Question

我需要使用 IDirectInputDevice8 界面对直接输入设备进行阻止和非阻止调用进行轮询。

在linux中进行阻止，我们使用选择 ex：

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 );
}

如何使用 idirectinputdevice8 界面执行相同的操作： https://msdn.microsoft.com/en-us/library/windows/desktop/ee417816(v=vs.85).aspx

即使我设置 IDirectInputDevice8 :: SetEventNotification（），我仍然必须每次调用poll（）来获取新数据，这是不可行的解决方案，因为它会导致cpu旋转。

我怎样才能做到这一点？

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

...这是我的实验/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;
        }
    }
}

Answer 1

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

您需要致电CreateEvent()并将返回的HANDLE作为参数提供给SetEventNotification()。当状态发生变化时，将向您发出事件信号。您可以等待该事件，然后在收到通知后，您将使用IDirectInputDevice8::GetDeviceState()获取新的状态数据。

所有标准Wait Functions适用于等待发出信号的事件。以下代码段使用MsgWaitForMultipleObjects()：

向您展示了一种方式

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。您应该轮询它们，因为它们无法以您希望的方式运行。

一些操纵杆和其他游戏设备，或其上的特定物体，do not generate hardware interrupts and do not return any data or signal any events until you call the IDirectInputDevice8::Poll method。

只有当您需要通知设备时，才会进行投票。上面的链接解释了如何确定是否有必要进行轮询。

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

1 个答案: