CODEWITHSUNDEEP
direct2ddirect3d11dxgi
Christoph
Christoph

Reputation: 2004

Use a texture array as Direct2D surface render target

I try to create a Direct3D 11 texture array holding multiple pages of text rendered using DirectWrite and Direct2D. Suppose layout holds the IDWriteTextLayouts for the individual pages, then I try to do the following:

{
    D3D11_TEXTURE2D_DESC desc;
    ::ZeroMemory(&desc, sizeof(desc));
    desc.ArraySize = static_cast<UINT>(layouts.size());
    desc.BindFlags = D3D11_BIND_RENDER_TARGET;
    desc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
    desc.Height = height;
    desc.MipLevels = 1;
    desc.SampleDesc.Count = 1;
    desc.Usage = D3D11_USAGE_DEFAULT;
    desc.Width = width;

    auto hr = this->_d3dDevice->CreateTexture2D(&desc, nullptr, &retval.Texture);
    if (FAILED(hr)) {
        throw std::system_error(hr, com_category());
    }
}

for (auto &l : layouts) {
    ATL::CComPtr<IDXGISurface> surface;

    {
        auto hr = retval.Texture->QueryInterface(&surface);
        if (FAILED(hr)) {
             // The code fails here with E_NOINTERFACE "No such interface supported."
             throw std::system_error(hr, com_category());
        }
    }

    // Go on creating the RT from 'surface'.
}

The problem is that the code fails at the designated line where I try to obtain the IDXGISurface interface from the ID3D11Texture2D if there is more than one page (desc.ArraySize > 1). I eventually found in the documentation (https://learn.microsoft.com/en-us/windows/win32/api/dxgi/nn-dxgi-idxgisurface) that this is by deisgn:

If the 2D texture [...] does not consist of an array of textures, QueryInterface succeeds and returns a pointer to the IDXGISurface interface pointer. Otherwise, QueryInterface fails and does not return the pointer to IDXGISurface.

Is there any other way to obtain the individual DXGI surfaces in the texture array to draw to them one after the other using Direct2D?

Upvotes: 1

Views: 607

Answers (1)

Christoph
Christoph

Reputation: 2004

As I could not find any way to address the sub-surfaces, I now create a staging texture with one layer to render to and copy the result into the texture array using ID3D11DeviceContext::CopySubresourceRegion.

Upvotes: 0

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