ID3D12GraphicsCommandList::ResolveQueryData method

Extracts data from a query. ResolveQueryData works with all heap types (default, upload, and readback).

Syntax

void ResolveQueryData(
  ID3D12QueryHeap  *pQueryHeap,
  D3D12_QUERY_TYPE Type,
  UINT             StartIndex,
  UINT             NumQueries,
  ID3D12Resource   *pDestinationBuffer,
  UINT64           AlignedDestinationBufferOffset
);

Parameters

pQueryHeap

Type: ID3D12QueryHeap*

Specifies the ID3D12QueryHeap containing the queries to resolve.

Type

Type: D3D12_QUERY_TYPE

Specifies the type of query, one member of D3D12_QUERY_TYPE.

StartIndex

Type: UINT

Specifies an index of the first query to resolve.

NumQueries

Type: UINT

Specifies the number of queries to resolve.

pDestinationBuffer

Type: ID3D12Resource*

Specifies an ID3D12Resource destination buffer, which must be in the state D3D12_RESOURCE_STATE_COPY_DEST.

AlignedDestinationBufferOffset

Type: UINT64

Specifies an alignment offset into the destination buffer. Must be a multiple of 8 bytes.

Return Value

This method does not return a value.

Remarks

ResolveQueryData performs a batched operation which writes query data into a destination buffer. Query data is written contiguously to the destination buffer, and the parameter.

Binary occlusion queries write 64-bits per query. The least significant bit is either 0 or 1. The rest of the bits are 0.

The core runtime will validate the following:

  • StartIndex and NumQueries are within range.
  • AlignedDestinationBufferOffset is a multiple of 8 bytes.
  • DestinationBuffer is a buffer.
  • The written data will not overflow the output buffer.
  • The query type must be supported by the command list type.
  • The query type must be supported by the query heap.
The debug layer will issue a warning if the destination buffer is not in the D3D12_RESOURCE_STATE_COPY_DEST state.

Examples

The D3D12PredicationQueries sample uses ID3D12GraphicsCommandList::ResolveQueryData as follows:

// Fill the command list with all the render commands and dependent state.
void D3D12PredicationQueries::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_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_commandList->Reset(m_commandAllocators[m_frameIndex].Get(), m_pipelineState.Get()));

    // Set necessary state.
    m_commandList->SetGraphicsRootSignature(m_rootSignature.Get());

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

    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);
    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);

    // Draw the quads and perform the occlusion query.
    {
        CD3DX12_GPU_DESCRIPTOR_HANDLE cbvFarQuad(m_cbvHeap->GetGPUDescriptorHandleForHeapStart(), m_frameIndex * CbvCountPerFrame, m_cbvSrvDescriptorSize);
        CD3DX12_GPU_DESCRIPTOR_HANDLE cbvNearQuad(cbvFarQuad, m_cbvSrvDescriptorSize);

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

        // Draw the far quad conditionally based on the result of the occlusion query
        // from the previous frame.
        m_commandList->SetGraphicsRootDescriptorTable(0, cbvFarQuad);
        m_commandList->SetPredication(m_queryResult.Get(), 0, D3D12_PREDICATION_OP_EQUAL_ZERO);
        m_commandList->DrawInstanced(4, 1, 0, 0);

        // Disable predication and always draw the near quad.
        m_commandList->SetPredication(nullptr, 0, D3D12_PREDICATION_OP_EQUAL_ZERO);
        m_commandList->SetGraphicsRootDescriptorTable(0, cbvNearQuad);
        m_commandList->DrawInstanced(4, 1, 4, 0);

        // Run the occlusion query with the bounding box quad.
        m_commandList->SetGraphicsRootDescriptorTable(0, cbvFarQuad);
        m_commandList->SetPipelineState(m_queryState.Get());
        m_commandList->BeginQuery(m_queryHeap.Get(), D3D12_QUERY_TYPE_BINARY_OCCLUSION, 0);
        m_commandList->DrawInstanced(4, 1, 8, 0);
        m_commandList->EndQuery(m_queryHeap.Get(), D3D12_QUERY_TYPE_BINARY_OCCLUSION, 0);

        // Resolve the occlusion query and store the results in the query result buffer
        // to be used on the subsequent frame.
        m_commandList->ResourceBarrier(1, &CD3DX12_RESOURCE_BARRIER::Transition(m_queryResult.Get(), D3D12_RESOURCE_STATE_PREDICATION, D3D12_RESOURCE_STATE_COPY_DEST));
        m_commandList->ResolveQueryData(m_queryHeap.Get(), D3D12_QUERY_TYPE_BINARY_OCCLUSION, 0, 1, m_queryResult.Get(), 0);
        m_commandList->ResourceBarrier(1, &CD3DX12_RESOURCE_BARRIER::Transition(m_queryResult.Get(), D3D12_RESOURCE_STATE_COPY_DEST, D3D12_RESOURCE_STATE_PREDICATION));
    }

    // 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());
}

See Example Code in the D3D12 Reference.

Requirements

   
Target Platform Windows
Header d3d12.h
Library D3d12.lib
DLL D3d12.dll

See Also

ID3D12GraphicsCommandList