In this post, I lay out the steps to follow to resolve the errors you see when creating your first MineRL agent on a macOS. This is a continuation of this post, which looks at resolving install errors on the minerl package.

I borrow heavily from this github issue comment.

  1. Clone the repository using the terminal command below

       git clone https://github.com/minerllabs/minerl.git

    This will create a minerl directory. Make sure that the path to the cloned repository does not have spaces in it (i.e. the path should not be /Users/<username>/minerl folder/minerl – you will get file not found errors in the next few steps otherwise)

  2. Open the patch file in the directory minerl/scripts/mcp_patch.diff, and replace version number 3.2.1 to 3.3.1 for lwjgl-opengl (github link to part of the file where the version number should be replaced)

  3. From inside the minerl folder on terminal, run the following command:

       pip3 install .

  4. If the installation fails, please go to this post and see if the steps outlined there can help.

  5. If the installation is successful, navigate to the minerl/minerl/MCP-Reborn folder and open the launchClient.sh file in a text editor of choice. Modify a line close to the end of the file that starts with Java ...., so that the new line becomes:

       java -Xmx$maxMem -XstartOnFirstThread -jar `\(fatjar --envPort=\)`port

  6. Navigate to MCP-Reborn/src/main/java/net/minecraft/client/MainWindow.java, and make the following changes:

    • Comment out the following line (add a // to the left of this line)

         GLFW.glfwSetWindowIcon(this.handle, buffer);

    • Comment out the body of the checkGlfwError method, it should look like this after commenting out the body (DO NOT comment out/delete the method declaration, else the next step will fail.):

       public static void checkGlfwError(BiConsumer<Integer, String> glfwErrorConsumer) {
 /* RenderSystem.assertThread(RenderSystem::isInInitPhase);
       try (MemoryStack memorystack = MemoryStack.stackPush()) {
    PointerBuffer pointerbuffer = memorystack.mallocPointer(1);
    int i = GLFW.glfwGetError(pointerbuffer);
    if (i != 0) {
       long j = pointerbuffer.get();
       String s = j == 0L ? "" : MemoryUtil.memUTF8(j);
       glfwErrorConsumer.accept(i, s);
    }
 } */

 }

  7. Navigate to the minerl/minerl/MCP-Reborn folder in terminal and rebuild MCP-Reborn using the command below:

       ./gradlew clean build shadowJar

    You should see a success message like the one below: Build Success

  8. Find the location where the minerl package was installed. If you use pyenv like I do, you can use the pyenv which python command in terminal, to get the version of python being used by the system. For example, if the version number is 3.11.2, then the location of the minerl package should be:

        /Users/<username>/.pyenv/versions/3.11.2/lib/python3.11/site-packages/minerl

  9. Navigate to the minerl folder above, and replace the MCP-Reborn folder in it with the MCP-Reborn folder you just built in step 7 above.

  10. Follow the steps to build your first agent, this should work now and you should see something like this: First Agent