[DirectX12]Hello Wolrd Sample - D3D12HelloTriangle - 2

Win32Aplication.cpp 에서 Win32Application::Run() 함수 내부를 살펴보는데 그중 우리가 살펴봐야할것들은 

전달인자로 받은 sample에서 호출하는 멤버함수들이다.

 

먼저 OnInit 함수부터 살펴보면...

 

void D3D12HelloTriangle::OnInit()
{
	LoadPipeline();
	LoadAssets();
}

특별히 달라진 내용은 없다.

LoadPipeline( )을 보자

 

void D3D12HelloTriangle::LoadPipeline()
{
	UINT dxgiFactoryFlags = 0;

#if defined(_DEBUG)
	// Enable the debug layer (requires the Graphics Tools "optional feature").
	// NOTE: Enabling the debug layer after device creation will invalidate the active device.
	{
		ComPtr<ID3D12Debug> debugController;
		if (SUCCEEDED(D3D12GetDebugInterface(IID_PPV_ARGS(&debugController))))
		{
			debugController->EnableDebugLayer();

			// Enable additional debug layers.
			dxgiFactoryFlags |= DXGI_CREATE_FACTORY_DEBUG;
		}
	}
#endif

	ComPtr<IDXGIFactory4> factory;
	ThrowIfFailed(CreateDXGIFactory2(dxgiFactoryFlags, IID_PPV_ARGS(&factory)));

	if (m_useWarpDevice)
	{
		ComPtr<IDXGIAdapter> warpAdapter;
		ThrowIfFailed(factory->EnumWarpAdapter(IID_PPV_ARGS(&warpAdapter)));

		ThrowIfFailed(D3D12CreateDevice(
			warpAdapter.Get(),
			D3D_FEATURE_LEVEL_11_0,
			IID_PPV_ARGS(&m_device)
			));
	}
	else
	{
		ComPtr<IDXGIAdapter1> hardwareAdapter;
		GetHardwareAdapter(factory.Get(), &hardwareAdapter);

		ThrowIfFailed(D3D12CreateDevice(
			hardwareAdapter.Get(),
			D3D_FEATURE_LEVEL_11_0,
			IID_PPV_ARGS(&m_device)
			));
	}

	// Describe and create the command queue.
	D3D12_COMMAND_QUEUE_DESC queueDesc = {};
	queueDesc.Flags = D3D12_COMMAND_QUEUE_FLAG_NONE;
	queueDesc.Type = D3D12_COMMAND_LIST_TYPE_DIRECT;

	ThrowIfFailed(m_device->CreateCommandQueue(&queueDesc, IID_PPV_ARGS(&m_commandQueue)));

	// Describe and create the swap chain.
	DXGI_SWAP_CHAIN_DESC1 swapChainDesc = {};
	swapChainDesc.BufferCount = FrameCount;
	swapChainDesc.Width = m_width;
	swapChainDesc.Height = m_height;
	swapChainDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
	swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
	swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_DISCARD;
	swapChainDesc.SampleDesc.Count = 1;

	ComPtr<IDXGISwapChain1> swapChain;
	ThrowIfFailed(factory->CreateSwapChainForHwnd(
		m_commandQueue.Get(),		// Swap chain needs the queue so that it can force a flush on it.
		Win32Application::GetHwnd(),
		&swapChainDesc,
		nullptr,
		nullptr,
		&swapChain
		));

	// This sample does not support fullscreen transitions.
	ThrowIfFailed(factory->MakeWindowAssociation(Win32Application::GetHwnd(), DXGI_MWA_NO_ALT_ENTER));

	ThrowIfFailed(swapChain.As(&m_swapChain));
	m_frameIndex = m_swapChain->GetCurrentBackBufferIndex();

	// Create descriptor heaps.
	{
		// Describe and create a render target view (RTV) descriptor heap.
		D3D12_DESCRIPTOR_HEAP_DESC rtvHeapDesc = {};
		rtvHeapDesc.NumDescriptors = FrameCount;
		rtvHeapDesc.Type = D3D12_DESCRIPTOR_HEAP_TYPE_RTV;
		rtvHeapDesc.Flags = D3D12_DESCRIPTOR_HEAP_FLAG_NONE;
		ThrowIfFailed(m_device->CreateDescriptorHeap(&rtvHeapDesc, IID_PPV_ARGS(&m_rtvHeap)));

		m_rtvDescriptorSize = m_device->GetDescriptorHandleIncrementSize(D3D12_DESCRIPTOR_HEAP_TYPE_RTV);
	}

	// Create frame resources.
	{
		CD3DX12_CPU_DESCRIPTOR_HANDLE rtvHandle(m_rtvHeap->GetCPUDescriptorHandleForHeapStart());

		// Create a RTV for each frame.
		for (UINT n = 0; n < FrameCount; n++)
		{
			ThrowIfFailed(m_swapChain->GetBuffer(n, IID_PPV_ARGS(&m_renderTargets[n])));
			m_device->CreateRenderTargetView(m_renderTargets[n].Get(), nullptr, rtvHandle);
			rtvHandle.Offset(1, m_rtvDescriptorSize);
		}
	}

	ThrowIfFailed(m_device->CreateCommandAllocator(D3D12_COMMAND_LIST_TYPE_DIRECT, IID_PPV_ARGS(&m_commandAllocator)));
}

 

코드가 엄청 길지만 이전 튜토리얼과 다른 점은 하나도 없다.

