This is a tool based on the Godot game engine that can be used to create textures procedurally. It can also be used as a Godot addon (but there's no good reason for not using it as a standalone tool).
Its user interface is based on Godot's GraphEditor: textures are described as interconnected texture generators and operators.
More details in the [user manual](https://rodzill4.github.io/godot-procedural-textures/doc/).
![Screenshot](addons/procedural_material/doc/images/screenshot.png)