[Bug Report] Installing box2d on colab

[qsimeon]

Describe the bug

It's not great that the example on the documentation home page does not work. I tried running that example (copy-pasted exactly from the home page) in a Google Colab notebook (after installing gymnasium with !pip install gymnasium) and was immediately faced with this error: "DependencyNotInstalled: Box2D is not installed, run pip install gymnasium[box2d]".
When I follow the suggestion and !pip install gymnasium[box2d] run in new code cell, the installation fails due this this error: "ERROR: Could not build wheels for box2d-py, which is required to install pyproject.toml-based projects".

Code example

!pip install gymnasium

Collecting gymnasium
  Using cached gymnasium-0.29.0-py3-none-any.whl (953 kB)
Requirement already satisfied: numpy>=1.21.0 in /usr/local/lib/python3.10/dist-packages (from gymnasium) (1.23.5)
Requirement already satisfied: cloudpickle>=1.2.0 in /usr/local/lib/python3.10/dist-packages (from gymnasium) (2.2.1)
Requirement already satisfied: typing-extensions>=4.3.0 in /usr/local/lib/python3.10/dist-packages (from gymnasium) (4.7.1)
Collecting farama-notifications>=0.0.1 (from gymnasium)
  Using cached Farama_Notifications-0.0.4-py3-none-any.whl (2.5 kB)
Installing collected packages: farama-notifications, gymnasium
Successfully installed farama-notifications-0.0.4 gymnasium-0.29.0

import gymnasium as gym
env = gym.make("LunarLander-v2", render_mode="human")
observation, info = env.reset(seed=42)
for _ in range(1000):
   action = env.action_space.sample()  # this is where you would insert your policy
   observation, reward, terminated, truncated, info = env.step(action)

   if terminated or truncated:
      observation, info = env.reset()

env.close()

---------------------------------------------------------------------------
ModuleNotFoundError                       Traceback (most recent call last)
/usr/local/lib/python3.10/dist-packages/gymnasium/envs/box2d/bipedal_walker.py in <module>
     14 try:
---> 15     import Box2D
     16     from Box2D.b2 import (

ModuleNotFoundError: No module named 'Box2D'

The above exception was the direct cause of the following exception:

DependencyNotInstalled                    Traceback (most recent call last)
15 frames
/usr/local/lib/python3.10/dist-packages/gymnasium/envs/box2d/bipedal_walker.py in <module>
     23     )
     24 except ImportError as e:
---> 25     raise DependencyNotInstalled(
     26         "Box2D is not installed, run `pip install gymnasium[box2d]`"
     27     ) from e

DependencyNotInstalled: Box2D is not installed, run `pip install gymnasium[box2d]`

!pip install gymnasium[box2d]

Requirement already satisfied: gymnasium[box2d] in /usr/local/lib/python3.10/dist-packages (0.29.0)
Requirement already satisfied: numpy>=1.21.0 in /usr/local/lib/python3.10/dist-packages (from gymnasium[box2d]) (1.23.5)
Requirement already satisfied: cloudpickle>=1.2.0 in /usr/local/lib/python3.10/dist-packages (from gymnasium[box2d]) (2.2.1)
Requirement already satisfied: typing-extensions>=4.3.0 in /usr/local/lib/python3.10/dist-packages (from gymnasium[box2d]) (4.7.1)
Requirement already satisfied: farama-notifications>=0.0.1 in /usr/local/lib/python3.10/dist-packages (from gymnasium[box2d]) (0.0.4)
Collecting box2d-py==2.3.5 (from gymnasium[box2d])
  Using cached box2d-py-2.3.5.tar.gz (374 kB)
  Preparing metadata (setup.py) ... done
Requirement already satisfied: pygame>=2.1.3 in /usr/local/lib/python3.10/dist-packages (from gymnasium[box2d]) (2.5.0)
Collecting swig==4.* (from gymnasium[box2d])
  Using cached swig-4.1.1-py2.py3-none-manylinux_2_5_x86_64.manylinux1_x86_64.whl (1.8 MB)
Building wheels for collected packages: box2d-py
  error: subprocess-exited-with-error
  
  × python setup.py bdist_wheel did not run successfully.
  │ exit code: 1
  ╰─> See above for output.
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
  Building wheel for box2d-py (setup.py) ... error
  ERROR: Failed building wheel for box2d-py
  Running setup.py clean for box2d-py
Failed to build box2d-py
ERROR: Could not build wheels for box2d-py, which is required to install pyproject.toml-based projects

### System info

Google Colab environment. 
Python 3.10.12. 
Gymnasium installed using `!pip install gymnasium`. 
gymnasium.__version__ == 0.29.0

### Additional context

_No response_

### Checklist

- [X] I have checked that there is no similar [issue](https://github.com/Farama-Foundation/Gymnasium/issues) in the repo

[robertoschiavone]

Not an actual bug, but it's more a lack of (critical, in my opinion) documentation. To run the example (or any env that requires box2d) in a Google Colab notebook, you need to install swig first:

!apt-get install swig
!pip install gymnasium[box2d]

[btjanaka]

@robertoschiavone @pseudo-rnd-thoughts I think the bug is a lot simpler than this. box2d does seem to depend on swig, but the dependency is in the wrong order, i.e., swig is placed after box2d:

Gymnasium/pyproject.toml

Line 39 in fa8a982

box2d = ["box2d-py ==2.3.5", "pygame >=2.1.3", "swig ==4.*"]

This means that box2d is installed before swig even though it depends on swig to be built.

I tried this in #677 but it actually does not work because it seems swig needs to be installed beforehand so that its executable can be called.

[pseudo-rnd-thoughts]

@robertoschiavone Would you be able to make a PR to improve the documentation. You should just need to modify the box2d environment's docstring

[btjanaka]

Hi @pseudo-rnd-thoughts, I created #683 to resolve this issue. Let me know what you think!

[turbotimon]

Hi @pseudo-rnd-thoughts can we improve the ImportError message to please? see my PR #1009