c++ - 如何使用Microsoft的IDirectInputDevice8在C++中实现操纵杆代码？

我需要执行阻止操作和非阻止操作 调用以使用 IDirectInputDevice8 接口(interface)在直接输入设备上进行轮询。

在linux中做阻塞，我们使用选择例如:

while( ::select(_jdev+1, &set, NULL, NULL, &tv) > 0)
{
    if( ::read( _jdev, &js, sizeof( js_event ) ) != sizeof( js_event ) )
    {
        perror( "Joystick : read error" );
        return;
    }

    _handleEvent( js );
}

我如何使用 idirectinputdevice8 接口(interface)做同样的事情:
https://msdn.microsoft.com/en-us/library/windows/desktop/ee417816(v=vs.85).aspx

即使我设置了 IDirectInputDevice8::SetEventNotification()，我仍然必须每次都调用poll()来获取新数据，但这不是可行的解决方案，因为它将导致cpu旋转。

我该怎么做？

***目前，我可以从操纵杆设备中查找，迭代，连接和获取数据。我只是没有实现阻止 call 。

...这里是我的实验/测试代码...请忽略语法错误

#include <windows.h>
#include <dinput.h>
#include <stdio.h>
#include <iostream>
#include <sstream>
#include "joystick.h"


LPDIRECTINPUT8 di;
HRESULT hr;
LPDIRECTINPUTDEVICE8 joystick;
DIDEVCAPS capabilities;

BOOL CALLBACK
enumCallback(const DIDEVICEINSTANCE* instance, VOID* context)
{
    HRESULT hr;
    hr = di->CreateDevice(instance->guidInstance, &joystick, NULL);
    if (FAILED(hr)) {
        return DIENUM_CONTINUE;
    }
    return DIENUM_STOP;
}

int JoyStickProp()
{
    if (FAILED(hr = joystick->SetDataFormat(&c_dfDIJoystick2))) {
        return hr;
    }
    if (FAILED(hr = joystick->SetCooperativeLevel(NULL, DISCL_EXCLUSIVE |
        DISCL_FOREGROUND))) {
        return hr;
    }
    capabilities.dwSize = sizeof(DIDEVCAPS);
    if (FAILED(hr = joystick->GetCapabilities(&capabilities))) {
        return hr;
    }
}

HRESULT JoyStickPoll(DIJOYSTATE2 *js)
{
    HRESULT     hr;

    if (joystick == NULL) {
        return S_OK;
    }

    // Poll the device to read the current state
    hr = joystick->Poll();
    if (FAILED(hr)) {
        hr = joystick->Acquire();
        while (hr == DIERR_INPUTLOST) {
            hr = joystick->Acquire();
        }

        if ((hr == DIERR_INVALIDPARAM) || (hr == DIERR_NOTINITIALIZED)) {
            return E_FAIL;
        }

        // If another application has control of this device, return successfully.
        // We'll just have to wait our turn to use the joystick.
        if (hr == DIERR_OTHERAPPHASPRIO) {
            return S_OK;
        }
    }

    // Get the input's device state
    if (FAILED(hr = joystick->GetDeviceState(sizeof(DIJOYSTATE2), js))) {
        return hr; // The device should have been acquired during the Poll()
    }

    return S_OK;
}

int main()
{


    // Create a DirectInput device
    if (FAILED(hr = DirectInput8Create(GetModuleHandle(NULL), DIRECTINPUT_VERSION,
        IID_IDirectInput8, (VOID**)&di, NULL))) {
        return hr;
    }

    // Look for the first simple joystick we can find.
    if (FAILED(hr = di->EnumDevices(DI8DEVCLASS_GAMECTRL, enumCallback,
        NULL, DIEDFL_ATTACHEDONLY))) {
        return hr;
    }
    // Make sure we got a joystick
    if (joystick == NULL) {
        printf("Joystick not found.\n");
        return E_FAIL;
    }

    JoyStickProp();
    DIJOYSTATE2 diState;

    HANDLE ghWriteEvent;
    // Create joystick event stuff here
    ghWriteEvent = CreateEvent(
        NULL,               // default security attributes
        FALSE,               // manual-reset event
        FALSE,              // initial state is nonsignaled
        TEXT("WriteEvent")  // object name
        );

    //makesure we can read fromt the joystick before waiting for an event
    JoyStickPoll(&diState);
    printf("x axis %d", diState.lX);
    printf("y axis %d", diState.lY);
    JoyStickPoll(&diState);
    printf("x axis %d", diState.lX);
    printf("y axis %d", diState.lY);
    JoyStickPoll(&diState);
    printf("x axis %d", diState.lX);
    printf("y axis %d", diState.lY);
    JoyStickPoll(&diState);
    printf("x axis %d", diState.lX);
    printf("y axis %d", diState.lY);
    JoyStickPoll(&diState);
    printf("x axis %d", diState.lX);
    printf("y axis %d", diState.lY);
    JoyStickPoll(&diState);
    printf("x axis %d", diState.lX);
    printf("y axis %d", diState.lY);
joystick->SetEventNotification(ghWriteEvent);
    while (TRUE) {

        DWORD dwResult = WaitForSingleObject(
            ghWriteEvent, // event handle
            INFINITE);

        switch (dwResult) {
        case WAIT_OBJECT_0:
            // Event 1 has been set. If the event was created as
            // autoreset, it has also been reset.
            int x = 0;
            //ProcessInputEvent1();
            break;
        }
    }
}

最佳答案

IDirectInputDevice8::SetEventNotification() 的MSDN文档为您提供了相关的代码段。

您需要调用 CreateEvent() 并将返回的HANDLE提供为SetEventNotification()的参数。状态更改发生时，将为您发出事件信号。您可以等待事件，然后在收到通知后，使用 IDirectInputDevice8::GetDeviceState() 获取新的状态数据。

所有标准Wait Functions适用于等待事件被信号通知。以下代码段向您展示了一种使用 MsgWaitForMultipleObjects() 的方式:

while (TRUE) {

    dwResult = MsgWaitForMultipleObjects(2, ah, FALSE, INFINITE, QS_ALLINPUT);
    switch (dwResult) {
        case WAIT_OBJECT_0:
            // Event 1 has been set. If the event was created as
            // autoreset, it has also been reset.
            ProcessInputEvent1();
            break;

IDirectInputDevice8::Poll() 方法用于不生成事件通知的设备。您应该对它们进行轮询，因为它们无法按照您希望的方式进行操作。



仅在需要通知的设备不起作用时才轮询。上面的链接说明了如何确定是否需要轮询。