cpp-port

A WPILib C++ port of the robot code using the OpMode framework and Commands V2

Systems

OpModes

OpModes are automatically added using a system similar to annotations.

// The Java version of the OpMode framework allows for a @Auto, @Teleop, or an @Utility decorator before an OpMode to automatically register it.
// The C++ version doesn't, so I made an equivalent system
class ExampleOpMode : wpi::PeriodicOpMode {
    ExampleOpMode() {}
    void Start() override {}
    void Periodic() override {}
    void End() override {}
}
// The decorator equivalent goes after the OpMode
RegisteredOpMode<ExampleOpMode> exampleopmode(MODE, "name", "group", "description");
// There are three classes which inherit RegisteredOpMode to make it even more similar to the decorator version: Auto, Teleop, and Utility. They function the same as RegisteredOpMode but automatically fill in the MODE parameter, they should always be used instead of this underlying class for clarity.

Check out ExampleAuto.cpp, ExampleTeleop.cpp, and ExampleUtility.cpp to see the system in action. Run a simulation and see how they all appear in the OpMode selector.

How it works

When a RegisteredOpMode is declared as a global class like this, the constructor runs before the program starts, adding the class to an internal list which is tracked in RegisteredOpMode.cpp. Once the robot program is ready, all of the RegisteredOpModes in the list add their OpMode to the robot.

Subsystems

Subsystems are automatically added to the robot in a similar way to the OpModes. Subsystem periodic performance is added to networktables automatically under Subsystem Periodic Execution Time (ms). This can be graphed in AdvantageScope to compare the performance of different subsystems.
Unlike OpModes, Subsystems require a header to define the available functions and a separate source file to define the implementations. The header files become a sort of documentation for how a subsystem can be used.

// ExampleSubsystem.hpp
class ExampleSybsystem : Subsystem() {
    // No hardware should be initialized in the constructor
    // The purpose of the constructor is to add the subsystem to a list and to pass a name to be used for the periodic execution time diagnostics.
    ExampleSubsystem();
    // All hardware is initialized here
    void init() override;
    // Is run and timed every 20ms
    void periodic() override;
}

// ExampleSubsystem.cpp

// Pass the subsystem name to the parent class for diagnostics
ExampleSubsystem::ExampleSubsystem() : Subsystem("Subsystem Name") {}

void ExampleSubsystem::init() {}
void ExampleSubsystem::periodic() {}

The subsystem can be added to the robot by simply adding it to the Robot class in the Robot.hpp header file as a public member.

class Robot : wpi::OpModeRobot<Robot> {
public:
    // Subsystems
    ExampleSubsystem examplesubsystem;
    ...
}