c++ programming for joystick in windows

Question

i want to connect joystick to my c++ qt program in windows.I studied about programming with win32 api using the joystickapi library in microsoft guid for joystick program But I didn't understand exactly What should I do after checking the system compatibility?

Completion description:

my code for system compatibility:

JOYINFO joyinfo;
UINT wNumDevs, wDeviceID;
BOOL bDev1Attached, bDev2Attached;
void joyCapablitis(){
    if((wNumDevs = joyGetNumDevs()) == 0)
        qDebug()<<"no driver available";
    bDev1Attached = joyGetPos(JOYSTICKID1,&joyinfo) != JOYERR_UNPLUGGED;
    bDev2Attached = wNumDevs == 2 && joyGetPos(JOYSTICKID2,&joyinfo) !=
            JOYERR_UNPLUGGED;
    if(bDev1Attached || bDev2Attached)   // decide which joystick to use
    {

        wDeviceID = bDev1Attached ? JOYSTICKID1 : JOYSTICKID2;

    }
    else
        qDebug()<<"no device available";

}

I want to track the movement of buttons and simulate it in software.How can I get joystick information (such as number of button and button on or off) from win32 api?

Answer 1

I wrote a QJoystick lib in a form of a Qt module but it's not yet released.

Here is a bit of code for Windows.

First, you need to initialize DirectInput:

#include "comdef.h"

#define SAFE_DELETE(p)  { if(p) { delete (p);     (p) = nullptr; }}
#define SAFE_RELEASE(p) { if(p) { (p)->Release(); (p) = nullptr; }}

#define AS(x, p) reinterpret_cast<x>(p)

BOOL CALLBACK EnumJoysticksCallback(const DIDEVICEINSTANCE*       deviceInstance, void* controller);
BOOL CALLBACK EnumObjectsCallback  (const DIDEVICEOBJECTINSTANCE* objectInstance, void* controller);

static LPDIRECTINPUT8 DirectInputPtr = nullptr;

HRESULT hr;

if (DirectInputPtr == nullptr)
{
    if (FAILED(hr = DirectInput8Create(GetModuleHandle(nullptr), DIRECTINPUT_VERSION, IID_IDirectInput8, AS(void**, &DirectInputPtr), nullptr)))
        qCritical("QJoystick failed to obtain direct input interface: %s", qPrintable(hrError(hr)));
}

Second, setup callbacks:

if (DirectInputPtr)
{
    if (FAILED(hr = DirectInputPtr->EnumDevices(DI8DEVCLASS_GAMECTRL, EnumJoysticksCallback, this, DIEDFL_ATTACHEDONLY)))
        qDebug("QJoystick EnumDevices failed");

    if (joystickPtr)
    {
        if (FAILED(hr = joystickPtr->SetDataFormat(&c_dfDIJoystick2)))
            qWarning("QJoystick: failed to set data format for id %d", deviceId);

        if (SUCCEEDED(hr = joystickPtr->EnumObjects(EnumObjectsCallback, this, DIDFT_ALL)))
        {
            DIDEVICEINSTANCE joystickinfo;
            joystickinfo.dwSize = sizeof(joystickinfo);

            if (FAILED(hr = joystickPtr->GetDeviceInfo(&joystickinfo)))
            {
                qCritical() << "QJoystick GetDeviceInfo failed:" << hrError(hr);
                SAFE_RELEASE(joystickPtr)
            }

            description = QString::fromWCharArray(joystickinfo.tszProductName);
            guid        = QString("%1").arg(joystickinfo.guidProduct.Data1, 8, 16, QLatin1Char('0'));
        }
        else
            qCritical("QJoystick: set callback on EnumObjects failed for %d", deviceId);
    }
}

EnumJoysticksCallback is where you create a virtual device for your joystick:

BOOL CALLBACK EnumJoysticksCallback(const DIDEVICEINSTANCE* deviceInstance, void* pController)
{
    QJoystickPrivate* controller = AS(QJoystickPrivate*, pController);
    BOOL result = DIENUM_CONTINUE;

    if (controller->enumCounter == controller->deviceId)
    {
        HRESULT hr = DirectInputPtr->CreateDevice(deviceInstance->guidInstance, &(controller->joystickPtr), nullptr);

        if (SUCCEEDED(hr))
            result = DIENUM_STOP;
        else
            qWarning("QJoystick: CreateDevice failed %d", controller->deviceId);
    }
    else
        ++controller->enumCounter;

    return result;
}

And EnumObjectsCallback will be executed for every button or axis during the enumeration process:

BOOL CALLBACK EnumObjectsCallback(const DIDEVICEOBJECTINSTANCE* objectInstance, void* pController)
{
    QJoystickPrivate* controller = AS(QJoystickPrivate*, pController);

    //Set the range for axis
    if (objectInstance->dwType & DIDFT_AXIS)
    {
        DIPROPRANGE diprg;

        diprg.diph.dwSize       = sizeof(DIPROPRANGE);
        diprg.diph.dwHeaderSize = sizeof(DIPROPHEADER);
        diprg.diph.dwHow        = DIPH_BYID;
        diprg.diph.dwObj        = objectInstance->dwType; // Specify the enumerated axis

        diprg.lMin = -1000;
        diprg.lMax = +1000;

        if (FAILED(controller->joystickPtr->SetProperty(DIPROP_RANGE, &diprg.diph)))
            return DIENUM_STOP;
    }

    if (objectInstance->guidType == GUID_XAxis  || objectInstance->guidType == GUID_YAxis  || objectInstance->guidType == GUID_ZAxis  ||
        objectInstance->guidType == GUID_RxAxis || objectInstance->guidType == GUID_RyAxis || objectInstance->guidType == GUID_RzAxis ||
        objectInstance->guidType == GUID_Slider)
    {
        // axis
    }
    else if (objectInstance->guidType == GUID_POV)
        // pov...
    else if (objectInstance->guidType == GUID_Button)
        // button...
    else if (objectInstance->guidType == GUID_Unknown)
        // unknown...

    return DIENUM_CONTINUE;
}