Up to 1 million particles at your fingertips, including gravity simulation.
Chose any number of particles between 10000 and 1 million. Optimized for quad core CPUs, on mid end devices you can get over 10 FPS with 1 million particles on screen. You can move them with your fingers (the brush size is pressure sensitive, if your device supports it), and/or you can set attractors that will attract or repulse the particles. You can set up as many attractors as you want, so long as the number is under 50.
You can also use pinch to zoom (in and out) and shake the phone on two axis to scatter the particles.
To get to the main menu, just press the "back" button.
The entire program is written in C, using SDL2, so it is quite fast. If there is enough interest, I will also provide a desktop version and I'll add new features.
The reading storage permission is needed by SDL2 in order to be able to load/save the configuration.
Update (14th January 2018). I decided to release the source code, you can find it here: https://github.com/raduprv/1-million-particles