name="Folders in code2, middle"></Keywords>
<Keywords name="Folders in code2, close"></Keywords>
<Keywords name="Folders in comment, open"></Keywords>
<Keywords name="Folders in comment, middle"></Keywords>
<Keywords name="Folders in comment, close"></Keywords>
<Keywords name="Keywords1">attribute const uniform varying buffer shared
coherent volatile restrict readonly writeonly
struct
layout
centroid flat smooth noperspective
patch sample
break continue do for while switch case default 
if else
subroutine
in out inout
true false
invariant
discard return

lowp mediump highp precision
std140 std430 packed binding

context [[FX]] compile</Keywords>
<Keywords name="Keywords2">sampler1D sampler2D sampler3D samplerCube
sampler1DShadow sampler2DShadow samplerCubeShadow
sampler1DArray sampler2DArray
sampler1DArrayShadow sampler2DArrayShadow
isampler1D isampler2D isampler3D isamplerCube
isampler1DArray isampler2DArray
usampler1D usampler2D usampler3D usamplerCube
usampler1DArray usampler2DArray
sampler2DRect sampler2DRectShadow isampler2DRect usampler2DRect
samplerBuffer isamplerBuffer usamplerBuffer
sampler2DMS isampler2DMS usampler2DMS
sampler2DMSArray isampler2DMSArray usampler2DMSArray
samplerCubeArray samplerCubeArrayShadow isamplerCubeArray usamplerCubeArray
image1D iimage1D uimage1D
image2D iimage2D uimage2D
image3D iimage3D uimage3D
image2DRect iimage2DRect uimage2DRect
imageCube iimageCube uimageCube
imageBuffer iimageBuffer uimageBuffer
image1DArray iimage1DArray uimage1DArray
image2DArray iimage2DArray uimage2DArray
imageCubeArray iimageCubeArray uimageCubeArray
image2DMS iimage2DMS uimage2DMS
image2DMSArray iimage2DMSArray uimage2DMSArray
atomic_uint
mat2 mat3 mat4 dmat2 dmat3 dmat4
mat2x2 mat2x3 mat2x4 dmat2x2 dmat2x3 dmat2x4
mat3x2 mat3x3 mat3x4 dmat3x2 dmat3x3 dmat3x4
mat4x2 mat4x3 mat4x4 dmat4x2 dmat4x3 dmat4x4
vec2 vec3 vec4 ivec2 ivec3 ivec4 bvec2 bvec3 bvec4 dvec2 dvec3 dvec4 float double int void bool 
uint uvec2 uvec3 uvec4
x y z w xy xyz xyzw r g b a rgb rgba s t p q st stp
points triangle_strip max_vertices

float4
Wrap Clamp None Bilinear Trilinear Always Equal Less LessEqual Greater GreaterEqual Replace Blend Add AddBlended Mult Back Front </Keywords>
<Keywords name="Keywords3">#
#define
#undef
#if
#ifdef
#ifndef
#else
#elif
#endif
#error
#pragma
#extension 
#version 
#line
#include</Keywords>
<Keywords name="Keywords4">gl_NumWorkGroups
gl_WorkGroupSize
gl_WorkGroupID
gl_LocalInvocationID
gl_GlobalInvocationID
gl_LocalInvocationIndex
gl_VertexID
gl_InstanceID
gl_PerVertex 
gl_Position
gl_PointSize
gl_ClipDistance
gl_in
gl_PrimitiveIDIn
gl_InvocationID
gl_Layer
gl_ViewportIndex
gl_PatchVerticesIn
gl_InvocationID
gl_out
gl_TessLevelOuter
gl_TessLevelInner
gl_PatchVerticesIn
gl_PrimitiveID
gl_TessCoord
gl_FragCoord
gl_FrontFacing
gl_ClipDistance
gl_PointCoord
gl_PrimitiveID
gl_SampleID
gl_SamplePosition
gl_SampleMaskIn
gl_Layer
gl_ViewportIndex
gl_FragDepth
gl_SampleMask</Keywords>
<Keywords name="Keywords5">gl_MaxComputeWorkGroupCount
gl_MaxComputeWorkGroupSize
gl_MaxComputeUniformComponents
gl_MaxComputeTextureImageUnits
gl_MaxComputeImageUniforms
gl_MaxComputeAtomicCounters
gl_MaxComputeAtomicCounterBuffers
gl_MaxVertexAttribs
gl_MaxVertexUniformComponents
gl_MaxVaryingComponents
gl_MaxVertexOutputComponents
