ID3D12GraphicsCommandList：：ExecuteIndirect 方法 (d3d12.h)

發行項
08/23/2023

應用程式會使用 ExecuteIndirect 方法執行間接繪製/分派。

語法

void ExecuteIndirect(
  [in]           ID3D12CommandSignature *pCommandSignature,
  [in]           UINT                   MaxCommandCount,
  [in]           ID3D12Resource         *pArgumentBuffer,
  [in]           UINT64                 ArgumentBufferOffset,
  [in, optional] ID3D12Resource         *pCountBuffer,
  [in]           UINT64                 CountBufferOffset
);

參數

[in] pCommandSignature

類型： ID3D12CommandSignature*

指定 ID3D12CommandSignature。 pArgumentBuffer所參考的資料會根據命令簽章的內容來解譯。如需用來建立命令簽章的 API，請參閱間接繪圖。

[in] MaxCommandCount

類型： UINT

有兩種方式可以指定命令計數：

如果 pCountBuffer 不是 Null， 則 MaxCommandCount 會指定將執行的作業數目上限。實際執行的作業數目是由此值的最小值所定義，以及 pCountBuffer 中所包含的 32 位不帶正負號整數， (CountBufferOffset 所指定的位元組位移) 。
如果 pCountBuffer 為 Null， MaxCommandCount 會指定將執行的確切作業數目。

[in] pArgumentBuffer

類型： ID3D12Resource*

指定一或多個 ID3D12Resource 物件，其中包含命令引數。

[in] ArgumentBufferOffset

類型： UINT64

指定 pArgumentBuffer 中的位移，以識別第一個命令引數。

[in, optional] pCountBuffer

類型： ID3D12Resource*

指定 ID3D12Resource的指標。

[in] CountBufferOffset

類型： UINT64

指定位移至 pCountBuffer的 UINT64，識別引數計數。

傳回值

無

備註

此 API 的語意會使用下列虛擬程式碼來定義：

非 Null pCountBuffer：

// Read draw count out of count buffer
UINT CommandCount = pCountBuffer->ReadUINT32(CountBufferOffset);

CommandCount = min(CommandCount, MaxCommandCount)

// Get pointer to first Commanding argument
BYTE* Arguments = pArgumentBuffer->GetBase() + ArgumentBufferOffset;

for(UINT CommandIndex = 0; CommandIndex < CommandCount; CommandIndex++)
{
  // Interpret the data contained in *Arguments
  // according to the command signature
  pCommandSignature->Interpret(Arguments);

  Arguments += pCommandSignature->GetByteStride();
}

Null pCountBuffer：

// Get pointer to first Commanding argument
BYTE* Arguments = pArgumentBuffer->GetBase() + ArgumentBufferOffset;

for(UINT CommandIndex = 0; CommandIndex < MaxCommandCount; CommandIndex++)
{
  // Interpret the data contained in *Arguments
  // according to the command signature
  pCommandSignature->Interpret(Arguments);

  Arguments += pCommandSignature->GetByteStride();
}

如果計數緩衝區或引數緩衝區不是處於D3D12_RESOURCE_STATE_INDIRECT_ARGUMENT狀態，偵錯層就會發出錯誤。核心執行時間將會驗證：

CountBufferOffset 和 ArgumentBufferOffset 對齊 4 位元組
pCountBuffer 和 pArgumentBuffer 是緩衝區資源， (任何堆積類型)
MaxCommandCount、ArgumentBufferOffset和繪圖程式步幅所隱含的位移，不會超過pArgumentBuffer的界限， (同樣適用于計數緩衝區)
命令清單是直接命令清單或計算命令清單， (不是複製或 JPEG 解碼命令清單)
命令清單的根簽章符合命令簽章的根簽章

來自舊版 Direct3D DrawInstancedIndirect 和 DrawIndexedInstancedIndirect 的兩個 API 功能是由 ExecuteIndirect所包含。