 

그러므로 LoadAssets( )함수를 살펴보자.

 

void D3D12HelloTriangle::LoadAssets()
{
	// Create an empty root signature.
	{
		CD3DX12_ROOT_SIGNATURE_DESC rootSignatureDesc;
		rootSignatureDesc.Init(0, nullptr, 0, nullptr, D3D12_ROOT_SIGNATURE_FLAG_ALLOW_INPUT_ASSEMBLER_INPUT_LAYOUT);

		ComPtr<ID3DBlob> signature;
		ComPtr<ID3DBlob> error;
		ThrowIfFailed(D3D12SerializeRootSignature(&rootSignatureDesc, D3D_ROOT_SIGNATURE_VERSION_1, &signature, &error));
		ThrowIfFailed(m_device->CreateRootSignature(0, 
							    signature->GetBufferPointer(),
							    signature->GetBufferSize(),
							    IID_PPV_ARGS(&m_rootSignature)));
	}

	// Create the pipeline state, which includes compiling and loading shaders.
	{
		ComPtr<ID3DBlob> vertexShader;
		ComPtr<ID3DBlob> pixelShader;

#if defined(_DEBUG)
		// Enable better shader debugging with the graphics debugging tools.
		UINT compileFlags = D3DCOMPILE_DEBUG | D3DCOMPILE_SKIP_OPTIMIZATION;
#else
		UINT compileFlags = 0;
#endif

		ThrowIfFailed(D3DCompileFromFile(GetAssetFullPath(L"shaders.hlsl").c_str(), 
						 nullptr,
						 nullptr,
						 "VSMain",
						 "vs_5_0",
						 compileFlags,
						 0,
						 &vertexShader,
						 nullptr));
		ThrowIfFailed(D3DCompileFromFile(GetAssetFullPath(L"shaders.hlsl").c_str(),
						 nullptr,
						 nullptr,
						 "PSMain",
						 "ps_5_0",
						 compileFlags,
						 0,
						 &pixelShader,
						 nullptr));

		// Define the vertex input layout.
		D3D12_INPUT_ELEMENT_DESC inputElementDescs[] =
		{
			{ "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
			{ "COLOR", 0, DXGI_FORMAT_R32G32B32A32_FLOAT, 0, 12, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 }
		};

		// Describe and create the graphics pipeline state object (PSO).
		D3D12_GRAPHICS_PIPELINE_STATE_DESC psoDesc = {};
		psoDesc.InputLayout = { inputElementDescs, _countof(inputElementDescs) };
		psoDesc.pRootSignature = m_rootSignature.Get();
		psoDesc.VS = CD3DX12_SHADER_BYTECODE(vertexShader.Get());
		psoDesc.PS = CD3DX12_SHADER_BYTECODE(pixelShader.Get());
		psoDesc.RasterizerState = CD3DX12_RASTERIZER_DESC(D3D12_DEFAULT);
		psoDesc.BlendState = CD3DX12_BLEND_DESC(D3D12_DEFAULT);
		psoDesc.DepthStencilState.DepthEnable = FALSE;
		psoDesc.DepthStencilState.StencilEnable = FALSE;
		psoDesc.SampleMask = UINT_MAX;
		psoDesc.PrimitiveTopologyType = D3D12_PRIMITIVE_TOPOLOGY_TYPE_TRIANGLE;
		psoDesc.NumRenderTargets = 1;
		psoDesc.RTVFormats[0] = DXGI_FORMAT_R8G8B8A8_UNORM;
		psoDesc.SampleDesc.Count = 1;
		ThrowIfFailed(m_device->CreateGraphicsPipelineState(&psoDesc, IID_PPV_ARGS(&m_pipelineState)));
	}

	// Create the command list.
	ThrowIfFailed(m_device->CreateCommandList(0, 
						  D3D12_COMMAND_LIST_TYPE_DIRECT, 
						  m_commandAllocator.Get(), 
						  m_pipelineState.Get(), 
						  IID_PPV_ARGS(&m_commandList)));

