Direct3D 11 学习笔记（二）

Direct3D 11 学习笔记（二）

DXUT

　　DXUT 能够提供一个简单的接口来处理 window 的创建，D3D device 的创建。

　　在不使用 DXUT 框架的时候，我们需要自己调用 windows 的 API 来创建窗口：

// Register class
WNDCLASSEX wcex;
wcex.cbSize = sizeof( WNDCLASSEX );
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon( hInstance, ( LPCTSTR )IDI_TUTORIAL1 );
wcex.hCursor = LoadCursor( nullptr, IDC_ARROW );
wcex.hbrBackground = ( HBRUSH )( COLOR_WINDOW + 1 );
wcex.lpszMenuName = nullptr;
wcex.lpszClassName = L"TutorialWindowClass";
wcex.hIconSm = LoadIcon( wcex.hInstance, ( LPCTSTR )IDI_TUTORIAL1 );
if( !RegisterClassEx( &wcex ) )
return E_FAIL;

// Create window
g_hInst = hInstance;
RECT rc = { 0, 0, 800, 600 };
AdjustWindowRect( &rc, WS_OVERLAPPEDWINDOW, FALSE );
g_hWnd = CreateWindow( L"TutorialWindowClass", L"Direct3D 11 Tutorial 7",
WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU | WS_MINIMIZEBOX,
CW_USEDEFAULT, CW_USEDEFAULT, rc.right - rc.left,
rc.bottom - rc.top, nullptr, nullptr, hInstance,
nullptr );
if( !g_hWnd )
return E_FAIL;

ShowWindow( g_hWnd, nCmdShow );

return S_OK;

　　需要自己调用 D3D11CreateDeviceAndSwapChain 来创建 device 和 swap chain，代码如下：

HRESULT hr = S_OK;

RECT rc;
GetClientRect( g_hWnd, &rc );
UINT width = rc.right - rc.left;
UINT height = rc.bottom - rc.top;

UINT createDeviceFlags = 0;
#ifdef _DEBUG
createDeviceFlags |= D3D11_CREATE_DEVICE_DEBUG;
#endif

D3D_DRIVER_TYPE driverTypes[] =
{
D3D_DRIVER_TYPE_HARDWARE,
D3D_DRIVER_TYPE_WARP,
D3D_DRIVER_TYPE_REFERENCE,
};
UINT numDriverTypes = ARRAYSIZE( driverTypes );

D3D_FEATURE_LEVEL featureLevels[] =
{
D3D_FEATURE_LEVEL_11_1,
D3D_FEATURE_LEVEL_11_0,
D3D_FEATURE_LEVEL_10_1,
D3D_FEATURE_LEVEL_10_0,
};
UINT numFeatureLevels = ARRAYSIZE( featureLevels );

for( UINT driverTypeIndex = 0; driverTypeIndex < numDriverTypes; driverTypeIndex++ )
{
g_driverType = driverTypes[driverTypeIndex];
hr = D3D11CreateDevice( nullptr, g_driverType, nullptr, createDeviceFlags,
featureLevels, numFeatureLevels, D3D11_SDK_VERSION,
&g_pd3dDevice, &g_featureLevel, &g_pImmediateContext );

if ( hr == E_INVALIDARG )
{
// DirectX 11.0 platforms will not recognize D3D_FEATURE_LEVEL_11_1 so we need to retry without it
hr = D3D11CreateDevice( nullptr, g_driverType, nullptr, createDeviceFlags,
&featureLevels[1], numFeatureLevels - 1, D3D11_SDK_VERSION,
&g_pd3dDevice, &g_featureLevel, &g_pImmediateContext );
}

if( SUCCEEDED( hr ) )
break;
}
if( FAILED( hr ) )
return hr;

// Obtain DXGI factory from device (since we used nullptr for pAdapter above)
IDXGIFactory1* dxgiFactory = nullptr;
{
IDXGIDevice* dxgiDevice = nullptr;
hr = g_pd3dDevice->QueryInterface( __uuidof(IDXGIDevice),
reinterpret_cast<void**>(&dxgiDevice) );
if (SUCCEEDED(hr))
{
IDXGIAdapter* adapter = nullptr;
hr = dxgiDevice->GetAdapter(&adapter);
if (SUCCEEDED(hr))
{
hr = adapter->GetParent( __uuidof(IDXGIFactory1),
reinterpret_cast<void**>(&dxgiFactory) );
adapter->Release();
}
dxgiDevice->Release();
}
}
if (FAILED(hr))
return hr;

// Create swap chain
IDXGIFactory2* dxgiFactory2 = nullptr;
hr = dxgiFactory->QueryInterface( __uuidof(IDXGIFactory2),
reinterpret_cast<void**>(&dxgiFactory2) );
if ( dxgiFactory2 )
{
// DirectX 11.1 or later
hr = g_pd3dDevice->QueryInterface( __uuidof(ID3D11Device1),
reinterpret_cast<void**>(&g_pd3dDevice1) );
if (SUCCEEDED(hr))
{
(void) g_pImmediateContext->QueryInterface( __uuidof(ID3D11DeviceContext1),
reinterpret_cast<void**>(&g_pImmediateContext1) );
}

