Troubleshooting

This chapter contains tips for troubleshooting common problems in building and running OceanWATERS.

Table of Contents

• Build Problems
  • ow_simulator/ow_ephemeris
• Runtime Problems
  • Graphics Driver
  • Gazebo
    • Ignition Transport failure on VPN
    • Scaling and window corruption
    • Terrain display problems

Build Problems

ow_simulator/ow_ephemeris

If the build fails with an error like this:

CMake Error at ....ow/src/ow_simulator/ow_ephemeris/CMakeLists.txt:42 (message):
  ....ow/src/ow_simulator/ow_ephemeris/data/jup365.bsp

The problem is that the download of jup365.bsp (over 1GB) failed, timed out, or is corrupted. A workaround is to download this file manually:

https://naif.jpl.nasa.gov/pub/naif/generic_kernels/spk/satellites/jup365.bsp

and place it in ow_simulator/ow_ephemeris/data. Then retry catkin build.

Runtime Problems

Graphics Driver

A variety of error and warning messages, and failure of the simulator to start properly, can indicate that your graphics driver is in a bad state. Indicative messages include the following. Rebooting your machine is the first course of action, and should resolve the issue.

[ WARN]: OGRE EXCEPTION(3:RenderingAPIException): Unable to create a suitable GLXContext in GLXContext::GLXContext at /build/ogre-1.9-kiU5_5/ogre-1.9-1.9.0+dfsg1/RenderSystems/GL/src/GLX/OgreGLXContext.cpp (line 61)                                           
rviz::RenderSystem: error creating render window: OGRE EXCEPTION(3:RenderingAPIException): Unable to create a suitable GLXContext in GLXContext::GLXContext at /build/ogre-1.9-kiU5_5/ogre-1.9-1.9.0+dfsg1/RenderSystems/GL/src/GLX/OgreGLXContext.cpp (line 61)
[ WARN]: Resolution not specified for Octomap. Assuming resolution = 0.1 instead

Gazebo

Ignition Transport failure on VPN

ignition transport is used for Gazebo's internal messaging. Sometimes it doesn't work if you are connected on a VPN. Symptoms include console messages such as these:

• [gzclient --verbose -2] Exception sending a message
• [Err] [Scene.cc:227] Service call[/shadow_caster_material_name] timed out
• [Err] [Scene.cc:249] Service call[/shadow_caster_render_back_faces] timed out
• [Wrn] [Scene.cc:463] Ignition transport [/scene_info] service call failed, falling back to gazebo transport [scene_info] request.

A visual symptom is bits of lit terrain appearing inside terrain shadows. This happens when the shadow_caster_render_back_faces service call fails.

To prevent this problem, do the following:

export IGN_IP=127.0.0.1

For convenience you can add this to your shell init file, e.g. .profile or .bashrc.

Scaling and window corruption

If your Gazebo window is partially filled with "garbage" (e.g. remnants of other windows that were open, or like the image at the top of this page), try adding the following lines to your shell init file (e.g. .bashrc). This problem tends to occur on laptops with high-resolution screens.

export QT_AUTO_SCREEN_SCALE_FACTOR=0
export QT_SCREEN_SCALE_FACTORS=[1.0]

This has worked in Ubuntu 18.04 with Gazebo 9.19.0 and Ubuntu 20.04 with Gazebo 11.10.2.

Terrain display problems

If your terrain looks wrong in any way, especially after having edited it, try clearing the Gazebo cache. Look in the directory ~/.gazebo/paging and remove the directory for the terrain in question.