	// Command lists are created in the recording state, but there is nothing
	// to record yet. The main loop expects it to be closed, so close it now.
	ThrowIfFailed(m_commandList->Close());

	// Create the vertex buffer.
	{
		// Define the geometry for a triangle.
		Vertex triangleVertices[] =
		{
			{ { 0.0f, 0.25f * m_aspectRatio, 0.0f }, { 1.0f, 0.0f, 0.0f, 1.0f } },
			{ { 0.25f, -0.25f * m_aspectRatio, 0.0f }, { 0.0f, 1.0f, 0.0f, 1.0f } },
			{ { -0.25f, -0.25f * m_aspectRatio, 0.0f }, { 0.0f, 0.0f, 1.0f, 1.0f } }
		};

		const UINT vertexBufferSize = sizeof(triangleVertices);

		// Note: using upload heaps to transfer static data like vert buffers is not 
		// recommended. Every time the GPU needs it, the upload heap will be marshalled 
		// over. Please read up on Default Heap usage. An upload heap is used here for 
		// code simplicity and because there are very few verts to actually transfer.
		ThrowIfFailed(m_device->CreateCommittedResource(
			&CD3DX12_HEAP_PROPERTIES(D3D12_HEAP_TYPE_UPLOAD),
			D3D12_HEAP_FLAG_NONE,
			&CD3DX12_RESOURCE_DESC::Buffer(vertexBufferSize),
			D3D12_RESOURCE_STATE_GENERIC_READ,
			nullptr,
			IID_PPV_ARGS(&m_vertexBuffer)));

		// Copy the triangle data to the vertex buffer.
		UINT8* pVertexDataBegin;
		CD3DX12_RANGE readRange(0, 0);		// We do not intend to read from this resource on the CPU.
		ThrowIfFailed(m_vertexBuffer->Map(0, &readRange, reinterpret_cast<void**>(&pVertexDataBegin)));
		memcpy(pVertexDataBegin, triangleVertices, sizeof(triangleVertices));
		m_vertexBuffer->Unmap(0, nullptr);

		// Initialize the vertex buffer view.
		m_vertexBufferView.BufferLocation = m_vertexBuffer->GetGPUVirtualAddress();
		m_vertexBufferView.StrideInBytes = sizeof(Vertex);
		m_vertexBufferView.SizeInBytes = vertexBufferSize;
	}

	// Create synchronization objects and wait until assets have been uploaded to the GPU.
	{
		ThrowIfFailed(m_device->CreateFence(0, D3D12_FENCE_FLAG_NONE, IID_PPV_ARGS(&m_fence)));
		m_fenceValue = 1;

		// Create an event handle to use for frame synchronization.
		m_fenceEvent = CreateEvent(nullptr, FALSE, FALSE, nullptr);
		if (m_fenceEvent == nullptr)
		{
			ThrowIfFailed(HRESULT_FROM_WIN32(GetLastError()));
		}

		// Wait for the command list to execute; we are reusing the same command 
		// list in our main loop but for now, we just want to wait for setup to 
		// complete before continuing.
		WaitForPreviousFrame();
	}
}

 

정말 엄청 길다...

이전 코드에서 추가된 부분보다는 거의 전체적으로 확 바뀌었기 때문에 차근차근 살펴보자.

 

맨 먼저 빈 root signature(루트 서명) 생성 이라는 주석과 함께 코드가 적혀져 있다.

root signature(루트 서명)은 그리기 호출 전에 응용프로그램이 반드시 렌더링 파이프라인에 묶어야 하는 자원들이 뭔지

그 자원들이 셰이더 입력 레지스터들에게 어떻게 대응 되는지를 정의한다.

init을 할때 D3D12_ROOT_SIGNATURE_FLAG_ALLOW_INPUT_ASSEMBLER_INPUT_LAYOUT 이라는 플래그를 주었는데

이 플래그는 "앱이 입력 어셈블러 (버텍스 버퍼 바인딩 세트를 정의하는 입력 레이아웃이 필요함)를 사용하도록 선택합니다. 이 플래그를 생략하면 하나의 루트 인수 공간이 일부 하드웨어에 저장 될 수 있습니다. 입력 어셈블러가 필요하지 않은 경우에는이 플래그를 생략하십시오. 단, 최적화는 중요하지 않습니다." 라고 한다.... 관련된 부분은 MSDN을 한번 살펴보자 ( 링크 ) 

 

아무튼 ID3DBlob 이라는 형으로 signature와 error 을 생성했는데 Interface D3D Blob(Binary Large Object, [블랍? 이라고 읽나?]) 라는 뜻이다.

 

Init을하고 Serialize를 하고 디바이스에서 root Signature을 생성한다.

 

다음 글에서는 파이프라인 생성단계이고 셰이더를 컴파일 및 포함에 대해서 적을 예정

 

 

다음글에서...