Both processes use OpenGL, but only gzclient displays a gui. Starting gzserver will result in this error, but only occasionally. Starting gzclient will result in the error more frequently - perhaps once in every 5-10 invocations. Closing the gzclient window will also often produce the error.
It's easy to reproduce using Gazebo.
1. Install Gazebo: http:// gazebosim. org/wiki/ 1.6/install
2. Run gzserver in one terminal
3. Run gzclient in another
Both processes use OpenGL, but only gzclient displays a gui. Starting gzserver will result in this error, but only occasionally. Starting gzclient will result in the error more frequently - perhaps once in every 5-10 invocations. Closing the gzclient window will also often produce the error.