学步园

第一步

添加类

class CUImageDC
{
public:

 CUImageDC();
 virtual ~CUImageDC();

 void Delete();
 void Create(int nWidth, int nHeight);

 HDC GetSafeHdc(void){
  return m_hDC;
 }
 HBITMAP GetBmpHandle(void){
  return m_hBmp;
 }
 DWORD* GetBits(void){
  return (DWORD*)m_pBits;
 }

protected:

 HBITMAP m_hBmp;
 HDC  m_hDC;
 char*   m_pBits;
};

CUImageDC::CUImageDC()
{
 m_pBits = NULL;
 m_hBmp  = NULL;
 m_hDC = NULL;
}

CUImageDC::~CUImageDC()
{
 Delete();
}

void CUImageDC::Create(int nWidth, int nHeight)
{
 BITMAPINFOHEADER bih;
 memset(&bih, 0, sizeof(BITMAPINFOHEADER));
 bih.biSize  = sizeof(BITMAPINFOHEADER);
 bih.biWidth  = ((((int)nWidth * 8) + 31) & ~31) >> 3;
 bih.biHeight = nHeight;
 bih.biPlanes = 1;
 bih.biBitCount = 32;
 bih.biCompression = BI_RGB;
 m_hBmp = NULL;
 m_hDC = CreateCompatibleDC(NULL);
 m_hBmp = ::CreateDIBSection(
  GetSafeHdc(), (BITMAPINFO*)&bih,
  DIB_RGB_COLORS, (void**)(&m_pBits), NULL, 0);
 SelectObject(m_hDC, m_hBmp);
}

void CUImageDC::Delete()
{
 if (m_hBmp)
  DeleteObject(m_hBmp);
 if (m_hDC)
  DeleteDC(m_hDC);
}

第二步

创建变量

LPDIRECT3DSURFACE9      g_pd3dSurface   = NULL;
CUImageDC   g_dcSurface;

第三步

在创建好设备后添加

 if (FAILED(g_D3DDevice->CreateRenderTarget(640, 480,
    D3DFMT_A8R8G8B8, D3DMULTISAMPLE_NONE, 0,
    /*!g_is9Ex*/false, // lockable
    &g_pd3dSurface, NULL)))
   {
    return NULL;
   }
   g_D3DDevice->SetRenderTarget(0, g_pd3dSurface);
   g_D3DDevice->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);
   // turn off D3D lighting to use vertex colors
   g_D3DDevice->SetRenderState(D3DRS_LIGHTING, FALSE);
   // Enable alpha blending.
   g_D3DDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, TRUE);

   g_dcSurface.Create(640, -480);
    SetWindowLong(hWnd, GWL_EXSTYLE, (GetWindowLong(hWnd, GWL_EXSTYLE) & ~WS_EX_TRANSPARENT) | WS_EX_LAYERED);

第四步

在渲染函数中添加

   D3DLOCKED_RECT lockedRect;

   RECT rc, rcSurface = {0, 0, 640, 480};
   ::GetWindowRect(hWnd, &rc);
   POINT ptWinPos = { rc.left, rc.top};
   POINT ptSrc = { 0, 0};
   SIZE szWin = { 640, 480 };
   BLENDFUNCTION stBlend = { AC_SRC_OVER, 0, 255, AC_SRC_ALPHA };
   HDC  hdcWnd = GetWindowDC(hWnd);
   LPDIRECT3DSURFACE9      g_psysSurface   = NULL;
   g_D3DDevice->CreateOffscreenPlainSurface(640, 480,
    D3DFMT_A8R8G8B8, D3DPOOL_SYSTEMMEM, &g_psysSurface, NULL);
   g_D3DDevice->GetRenderTargetData(g_pd3dSurface, g_psysSurface);
   g_psysSurface->LockRect(&lockedRect, &rcSurface, D3DLOCK_READONLY);
   memcpy(g_dcSurface.GetBits(), lockedRect.pBits, 4 * 640 * 480);
   UpdateLayeredWindow(hWnd, hdcWnd, &ptWinPos, &szWin, g_dcSurface.GetSafeHdc(), &ptSrc, RGB(255,255,255), &stBlend, ULW_ALPHA| ULW_COLORKEY);
   g_psysSurface->UnlockRect();
   g_psysSurface->Release();

完成后 窗体为透明色,  可以绘制各种无窗体的图形和文理