Developing a project for NAO using third-party software

Here is a quick tutorial to explain how you can develop your project using some third-party software not provided by the OpenNAO system.

Warning

This section deals with cross-compilation which is currently only available on Linux.

Overview

Assuming you are developing a project called bar depending on libupnp.

Before being able to run the final application on the robot, there are some steps to successfully build then deploy this application. Briefly they are:

  1. Build the third-party dependencies in the OpenNAO virtual machine;
  2. Convert the binary package built in the OpenNAO virtual machine into a qiBuild package;
  3. Add the qiBuild package to the cross-toolchain;
  4. Build the application;
  5. Deploy the application on the robot.

Hereafter is the step-by-step tutorial.

Building the third-party software

Step Action (in the virtual machine)

Search for the missing dependency:

emerge -s libupnp

Luckily, libupnp is provided by portage.

Install the missing dependency:

su
emerge libupnp
exit

After the installation of a package in the virtual machine, the binary packages are locally stored in /home/nao/opennao-distro/packages.

The following command will show you all built packages:

tree ``/home/nao/opennao-distro/packages``

Checking the content of the newly installed package:

equery files libupnp

For further details about emerge usage, see emerge usage.

From here, you can retrieve the binary package on the host system (i.e. outside the OpenNAO virtual machine):

Step Action (from the host system)

Retrieve the binary package on the host system:

scp -r -P 2222 nao@localhost:/home/nao/opennao-distro/packages/net-libs/ .

For further details about exchanging data between the host system and the OpenNAO virtual machine, see Exchanging data between the host and the OpenNAO virtual machine.

Importing Gentoo binary packages into a cross-toolchain

Warning

This section deals with cross-compilation which is currently only available on Linux.

Once the binary package is on the host system, import it into a cross-toolchain running:

qitoolchain import-package -c cross-atom libupnp /path/to/libupnp-1.6.6.tar.bz2

This will look for any CMake module provided by the package itself or by qiBuild. If none is found, then it will open an automatically generated CMake module in a text-editor. Here you can remove some unnecessary flib lines (e.g. test librairies, etc). After that, save it and the package is automatically added to the cross-toolchain.

To check out all packages added to the cross-toolchain:

qitoolchain info cross-atom

For further information about writing a CMake module, see Writing a custom -config.cmake module file.

For further details about qitoolchain, refer to the qitoolchain man page.

Building an application linking against third-party software

Once the third-party software package has been added to the cross-toolchain, it is possible to build the whole project you are working on, then deploying it on the robot.

Say you write an executable called bar which belongs to the project bar and depends on libupnp.

Here’s what the CMakeLists should look like:

cmake_minimum_required(VERSION 2.8)
project(bar)
find_package(qibuild)

qi_create_bin(bar bar.cpp)
qi_use_lib(bar UPNP)

Then, you should be able to use:

qibuild configure -c cross-atom
qibuild make -c cross-atom

Deploying the application

The last step is to use qibuild to generate a standalone package, check out qibuild man page.

First, edit the qiproject.xml to look like (see qiproject.xml reference page):

<project name="bar">
  <depends buildtime="true" runtime="true" names="libupnp" />
</project>

This will tell qibuild that the bar project needs the libupnp library both for compilation (buildtime), and for execution (runtime).

Then, run:

qibuild package --include-deps --runtime --release -c cross-atom bar

This will configure and build the bar project, then install the runtime components from both the bar project and the libupnp package, in a temporary directory, and then generate a nice .tar.gz out of the temporary install directory.

The package is relocatable, which means once it is extracted on the robot, the bar executable will always be able to find the libupnp library.

This means that you can put the package in /home/nao on the robot, without having to become root or risking changing the system libraries.

The last thing to do here is sending the package on the robot:

scp bar.tar.gz nao@nao.local:.

Extract the package on the robot:

ssh nao@nao.local
tar xaf bar.tar.gz

And run the bar executable on the robot:

ssh nao@nao.local
./bar/bin/bar

Enjoy ;-)

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