ID3D12GraphicsCommandList::IASetPrimitiveTopology method

void IASetPrimitiveTopology(
  [in] D3D12_PRIMITIVE_TOPOLOGY PrimitiveTopology
);

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;

void D3D12HelloTriangle::PopulateCommandList()
{
    // 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.
    m_commandList->ResourceBarrier(1, &CD3DX12_RESOURCE_BARRIER::Transition(m_renderTargets[m_frameIndex].Get(), D3D12_RESOURCE_STATE_PRESENT, D3D12_RESOURCE_STATE_RENDER_TARGET));

    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, &CD3DX12_RESOURCE_BARRIER::Transition(m_renderTargets[m_frameIndex].Get(), D3D12_RESOURCE_STATE_RENDER_TARGET, D3D12_RESOURCE_STATE_PRESENT));

    ThrowIfFailed(m_commandList->Close());
}