D3D 的初始化（万事开头难，找了很久哦）

/****************************************************************
* example2
* shows the user how to setup a windowed directx application
* which clears the window to a blue color
****************************************************************/
#include <windows.h>

// include directx9
#include <d3d9.h>

#pragma comment(lib,"d3d9.lib")
#pragma comment(lib,"d3dx9.lib")

// global variables
HINSTANCE hInst;       // application instance
HWND wndHandle;        // application window handle

LPDIRECT3D9             pD3D;    // the Direct3D Object
LPDIRECT3DDEVICE9       pd3dDevice;   // the Direct3D Device

// forward declarations
bool initWindow(HINSTANCE hInstance);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

// DirectX functions
bool initDirect3D(); 
void render(void);

/*********************************************************************
* WinMain
*********************************************************************/
int WINAPI WinMain(HINSTANCE hInstance,
       HINSTANCE hPrevInstance,
       LPTSTR lpCmdLine, int nCmdShow)
{
 if (!initWindow(hInstance))
 {
  MessageBox(NULL, "Unable to create window", "ERROR", MB_OK);
  return false;
 }

 if (!initDirect3D())
 {
  MessageBox(NULL, "Unable to init Direct3D", "ERROR", MB_OK);
  return false;
 }

 // Main message loop:
    MSG msg;
    ZeroMemory( &msg, sizeof(msg) );
    while( msg.message!=WM_QUIT )
    {
  if( PeekMessage( &msg, NULL, 0U, 0U, PM_REMOVE ) )
        {
   TranslateMessage( &msg );
            DispatchMessage( &msg );
        }  
  else
  {
   render();
  }
    }

 // release the device and the direct3D object
 if( pd3dDevice != NULL)
        pd3dDevice->Release();

    if( pD3D != NULL)
        pD3D->Release();
  
 return (int) msg.wParam;
}

/*********************************************************************
* initWindow
*********************************************************************/
bool initWindow(HINSTANCE hInstance)
{
 WNDCLASSEX wcex;

 wcex.cbSize = sizeof(WNDCLASSEX);
 wcex.style   = CS_HREDRAW | CS_VREDRAW;
 wcex.lpfnWndProc = (WNDPROC)WndProc;
 wcex.cbClsExtra  = 0;
 wcex.cbWndExtra  = 0;
 wcex.hInstance  = hInstance;
 wcex.hIcon   = 0;
 wcex.hCursor  = LoadCursor(NULL, IDC_ARROW);
 wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
 wcex.lpszMenuName = NULL;
 wcex.lpszClassName = "DirectXExample";
 wcex.hIconSm  = 0;
 RegisterClassEx(&wcex);

 // create the window
 wndHandle = CreateWindow("DirectXExample",
        "DirectXExample",
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        640,
        480,
        NULL,
        NULL,
        hInstance,
        NULL);
   if (!wndHandle)
      return false;
  
   ShowWindow(wndHandle, SW_SHOW);
   UpdateWindow(wndHandle);

   return true;
}

/*********************************************************************
* WndProc
*********************************************************************/
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
 switch (message)
 {
  case WM_DESTROY:
   PostQuitMessage(0);
   break;
 }
 return DefWindowProc(hWnd, message, wParam, lParam);
}

/*********************************************************************
* initDirect3D
* initializes direct3D
*********************************************************************/
bool initDirect3D()
{
 pD3D = NULL;
 pd3dDevice = NULL;

 // create the directX object
 if( NULL == ( pD3D = Direct3DCreate9( D3D_SDK_VERSION ) ) )
 {
  return false;
 }

 // fill the presentation parameters structure
 D3DPRESENT_PARAMETERS d3dpp;
    ZeroMemory( &d3dpp, sizeof(d3dpp) );
    d3dpp.Windowed = TRUE;
    d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
    d3dpp.BackBufferFormat = D3DFMT_UNKNOWN;
 d3dpp.BackBufferCount  = 1;
 d3dpp.BackBufferHeight = 480;
 d3dpp.BackBufferWidth  = 640;
 d3dpp.hDeviceWindow    = wndHandle;

 // create a default directx device
    if( FAILED( pD3D->CreateDevice( D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, wndHandle,
                                      D3DCREATE_SOFTWARE_VERTEXPROCESSING,
                                      &d3dpp, &pd3dDevice ) ) )
    {
        return false;
    }
 return true;
}

/*********************************************************************
* render
*********************************************************************/
void render(void)
{
 // check to make sure we have a valid Direct3D Device
 if( NULL == pd3dDevice )
        return;

    // Clear the backbuffer to a blue color
    pd3dDevice->Clear( 0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0,0,255), 1.0f, 0 );

 // Present the backbuffer contents to the display
    pd3dDevice->Present( NULL, NULL, NULL, NULL );
}