[DirectX][DirectInput]Summarize:Using the Keyboard

Step 1: Creating the DirectInput Object

// HINSTANCE  g_hinst; // initialized earlier
HRESULT         hr;
LPDIRECTINPUT8  g_lpDI;

hr = DirectInput8Create(g_hinst, DIRECTINPUT_VERSION,
        IID_IDirectInput8, (void**)&g_lpDI, NULL);
if FAILED(hr)
{
    // DirectInput not available; take appropriate action
}

Step 2: Creating the DirectInput Keyboard Device

HRESULT               hr; 
LPDIRECTINPUTDEVICE8  g_lpDIDevice 

hr = g_lpDI->CreateDevice(GUID_SysKeyboard, &g_lpDIDevice, NULL); 
if FAILED(hr) { 
    DI_Term(); 
    return FALSE; 
} 

Step 3: Setting the Keyboard Data Format 
 
hr = g_lpDIDevice->SetDataFormat(&c_dfDIKeyboard); 

if FAILED(hr) { 
    DI_Term(); 
    return FALSE; 
} 
 
Step 4: Setting the Keyboard Behavior  
 
hr = g_lpDIDevice->SetCooperativeLevel(g_hwndMain, 
		DISCL_FOREGROUND | DISCL_NONEXCLUSIVE); 

 if FAILED(hr) { 
    DI_Term(); 
    return FALSE; 
} 
 
Step 5: Gaining Access to the Keyboard 
 
if (g_lpDIDevice) g_lpDIDevice->Acquire(); 
 
Step 6: Retrieving Data from the Keyboard 
void WINAPI ProcessKBInput() 
{ 
    #define KEYDOWN(name, key) (name[key] & 0x80) 

 	char     buffer[256]; 
	HRESULT  hr; 

 
    hr = g_lpDIDevice->GetDeviceState(sizeof(buffer),(LPVOID)&buffer); 
	if FAILED(hr) 
	{ 
		// If it failed, the device has probably been lost. 
		// Check for (hr == DIERR_INPUTLOST) 
		// and attempt to reacquire it here. 
		return; 
	} 

 	// Turn the spaceship right or left 
    if (KEYDOWN(buffer, DIK_RIGHT)); 
		// Turn right. 
	else if(KEYDOWN(buffer, DIK_LEFT)); 
		// Turn left. 

 	// Thrust or stop the spaceship 
	if (KEYDOWN(buffer, DIK_UP)) ; 
		// Move the spaceship forward. 
	else if (KEYDOWN(buffer, DIK_DOWN)); 
		// Stop the spaceship. 
} 
 
Step 7: Closing Down the DirectInput System 
When an application is about to close, it should destroy all Microsoft® DirectInput® objects. This is a three-step process. 
  
Release access to all DirectInput devices (IDirectInputDevice8::Unacquire). 
Release all DirectInput devices (IDirectInputDevice8::Release). 
Release the DirectInput object (IDirectInput8::Release).
 
Sample Function 1: DI_Init
/* The following variables are presumed to be initialized:
HINSTANCE             g_hinst;    // application instance
HWND                  g_hwndMain; // application window
*/

LPDIRECTINPUT8        g_lpDI; 
LPDIRECTINPUTDEVICE8  g_lpDIDevice; 

BOOL WINAPI DI_Init() 
{ 
    HRESULT hr; 

    // Create the DirectInput object. 
    hr = DirectInput8Create(g_hinst, DIRECTINPUT_VERSION, 
                            IID_IDirectInput8, (void**)&g_lpDI, NULL); 

    if FAILED(hr) return FALSE; 

    // Retrieve a pointer to an IDirectInputDevice8 interface 
    hr = g_lpDI->CreateDevice(GUID_SysKeyboard, &g_lpDIDevice, NULL); 

    if FAILED(hr) 
    { 
        DI_Term(); 
        return FALSE; 
    } 

    // Now that you have an IDirectInputDevice8 interface, get 
    // it ready to use. 

    // Set the data format using the predefined keyboard data 
    // format provided by the DirectInput object for keyboards. 

    hr = g_lpDIDevice->SetDataFormat(&c_dfDIKeyboard); 

    if FAILED(hr) 
    { 
        DI_Term(); 
        return FALSE; 
    } 

    // Set the cooperative level 
    hr = g_lpDIDevice->SetCooperativeLevel(g_hwndMain, 
                             DISCL_FOREGROUND | DISCL_NONEXCLUSIVE); 
    if FAILED(hr) 
    { 
        DI_Term(); 
        return FALSE; 
    } 

    // Get access to the input device. 
    hr = g_lpDIDevice->Acquire(); 
    if FAILED(hr) 
    { 
        DI_Term(); 
        return FALSE; 
    } 

    return TRUE; 
}
Sample Function 2: DI_Term
/* The following variables are presumed initialized:
LPDIRECTINPUT8        g_lpDI; 
LPDIRECTINPUTDEVICE8  g_lpDIDevice; 
*/
 
void WINAPI DI_Term() 
{ 
    if (g_lpDI) 
    { 
        if (g_lpDIDevice) 
        { 
        // Always unacquire device before calling Release(). 
            g_lpDIDevice->Unacquire(); 
            g_lpDIDevice->Release();
            g_lpDIDevice = NULL; 
        } 
        g_lpDI->Release();
        g_lpDI = NULL; 
    } 
}