GLEW initalization error: Missing GL version

I have the following code

Code:

#include "mujoco.h"
#include "glfw3.h"


mjModel* m;
mjrContext c;
char error[300];

int main(int argc, const char** argv) {
  mjr_defaultContext(&c);
  GLFWwindow* window = glfwCreateWindow(800, 800, "Invisible window", NULL, NULL);
  glfwMakeContextCurrent(window);
  m = mj_loadXML(argv[1], 0, error, 1000);
  mjr_makeContext(m, &c, mjFONTSCALE_150);
  mjr_freeContext(&c);
}

For some reason, when I run this, I get

Code:

❯ ./glfw-bug 
ERROR: GLEW initalization error: Missing GL version

Press Enter to exit ...

I have looked at a few similar problems on other forums but the comments were either vague, or the solutions didn't work. I appreciate your help with this.

Versions:
Using mjPro150 on Ubuntu 16.04.

Code:

❯ apt show libglfw3             
Package: libglfw3
Version: 3.1.2-3
Priority: optional
Section: universe/libs
Source: glfw3
Origin: Ubuntu
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Original-Maintainer: Debian Games Team <pkg-games-devel@lists.alioth.debian.org>
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Installed-Size: 113 kB
Depends: libc6 (>= 2.15), libx11-6 (>= 2:1.2.99.901), libxcursor1 (>> 1.1.2), libxi6 (>= 2:1.2.99.4), libxinerama1, libxrandr2 (>= 2:1.2.99.3), libxxf86vm1
Homepage: http://www.glfw.org/
Download-Size: 38.5 kB
APT-Manual-Installed: yes
APT-Sources: http://us.archive.ubuntu.com/ubuntu xenial/universe amd64 Packages
Description: portable library for OpenGL, window and input (libraries)
GLFW is an Open Source, multi-platform library for creating
windows with OpenGL contexts and managing input and events.
It is easy to integrate into existing applications and does
not lay claim to the main loop.
.
This package provides shared libraries.

 

Actually, the original code was

Code:

#include "mujoco.h"
#include "glfw3.h"


mjModel* m;
mjrContext c;
char error[300];

int main(int argc, const char** argv) {
  mjr_defaultContext(&c);
  glfwInit();
  GLFWwindow* window = glfwCreateWindow(800, 800, "Invisible window", NULL, NULL);
  glfwMakeContextCurrent(window);
  m = mj_loadXML(argv[1], 0, error, 1000);
  mjr_makeContext(m, &c, mjFONTSCALE_150);
  mjr_freeContext(&c);
}

I took out glfwInit() to make make the example look more like the code in http://www.mujoco.org/book/programming.html#Rendering. Adding glfwInit() makes no difference except it creates an empty window. I still get

Code:

ERROR: GLEW initalization error: Missing GL version

Press Enter to exit ...

 

Ok I added the initialization code:

Code:

#include "mujoco.h"
#include "glfw3.h"


mjModel* m;
mjrContext c;
char error[300];

int main(int argc, const char** argv) {
  mj_activate("mjkey.txt");
  mjr_defaultContext(&c);
  glfwInit();
  GLFWwindow* window = glfwCreateWindow(800, 800, "Invisible window", NULL, NULL);
  glfwMakeContextCurrent(window);
  m = mj_loadXML(argv[1], 0, error, 1000);
  mjr_makeContext(m, &c, mjFONTSCALE_150);
  mjr_freeContext(&c);
}

Same error. To give some context to this bug, this is an issue that several mujoco-py users are experiencing (https://github.com/openai/mujoco-py/issues/75, https://github.com/openai/mujoco-py/issues/44). As best as I was able to tell, this is essentially the series of mujoco functions called by mujoco-py, although there is a lot of python wrapped around them.

Print statements indicate that the problem happens in mjr_makeContext.

 

Yes to all three. So the culprit, it seems was that mujoco-py was compiling with libglewosmesa and osmesa instead of libglew, which works.

This is definitely a big help, although it looks like mujoco-py uses some code that is specifically dependent on these osmesa libraries.

Can you offer some advice on switching that code out with libglew code?

 

Well, I appreciate your willingness to go into the weeds a little with me on this. Currently, mujoco-py depends on a file called 'osmesashim.c' (https://github.com/openai/mujoco-py/blob/master/mujoco_py/gl/osmesashim.c). This file looks like it adapts certain osmesa functions to a common interface used by mujoco-py (https://github.com/openai/mujoco-py/blob/master/mujoco_py/gl/glshim.h). The other shim file in the mujoco-py repository is eglshim.c (https://github.com/openai/mujoco-py/blob/master/mujoco_py/gl/eglshim.c). I tried swapping in this file, but go the same 'GLEW initalization error.' My guess is that I need to implement something like 'glewshim.c.'

In the future, I will also want to get this to work with rendering on the GPU. My limited understanding is that the GPU would need to use EGL, which is not working right now unfortunately. Please feel free to offer any suggestions on this point if you have them.

 

Actually, none of the above proved necessary. I was actually able to fix the issue on my machine by changing the build instructions to use glew, gl, and OSMesa. Now it works

 

@Ethan Brooks

Could you post how you did this? I am having the same issue.

 

@Matthew Wilson I just used essentially the same build instructions that are in mjpro150/sample/makefile. I've attached an example of the exact instructions that I am using.