Write an interactive visualization for a galaxy collision simulation

This week wasn’t super productive but I did spend some time on a bit of a tangent looking at the sim code itself rather than the visualisation part. I continued with Cherno’s OpenGL series so that was good but I also revisitied the Barnes Hutt alg to try work out why it was giving different results. I think I have identified the discrepancy but it’s a bit concerning as it’s basically to do with the order of adding large/small numbers together, specifically floats, which is a known problem but honestly using doubles shouldn’t be an issue, so this is a problem, to be continued…

I don’t know if I’ll learn enough OpenGL before the end of DK30 to get the visualisation up but I’m definitely taking forward steps!

Also for some context, as mentioned this simulation already works (though the Barnes Hutt alg is still buggy) and it is possible to do visualisations, just not super nice ones. An example of two Plummer spheres (balls of stars) done with the existing code can be found here

https://www.dropbox.com/s/qb2e9uv49lgp52n/large_sim.MP4?dl=0

So i’ve got the imGUI stuff compiling better but I got lost down a rabbit hole of trying to understand why a parallel (via openmp) part of my code wasn’t working (notably trying to use the symmetry of Newtonian force to save some cycles but I was getting a different answer when I increased the number of threads, was quite odd, no obvious race conditions occuring). In the end I think it’s best to not be a dog with a bone, put that on the back burner, and get back to the task at hand. So I will be dumping the old code on a separate archive branch and begin some basic tidying up of the code in preparation for better visualization. In order to do said visualisation I plan to get through as much of Cherno’s OpenGL series as I can this week, which I think culminates in batch rendering which will definitely be useful when I have thousands of particles!