wpilibc/sim/include/AnalogPotentiometer.h

/*----------------------------------------------------------------------------*/
/* Copyright (c) FIRST 2016-2017. All Rights Reserved.                        */
/* Open Source Software - may be modified and shared by FRC teams. The code   */
/* must be accompanied by the FIRST BSD license file in the root directory of */
/* the project.                                                               */
/*----------------------------------------------------------------------------*/

#pragma once

#include <memory>
#include <string>

#include "AnalogInput.h"
#include "LiveWindow/LiveWindowSendable.h"
#include "interfaces/Potentiometer.h"

namespace frc {

/**
 * Class for reading analog potentiometers. Analog potentiometers read
 * in an analog voltage that corresponds to a position. Usually the
 * position is either degrees or meters. However, if no conversion is
 * given it remains volts.
 */
class AnalogPotentiometer : public Potentiometer, public LiveWindowSendable {
 public:
  /**
   * AnalogPotentiometer constructor.
   *
   * Use the scaling and offset values so that the output produces meaningful
   * values. I.E: you have a 270 degree potentiometer and you want the output
   * to be degrees with the halfway point as 0 degrees. The scale value is
   * 270.0(degrees)/5.0(volts) and the offset is -135.0 since the halfway point
   * after scaling is 135 degrees.
   *
   * @param channel The analog channel this potentiometer is plugged into.
   * @param scale   The scaling to multiply the voltage by to get a meaningful
   *                unit.
   * @param offset  The offset to add to the scaled value for controlling the
   *                zero value
   */
  explicit AnalogPotentiometer(int channel, double scale = 1.0,
                               double offset = 0.0);

  AnalogPotentiometer(AnalogInput* input, double scale = 1.0,
                      double offset = 0.0);

  AnalogPotentiometer(AnalogInput& input, double scale = 1.0,
                      double offset = 0.0);

  virtual ~AnalogPotentiometer();

  /**
   * Get the current reading of the potentiomere.
   *
   * @return The current position of the potentiometer.
   */
  virtual double Get() const;

  /**
   * Implement the PIDSource interface.
   *
   * @return The current reading.
   */
  double PIDGet() override;

  /*
   * Live Window code, only does anything if live window is activated.
   */
  std::string GetSmartDashboardType() const override;
  void InitTable(std::shared_ptr<ITable> subtable) override;
  void UpdateTable() override;
  std::shared_ptr<ITable> GetTable() const override;

  /**
   * AnalogPotentiometers don't have to do anything special when entering the
   * LiveWindow.
   */
  void StartLiveWindowMode() override {}

  /**
   * AnalogPotentiometers don't have to do anything special when exiting the
   * LiveWindow.
   */
  void StopLiveWindowMode() override {}

 private:
  double m_scale, m_offset;
  AnalogInput* m_analog_input;
  std::shared_ptr<ITable> m_table;
  bool m_init_analog_input;

  /**
   * Common initialization code called by all constructors.
   */
  void initPot(AnalogInput* input, double scale, double offset);
};

}  // namespace frc