ID3D12GraphicsCommandList::DrawInstanced method

Draws non-indexed, instanced primitives.

Syntax

void DrawInstanced(
  UINT VertexCountPerInstance,
  UINT InstanceCount,
  UINT StartVertexLocation,
  UINT StartInstanceLocation
);

Parameters

VertexCountPerInstance

Type: UINT

Number of vertices to draw.

InstanceCount

Type: UINT

Number of instances to draw.

StartVertexLocation

Type: UINT

Index of the first vertex.

StartInstanceLocation

Type: UINT

A value added to each index before reading per-instance data from a vertex buffer.

Return Value

Returns nothing

Remarks

A draw API submits work to the rendering pipeline.

Instancing might extend performance by reusing the same geometry to draw multiple objects in a scene. One example of instancing could be to draw the same object with different positions and colors.

The vertex data for an instanced draw call typically comes from a vertex buffer that is bound to the pipeline. But, you could also provide the vertex data from a shader that has instanced data identified with a system-value semantic (SV_InstanceID).

Examples

The D3D12HelloTriangle sample uses ID3D12GraphicsCommandList::DrawInstanced as follows:

C++
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;
C++
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-&gt;Reset(m_commandAllocator.Get(), m_pipelineState.Get()));

// Set necessary state.
m_commandList-&gt;SetGraphicsRootSignature(m_rootSignature.Get());
m_commandList-&gt;RSSetViewports(1, &amp;m_viewport);
m_commandList-&gt;RSSetScissorRects(1, &amp;m_scissorRect);

// Indicate that the back buffer will be used as a render target.
m_commandList-&gt;ResourceBarrier(1, &amp;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-&gt;GetCPUDescriptorHandleForHeapStart(), m_frameIndex, m_rtvDescriptorSize);
m_commandList-&gt;OMSetRenderTargets(1, &amp;rtvHandle, FALSE, nullptr);

// Record commands.
const float clearColor[] = { 0.0f, 0.2f, 0.4f, 1.0f };
m_commandList-&gt;ClearRenderTargetView(rtvHandle, clearColor, 0, nullptr);
m_commandList-&gt;IASetPrimitiveTopology(D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
m_commandList-&gt;IASetVertexBuffers(0, 1, &amp;m_vertexBufferView);
m_commandList-&gt;DrawInstanced(3, 1, 0, 0);

// Indicate that the back buffer will now be used to present.
m_commandList-&gt;ResourceBarrier(1, &amp;CD3DX12_RESOURCE_BARRIER::Transition(m_renderTargets[m_frameIndex].Get(), D3D12_RESOURCE_STATE_RENDER_TARGET, D3D12_RESOURCE_STATE_PRESENT));

ThrowIfFailed(m_commandList-&gt;Close());

}

See Example Code in the D3D12 Reference.

Requirements

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

See Also

ID3D12GraphicsCommandList