Switch to using GameController by default, use Robot constructor, and fix some bugs in SDL usage

Author: bhall-ctre

CMakeLists.txt

@@ -22,8 +22,8 @@ find_package(SDL2 REQUIRED)
 add_definitions(-DUNIT_LIB_DISABLE_FMT -DUNIT_LIB_ENABLE_IOSTREAM)
 
 # Add all CPP files to the executable
-# Note: Users using GameController should swap out Joystick.cpp with GameController.cpp
-add_executable(${PROJECT_NAME} main.cpp RobotBase.cpp Joystick.cpp)
+# Note: Users using Joystick should swap out GameController.cpp with Joystick.cpp
+add_executable(${PROJECT_NAME} main.cpp RobotBase.cpp GameController.cpp)
 
 # Specify libraries to link against
 target_link_libraries(${PROJECT_NAME} phoenix6)

GameController.cpp

@@ -12,7 +12,7 @@ bool GameController::IsConnected() const
 
     /* poll for game controller disconnects */
     SDL_Event event;
-    if (SDL_PollEvent(&event)) {
+    while (SDL_PollEvent(&event)) {
         if (event.type == SDL_QUIT) {
             /* SDL shut down */
             return false;

GameController.hpp

@@ -8,8 +8,6 @@
 
 /**
  * Manages a game controller using the SDL 2 library.
- *
- * Note: This requires Ubuntu 22.04+ or Debian Bullseye.
  */
 class GameController {
 private:
@@ -155,7 +153,7 @@ class GameController {
     }
 
 private:
-    static constexpr auto kErrorTimeMs = 2000;
+    static constexpr auto kErrorTimeMs = 3000;
     std::chrono::time_point<std::chrono::steady_clock> _lastErrorTime = std::chrono::steady_clock::now();
 
     /** Reports a missing game controller with debouncing. */

Joystick.cpp

@@ -12,7 +12,7 @@ bool Joystick::IsConnected() const
 
     /* poll for joystick disconnects */
     SDL_Event event;
-    if (SDL_PollEvent(&event)) {
+    while (SDL_PollEvent(&event)) {
         if (event.type == SDL_QUIT) {
             /* SDL shut down */
             return false;

Joystick.hpp

@@ -9,9 +9,8 @@
 /**
  * Manages a joystick using the SDL 2 library.
  *
- * Note: This is a legacy class for users on Ubuntu
- *       20.04 and older. Users on newer systems
- *       can use the GameController class.
+ * Note: This is a legacy class for users with
+ *       joysticks not supported by GameController.
  */
 class Joystick {
 private:
@@ -193,7 +192,7 @@ class Joystick {
     }
 
 private:
-    static constexpr auto kErrorTimeMs = 2000;
+    static constexpr auto kErrorTimeMs = 3000;
     std::chrono::time_point<std::chrono::steady_clock> _lastErrorTime = std::chrono::steady_clock::now();
 
     /** Reports a missing joystick with debouncing. */

RobotBase.cpp

@@ -1,12 +1,9 @@
 #include "RobotBase.hpp"
-#include "ctre/phoenix6/unmanaged/Unmanaged.hpp"
+#include <ctre/phoenix6/unmanaged/Unmanaged.hpp>
 
 int RobotBase::Run()
 {
-    printf("Starting robot program...\n");
-
-    /* this is robot startup, run robot init */
-    RobotInit();
+    printf("Robot program startup complete\n");
 
     while (IsRunning()) {
         auto const start = std::chrono::steady_clock::now();
@@ -59,10 +56,6 @@ int RobotBase::Run()
             SleepFor(0_ms);
         }
     }
-
-    /* program shutting down */
-    printf("Stopping robot program...\n");
-
     return 0;
 }
 

RobotBase.hpp

@@ -1,6 +1,6 @@
 #pragma once
 
-#include "units/time.h"
+#include <units/time.h>
 #include <chrono>
 #include <optional>
 #include <thread>
@@ -10,8 +10,26 @@
  * Manages a robot program.
  */
 class RobotBase {
+    units::millisecond_t _loopTime;
+    std::optional<bool> _lastEnabled;
+
 public:
-    virtual void RobotInit() = 0;
+    RobotBase(units::millisecond_t loopTime = 20_ms) :
+        _loopTime{loopTime}
+    {}
+
+    template <std::derived_from<RobotBase> Robot, typename... Args>
+    static int StartRobot(Args&&... args)
+    {
+        printf("Starting robot program...\n");
+
+        Robot robot(std::forward<Args>(args)...);
+        int const retval = robot.Run();
+
+        printf("Stopping robot program...\n");
+        return retval;
+    }
+
     virtual void RobotPeriodic() = 0;
 
