Edit

ID3D12CommandAllocator::Reset method (d3d12.h)

  • Article

Indicates to re-use the memory that is associated with the command allocator.

Syntax

HRESULT Reset();

Return value

Type: HRESULT

This method returns E_FAIL if there is an actively recording command list referencing the command allocator. The debug layer will also issue an error in this case.
See Direct3D 12 Return Codes for other possible return values.

Remarks

Apps call Reset to re-use the memory that is associated with a command allocator. From this call to Reset, the runtime and driver determine that the graphics processing unit (GPU) is no longer executing any command lists that have recorded commands with the command allocator.

Unlike ID3D12GraphicsCommandList::Reset, it is not recommended that you call Reset on the command allocator while a command list is still being executed.

The debug layer will issue a warning if it can't prove that there are no pending GPU references to command lists that have recorded commands in the allocator.

The debug layer will issue an error if Reset is called concurrently by multiple threads (on the same allocator object).

Examples

The D3D12HelloTriangle sample uses ID3D12CommandAllocator::Reset as follows:

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;


// 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());

Refer to the Example Code in the D3D12 Reference.

Requirements

Requirement Value
Target Platform Windows
Header d3d12.h
Library D3D12.lib
DLL D3D12.dll

See also

ID3D12CommandAllocator