This is a heightmap-based terrain node for Godot Engine 2.1, written in GDScript.

Simply select terrain, select vertex paint, choose a combo of colors, choose a brush and off you go.
You no longer need to manually select colors, there are now terrain type icons, simply select the icon and paint your terrain. Easy :) Optionally you can still paint blends of textures using the 5th button on the top row and the color picker if you like.