Add tutorial for graphical output of gym environments

README.md

+# Jupyter Tutorials
+
+This is a collection of tutorials for Jupyter Notebooks.

gym-graphic-output.ipynb

+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "cb5980cf-bb11-477c-975d-c555dbd61e22",
+   "metadata": {},
+   "source": [
+    "# Graphic Output of Gymnasium Environments\n",
+    "\n",
+    "Although values are probably better to monitor, when you got some experience, in the beginning, for debugging and for presentations you like to watch your agent playing games. Depending on the IDE there are partially different ways to do it.\n",
+    "\n",
+    "## Recording Videos\n",
+    "\n",
+    "The best solution is probably to make periodic videos. In this way, you can look at the capabilities at different learning states and you can rewatch it later on. In JupyterLab right-click on a video and select *Open in New Browser Tab*."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "id": "b425cecc-4212-434f-b57c-a9292c5a08d1",
+   "metadata": {
+    "tags": []
+   },
+   "outputs": [],
+   "source": [
+    "import gymnasium as gym\n",
+    "\n",
+    "# env = gym.make(\"Pong-v4\", render_mode=\"rgb_array\")\n",
+    "# env.metadata['render_fps'] = 30\n",
+    "\n",
+    "env = gym.make(\"LunarLander-v2\", render_mode=\"rgb_array\")\n",
+    "\n",
+    "env = gym.wrappers.RecordVideo(env, './video/', disable_logger=True,\n",
+    "                               episode_trigger=lambda episode_id: episode_id % 5 == 0) # every 5th episode\n",
+    "\n",
+    "observation, info = env.reset()\n",
+    "for _ in range(1000):\n",
+    "    action = env.action_space.sample()\n",
+    "    observation, reward, terminated, truncated, info = env.step(action)\n",
+    "    if terminated or truncated:\n",
+    "        observation, info = env.reset()\n",
+    "env.close()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "9f7a4b36-5204-4783-9b6e-55eb3568b591",
+   "metadata": {},
+   "source": [
+    "## Live View using Matplotlib\n",
+    "\n",
+    "You can also watch the game live during training, maybe every few episodes or so. For that, choose `render_mode=\"rgb_array\"` and make a first `imshow` plot. *Very important: The cell has to end after making the plot, because the plot will only be visible when the cell finishes.* In the second cell the plot gets updated."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "17be9d89-1246-4cd7-9258-49cff9ee6da9",
+   "metadata": {
+    "tags": []
+   },
+   "outputs": [],
+   "source": [
+    "import gymnasium as gym\n",
+    "import matplotlib.pyplot as plt\n",
+    "# you maybe have to restart your kernel, if you changed the matplotlib backend before\n",
+    "%matplotlib widget\n",
+    "\n",
+    "env = gym.make(\"LunarLander-v2\", render_mode=\"rgb_array\")\n",
+    "observation, info = env.reset() # is required once before calling env.render()\n",
+    "img = plt.imshow(env.render()) # only call this once to bring up the plot\n",
+    "plt.show()\n",
+    "# IMPORTANT: Split your code at this point into two cells, so the plot can be drawn"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "fe77c845-f5b0-4462-a4e6-c2b5c7fd71cf",
+   "metadata": {
+    "tags": []
+   },
+   "outputs": [],
+   "source": [
+    "observation, info = env.reset()\n",
+    "for _ in range(150):\n",
+    "    action = env.action_space.sample()\n",
+    "    observation, reward, terminated, truncated, info = env.step(action)\n",
+    "    if terminated or truncated:\n",
+    "        observation, info = env.reset()\n",
+    "\n",
+    "    # update plot\n",
+    "    img.set_data(env.render())\n",
+    "    plt.gcf().canvas.draw()\n",
+    "env.close()\n",
+    "print('done.')"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.10.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}