Question

How do we copy an arbitrary polygonal region of one Direct3D 11 2D texture to another texture? I’ve tried using ID3D11DeviceContext::CopySubresourceRegion Method but it copies only rectangular portions. I use Visual C++.

pKeyedMutex11->AcquireSync(1, INFINITE);
pImmediateContext->CopySubresourceRegion( pBackBuffer11, 0, max(size.width-turned,0.0f), 0, 0, pSharedTexture11, 0, &sourceRegion );            
pKeyedMutex11->ReleaseSync(0);

pKeyedMutex11_2->AcquireSync(1, INFINITE);
pImmediateContext->CopySubresourceRegion( pBackBuffer11, 0, max(size_1.width - 2*turned,0.0f) , 0, 0, pSharedTexture11_2, 0, &sourceRegion_2 );         
pKeyedMutex11_2->ReleaseSync(0);

pKeyedMutex11_1->AcquireSync(1, INFINITE);
        // Copy the content from the shared texture to the back-buffer          
pImmediateContext->CopySubresourceRegion( pBackBuffer11, 0, 0, 0, 0, pSharedTexture11_1, 0, &sourceRegion_1 );
pKeyedMutex11_1->ReleaseSync(0);

edit: Added the code snippet.

Answer 1

I don’t know if there exist a direct method to copy a polygonal region. But you can use a
stencil buffer. Draw the arbitrary polygon to the stencil buffer. And copy the entire texture to another by applying the stencil. You would get the same effect.

EDIT :: Citation Added

You can have a look at this tutorial.
http://www.rastertek.com/dx11tut03.html

Now we need to setup the depth stencil description. This allows us to control what type of depth test Direct3D will do for each pixel.

// Initialize the description of the stencil state.
ZeroMemory(&depthStencilDesc, sizeof(depthStencilDesc));

// Set up the description of the stencil state.
depthStencilDesc.DepthEnable = true;
depthStencilDesc.DepthWriteMask = D3D11_DEPTH_WRITE_MASK_ALL;
depthStencilDesc.DepthFunc = D3D11_COMPARISON_LESS;

depthStencilDesc.StencilEnable = true;
depthStencilDesc.StencilReadMask = 0xFF;
depthStencilDesc.StencilWriteMask = 0xFF;

// Stencil operations if pixel is front-facing.
depthStencilDesc.FrontFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
depthStencilDesc.FrontFace.StencilDepthFailOp = D3D11_STENCIL_OP_INCR;
depthStencilDesc.FrontFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
depthStencilDesc.FrontFace.StencilFunc = D3D11_COMPARISON_ALWAYS;

// Stencil operations if pixel is back-facing.
depthStencilDesc.BackFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
depthStencilDesc.BackFace.StencilDepthFailOp = D3D11_STENCIL_OP_DECR;
depthStencilDesc.BackFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
depthStencilDesc.BackFace.StencilFunc = D3D11_COMPARISON_ALWAYS;

With the description filled out we can now create a depth stencil state.

// Create the depth stencil state.
result = m_device->CreateDepthStencilState(&depthStencilDesc, &m_depthStencilState);
if(FAILED(result))
{
    return false;
}

With the created depth stencil state we can now set it so that it takes effect. Notice we use the device context to set it.

// Set the depth stencil state.
m_deviceContext->OMSetDepthStencilState(m_depthStencilState, 1);

The next thing we need to create is the description of the view of the depth stencil buffer. We do this so that Direct3D knows to use the depth buffer as a depth stencil texture. After filling out the description we then call the function CreateDepthStencilView to create it.

// Initailze the depth stencil view.
ZeroMemory(&depthStencilViewDesc, sizeof(depthStencilViewDesc));

// Set up the depth stencil view description.
depthStencilViewDesc.Format = DXGI_FORMAT_D24_UNORM_S8_UINT;
depthStencilViewDesc.ViewDimension = D3D11_DSV_DIMENSION_TEXTURE2D;
depthStencilViewDesc.Texture2D.MipSlice = 0;

// Create the depth stencil view.
result = m_device->CreateDepthStencilView(m_depthStencilBuffer, &depthStencilViewDesc, &m_depthStencilView);
if(FAILED(result))
{
    return false;
}

With that created we can now call OMSetRenderTargets. This will bind the render target view and the depth stencil buffer to the output render pipeline. This way the graphics that the pipeline renders will get drawn to our back buffer that we previously created. With the graphics written to the back buffer we can then swap it to the front and display our graphics on the user’s screen.

// Bind the render target view and depth stencil buffer to the output render pipeline.
m_deviceContext->OMSetRenderTargets(1, &m_renderTargetView, m_depthStencilView);