c++ – DirectX 11 Desktop Duplication API: Captured Frame Data is All Zeros

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I’m developing a screen capture application using DirectX 11 and the Desktop Duplication API in C++. The goal is to capture the screen content and process it. However, I’m encountering an issue where the captured frame data is always all zeros.

Steps I’ve Taken

Initialized DirectX Components:
Created ID3D11Device, ID3D11DeviceContext, and IDXGIOutputDuplication.

Acquired the Frame:
Used AcquireNextFrame to capture the frame.

Converted the Resource to Texture:
Used QueryInterface to convert the resource to ID3D11Texture2D.

Copied the Resource to a Staging Texture:
Used CopyResource to copy the acquired texture to a staging texture.

Mapped the Staging Texture:
Mapped the staging texture to access the data.

Debugging Steps

Enabled the DirectX Debug Layer.

Verified that the acquired and staging textures have matching descriptions.

Ensured the staging texture is correctly initialized.

Issue

Despite following these steps, the captured frame data is always zeros. The debug output shows no errors, and the texture descriptions match.

Here are the relevant code snippets:

Initialization and Frame Acquisition:

HRESULT hr;
Microsoft::WRL::ComPtr dxgiDevice;
Microsoft::WRL::ComPtr device;
Microsoft::WRL::ComPtr context;
hr = D3D11CreateDevice(nullptr, D3D_DRIVER_TYPE_HARDWARE, nullptr, 0, nullptr, 0, D3D11_SDK_VERSION, &device, nullptr, &context);
device.As(&dxgiDevice);
Microsoft::WRL::ComPtr dxgiOutput1;
Microsoft::WRL::ComPtr deskDupl;
dxgiOutput1->DuplicateOutput(device.Get(), &deskDupl);
Microsoft::WRL::ComPtr desktopResource;
DXGI_OUTDUPL_FRAME_INFO frameInfo;
deskDupl->AcquireNextFrame(500, &frameInfo, &desktopResource);

Resource to Texture Conversion:

Microsoft::WRL::ComPtr acquiredDesktopImage;
desktopResource.As(&acquiredDesktopImage);

Copying Resource to Staging Texture:

D3D11_TEXTURE2D_DESC desc;
desc.Width = 1920;
desc.Height = 1080;
desc.MipLevels = 1;
desc.ArraySize = 1;
desc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
desc.SampleDesc.Count = 1;
desc.Usage = D3D11_USAGE_STAGING;
desc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
Microsoft::WRL::ComPtr stagingTex;
device->CreateTexture2D(&desc, nullptr, &stagingTex);
context->CopyResource(stagingTex.Get(), acquiredDesktopImage.Get());

Mapping and Accessing Staging Texture Data:

D3D11_MAPPED_SUBRESOURCE mappedResource;
context->Map(stagingTex.Get(), 0, D3D11_MAP_READ, 0, &mappedResource);
std::vector buffer(mappedResource.RowPitch * desc.Height);
memcpy(buffer.data(), mappedResource.pData, buffer.size());
context->Unmap(stagingTex.Get(), 0);

Output:

Output Device: \\.\DISPLAY6
Frame acquired successfully.
Resource converted to texture successfully.
Acquired Texture Width: 1920 Height: 1080
Acquired Texture Format: 87
CopyResource called.
Staging Texture Width: 1920 Height: 1080
RowPitch: 7680
First 64 bytes of mapped data after CopyResource:
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Why is the captured frame data all zeros despite following these steps? How can I resolve this issue and correctly capture the screen content using the Desktop Duplication API?

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