Thank you for your reply.
I checked the the threads of the last 2 months (or even more) before posting this and haven’t found something. It’s very likely that I missed it.
I had a similiar approach to what’s in your tutorial with using stencil maps.
But the problem pops up the moment you want to have more than two textures.
Let’s say I use three textures; gras, dirt and sand.
I could use the gras as underlay texture which fills up the whole area.
Then I would add a stencil map which overlays it with the dirt texture.
Now when I want to have dirt I modify this stencil map and paint white areas on it, or when I want to have gras again I paint those areas black.
Now I add the sand texture which overlays the gras and the dirt.
When I want to have dirt somewhere but there is already sand, then I need to open the stencil map for sand and remove those areas, and after that I would need to open the dirt stencil map and paint the areas where I want to have the dirt.
This method would take way too long and is a hassle to work with, especially on making the final touch.
Then an idea struk me and I thought it would be a solution, but I was wrong.
I thought about making a node network and substract one stencil map from the others and vice versa. So this way it would work like it does in some editors. When I paint on the dirt stencil map and hit an area with sand on it, it would automatically substract it from the sand stencil map.
But here comes the part why it wouldn’t work. On the material node screen I would get it to work, but I have no way on outputting it as a texture (stencil map).
So obviously I need to do it on the texture node screen which would work fine, but Blender doesn’t allow to have the texture you are node networking in the be used as input (a red texture with white line appears instead).
And this is the point where I’m stuck now.
But I never worked with nodes before, so hopefully someone knows a nice trick to it to make it work.