As part of the core Plasma team I have spent a long time helping in the migration to make everything QtQuick2.0 based, making sure we get the most out of the OpenGL backing.
This weekend I wanted to make some sort of demo which shows the power of this in the form of an interactive wallpaper.
Clicking on the desktop simulates a firework at that location. Frantic clicking will simulate the entirety of November the 5th (or July the 4th for people across the pond). When not active the whole thing only uses as much resources as any regular static wallpaper.
Download the complete zipfile here.
Install with the command line
plasmapkg2 -t wallpaperplugin -i fireworks.zip
Then under "Desktop Settings" change the wallpaper type to "fireworks".
Realistically this isn't something that would ever go in the default desktop installation. However by getting good at silly initiatives, we build and optimise for useful things; smooth subtle animations and shadows where it's actually useful.
The actual source code is fairly straightforward.
The QML Particle system is very much like the particle system found in Blender (The main similarity being that I don't understand how to use the particle system in Blender) with emitters and affectors.
In this case a circular emitter forms the base of the firework emitting a burst of coloured particles in all directions; a trail emitter then follows each coloured particles emitting a spread of small white particles to create a sparkly trail effect.