Week 2 progress update

Here is the first weekly update. This is for the previous week, 7-11 Nov 2022.

BTW, I’ll be numbering weeks from the 31st of October 2022, the day I started working full-time on this project.

I started the week working on creating assets for the ladder paradox demo. I spent some time dealing with problems with coordinate transformations, which I chose unwisely a long time ago. In particular, I created assets outside the game, choosing arbitrary lengths, etc. It turns out this is a bad idea when you want the assets to be part of the same scene. The Blender Guru explains it well here https://youtu.be/R1-Ef54uTeU?t=781. I wish I had watched his video sooner.

I worked on analytic positioning of bodies in SR and classical mechanics. The idea is to move a body so it has a desired final position and final velocity by applying a constant force (uniform acceleration.) This turned out to be more complicated than I expected. It is a non-trivial problem even in classical mechanics and requires two distinct subsequent uniform accelerations. I plan to write a blog on the solutions for the classical case and the SR case.

I have also worked on adjusting the engine to improve its suitability for recording videos. In particular, I added a headless mode that fixes the timestep and does not care about missing the display’s VSYNC. This will be useful for rendering videos and controlling the frame-rate. In fact, I created my first video of an SDF scene using my game engine, which I share with this post.

However, I drifted a bit on refactoring the main loop of my game engine. I ended up adding code to record time statistics. The idea was that these statistics could be used in the engine itself to predict the presentation time for the next frame. Maybe they can, although I haven’t yet wired up things this way. In the end, I spent more time than I could have on this task. At least, I now have easy access to data about how much time it takes for rendering and physics (sort of.) I also know that physics calculations sometimes cause frame drops. I suspect this is due to Lua’s GC, but I haven’t confirmed.

One interesting thing to notice is that I found GitHub can be used to produce websites and static pages. See for example, https://github.com/mwalczyk . This seems much more promising than WordPress, which is the system I have been experimenting with previously. GitHub pages seem much more aligned with my needs and the way I like to work.