PAINTicle is a Blender add-on, that allows texture painting with particle systems.
To install the add-on grab a release from GitHub's releases
page. The downloaded zip file can be installed via Edit > Preferences > Add-ons > Install...
This add-on makes use of the python module moderngl under the MIT license. This module should be installed automatically when activating the add-on. The preferences panel shows a successful installation by showing a blue/checked button "Install dependencies". If the dependencies are not available, this button will be clickable gray and it can trigger the installation of the dependencies.
The add-on requires a GPU capable of OpenGL 4.3, which provides support for compute shaders. This is a higher level
than Blender requires. It might be, that your system can run Blender, but it can't support this add-on. Please advice
Blenders system information Help > Save System Info if your system supports at least the required version.