Feature requests for Paint Texture

Apart from the Paint Texture being a dedicated menu button, because it has got nothing in common with all the other terrain menu items which modify the height, it would be awesome if Paint Texture got extended with filters.

Ones which come to mind:

* limit texture painting to a height interval (e. g. for snow on mountains)
* limit texture painting depending on concavity
* filter by noise

Thank you very much for the consideration.