     virtual bool IsEnabled() = 0;
@@ -23,11 +41,6 @@ class RobotBase {
 
     virtual bool IsRunning() { return true; }
 
-private:
-    units::millisecond_t _loopTime = 20_ms;
-    std::optional<bool> _lastEnabled;
-
-public:
     /**
      * Sleeps for the specified amount of time.
      */
@@ -44,15 +57,15 @@ class RobotBase {
         _loopTime = loopTime;
     }
 
+private:
+    static constexpr auto kErrorTimeMs = 3000;
+    std::chrono::time_point<std::chrono::steady_clock> _lastErrorTime = std::chrono::steady_clock::now();
+
     /**
      * Runs the robot program.
      */
     int Run();
 
-private:
-    static constexpr auto kErrorTimeMs = 3000;
-    std::chrono::time_point<std::chrono::steady_clock> _lastErrorTime = std::chrono::steady_clock::now();
-
     /** Reports a loop overrun with debouncing. */
     void ReportLoopOverrun(units::millisecond_t measured);
 };

main.cpp

@@ -1,6 +1,6 @@
-#include "ctre/phoenix6/TalonFX.hpp"
+#include <ctre/phoenix6/TalonFX.hpp>
 #include "RobotBase.hpp"
-#include "Joystick.hpp"
+#include "GameController.hpp"
 
 using namespace ctre::phoenix6;
 
@@ -25,11 +25,12 @@ class Robot : public RobotBase {
     controls::DutyCycleOut rightOut{0};
 
     /* joystick */
-    Joystick joy{0};
+    GameController joy{0};
 
 public:
+    Robot();
+
     /* main robot interface */
-    void RobotInit() override;
     void RobotPeriodic() override;
 
     bool IsEnabled() override;
@@ -40,10 +41,8 @@ class Robot : public RobotBase {
     void DisabledPeriodic() override;
 };
 
-/**
- * Runs once at code initialization.
- */
-void Robot::RobotInit()
+Robot::Robot()
+    // : RobotBase{20_ms} // optionally specify loop time for periodic calls
 {
     configs::TalonFXConfiguration fx_cfg{};
 
@@ -74,10 +73,8 @@ void Robot::RobotPeriodic()
  */
 bool Robot::IsEnabled()
 {
-    /* enable while joystick is an Xbox controller (6 axes),
-     * and we are holding the right bumper */
-    if (joy.GetNumAxes() < 6) return false;
-    return joy.GetButton(5); // SDL_CONTROLLER_BUTTON_RIGHTSHOULDER
+    /* enable while holding the right bumper */
+    return joy.GetButton(SDL_CONTROLLER_BUTTON_RIGHTSHOULDER);
 }
 
 /**
@@ -91,11 +88,11 @@ void Robot::EnabledInit() {}
 void Robot::EnabledPeriodic()
 {
     /* arcade drive */
-    double speed = -joy.GetAxis(1); // SDL_CONTROLLER_AXIS_LEFTY
-    double turn = joy.GetAxis(4); // SDL_CONTROLLER_AXIS_RIGHTX
+    double speed = -joy.GetAxis(SDL_CONTROLLER_AXIS_LEFTY);
+    double turn = -joy.GetAxis(SDL_CONTROLLER_AXIS_RIGHTX);
 
-    leftOut.Output = speed + turn;
-    rightOut.Output = speed - turn;
+    leftOut.Output = speed - turn;
+    rightOut.Output = speed + turn;
 
     leftLeader.SetControl(leftOut);
     rightLeader.SetControl(rightOut);
@@ -120,7 +117,5 @@ void Robot::DisabledPeriodic()
 int main()
 {
     /* create and run robot */
-    Robot robot{};
-    // robot.SetLoopTime(20_ms); // optionally change loop time for periodic calls
-    return robot.Run();
+    return RobotBase::StartRobot<Robot>();
 }

readme.md

@@ -11,7 +11,7 @@
 
 The main robot program is located inside main.cpp.
 
-By default, the Joystick class is used for controller input. Users may choose to use the GameController class instead.
+By default, the GameController class is used for controller input. Users may choose to use the Joystick class instead.
 
 # Build Process