Merge pull request #60 from huangshiyu13/dev

- add colab
- fix some bugs

README.md

@@ -97,10 +97,13 @@ pip install -e .
 openrl --version
 ```
 
+**Tips**：无需安装，通过Colab在线试用OpenRL: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/15VBA-B7AJF8dBazzRcWAxJxZI7Pl9m-g?usp=sharing)
+
 ## 使用Docker
 
 OpenRL目前也提供了包含显卡支持和非显卡支持的Docker镜像。
 如果用户的电脑上没有英伟达显卡，则可以通过以下命令获取不包含显卡插件的镜像：
+
 ```bash
 sudo docker pull openrllab/openrl-cpu
 ```

README_en.md

@@ -120,6 +120,8 @@ After installation, users can check the version of OpenRL through command line:
 openrl --version
 ```
 
+**Tips**: No installation required, try OpenRL online through Colab: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/15VBA-B7AJF8dBazzRcWAxJxZI7Pl9m-g?usp=sharing)
+
 ## Use Docker
 
 OpenRL currently provides Docker images with and without GPU support. 

openrl/envs/vec_env/base_venv.py

@@ -15,6 +15,7 @@
 # limitations under the License.
 
 """"""
+import sys
 import warnings
 from abc import ABC, abstractmethod
 from typing import Any, List, Optional, Sequence, Union
@@ -24,6 +25,8 @@
 
 from openrl.envs.vec_env.utils.util import tile_images
 
+IN_COLAB = "google.colab" in sys.modules
+
 
 class BaseVecEnv(
     ABC,
@@ -158,10 +161,15 @@ def render(self, mode: Optional[str] = None) -> Optional[np.ndarray]:
         # Create a big image by tiling images from subprocesses
         bigimg = tile_images(imgs)
         if mode == "human":
-            import cv2  # pytype:disable=import-error
+            if IN_COLAB:
+                from google.colab.patches import cv2_imshow
+
+                cv2_imshow(bigimg[:, :, ::-1])
+            else:
+                import cv2  # pytype:disable=import-error
 
-            cv2.imshow("Vec_Env:{}".format(self.env_name), bigimg[:, :, ::-1])
-            cv2.waitKey(1)
+                cv2.imshow("Vec_Env:{}".format(self.env_name), bigimg[:, :, ::-1])
+                cv2.waitKey(1)
         elif mode in [None, "rgb_array"]:
             return bigimg
         else: