Being “unable to find OpenGL rendering system” suggests that the LD_LIBRARY_PATH is missing some paths for the OpenGL libraries. As your commands are using the desktop-related interfaces I would recommend using a desktop- helper and prepending the command with desktop-launch:
name: mobile-base-snap
version: '0.1'
summary: Trying to snap the complete workspace.
description: That's all.
grade: stable
confinement: devmode
apps:
system:
command: desktop-launch roslaunch mobile_base_snap mobile_base_snap.launch --screen
plugs: [network, network-bind, home, x11, opengl, network-control, mount-observe]
gazebo:
command: desktop-launch roslaunch gazebo_ros empty_world.launch --screen
plugs: [network, network-bind, home, x11, opengl, network-control, mount-observe]
parts:
simulation:
after: [desktop-glib-only] # possibly want desktop-qt5, desktop-qt4, desktop-gtk3 or desktop-gtk2 instead.
plugin: catkin
rosdistro: indigo
catkin-packages: [mobile_base_snap, mobile_base_description, mobile_base_simulator]
install:
sed --in-place "s:setup_path=.*:setup_path=/snap/mobile-base-snap/current/usr/share/gazebo:g" "$SNAPCRAFT_PART_INSTALL/opt/ros/indigo/lib/gazebo_ros/debug";
sed --in-place "s:setup_path=.*:setup_path=/snap/mobile-base-snap/current/usr/share/gazebo:g" "$SNAPCRAFT_PART_INSTALL/opt/ros/indigo/lib/gazebo_ros/gazebo";
sed --in-place "s:setup_path=.*:setup_path=/snap/mobile-base-snap/current/usr/share/gazebo:g" "$SNAPCRAFT_PART_INSTALL/opt/ros/indigo/lib/gazebo_ros/gzclient";
sed --in-place "s:setup_path=.*:setup_path=/snap/mobile-base-snap/current/usr/share/gazebo:g" "$SNAPCRAFT_PART_INSTALL/opt/ros/indigo/lib/gazebo_ros/gzserver";
sed --in-place "s:setup_path=.*:setup_path=/snap/mobile-base-snap/current/usr/share/gazebo:g" "$SNAPCRAFT_PART_INSTALL/opt/ros/indigo/lib/gazebo_ros/perf";