TheBeely: I am trying to break the silence on this issue. Nobody ever talks about texture splatting on here, which I find strange considering that this is a method that most commercial games use. There are a lot of people who are way better at this stuff than I am, and I'm hopeing to see how other people have approached this in DBPro.
Dream And Death: You should check out my shader. Even if you don't want to use it (it's far from perfect, but it works) it may give you some ideas. Here's how it's used:
In DB, load the fx file and set some options
load effect "mt3a.fx",1,0
`the "layers" variable tells the shader how many layers you plan on using (the base texture counts as a layer)
set effect constant integer 1,"layers",4
`the "texScale" variable controls how many times the textures are tiled across the object
set effect constant float 1,"texScale",50.0
Load your terrain object. If your terrain is one large object then you may have to split it up, as the shader dosen't seem to be able to render really large objects.
Texture the object. The layers should go as follows:
layer 0 - lightmap
layer 1 - base texture
layer 2 - layer 2 alpha map
layer 3 - layer 2 texture
layer 4 - layer 3 alpha map
layer 5 - layer 3 texture
layer 6 - layer 4 alpha map
layer 7 - layer 4 texture
If you do not have a lightmap, you can simply texture layer0 with a white image, or you can change the technique to "mt3a" (the default is "mt3aLM"). If you only wanted to use...say...the base texture and one alpha layer you would have to change the "layers" variable to 2.
After that you just set the effect like so:
set object effect objnum,1
The fx file is attached to this post.