束

ID3D12GraphicsCommandList：：ExecuteIndirect 只有在下列所有專案都成立時，才允許在套件組合命令清單中：

CountBuffer 是 Null (CPU 指定的計數，只) 。
命令簽章只包含一個作業。這表示命令簽章不包含根引數變更，也不會包含 VB/IB 系結變更。

取得緩衝區虛擬位址

ID3D12Resource：：GetGPUVirtualAddress方法可讓應用程式擷取緩衝區的 GPU 虛擬位址。

應用程式可以自由地將位元組位移套用至虛擬位址，再將它們放在間接引數緩衝區中。請注意，VB/IB/CB 的所有 D3D12 對齊需求仍適用于產生的 GPU 虛擬位址。

範例

D3D12ExecuteIndirect範例使用ID3D12GraphicsCommandList：：ExecuteIndirect，如下所示：

// Data structure to match the command signature used for ExecuteIndirect.
struct IndirectCommand
{
    D3D12_GPU_VIRTUAL_ADDRESS cbv;
    D3D12_DRAW_ARGUMENTS drawArguments;
};

對 ExecuteIndirect的呼叫接近此清單結尾，在批註下方「繪製尚未加以擷取的三角形」。

// Fill the command list with all the render commands and dependent state.
void D3D12ExecuteIndirect::PopulateCommandLists()
{
    // 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_computeCommandAllocators[m_frameIndex]->Reset());
    ThrowIfFailed(m_commandAllocators[m_frameIndex]->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_computeCommandList->Reset(m_computeCommandAllocators[m_frameIndex].Get(), m_computeState.Get()));
    ThrowIfFailed(m_commandList->Reset(m_commandAllocators[m_frameIndex].Get(), m_pipelineState.Get()));

    // Record the compute commands that will cull triangles and prevent them from being processed by the vertex shader.
    if (m_enableCulling)
    {
        UINT frameDescriptorOffset = m_frameIndex * CbvSrvUavDescriptorCountPerFrame;
        D3D12_GPU_DESCRIPTOR_HANDLE cbvSrvUavHandle = m_cbvSrvUavHeap->GetGPUDescriptorHandleForHeapStart();

        m_computeCommandList->SetComputeRootSignature(m_computeRootSignature.Get());

        ID3D12DescriptorHeap* ppHeaps[] = { m_cbvSrvUavHeap.Get() };
        m_computeCommandList->SetDescriptorHeaps(_countof(ppHeaps), ppHeaps);

        m_computeCommandList->SetComputeRootDescriptorTable(
            SrvUavTable,
            CD3DX12_GPU_DESCRIPTOR_HANDLE(cbvSrvUavHandle, CbvSrvOffset + frameDescriptorOffset, m_cbvSrvUavDescriptorSize));

        m_computeCommandList->SetComputeRoot32BitConstants(RootConstants, 4, reinterpret_cast<void*>(&m_csRootConstants), 0);

        // Reset the UAV counter for this frame.
        m_computeCommandList->CopyBufferRegion(m_processedCommandBuffers[m_frameIndex].Get(), CommandBufferSizePerFrame, m_processedCommandBufferCounterReset.Get(), 0, sizeof(UINT));

        D3D12_RESOURCE_BARRIER barrier = CD3DX12_RESOURCE_BARRIER::Transition(m_processedCommandBuffers[m_frameIndex].Get(), D3D12_RESOURCE_STATE_COPY_DEST, D3D12_RESOURCE_STATE_UNORDERED_ACCESS);
        m_computeCommandList->ResourceBarrier(1, &barrier);

        m_computeCommandList->Dispatch(static_cast<UINT>(ceil(TriangleCount / float(ComputeThreadBlockSize))), 1, 1);
    }

    ThrowIfFailed(m_computeCommandList->Close());

    // Record the rendering commands.
    {
        // Set necessary state.
        m_commandList->SetGraphicsRootSignature(m_rootSignature.Get());

        ID3D12DescriptorHeap* ppHeaps[] = { m_cbvSrvUavHeap.Get() };
        m_commandList->SetDescriptorHeaps(_countof(ppHeaps), ppHeaps);

        m_commandList->RSSetViewports(1, &m_viewport);
        m_commandList->RSSetScissorRects(1, m_enableCulling ? &m_cullingScissorRect : &m_scissorRect);

