何時調用RTV/DSV上的DiscardView？

Question

在清除相關視圖之前立即致電DiscardView是否安全策略？看起來濫用這個API可能導致不好的事情，所以關於如何有效地使用這個的一些解釋將非常感謝。

Answer 1

DiscardView是平鋪硬件渲染的優化，所以不是嚴格要求。

在標準的Windows 8商店的Windows Phone 8，和通用Windows應用程序模板，這就是所謂的後右Present

void DX::DeviceResources::Present() 
{ 
    // The first argument instructs DXGI to block until VSync, putting the application 
    // to sleep until the next VSync. This ensures we don't waste any cycles rendering 
    // frames that will never be displayed to the screen. 
    HRESULT hr = m_swapChain->Present(1, 0); 

    // Discard the contents of the render target. 
    // This is a valid operation only when the existing contents will be entirely 
    // overwritten. If dirty or scroll rects are used, this call should be removed. 
    m_d3dContext->DiscardView(m_d3dRenderTargetView.Get()); 

    // Discard the contents of the depth stencil. 
    m_d3dContext->DiscardView(m_d3dDepthStencilView.Get()); 

    // If the device was removed either by a disconnection or a driver upgrade, we 
    // must recreate all device resources. 
    if (hr == DXGI_ERROR_DEVICE_REMOVED || hr == DXGI_ERROR_DEVICE_RESET) 
    { 
     HandleDeviceLost(); 
    } 
    else 
    { 
     DX::ThrowIfFailed(hr); 
    } 
}