Creating Swap Chain causes Window Handle to become Invalid - c++

Question

I'm trying to work with both Direct2D and Direct3D. Right now, I'm having Direct2D draw content to a separate Device Context (with an HDC) and then copy the contents of that Device Context into my window. I could show the code I use to set that up in an edit to this post if requested, but before Direct3D gets involved, that part works.
Here is a simplified version of the Window Drawing code I use.
if (d3dEngine.Get()) // Object used to hold Direct3D Resources (.Get() returns a pointer for a null check)
{
// d3dEngine->PrepareScene(D2D1::ColorF(D2D1::ColorF::Wheat));
}
// Drawing Board holds the Direct 2D Render Target
drawingBoard->GetRenderer()->BeginDraw();
drawingBoard->GetRenderer()->Clear(D2D1::ColorF(1.0f,1.0f,1.0f,1.0f));
mainPage->Draw(); // Main Page Holds various objects that draw to Direct2D
if (d3dEngine.Get())
d3dEngine->FinalizeScene();
drawingBoard->GetRenderer()->EndDraw();
// Get the Secondary Device Context that Direct2D draws to
HDC dc = drawingBoard->GetDc();
RECT r{ 0,0,0,0 };
int err = 0;
// Retrieve the Rectangle for the window (currentWindow is the window handle used)
if(!GetClientRect(currentWindow, &r))
err = GetLastError();
// Use the BitBlt function to copy Direct2D content into a window
if (!BitBlt(GetDC(currentWindow), r.left, r.top, r.right - r.left, r.bottom - r.top, dc, 0, 0, SRCCOPY))
err = GetLastError();
Before any Direct3D resources are created (and the d3dEngine.Get() call returns null), this code runs to my satisfaction.
However, following the creation of Direct3D resources, the code fails:
RECT r{ 0,0,0,0 };
int err = 0;
// Retrieve the Rectangle for the window (currentWindow is the window handle used)
if(!GetClientRect(currentWindow, &r))
err = GetLastError();
The window handle currentWindow becomes invalid as GetLastError() returns 1400 after the call to GetClientRect. I suspect that the Swap Chain in Direct3D 11 may play a role due to the following code used to activate Direct3D.
GetClientRect(window, &Location);
unsigned int width = Location.right - Location.left,
height = Location.bottom - Location.top;
D3D_DRIVER_TYPE dTypes[] =
{
D3D_DRIVER_TYPE_HARDWARE//, D3D_DRIVER_TYPE_WARP
};
int tTypes = ARRAYSIZE(dTypes);
D3D_FEATURE_LEVEL dLevels[] =
{
D3D_FEATURE_LEVEL_11_1, D3D_FEATURE_LEVEL_11_0,
D3D_FEATURE_LEVEL_10_1, D3D_FEATURE_LEVEL_10_0
};
int tLevels = ARRAYSIZE(dLevels);
DXGI_SWAP_CHAIN_DESC swapChainDescription;
// Initialize the swap cahin
swapChainDescription.BufferCount = 2;
swapChainDescription.BufferDesc.Width = Location.right - Location.left;
swapChainDescription.BufferDesc.Height = Location.bottom - Location.top;
swapChainDescription.BufferDesc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
swapChainDescription.BufferDesc.RefreshRate.Numerator = 30;
swapChainDescription.BufferDesc.RefreshRate.Denominator = 1;
swapChainDescription.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
swapChainDescription.OutputWindow = window;
swapChainDescription.Windowed = true;
swapChainDescription.SampleDesc.Count = 1;
swapChainDescription.SampleDesc.Quality = 0;
swapChainDescription.BufferDesc.Scaling = DXGI_MODE_SCALING_UNSPECIFIED;
swapChainDescription.BufferDesc.ScanlineOrdering = DXGI_MODE_SCANLINE_ORDER_UNSPECIFIED;
swapChainDescription.Flags = DXGI_SWAP_CHAIN_FLAG_GDI_COMPATIBLE;
swapChainDescription.SwapEffect = DXGI_SWAP_EFFECT_FLIP_DISCARD;// DXGI_SWAP_EFFECT_DISCARD;
unsigned int flags = D3D11_CREATE_DEVICE_BGRA_SUPPORT;
/// Other initialization Code
HRESULT results = 0;
// Initialize ID3D11Device "graphicsDevice"
IDXGISwapChain* sc = nullptr;
results = dxFact->CreateSwapChain(graphicsDevice, &swapChainDescription, &sc);
This code is in a different class than the Window drawing code towards the beginning.
The window variable in the Direct3D code holds the same value that currentWindow holds in the Window Code.
Is there anyone who could provide insight as to what is going on and why the window handle stops working? And perhaps suggest a workaround?

Answer 1

While I'm still unsure why the window handle seemed to be useless when I checked, I was able to develop a workaround.
Basically, I have my Window class hold a RECT indicating the size of the Window and I use that instead of getting the RECT from the Window every time.
RECT r{ 0,0,0,0 };
int err = 0;
// Retrieve the Rectangle for the window (currentWindow is the window handle used)
if(!GetClientRect(currentWindow, &r))
err = GetLastError();
// Use the BitBlt function to copy Direct2D content into a window
if (!BitBlt(GetDC(currentWindow), r.left, r.top, r.right - r.left, r.bottom - r.top, dc, 0, 0, SRCCOPY))
err = GetLastError();
// Now, it uses a 'size' attribute
int err = 0;
if (!BitBlt(GetTWindowDc(), size.left, size.top, size.right - size.left, size.bottom - size.top, dc, 0, 0, SRCCOPY))
err = GetLastError();
When it comes to getting the Window Device Context, the new GetTWindowDc() method takes care of that:
if (d3dEngine.Get())
return d3dEngine->GetDC();
return GetDC(currentWindow);
Basically, if Direct3D is activated, the 3D manager object (which holds a DXGISurface) retrieves the HDC from Direct3D to use.
HDC TWindowEngine::GetDC()
{
if (!surface.Get()) // My Unique Smart pointer to a DXGISurface1 object
return 0;
HDC dc;
assert(SUCCEEDED(surface->GetDC(FALSE, &dc)));
return dc;
}
According to Surface-GetDc Documentation, you need to call the corresponding ReleaseDc on the DXGISurface1 object. So this is how I do it.
In the Window Draw code:
if (!BitBlt(GetTWindowDc(), size.left, size.top, size.right - size.left, size.bottom - size.top, dc, 0, 0, SRCCOPY))
err = GetLastError();
FlushDc();
Here is the FlushDc method:
void TWindow::FlushDc()
{
if (d3dEngine.Get())
d3dEngine->ClearDC();
}
And the ClearDC method is impelented.
void TWindowEngine::ClearDC()
{
if (surface.Get())
surface->ReleaseDC(nullptr);
}