Normally you do use distance and camera location.
If you want to make your material.perfrom well you will also make a hard UV line at about 10 or 20m from the camera locatiom and only add an extra twxture sample to cover this hard line.
The formula is all derived from WPO and Camera placed into a distance node.
Or you can get the vector lenght and do math your self, but the distance node is the same.
Subtract the distance you want the line to be at. Make it a scalar and play with the material instance.
Then, since I want my mask to move with it, I use that distance ± an offset to create the area where the other texture is blended upon.
Other things that I Used to think were good but aren’t is additional samples.
Let’s be 100% clear. An unotimized landscape plus a bad material can eat up to 50ms.
the first thing you should do is to make sure that the landacape you are using with no material on isn’t running your frame cost above the 8ms.
if it is, you need to balance the LODs (which with the new system since .19 it kinda sucks but it can be done).
After that your landscape material really only needs 2 textures. A diffuse and a normal.
you pack whatever you want in their alpha channels.
For roughness and specularity you can play with one of the channel results off the diffuse.
Its not the same as using the proper texture… though I suppose with very minimal diffuse change you could replace the real texture into the most similar looking channel.
the problem doing that is that it may not always be the same pin. So avoid it and standardize it by using the same pin to derive somewhat similar information.
the alpha channels normally contain displacement, or an alpha.
I use the alpha off the normal as an alpha mask to blend grass colors and match the landscape, for instance.
After a few weeks of tweaking the result is a scene (mind you just landscape, grass, and athmosphere/light) running above 80fps on a 1080ti at 4k.
introducing an extra packed texture into the mix takes it down below 60fps, so the cost is Very high compared to the quality of the result.