Differences between revisions 8 and 25 (spanning 17 versions)

Note: This tutorial assumes that you have completed the previous tutorials:nodelet/Tutorials/Running a nodelet.

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Porting nodes to nodelets

Description:

Tutorial Level: BEGINNER

Contents

Minimal Nodelet

Work in progress...(see nodelet_tutorial_math for an example)

add the necessary #includes
get rid of int main()
subclass nodelet::Nodelet
move code from constructor to onInit()
add the PLUGINLIB_EXPORT_CLASS macro
add <build_depend> and <run_depend> dependencies on nodelet in the package manifest.
add the <nodelet> item in the <export> part of the package manifest
create the .xml file to define the nodelet as a plugin
make the necessary changes to CMakeLists.txt (comment out a rosbuild_add_executable, add a rosbuild_add_library)

Minimal Nodelet

MyNodeletClass.h

Here we define the Class of our Nodelet. It's a good practice to place the header file under include/package_name/.

NB: The usage of the namespace is a good practice but not mandatory, in the following example we will proceed with the namespace example_pkg

#include <nodelet/nodelet.h>

namespace example_pkg
{

    class MyNodeletClass : public nodelet::Nodelet
    {
        public:
            virtual void onInit();
    };

}

MyNodeletClass.cpp

This file should be placed under the src/ folder of your actual package

// this should really be in the implementation (.cpp file)
#include <pluginlib/class_list_macros.h>

// Include your header
#include <example_pkg/MyNodeletClass.h>

// watch the capitalization carefully
PLUGINLIB_EXPORT_CLASS(example_pkg::MyNodeletClass, nodelet::Nodelet)

namespace example_pkg
{
    void MyNodeletClass::onInit()
    {
        NODELET_DEBUG("Initializing nodelet...");
    }
}

nodelet_plugins.xml

This file should be placed along with the package.xml file

<library path="lib/libMyNodeletClass">
  <class name="example_pkg/MyNodeletClass" type="example_pkg::MyNodeletClass" base_class_type="nodelet::Nodelet">
  <description>
  This is my nodelet.
  </description>
  </class>
</library>

package.xml

...
<build_depend>nodelet</build_depend>
<run_depend>nodelet</run_depend>
<export>
  <nodelet plugin="${prefix}/nodelet_plugins.xml" />
</export>
...

mynodelet.launch

Launch file should be placed under the launch/ repertory of your package, you can create it if it does not exist.

<launch>
  <node pkg="nodelet" type="nodelet" name="standalone_nodelet"  args="manager" output="screen"/>

  <node pkg="nodelet" type="nodelet" name="MyNodeletClass" args="load example_pkg/MyNodeletClass standalone_nodelet" output="screen">
  </node>
</launch>

-  ⇤ ← Revision 8 as of 2011-01-11 02:25:53 → 
  Size: 2726
  Editor: TullyFoote
  Comment:
+   ← Revision 25 as of 2018-11-06 11:43:32 → ⇥
  Size: 3567
  Editor: Markus Bader
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 7:
-## note = [[pluginlib/Tutorials/Writing and Using a Simple Plugin]]
## for the canned note of "This tutorial assumes that you have completed the previous tutorials:" just add the links 
## note.0=
+## note = This tutorial assumes that you have completed the previous tutorials:[[nodelet/Tutorials/Running a nodelet]]
## for the canned note of "This tutorial assumes that you have completed the previous tutorials:" just add the links
## note.0=
 Line 12:
-## multi-line description to be displayed in search 
## description =
+## multi-line description to be displayed in search
## description =
 Line 19:
 ## what level user is this tutorial for
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-Line 34:
+Line 33:
- * add the PLUGINLIB_DECLARE_CLASS macro
+ * add the PLUGINLIB_EXPORT_CLASS macro
 * add <build_depend> and <run_depend> dependencies on nodelet in the package manifest.
 Line 39:
+== Minimal Nodelet ==
!MyNodeletClass.h
-Line 40:
+Line 42:
-== Minimal Nodelet (may not be correct) ==
+Here we define the Class of our Nodelet. It's a good practice to place the header file under include/''package_name''/.
-Line 42:
+Line 44:
-!MyNodelet.h
+''NB: The usage of the namespace is a good practice but not mandatory, in the following example we will proceed with the namespace example_pkg''
-Line 46:
+Line 49:
-namespace nodelets
+namespace example_pkg
-Line 49:
+Line 52:
-    class MyNodlet : public nodelet::Nodelet
+    class MyNodeletClass : public nodelet::Nodelet
-Line 57:
+Line 60:
+!MyNodeletClass.cpp
-Line 58:
+Line 62:
-!MyNodelet.cpp
+This file should be placed under the src/ folder of your actual package
-Line 63:
+Line 68:
-PLUGINLIB_DECLARE_CLASS(nodelets, my_nodelet, nodelets::MyNodlet, nodelet::Nodelet)
+// Include your header
#include <example_pkg/MyNodeletClass.h>
-Line 65:
+Line 71:
-namespace nodelets
+// watch the capitalization carefully
PLUGINLIB_EXPORT_CLASS(example_pkg::MyNodeletClass, nodelet::Nodelet)

namespace example_pkg
-Line 67:
+Line 76:
-    MyNodelet::onInit()
+    void MyNodeletClass::onInit()
-Line 72:
+Line 81:
+}}}
nodelet_plugins.xml
-Line 73:
+Line 84:
-}}}
+This file should be placed along with the package.xml file
-Line 75:
+Line 86:
-nodelet_plugins.xml
-Line 78:
+Line 87:
-<library path="lib/libmynodelet">
  <class name="nodelets/my_nodelet" type="nodelets::MyNodlet" base_class_type="nodelet::Nodelet">
+<library path="lib/libMyNodeletClass">
  <class name="example_pkg/MyNodeletClass" type="example_pkg::MyNodeletClass" base_class_type="nodelet::Nodelet">
-Line 81:
+Line 90:
-  This is an example nodelet
+  This is my nodelet.
-Line 86:
+Line 95:
+package.xml
-Line 87:
+Line 97:
-manifest.xml
-Line 90:
+Line 99:
+<build_depend>nodelet</build_depend>
<run_depend>nodelet</run_depend>
-Line 91:
+Line 102:
-  <nodelet plugin="${prefix}/nodlet_plugins.xml" />
+  <nodelet plugin="${prefix}/nodelet_plugins.xml" />
-Line 95:
+Line 106:
+mynodelet.launch
-Line 96:
+Line 108:
-mynodelet.launch
+Launch file should be placed under the launch/ repertory of your package, you can create it if it does not exist.
-Line 101:
+Line 114:
-  <node pkg="nodelet" type="nodelet" name="MyNodelet" args="load nodelets/my_nodelet standalone_nodelet" output="screen">
  </node>
+  <node pkg="nodelet" type="nodelet" name="MyNodeletClass" args="load example_pkg/MyNodeletClass standalone_nodelet" output="screen">
  </node>
-Line 104:
+Line 117:
-Line 106:
+Line 118:
 ## AUTOGENERATED DO NOT DELETE

ROS 2 Documentation

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Porting nodes to nodelets

Minimal Nodelet