Utilities

This page will contain high-level documentation on the various utilities for RJ RoboCup Software. Utilities are everything not directly necessary to launch our AI program, soccer (what a confusing name).

External Referee

First, read the Referee section of the Our Stack page and this section of the rulebook. This will give you some background on what the SSL Game Controller does. This program is given by the league and helps simulate what it will be like at competition, where the (human) referee sits at a different computer to the one that runs our software and gives game commands from there.

Installation is simple. First, create an empty directory named ssl-game-controller at the same level as your clone of robocup-software:

~/coding/robocup/ ├── robocup-software/ ├── ssl-game-controller/

Then, download the latest release binary in the SSL GC repo and put it into that folder. Finally, make the release binary executable by cd``ing to the ``ssl-game-controller repo and running chmod +x <name of release binary>.

When you want to launch the game controller, cd to your ssl-game-controller directory and run the release binary with ./<name of release binary>. (You can tab-complete this by typing ./ and then hitting tab.) The binary will output a message saying it has launched the UI at a specific URL–click that link to open the UI.

Operation instructions can be found in the FAQ of the SSL GC repo.

Launch

Our launch files are pretty similar to the ones introduced in ROS wiki tutorials, but we also use flags on launch to easily switch between certain nodes (for example we can switch between sim radio and network radio by setting a particular to the proper boolean value). Alias for common launch configurations can be found in the makefile.

Build System

We use cmake and ninja. We prefer using clang as the C++ compiler compared to gcc, but either will work. Most of the details on the high-level construction of our build system can been ascertained by reading the root CMakeLists.txt. If you are adding a new C++ file, it is best to just follow the existing format by reading through CMakeLists.txt in the relevant directories.

Debugging C++ Code

Setting up a debugger for our C++ side code is actually quite simple! In particular, we have had success using LLDB, made by the same group that develops the clang compiler. As of summer 2022, the ubuntu-setup script installs clang-10 using a script which also includes lldb-10 (so you should not need to install anything new for this). All you need to do is start soccer or sim in one terminal tab, and in another tab, run sudo lldb-10 -n name_of_particular_proc.

How do you find this particular name? Well it depends on what file/node you wish to debug. As of the time of writing this article, we do not use any ros2 node composition, so each node is its own process. Looking in the soccer launch file a node’s “executable_name” corresponds to the process name to place after -n. Another method to find the process names of nodes is to run top in a new terminal tab and look in there.

How do you use lldb? Google what you want to do and follow the top result or follow the lldb tutorial on their website. CS2110 and CS2200 will introduce you to gdb which is another debugger for C/C++; if you already know that, the commands are basically the same (the syntax is different in many places though).

There is also another method which involves commenting out the node you want to run in the launch files and running it separately in a new terminal tab with a debugging prefix. This method is slower and not as consistent, so I won’t explain it here. Check out util/debug-cpp.sh if you are curious, or if the first method I explained stops working.

Continuous Integration

We use Github Actions. The configuration for that can be found in .github/workflows.