gl_MaxGeometryInputComponents
gl_MaxGeometryOutputComponents
gl_MaxFragmentInputComponents
gl_MaxVertexTextureImageUnits
gl_MaxCombinedTextureImageUnits
gl_MaxTextureImageUnits
gl_MaxImageUnits 
gl_MaxCombinedImageUnitsAndFragmentOutputs
gl_MaxImageSamples
gl_MaxVertexImageUniforms
gl_MaxTessControlImageUniforms
gl_MaxTessEvaluationImageUniforms
gl_MaxGeometryImageUniforms
gl_MaxFragmentImageUniforms
gl_MaxCombinedImageUniforms
gl_MaxFragmentUniformComponents
gl_MaxDrawBuffers
gl_MaxClipDistances
gl_MaxGeometryTextureImageUnits
gl_MaxGeometryOutputVertices
gl_MaxGeometryTotalOutputComponents
gl_MaxGeometryUniformComponents
gl_MaxGeometryVaryingComponents
gl_MaxTessControlInputComponents 
gl_MaxTessControlOutputComponents 
gl_MaxTessControlTextureImageUnits 
gl_MaxTessControlUniformComponents 
gl_MaxTessControlTotalOutputComponents 
gl_MaxTessEvaluationInputComponents 
gl_MaxTessEvaluationOutputComponents 
gl_MaxTessEvaluationTextureImageUnits 
gl_MaxTessEvaluationUniformComponents 
gl_MaxTessPatchComponents 
gl_MaxPatchVertices 
gl_MaxTessGenLevel 
gl_MaxViewports 
gl_MaxVertexUniformVectors 
gl_MaxFragmentUniformVectors 
gl_MaxVaryingVectors 
gl_MaxVertexAtomicCounters 
gl_MaxTessControlAtomicCounters 
gl_MaxTessEvaluationAtomicCounters 
gl_MaxGeometryAtomicCounters 
gl_MaxFragmentAtomicCounters 
gl_MaxCombinedAtomicCounters 
gl_MaxAtomicCounterBindings 
gl_MaxVertexAtomicCounterBuffers 
gl_MaxTessControlAtomicCounterBuffers 
gl_MaxTessEvaluationAtomicCounterBuffers 
gl_MaxGeometryAtomicCounterBuffers 
gl_MaxFragmentAtomicCounterBuffers 
gl_MaxCombinedAtomicCounterBuffers 
gl_MaxAtomicCounterBufferSize 
gl_MinProgramTexelOffset 
gl_MaxProgramTexelOffset</Keywords>
<Keywords name="Keywords6">radians
degrees
sin
cos
tan
asin
acos
atan
sinh
cosh
tanh
asinh
acosh
atanh
pow
exp
log
exp2
log2
sqrt
inversqrt
abs
sign
floor
trunc
round
roundEven
ceil
fract
mod
modf
min
max
clamp
mix
step
smoothstep
isnan
isinf
floatBitsToInt
floatBitsToUInt
intBitsToFloat
uintBitsToFloat
fma
frexp
ldexp
packUnorm2x16
packSnorm2x16
packUnorm4x8
packSnorm4x8
unpackUnorm2x16
unpackSnorm2x16
unpackUnorm4x8
unpackSnorm4x8 
packDouble2x32
unpackDouble2x32
packHalf2x16
unpackHalf2x16
length
distance
dot
cross
normalize
faceforward
reflect
refract
matrixCompMult
outerProduct
transpose
determinant
inverse
lessThan
lessThanEqual
greaterThan
greaterThanEqual
equal
notEqual
any
all
not
uaddCarry
usubBorrow
umulExtended
imulExtended
bitfieldExtract
bitfieldInsert
bitfieldReverse
findLSB
bitCount
findMSB
textureSize
textureQueryLod
textureQueryLevels
texture
textureProj
textureLod
textureOffset
texelFetch
texelFetchOffset
textureProjOffset
textureLodOffset
textureProjLod
textureProjLodOffset
textureGrad
textureGradOffset
textureProjGrad
textureProjGradOffset
textureGather
textureGatherOffset
textureGatherOffsets
texture1D 
texture1DProj
texture1DLod
texture1DProjLod
texture2D
texture2DProj
texture2DLod
texture2DProjLod
texture3D
texture3DProj
texture3DLod
texture3DProjLod
textureCube
textureCubeLod
shadow1D
shadow2D
shadow1DProj
shadow2DProj
shadow1DLod
shadow2DLod
shadow1DProjLod
shadow2DProjLod
atomicCounterIncrement
atomicCounterDecrement
atomicCounter
atomicAdd
atomicMin
atomicMax
atomicAnd
atomicOr
atomicXor
atomicExchange
atomicCompSwap
imageSize
