IASetIndexBuffer

void IASetIndexBuffer(
    const D3D12_INDEX_BUFFER_VIEW  pView
)

void FrameResource::PopulateCommandList(ID3D12GraphicsCommandList* pCommandList, ID3D12PipelineState* pPso1, ID3D12PipelineState* pPso2,
UINT frameResourceIndex, UINT numIndices, D3D12_INDEX_BUFFER_VIEW* pIndexBufferViewDesc, D3D12_VERTEX_BUFFER_VIEW* pVertexBufferViewDesc,
ID3D12DescriptorHeap* pCbvSrvDescriptorHeap, UINT cbvSrvDescriptorSize, ID3D12DescriptorHeap* pSamplerDescriptorHeap, ID3D12RootSignature* pRootSignature)
{
// If the root signature matches the root signature of the caller, then
// bindings are inherited, otherwise the bind space is reset.
pCommandList->SetGraphicsRootSignature(pRootSignature);

ID3D12DescriptorHeap* ppHeaps[] = { pCbvSrvDescriptorHeap, pSamplerDescriptorHeap };
pCommandList->SetDescriptorHeaps(_countof(ppHeaps), ppHeaps);
pCommandList->IASetPrimitiveTopology(D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST);

pCommandList->IASetIndexBuffer(pIndexBufferViewDesc);

pCommandList->IASetVertexBuffers(0, 1, pVertexBufferViewDesc);

pCommandList->SetGraphicsRootDescriptorTable(0, pCbvSrvDescriptorHeap->GetGPUDescriptorHandleForHeapStart());
pCommandList->SetGraphicsRootDescriptorTable(1, pSamplerDescriptorHeap->GetGPUDescriptorHandleForHeapStart());

// Calculate the descriptor offset due to multiple frame resources.
// 1 SRV + how many CBVs we have currently.
UINT frameResourceDescriptorOffset = 1 + (frameResourceIndex * m_cityRowCount * m_cityColumnCount);
CD3DX12_GPU_DESCRIPTOR_HANDLE cbvSrvHandle(pCbvSrvDescriptorHeap->GetGPUDescriptorHandleForHeapStart(), frameResourceDescriptorOffset, cbvSrvDescriptorSize);

BOOL usePso1 = TRUE;
for (UINT i = 0; i < m_cityRowCount; i++)
{
for (UINT j = 0; j < m_cityColumnCount; j++)
{
// Alternate which PSO to use; the pixel shader is different on
// each just as a PSO setting demonstration.
pCommandList->SetPipelineState(usePso1 ? pPso1 : pPso2);
usePso1 = !usePso1;

// Set this city's CBV table and move to the next descriptor.
pCommandList->SetGraphicsRootDescriptorTable(2, cbvSrvHandle);
cbvSrvHandle.Offset(cbvSrvDescriptorSize);

pCommandList->DrawIndexedInstanced(numIndices, 1, 0, 0, 0);
}
}
}