I am trying to make a desktop recorder, but all i get, is black screen, i have no clue why at all. I tried with dx9, but same thing when i use backbuffer, front buffer method does work, and it can capture the frames correctly, but it's too slow (33ms per frame, and all because of GetFrontBuffer).
So i decided to try with dx11, there are no errors from return, no errors when creating swapchain and device, everything is fine, and in fact the frames are captured(i measure the time and fps, and something is going on), but they are all black, like it's not coming from the desktop, but from somewhere else.
This is the capture method
if(contains_errors()){return;}
m_swap_chain->GetBuffer(0, __uuidof(ID3D11Resource), (void**)&m_back_buffer_ptr);
return_if_null(m_back_buffer_ptr);
HRESULT hr = m_back_buffer_ptr->QueryInterface(__uuidof(ID3D11Resource), (void**)&m_back_buffer_data);
return_if_failed(hr);
hr = m_swap_chain->GetDevice(__uuidof(ID3D11Device), (void**)&m_device);
return_if_failed(hr);
hr = m_swap_chain->GetDesc(&m_desc);
return_if_failed(hr);
ID3D11Texture2D* texture = nullptr;
hr = m_device->CreateTexture2D(&m_tex_desc, 0, &texture);
return_if_failed(hr);
ID3D11DeviceContext* context = nullptr;
m_device->GetImmediateContext(&context);
return_if_null(context);
context->CopyResource(texture, m_back_buffer_data);
D3D11_MAPPED_SUBRESOURCE map_subres = {0, 0, 0};
hr = context->Map(texture, 0, D3D11_MAP_READ, 0, &map_subres);
return_if_failed(hr);
if(m_current_frame == 0)
{
m_current_frame = new BYTE[map_subres.DepthPitch];
}
memcpy(m_current_frame, map_subres.pData, map_subres.DepthPitch);
texture->Release();
m_device->Release();
This is the texture desc setup
ZeroMemory(&m_tex_desc, sizeof(m_tex_desc));
m_tex_desc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
m_tex_desc.Width = m_desc.BufferDesc.Width;
m_tex_desc.Height = m_desc.BufferDesc.Height;
m_tex_desc.MipLevels = 1;
m_tex_desc.ArraySize = 1;
m_tex_desc.SampleDesc.Count = 1;
m_tex_desc.Usage = D3D11_USAGE_STAGING;
m_tex_desc.BindFlags = 0;
m_tex_desc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
m_tex_desc.MiscFlags = 0;
This is swapchain desc
m_desc.BufferDesc.Width = 1366;
m_desc.BufferDesc.Height = 768;
m_desc.BufferDesc.RefreshRate.Numerator = 1;
m_desc.BufferDesc.RefreshRate.Denominator = 60;
m_desc.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
m_desc.BufferDesc.ScanlineOrdering = DXGI_MODE_SCANLINE_ORDER_UNSPECIFIED;
m_desc.BufferDesc.Scaling = DXGI_MODE_SCALING_UNSPECIFIED;
m_desc.SampleDesc.Count = 2;
m_desc.SampleDesc.Quality = 0;
m_desc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
m_desc.BufferCount = 1;
m_desc.OutputWindow = (HWND)m_dx_win->winId();
m_desc.Windowed = true;
m_desc.SwapEffect = DXGI_SWAP_EFFECT_DISCARD;
m_desc.Flags = 0;
Class members
private:
IDXGISwapChain* m_swap_chain = 0;
ID3D11DeviceContext* m_context = 0;
Dx_Output_Window* m_dx_win = 0;
IDXGIResource* m_back_buffer_ptr = 0;
ID3D11Resource* m_back_buffer_data = 0;
ID3D11Device* m_device = 0;
D3D_FEATURE_LEVEL m_selected_feature;
DXGI_SWAP_CHAIN_DESC m_desc;
D3D11_TEXTURE2D_DESC m_tex_desc = {};
I look up basically all the resources i could, but i could not find any info why it does work, but the image is all black. I was thinking maybe there is something up with the display, but no, i took the raw data, and display the value, and all the pixel or whatever it was is, was exactly 0, which is black color.
In the "m_desc.OutputWindow = (HWND)m_dx_win->winId();" i tried to also use GetDesktopWindow(), but it doesn't change anything, in fact i got some warnings instead.
