Convert rendering code to pygame

[abaisero]

Gym 0.22.0 changed the way classic_control environments are rendered, breaking some implied dependencies. To be able to use gym>=0.21.0, GV should also change the way the environments are rendered.

[ashok-arora]

@abaisero Does the existing rendering not use pygame?

[abaisero]

@ashok-arora hello Ashok, apologies for the late reply, I was sort of off the grid for a while.

No, the existing rendering does not use pygame; I never found the right time and resources to spend to make the move to a pygame implementation. Another issue is that the current rendering allows to render either (or both) the state or the observation, while pygame only allows to open a single rendering window. But the main issue really is that I can't justify spending time on updating the whole rendering system to a whole new engine.

[ashok-arora]

@abaisero Oh okay, thank you for the response. Could you elaborate more on how the current rendering system works? If its not too complicated, can I shift it to pygame since almost all of the gymnasium envs use pygame.

[abaisero]

It's based on pyglet, which is what gym itself was using to render their 2d environments before their move to pygame. The important files in this respect are rendering_gym.py, which is a direct copy of a file from the gym library before their move to pygame, and then rendering.py which contains some additional code that I was using to adapt the gym rendering to gym-gridverse. Those are the two important files to look into.