        // Indicate that the command buffer will be used for indirect drawing
        // and that the back buffer will be used as a render target.
        D3D12_RESOURCE_BARRIER barriers[2] = {
            CD3DX12_RESOURCE_BARRIER::Transition(
                m_enableCulling ? m_processedCommandBuffers[m_frameIndex].Get() : m_commandBuffer.Get(),
                m_enableCulling ? D3D12_RESOURCE_STATE_UNORDERED_ACCESS : D3D12_RESOURCE_STATE_NON_PIXEL_SHADER_RESOURCE,
                D3D12_RESOURCE_STATE_INDIRECT_ARGUMENT),
            CD3DX12_RESOURCE_BARRIER::Transition(
                m_renderTargets[m_frameIndex].Get(),
                D3D12_RESOURCE_STATE_PRESENT,
                D3D12_RESOURCE_STATE_RENDER_TARGET)
        };

        m_commandList->ResourceBarrier(_countof(barriers), barriers);

        CD3DX12_CPU_DESCRIPTOR_HANDLE rtvHandle(m_rtvHeap->GetCPUDescriptorHandleForHeapStart(), m_frameIndex, m_rtvDescriptorSize);
        CD3DX12_CPU_DESCRIPTOR_HANDLE dsvHandle(m_dsvHeap->GetCPUDescriptorHandleForHeapStart());
        m_commandList->OMSetRenderTargets(1, &rtvHandle, FALSE, &dsvHandle);

        // Record commands.
        const float clearColor[] = { 0.0f, 0.2f, 0.4f, 1.0f };
        m_commandList->ClearRenderTargetView(rtvHandle, clearColor, 0, nullptr);
        m_commandList->ClearDepthStencilView(dsvHandle, D3D12_CLEAR_FLAG_DEPTH, 1.0f, 0, 0, nullptr);

        m_commandList->IASetPrimitiveTopology(D3D_PRIMITIVE_TOPOLOGY_TRIANGLESTRIP);
        m_commandList->IASetVertexBuffers(0, 1, &m_vertexBufferView);

        if (m_enableCulling)
        {
            // Draw the triangles that have not been culled.
            m_commandList->ExecuteIndirect(
                m_commandSignature.Get(),
                TriangleCount,
                m_processedCommandBuffers[m_frameIndex].Get(),
                0,
                m_processedCommandBuffers[m_frameIndex].Get(),
                CommandBufferSizePerFrame);
        }
        else
        {
            // Draw all of the triangles.
            m_commandList->ExecuteIndirect(
                m_commandSignature.Get(),
                TriangleCount,
                m_commandBuffer.Get(),
                CommandBufferSizePerFrame * m_frameIndex,
                nullptr,
                0);
        }

        // Indicate that the command buffer may be used by the compute shader
        // and that the back buffer will now be used to present.
        barriers[0].Transition.StateBefore = D3D12_RESOURCE_STATE_INDIRECT_ARGUMENT;
        barriers[0].Transition.StateAfter = m_enableCulling ? D3D12_RESOURCE_STATE_COPY_DEST : D3D12_RESOURCE_STATE_NON_PIXEL_SHADER_RESOURCE;
        barriers[1].Transition.StateBefore = D3D12_RESOURCE_STATE_RENDER_TARGET;
        barriers[1].Transition.StateAfter = D3D12_RESOURCE_STATE_PRESENT;

        m_commandList->ResourceBarrier(_countof(barriers), barriers);

        ThrowIfFailed(m_commandList->Close());
    }
}

請參閱 D3D12 參考中的範例程式碼。

需求


目標平台	Windows
標頭	d3d12.h
程式庫	D3d12.lib
Dll	D3d12.dll

另請參閱

ID3D12GraphicsCommandList

間接繪圖

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ID3D12GraphicsCommandList：：ExecuteIndirect 方法 (d3d12.h)

語法

參數

傳回值

備註

束

取得緩衝區虛擬位址

範例

需求

另請參閱

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意見反應

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