Hm, I just had a look through TF2's stock blending textures, and it appears most of them use bump mapping as well:
"WorldVertexTransition"
{
"$basetexture" "Nature/dirtground001"
"$basetexture2" "Nature/dirtground002"
"%tooltexture" "Nature/blendgroundtogravel001_tooltexture"
"$bumpmap" "Nature/dirtground001_height-ssbump"
"$bumpmap2" "Nature/dirtground002_height-ssbump"
"$blendmodulatetexture" "Nature/dirtground002_blendmask"
"%keywords" "tf"
"$ssbump" "1"
"$surfaceprop" "dirt"
}
I'll have to give that a go, it seems it should work fine like you said.
Edit: bleh, it didn't work. Here's what I did:
"WorldVertexTransition"
{
"$basetexture" "nature/rockwall003"
"$basetexture2" "snowvalley/snowground001"
"$bumpmap" "Nature/rockwall003_height-ssbump"
"$ssbump" "1"
"%tooltexture" "snowvalley/snowground001"
"%keywords" "blend"
}
I'm getting annoyed by this bloody thing...
Edit 2: Examining the texture from the line "$blendmodulatetexture" "Nature/dirtground002_blendmask", I'm starting to think it needs such a mask to blend bumpmapped textures... sigh.
Edit 3: Aaaaand I finally discovered that blending bump mapped textures requires DX9. Bummer.
Edit 4: DX9, no dice. This is becoming one hell of an issue. I need to sleep on it.