stella/src/emucore/Driving.hxx

//============================================================================
//
//   SSSS    tt          lll  lll
//  SS  SS   tt           ll   ll
//  SS     tttttt  eeee   ll   ll   aaaa
//   SSSS    tt   ee  ee  ll   ll      aa
//      SS   tt   eeeeee  ll   ll   aaaaa  --  "An Atari 2600 VCS Emulator"
//  SS  SS   tt   ee      ll   ll  aa  aa
//   SSSS     ttt  eeeee llll llll  aaaaa
//
// Copyright (c) 1995-2020 by Bradford W. Mott, Stephen Anthony
// and the Stella Team
//
// See the file "License.txt" for information on usage and redistribution of
// this file, and for a DISCLAIMER OF ALL WARRANTIES.
//============================================================================

#ifndef DRIVING_HXX
#define DRIVING_HXX

#include "Control.hxx"
#include "Event.hxx"

/**
  The standard Atari 2600 Indy 500 driving controller.

  @author  Bradford W. Mott
*/
class Driving : public Controller
{
  public:
    /**
      Create a new Indy 500 driving controller plugged into
      the specified jack

      @param jack   The jack the controller is plugged into
      @param event  The event object to use for events
      @param system The system using this controller
    */
    Driving(Jack jack, const Event& event, const System& system);
    virtual ~Driving() = default;

  public:
    /**
      Update the entire digital and analog pin state according to the
      events currently set.
    */
    void update() override;

    /**
      Returns the name of this controller.
    */
    string name() const override { return "Driving"; }

    /**
      Answers whether the controller is intrinsically an analog controller.
    */
    bool isAnalog() const override { return true; }

    /**
      Determines how this controller will treat values received from the
      X/Y axis and left/right buttons of the mouse.  Since not all controllers
      use the mouse the same way (or at all), it's up to the specific class to
      decide how to use this data.

      In the current implementation, the left button is tied to the X axis,
      and the right one tied to the Y axis.

      @param xtype  The controller to use for x-axis data
      @param xid    The controller ID to use for x-axis data (-1 for no id)
      @param ytype  The controller to use for y-axis data
      @param yid    The controller ID to use for y-axis data (-1 for no id)

      @return  Whether the controller supports using the mouse
    */
    bool setMouseControl(
      Controller::Type xtype, int xid, Controller::Type ytype, int yid) override;

    /**
      Sets the sensitivity for digital emulation of driving controlle movement
      using a keyboard.

      @param sensitivity  Value from 1 to 20, with larger values causing
                          more movement (10 represents the baseline)
    */
    static void setSensitivity(int sensitivity);

  private:
    // Counter to iterate through the gray codes
    Int32 myCounter{0};

    // Index into the gray code table
    uInt32 myGrayIndex{0};

    // Y axis value from last yaxis event that was used to generate a new
    // gray code
    int myLastYaxis{0};

    // Pre-compute the events we care about based on given port
    // This will eliminate test for left or right port in update()
    Event::Type myCWEvent, myCCWEvent, myFireEvent,
                myXAxisValue, myYAxisValue;

    // Controller to emulate in normal mouse axis mode
    int myControlID{-1};

    // Controllers to emulate in 'specific' mouse axis mode
    int myControlIDX{-1}, myControlIDY{-1};

    // User-defined sensitivity; adjustable since end-users may prefer different
    // speeds
    static float SENSITIVITY;

  private:
    // Following constructors and assignment operators not supported
    Driving() = delete;
    Driving(const Driving&) = delete;
    Driving(Driving&&) = delete;
    Driving& operator=(const Driving&) = delete;
    Driving& operator=(Driving&&) = delete;
};

#endif