imageLoad
imageStore
imageAtomicAdd
imageAtomicMin
imageAtomicMax
imageAtomicAnd
imageAtomicOr
imageAtomicXor
imageAtomicExchange
imageAtomicCompSwap
dFdx
dFdy
fwidth
interpolateAtCentroid
interpolateAtSample
interpolateAtOffset
noise1
noise2
noise3
noise4
EmitStreamVertex
EndStreamPrimitive
EmitVertex
EndPrimitive
barrier
memoryBarrier
memoryBarrierAtomicCounter
memoryBarrierBuffer
memoryBarrierShared
memoryBarrierImage
groupMemoryBarrier</Keywords>
<Keywords name="Keywords7">VertexShader PixelShader GeometryShader ComputeShader TessEvalShader TessControlShader ZWriteEnable ZEnable ZFunc BlendMode CullMode AlphaToCoverage TessPatchVertices
Texture TexUnit Address Filter MaxAnisotropy Usage</Keywords>
<Keywords name="Keywords8"></Keywords>
<Keywords name="Delimiters">00" 01 02" 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23</Keywords>
</KeywordLists>
<Styles>
<WordsStyle name="DEFAULT" fgColor="242424" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="COMMENTS" fgColor="008040" bgColor="FFFFFF" fontName="" fontStyle="2" nesting="0" />
<WordsStyle name="LINE COMMENTS" fgColor="008040" bgColor="FFFFFF" fontName="" fontStyle="2" nesting="0" />
<WordsStyle name="NUMBERS" fgColor="8000FF" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="KEYWORDS1" fgColor="0080FF" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="KEYWORDS2" fgColor="408080" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="KEYWORDS3" fgColor="C46200" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="KEYWORDS4" fgColor="8080FF" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="KEYWORDS5" fgColor="000000" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="KEYWORDS6" fgColor="FF8040" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="KEYWORDS7" fgColor="0000FF" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="KEYWORDS8" fgColor="000000" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="OPERATORS" fgColor="242424" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="FOLDER IN CODE1" fgColor="000000" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="FOLDER IN CODE2" fgColor="000000" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="FOLDER IN COMMENT" fgColor="000000" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="DELIMITERS1" fgColor="808000" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="32769" />
<WordsStyle name="DELIMITERS2" fgColor="363636" bgColor="FFFFFF" fontName="" fontStyle="7" nesting="0" />
<WordsStyle name="DELIMITERS3" fgColor="000000" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="DELIMITERS4" fgColor="000000" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="DELIMITERS5" fgColor="000000" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="DELIMITERS6" fgColor="000000" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="DELIMITERS7" fgColor="000000" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
<WordsStyle name="DELIMITERS8" fgColor="000000" bgColor="FFFFFF" fontName="" fontStyle="0" nesting="0" />
</Styles>
</UserLang>
</NotepadPlus>
Just import it in user defined languages dialog.
P.S. Maybe rename this thread to something like "Horde3D Shader Syntax Highlighting" and stick it? And use this thread for sharing of highlighting methods in different editors?