Directx9在窗口周围产生灰色轮廓

Question

所以我现在正在学习如何使用Directx9。我已经做了一个透明的窗口。我设法在屏幕上得到一个三角形，但是，每当我绘制时，透明窗口周围都会出现一条细的灰色线。我已经尝试使用DwmExtendFrameIntoClientArea使窗口透明，但是这样做时我看不到图形。我想知道是否有人知道为什么会这样，因为在我使用Directx9绘制之前，我的窗口是100％透明的，周围没有边框。先谢谢了！ （很抱歉，图片太大了，我不知道如何将其缩小）

Directx9代码：

 #include <DirectXDraw.h>

LPDIRECT3D9 d3d;
LPDIRECT3DDEVICE9 d3ddev;
LPDIRECT3DVERTEXBUFFER9 v_buffer;

#define CUSTOMFVF (D3DFVF_XYZRHW | D3DFVF_DIFFUSE)


struct CUSTOMVERTEX
{
    float x, y, z, rhw;
    DWORD color;
};

void InitD3D(HWND hWnd)
{
    d3d = Direct3DCreate9(D3D_SDK_VERSION);

    D3DPRESENT_PARAMETERS d3dpp;
    ZeroMemory(&d3dpp, sizeof(d3dpp));
    d3dpp.Windowed = true;
    d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
    d3dpp.hDeviceWindow = hWnd;

    d3d->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hWnd, D3DCREATE_SOFTWARE_VERTEXPROCESSING, &d3dpp, &d3ddev);

    if (hWnd == NULL)
    {
        std::cout << "hWNd is NULL";
    }
}

void Init_Graphics()
{
    CUSTOMVERTEX OurVertices[] =
    {
        {350, 50, 1.0f, 1.0f, D3DCOLOR_XRGB(500, 0, 0)},
        {550, 420, 1.0f, 1.0f, D3DCOLOR_XRGB(500, 0, 0)},
        {250, 420, 1.0f, 1.0f, D3DCOLOR_XRGB(500, 0, 0)},
    };    

    d3ddev->CreateVertexBuffer(3 * sizeof(CUSTOMVERTEX), 0, CUSTOMFVF, D3DPOOL_MANAGED, &v_buffer, NULL);

    void* pVoid;

    v_buffer->Lock(0, 0, &pVoid, NULL);

    memcpy(pVoid, OurVertices, sizeof(OurVertices));

    v_buffer->Unlock();
}

void Render_Frame()
{
    d3ddev->Clear(0, NULL, D3DCLEAR_TARGET, 0, 1.0f, 0);

    d3ddev->BeginScene();


    d3ddev->SetFVF(CUSTOMFVF);
    d3ddev->SetStreamSource(0, v_buffer, 0, sizeof(CUSTOMVERTEX));
    d3ddev->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 1);


    d3ddev->EndScene();

    d3ddev->Present(NULL, NULL, NULL, NULL);
}

void CleanD3D()
{
    v_buffer->Release();
    d3d->Release();
    d3ddev->Release();
}