DXGI屏幕捕获扭曲的图像

Question

Not only that the fps drops form 60 to 20-21 but the image also looks distorted like this. Second image is what it should look like

What it looks like What it should look like

if (captureVideo == 1) {
    pNewTexture = NULL;

    // Use the IDXGISwapChain::GetBuffer API to retrieve a swap chain surface ( use the uuid  ID3D11Texture2D for the result type ).
    pSwapChain->GetBuffer( 0, __uuidof( ID3D11Texture2D ), reinterpret_cast< void** >( &pSurface ) ); 

    /* The swap chain buffers are not mapable, so I need to copy it to a staging resource. */

    pSurface->GetDesc( &description ); //Use ID3D11Texture2D::GetDesc to retrieve the surface description

    // Patch it with a D3D11_USAGE_STAGING usage and a cpu access flag of D3D11_CPU_ACCESS_READ
    description.BindFlags = 0;
    description.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
    description.Usage = D3D11_USAGE_STAGING;

    // Create a temporary surface ID3D11Device::CreateTexture2D
    HRESULT hr = pDevice->CreateTexture2D( &description, NULL, &pNewTexture );
    if( pNewTexture )
    {
        // Copy to the staging surface ID3D11DeviceContext::CopyResource
        pContext->CopyResource( pNewTexture, pSurface );
        // Now I have a ID3D11Texture2D with the content of your swap chain buffer that allow you to use the ID3D11DeviceContext::Map API to read it on the CPU
        D3D11_MAPPED_SUBRESOURCE resource;
        pContext->Map( pNewTexture, D3D11CalcSubresource( 0, 0, 0), D3D11_MAP_READ, 0, &resource );

        const int pitch = w << 2;
        const unsigned char* source = static_cast< const unsigned char* >( resource.pData );
        unsigned char* dest = static_cast< unsigned char* >(m_lpBits);
        for( int i = 0; i < h; ++i )
        {
            memcpy( dest, source, w * 4 );
            source += pitch;
            dest += pitch;
        }

        AppendNewFrame(w, h, m_lpBits,24);

        pContext->Unmap( pNewTexture, 0);
        pNewTexture->Release();
    }
}

Answer 1

The code snippet even though incomplete shows several potential problems:

1. Number of 24 in AppendNewFrame line suggests that you are trying to treat the data as 24-bit RGB, and your data is 32-bit RGB. Such mistreatment matches the artifacts exhibited on the attached images;
2. Pitch/stride is taken as assumed default, while you have the effectively used one in D3D11_MAPPED_SUBRESOURCE structure and you should be using it.