I'm not dead (yet)
If I had an audience, they would probably wonder why I'm not posting anything for 3 months. Well, the reason for that is that 1. I had some exams so I was kinda busy and 2. I'm kinda stuck regarding LuaComputers.
The problem with LuaComputers is that the performance is not great. I know that I was able to boost it up by 100%, which is true, but even then it's just about 70 FPS with an FX-8350 and a GTX 960. This setup is certainly not a high-end gaming setup, however, it is still quite good which means that worse setups than mine would have even less FPS.
I did some testing and created a minimal version of LuaComputers using C++ and SFML, because they have an object called "RenderTexture". This object (to my understanding) allows me to draw stuff to like a buffer and at the end draw that buffer onto the actual screen. Using this technique I was able to draw pixels as they were set, eliminating the need to iterate through the whole array of pixels every frame, which I'm currently doing in the Java version. (I also didn't have to clear the screen all the time as you would just draw over old pixels)
This made me get >1000 FPS so it works really good, however, I did not find such an object on libGDX (the API I use for the Java version), which is currently my problem.
I'm not good at C++ so currently I am learning it a bit more and when I learned the most of it I'll port LuaComputers completely to C++ with either SFML or SDL.
Bare with me and see you, non-existing audience, next time! :)