A helper function to create descriptor heap from array of ID3D12Resource.

descriptor_heap_helper.cpp

ComPtr<ID3D12DescriptorHeap> afCreateDescriptorHeap(int numSrvs, ComPtr<ID3D12Resource> srvs[])
{
	ComPtr<ID3D12DescriptorHeap> heap;
	D3D12_DESCRIPTOR_HEAP_DESC srvHeapDesc = {};
	srvHeapDesc.NumDescriptors = numSrvs;
	srvHeapDesc.Type = D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV;
	srvHeapDesc.Flags = D3D12_DESCRIPTOR_HEAP_FLAG_SHADER_VISIBLE;
	HRESULT hr = deviceMan.GetDevice()->CreateDescriptorHeap(&srvHeapDesc, IID_PPV_ARGS(&heap));
	assert(hr == S_OK);
	for (int i = 0; i < numSrvs; i++) {
		D3D12_RESOURCE_DESC desc = srvs[i]->GetDesc();
		auto ptr = heap->GetCPUDescriptorHandleForHeapStart();
		ptr.ptr += deviceMan.GetDevice()->GetDescriptorHandleIncrementSize(D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV) * i;
		if (desc.Dimension == D3D12_RESOURCE_DIMENSION_BUFFER) {
			D3D12_CONSTANT_BUFFER_VIEW_DESC cbvDesc = {};
			cbvDesc.BufferLocation = srvs[i]->GetGPUVirtualAddress();
			cbvDesc.SizeInBytes = (UINT)desc.Width;
			assert((cbvDesc.SizeInBytes & 0xff) == 0);
			deviceMan.GetDevice()->CreateConstantBufferView(&cbvDesc, ptr);
		} else {
			deviceMan.GetDevice()->CreateShaderResourceView(srvs[i].Get(), nullptr, ptr);
		}
	}
	return heap;
}