DXGI_SWAP_CHAIN_DESC1 sd;
ZeroMemory(&sd, sizeof(sd));
sd.Width = width;
sd.Height = height;
sd.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
sd.SampleDesc.Count = 1;
sd.SampleDesc.Quality = 0;
sd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
sd.BufferCount = 1;

hr = dxgiFactory2->CreateSwapChainForHwnd( g_pd3dDevice, g_hWnd, &sd, nullptr,
nullptr, &g_pSwapChain1 );
if (SUCCEEDED(hr))
{
hr = g_pSwapChain1->QueryInterface( __uuidof(IDXGISwapChain),
reinterpret_cast<void**>(&g_pSwapChain) );
}

dxgiFactory2->Release();
}
else
{
// DirectX 11.0 systems
DXGI_SWAP_CHAIN_DESC sd;
ZeroMemory(&sd, sizeof(sd));
sd.BufferCount = 1;
sd.BufferDesc.Width = width;
sd.BufferDesc.Height = height;
sd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
sd.BufferDesc.RefreshRate.Numerator = 60;
sd.BufferDesc.RefreshRate.Denominator = 1;
sd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
sd.OutputWindow = g_hWnd;
sd.SampleDesc.Count = 1;
sd.SampleDesc.Quality = 0;
sd.Windowed = TRUE;

hr = dxgiFactory->CreateSwapChain( g_pd3dDevice, &sd, &g_pSwapChain );
}

// Note this tutorial doesn't handle full-screen swapchains so we block the ALT+ENTER shortcut
dxgiFactory->MakeWindowAssociation( g_hWnd, DXGI_MWA_NO_ALT_ENTER );

dxgiFactory->Release();

if (FAILED(hr))
return hr;

// Create a render target view
ID3D11Texture2D* pBackBuffer = nullptr;
hr = g_pSwapChain->GetBuffer( 0, __uuidof( ID3D11Texture2D ),
reinterpret_cast<void**>( &pBackBuffer ) );
if( FAILED( hr ) )
return hr;

hr = g_pd3dDevice->CreateRenderTargetView( pBackBuffer, nullptr, &g_pRenderTargetView );
pBackBuffer->Release();
if( FAILED( hr ) )
return hr;

// Create depth stencil texture
D3D11_TEXTURE2D_DESC descDepth;
ZeroMemory( &descDepth, sizeof(descDepth) );
descDepth.Width = width;
descDepth.Height = height;
descDepth.MipLevels = 1;
descDepth.ArraySize = 1;
descDepth.Format = DXGI_FORMAT_D24_UNORM_S8_UINT;
descDepth.SampleDesc.Count = 1;
descDepth.SampleDesc.Quality = 0;
descDepth.Usage = D3D11_USAGE_DEFAULT;
descDepth.BindFlags = D3D11_BIND_DEPTH_STENCIL;
descDepth.CPUAccessFlags = 0;
descDepth.MiscFlags = 0;
hr = g_pd3dDevice->CreateTexture2D( &descDepth, nullptr, &g_pDepthStencil );
if( FAILED( hr ) )
return hr;

// Create the depth stencil view
D3D11_DEPTH_STENCIL_VIEW_DESC descDSV;
ZeroMemory( &descDSV, sizeof(descDSV) );
descDSV.Format = descDepth.Format;
descDSV.ViewDimension = D3D11_DSV_DIMENSION_TEXTURE2D;
descDSV.Texture2D.MipSlice = 0;
hr = g_pd3dDevice->CreateDepthStencilView( g_pDepthStencil, &descDSV, &g_pDepthStencilView );
if( FAILED( hr ) )
return hr;

g_pImmediateContext->OMSetRenderTargets( 1, &g_pRenderTargetView, g_pDepthStencilView );

// Setup the viewport
D3D11_VIEWPORT vp;
vp.Width = (FLOAT)width;
vp.Height = (FLOAT)height;
vp.MinDepth = 0.0f;
vp.MaxDepth = 1.0f;
vp.TopLeftX = 0;
vp.TopLeftY = 0;
g_pImmediateContext->RSSetViewports( 1, &vp );

　　我们使用 DXUT 框架之后，只需要使用如下代码就可以完成上述内容：

// Parse the command line, show msgboxes on error, no extra command line params
DXUTInit( true, true, nullptr );

DXUTSetCursorSettings( true, true ); // Show the cursor and clip it when in full screen
DXUTCreateWindow( L"Tutorial08" );

// Only require 10-level hardware or later
DXUTCreateDevice( D3D_FEATURE_LEVEL_10_0, true, 800, 600 );

　　

　　

　　在上述代码完成后，我们直接使用 DXUTMainLoop() 就可以进入 DXUT 的循环，通过 DXUT 提供的回调函数来控制我们的渲染过程，回调函数如下：

// Set general DXUT callbacks
DXUTSetCallbackFrameMove( OnFrameMove );
DXUTSetCallbackKeyboard( OnKeyboard );
DXUTSetCallbackMsgProc( MsgProc );
DXUTSetCallbackDeviceChanging( ModifyDeviceSettings );
DXUTSetCallbackDeviceRemoved( OnDeviceRemoved );

// Set the D3D11 DXUT callbacks. Remove these sets if the app doesn't need to support D3D11
DXUTSetCallbackD3D11DeviceAcceptable( IsD3D11DeviceAcceptable );
DXUTSetCallbackD3D11DeviceCreated( OnD3D11CreateDevice );
DXUTSetCallbackD3D11SwapChainResized( OnD3D11ResizedSwapChain );
DXUTSetCallbackD3D11FrameRender( OnD3D11FrameRender );
DXUTSetCallbackD3D11SwapChainReleasing( OnD3D11ReleasingSwapChain );
DXUTSetCallbackD3D11DeviceDestroyed( OnD3D11DestroyDevice );

　　上述代码来源于微软 D3D11 官方教程源码。