Threads keep executing even after closing main thread

[fhtanaka]

This makes it harder to close the program in total without resorting to the task manager

[rithgroove]

There are two types of thread used:

1. The thread that handles the line chart
2. The process that handles the step function.

I'm assuming you are referring to the second type of thread. Here are the characteristics of these threads:

• Since it is a multiprocess class and not a normal thread class, it won't automatically close.
• These threads will automatically close after they finished calculating the path

The solution is to manually terminate these processes. Terminating them is not hard, because the threads are saved in the "simulator.threads" array.

I think we're going to solves this by handling exceptions in the renderer's main loop and kills the threads manually. And probably need to add the no-renderer run method in the simulator so we can call a method to kill these processes.

[rithgroove]

Okay, I just checked the UI code, I tried to fix it but got stuck. Apparently, since the UI uses a thread to run the code, the UI will be stuck on loading until the thread is finished. So far, I checked that there is no way to kill a thread in python (maybe I'm wrong)

[jair-pereira]

The PR that adds play/pause buttons may cause this too if you try to close the window while it is auto-running. I added a flag to wait until the step processing finishes before trying to close the window, but sometimes it still freezes and I haven't figure it out yet.