Gazebo resource setup for [[simulator_gazebo/GazeboConfiguration|C-Turtle and later]].

<<TOC(4)>>

Starting with C-Turtle, gazebo will no longer require environment variables: `LD_LIBRARY_PATH`, `GAZEBO_MEDIA_PATH` and `OGRE_RESOURCE_PATH`.  We are switching to using [[pluginlib]] to setup the corresponding resource variables.

== Ogre Resource Path ==
Previous to C-Turtle release, you need to specify the path to [[ogre]] library files either by putting it in `.gazeborc` or specifying it in the environment variable `OGRE_RESOURCE_PATH`.
{{{
<?xml version="1.0"?>
<gazeborc>
  <ogrePath>/u/hsu/projects/cturtle_wg_all/stacks/visualization_common/ogre/ogre/lib/OGRE</ogrePath>
</gazeborc>
}}}


== Gazebo Media Path ==
Gazebo automatically looks in subdirectory `Media/*` for resource files, e.g.:
 * `Media/models` - model mesh files
 * `Media/materials/textures` - ogre texture files
 * `Media/materials/scripts` - ogre material scripts
 * `Media/materials/programs` - ogre shading programs

Previous to C-Turtle release, you need to specify the path to `Media` directory either by putting it in `~/.gazeborc`
{{{
<?xml version="1.0"?>
<gazeborc>
  <gazeboPath>/u/hsu/projects/cturtle_wg_all/stacks/simulator_gazebo/gazebo/gazebo/share/gazebo</gazeboPath>
</gazeborc>
}}}
or by specifying it in the environment variable `GAZEBO_RESOURCE_PATH`.  For example:
{{{
  <param name="/use_sim_time" value="true" />
  <node name="gazebo" pkg="gazebo" type="gazebo" args="$(find gazebo_worlds)/worlds/empty.world" respawn="false" output="screen">
    <env name="GAZEBO_RESOURCE_PATH" value="$(find your_package_containing_a_Media_directory)" />
  </node>
}}}



== Gazebo Plugins Path ==
Previous to C-Turtle release, you have to specify the plugin library locations in environment variable `LD_LIBRARY_PATH`.  For example, if the plugin library is located in `gazebo_plugins`/lib/libgazebo_ros_myplugin.so, you have to include the following '''env''' tag in your gazebo node launch script:
{{{
  <node name="gazebo" pkg="gazebo" type="gazebo" args="$(find gazebo_worlds)/worlds/empty.world" respawn="false" >
    <env name="LD_LIBRARY_PATH" value="$(find gazebo_plugins)/lib:$(optenv LD_LIBRARY_PATH)" />
  </node>
}}}