Different rendering results for GYM envs when using rgb_array rendering mode

[ArgentumWalker]

Hi! I am trying to get an image as observation from PyBullet Gym Environments and faced that enabling GUI rendering also changes image rendered by "rgb_array" mode. For some environments it is crucial.

Code to reproduce:

import pybullet_envs
import gym
import matplotlib.pyplot as plt

env = gym.make("HalfCheetahBulletEnv-v0")
env.reset()
plt.imshow(env.render("rgb_array"))
plt.show()

env = gym.make("HalfCheetahBulletEnv-v0")
env.render()
env.reset()
plt.imshow(env.render("rgb_array"))
plt.show()

Example images:

[erwincoumans]

One uses a simple software CPU renderer (tinyrenderer) and the other a nicer OpenGL3 hardware GPU renderer.

Do you offer to implement the missing features into tinyrenderer?