This is a simple 2 dimensional, elastic particle simulator, written for funand to learn Rust. It comes with a simple script to run the simulation and generate a gif of the result using gnuplot.
The simulation is exact (to within floating point error and as far as I've been
able to confirm), not relying on error-prone timestep-based physics
simulations. As a result, it is quite efficient: it only performs the necessary
O(N^2) collision checks once per collision (not per timestep), and its memory
footprint is at most 2 vectors containing N particles. On the other hand, due
to its reliance on geometric formulas, it is not easily extensible to higher
dimensionality nor non-spherical particles, as this would require deriving and
implementing the higher dimensional forms.
To run the default simulation and generate a gif, do:
$ ./run.sh test1
Output in tmp/test1.(gif|dat|log)
which will generate a gif like this:
Note: gnuplot seems to be unable to create circles of precise sizes, which leads to the appearance of overlapping particles. I verified this by adding checks in the code that logs collisions and erroneous states.
You must have gnuplot installed (I used version 5.0), with the correct libraries to generate gifs.
This was easy enough with brew, but YMMV.