总体来说可以概括为以下几个步骤:
- 创建Device和Context
- 创建SwapChain
- 为BackBuffer创建View
- 创建Depth/Stencil Buffer,并为之创建View
- 将View绑定到Context中
- 设置Viewport
创建Device和Context
HRESULT D3D11CreateDevice(
IDXGIAdapter *pAdapter,
D3D_DRIVER_TYPE DriverType,
HMODULE Software,
UINT Flags,
const D3D_FEATURE_LEVEL *pFeatureLevels,
UINT FeatureLevels,
UINT SDKVersion,
ID3D11Device **ppDevice,
D3D_FEATURE_LEVEL *pFeatureLevel,
ID3D11DeviceContext **ppImmediateContext
);
主要调用D3D11CreateDevice创建ID3D11Device和ID3D11DeviceContext。接口说明可以查看API文档。这里注意第四个参数Flags。在Windows10系统下,如果要设置为D3D11_CREATE_DEVICE_DEBUG,则必须安装DirectX Graphics Tools。参见
创建SwapChain
HRESULT CreateSwapChain(
IUnknown *pDevice,
DXGI_SWAP_CHAIN_DESC *pDesc,
IDXGISwapChain **ppSwapChain
);
主要调用IDXGIFactory::CreateSwapChain创建IDXGISwapChain。接口说明可以查看API文档。我们通过上一步创建的ID3D11Device来获得IDXGIFactory:参见
IDXGIDevice * pDXGIDevice = nullptr;
hr = g_pd3dDevice->QueryInterface(__uuidof(IDXGIDevice), (void **)&pDXGIDevice);
IDXGIAdapter * pDXGIAdapter = nullptr;
hr = pDXGIDevice->GetAdapter( &pDXGIAdapter );
IDXGIFactory * pIDXGIFactory = nullptr;
pDXGIAdapter->GetParent(__uuidof(IDXGIFactory), (void **)&pIDXGIFactory);
其实,我们也可以直接调用D3D11CreateDeviceAndSwapChain同时创建Device和SwapChain,但是DXGI_SWAP_CHAIN_DESC结构中包含Multisample相关字段,而在Device创建之前,是无法通过ID3D11Device::CheckMultisampleQualityLevels获取到正确值的。
为BackBuffer创建View
创建SwapChain的时候BackBuffer已经自动创建好了,我们只需做的是为它创建一个View。
HRESULT CreateRenderTargetView(
ID3D11Resource *pResource,
const D3D11_RENDER_TARGET_VIEW_DESC *pDesc,
ID3D11RenderTargetView **ppRTView
);
View的用处其实就是用来指定的Buffer的用法,这样同一块Buffer可以多次复用。一个Buffer可以对应多个View。
创建Depth/Stencil Buffer,并为之创建View
HRESULT CreateTexture2D(
const D3D11_TEXTURE2D_DESC *pDesc,
const D3D11_SUBRESOURCE_DATA *pInitialData,
ID3D11Texture2D **ppTexture2D
);
HRESULT CreateDepthStencilView(
ID3D11Resource *pResource,
const D3D11_DEPTH_STENCIL_VIEW_DESC *pDesc,
ID3D11DepthStencilView **ppDepthStencilView
);
首先通过ID3D11Device::CreateTexture2D创建出Buffer,然后调用ID3D11Device::CreateDepthStencilView创建View。值得注意的是,D3D11_TEXTURE2D_DESC结构中的Usage字段:参见
Resource Usage | Default | Dynamic | Immutable | Staging |
---|---|---|---|---|
GPU-Read | yes | yes | yes | yes |
GPU-Write | yes | yes | ||
CPU-Read | yes | |||
CPU-Write | yes | yes |
将View绑定到Context中
void OMSetRenderTargets(
UINT NumViews,
ID3D11RenderTargetView * const *ppRenderTargetViews,
ID3D11DepthStencilView *pDepthStencilView
);
ID3D11DeviceContext负责绑定View。
设置Viewport
void RSSetViewports(
UINT NumViewports,
const D3D11_VIEWPORT *pViewports
);
ID3D11DeviceContext负责设置Viewport。