Example Code in the D3D12 Reference
Explains the use of example code in the Direct3D 12 documentation.
Example snippet code
The example code shown in the Direct3D 12 reference is not compilable or run-able code, it is simply a snippet of code giving an example of how the API is called. Some examples list the global variables and class members used by the calls, for example:
Global pipeline objects.
D3D12_VIEWPORT m_viewport;
D3D12_RECT m_scissorRect;
ComPtr<IDXGISwapChain3> m_swapChain;
ComPtr<ID3D12Device> m_device;
ComPtr<ID3D12Resource> m_renderTargets[FrameCount];
ComPtr<ID3D12CommandAllocator> m_commandAllocator;
ComPtr<ID3D12CommandQueue> m_commandQueue;
ComPtr<ID3D12RootSignature> m_rootSignature;
ComPtr<ID3D12DescriptorHeap> m_rtvHeap;
ComPtr<ID3D12PipelineState> m_pipelineState;
ComPtr<ID3D12GraphicsCommandList> m_commandList;
UINT m_rtvDescriptorSize;
Populating command lists.
// Command list allocators can only be reset when the associated
// command lists have finished execution on the GPU; apps should use
// fences to determine GPU execution progress.
ThrowIfFailed(m_commandAllocator->Reset());
// However, when ExecuteCommandList() is called on a particular command
// list, that command list can then be reset at any time and must be before
// re-recording.
ThrowIfFailed(m_commandList->Reset(m_commandAllocator.Get(), m_pipelineState.Get()));
// Set necessary state.
m_commandList->SetGraphicsRootSignature(m_rootSignature.Get());
m_commandList->RSSetViewports(1, &m_viewport);
m_commandList->RSSetScissorRects(1, &m_scissorRect);
// Indicate that the back buffer will be used as a render target.
auto barrier = CD3DX12_RESOURCE_BARRIER::Transition(m_renderTargets[m_frameIndex].Get(), D3D12_RESOURCE_STATE_PRESENT, D3D12_RESOURCE_STATE_RENDER_TARGET);
m_commandList->ResourceBarrier(1, &barrier);
CD3DX12_CPU_DESCRIPTOR_HANDLE rtvHandle(m_rtvHeap->GetCPUDescriptorHandleForHeapStart(), m_frameIndex, m_rtvDescriptorSize);
m_commandList->OMSetRenderTargets(1, &rtvHandle, FALSE, nullptr);
// Record commands.
const float clearColor[] = { 0.0f, 0.2f, 0.4f, 1.0f };
m_commandList->ClearRenderTargetView(rtvHandle, clearColor, 0, nullptr);
m_commandList->IASetPrimitiveTopology(D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
m_commandList->IASetVertexBuffers(0, 1, &m_vertexBufferView);
m_commandList->DrawInstanced(3, 1, 0, 0);
// Indicate that the back buffer will now be used to present.
m_commandList->ResourceBarrier(1, &barrier);
barrier = CD3DX12_RESOURCE_BARRIER::Transition(m_renderTargets[m_frameIndex].Get(), D3D12_RESOURCE_STATE_RENDER_TARGET, D3D12_RESOURCE_STATE_PRESENT);
ThrowIfFailed(m_commandList->Close());
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