joystickdriver.h

Go to the documentation of this file.

/*******************************************************************************
  Copyright(c) 2013-2026 Jasem Mutlaq. All rights reserved.
 
  Based on code by Keith Lantz.
 
  This program is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by the Free
  Software Foundation; either version 2 of the License, or (at your option)
  any later version.
 
  This program is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  more details.
 
  You should have received a copy of the GNU Library General Public License
  along with this library; see the file COPYING.LIB.  If not, write to
  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  Boston, MA 02110-1301, USA.
 
  The full GNU General Public License is included in this distribution in the
  file called LICENSE.
*******************************************************************************/
 
#pragma once
 
#include <iostream>
#include <functional>
#include <algorithm>
#include <fcntl.h>
#include <pthread.h>
#include <cmath>
#include <cstdint>
#include <linux/joystick.h>
#include <vector>
#include <unistd.h>
 
#define JOYSTICK_DEV "/dev/input/js0"
 
// ─────────────────────────────────────────────────────────────────────────────
// ABS event-code constants (subset of linux/input-event-codes.h).
// Duplicated so we don't require a separate evdev header.
// ─────────────────────────────────────────────────────────────────────────────
#ifndef ABS_X
#define ABS_X        0x00
#define ABS_Y        0x01
#define ABS_Z        0x02   
#define ABS_RX       0x03
#define ABS_RY       0x04
#define ABS_RZ       0x05   
#define ABS_THROTTLE 0x06
#define ABS_RUDDER   0x07
#define ABS_WHEEL    0x08
#define ABS_GAS      0x09
#define ABS_BRAKE    0x0a
#define ABS_HAT0X    0x10
#define ABS_HAT0Y    0x11
#define ABS_HAT1X    0x12
#define ABS_HAT1Y    0x13
#define ABS_HAT2X    0x14
#define ABS_HAT2Y    0x15
#define ABS_HAT3X    0x16
#define ABS_HAT3Y    0x17
#endif
 
typedef struct
{
    float theta, r, x, y;
} joystick_position;
 
typedef struct
{
    std::vector<signed short> button;
    std::vector<signed short> axis;
} joystick_state;
 
enum class JoyAxisType
{
    STICK,    
    TRIGGER,  
    HAT,      
    UNKNOWN
};
 
struct JoyAxisPair
{
    int     i0;     
    int     i1;     
    uint8_t absX;   
    uint8_t absY;   
    bool    isHat;  
    const char *name; 
};
 
class JoyStickDriver
{
    public:
        JoyStickDriver();
        ~JoyStickDriver();
 
        typedef std::function<void(int joystick_n, double mag, double angle)> joystickFunc;
        typedef std::function<void(int axis_n, double value)> axisFunc;
        typedef std::function<void(int button_n, int value)> buttonFunc;
 
        bool Connect();
        bool Disconnect();
 
        void setPort(const char *port);
        void setPoll(int ms);
 
        const char *getName();
        uint32_t getVersion();
 
        // ── Axis / joystick counts ────────────────────────────────────────
        uint8_t getNumOfAxes();
        uint8_t getNumrOfButtons();
 
        uint8_t getNumOfJoysticks();
 
        // ── Per-axis type information ─────────────────────────────────────
        uint8_t getAxisAbsCode(int axis) const;
 
        JoyAxisType getAxisType(int axis) const;
 
        const char *getAxisLabel(int axis) const;
 
        const JoyAxisPair *getJoystickPair(int n) const;
 
        // ── Position / button queries ─────────────────────────────────────
        joystick_position joystickPosition(int n);
        bool buttonPressed(int n);
 
        // ── Callbacks ─────────────────────────────────────────────────────
        void setJoystickCallback(joystickFunc joystickCallback);
        void setAxisCallback(axisFunc axisCallback);
        void setButtonCallback(buttonFunc buttonCallback);
 
        // ── Calibration ───────────────────────────────────────────────────
        void setAxisCalibration(int axis, int center, int minVal, int maxVal);
 
        void setAxisReversed(int axis, bool reversed);
 
    protected:
        static void joystickEvent(int joystick_n, double mag, double angle);
        static void axisEvent(int axis_n, int value);
        static void buttonEvent(int button_n, int value);
 
        static void *loop(void *obj);
        void readEv();
 
        joystickFunc joystickCallbackFunc;
        buttonFunc   buttonCallbackFunc;
        axisFunc     axisCallbackFunc;
 
    private:
        pthread_t thread;
        bool active;
        int joystick_fd;
        js_event      *joystick_ev;
        joystick_state *joystick_st;
        uint32_t version;
        uint8_t  axes;
        uint8_t  buttons;
        char name[256];
        char dev_path[256];
        int  pollMS;
 
        // ── Axis map (from JSIOCGAXMAP) ───────────────────────────────────
        std::vector<uint8_t> m_axmap;
 
        std::vector<JoyAxisPair> m_stickPairs;
 
        std::vector<int> m_axisToPairIndex;
 
        // ── Per-axis calibration ──────────────────────────────────────────
        std::vector<int>  m_calCenter;
        std::vector<int>  m_calMin;
        std::vector<int>  m_calMax;
 
        // ── Per-axis reversal ─────────────────────────────────────────────
        std::vector<bool> m_axisReversed;
 
        // ── Helpers ───────────────────────────────────────────────────────
        float normalizeAxis(int value, int idx) const;
 
        static JoyAxisType classifyAbsCode(uint8_t absCode);
 
        static const char *absCodeLabel(uint8_t code);
 
        void buildAxisPairs();
};