Some minor updates to d3d swap chain

2 files changed, 20 insertions, 2 deletions

diff --git a/Graphics/GraphicsEngineD3D11/src/SwapChainD3D11Impl.cpp b/Graphics/GraphicsEngineD3D11/src/SwapChainD3D11Impl.cpp
index 7b0f99b5..ca5faf08 100644
--- a/Graphics/GraphicsEngineD3D11/src/SwapChainD3D11Impl.cpp
+++ b/Graphics/GraphicsEngineD3D11/src/SwapChainD3D11Impl.cpp
@@ -157,6 +157,15 @@ void SwapChainD3D11Impl::UpdateSwapChain(bool CreateNew)
             if(CreateNew)
             {
                 m_pSwapChain.Release();
+
+                // Only one flip presentation model swap chain can be associated with an HWND.
+                // We must make sure that the swap chain is actually released by D3D11 before creating a new one.
+                // To force the destruction, we need to ensure no views are bound to pipeline state, and then call Flush 
+                // on the immediate context. Dstruction must be forced before calling IDXGIFactory2::CreateSwapChainForHwnd(), or
+                // IDXGIFactory2::CreateSwapChainForCoreWindow() again to create a new swap chain.
+                // https://msdn.microsoft.com/en-us/library/windows/desktop/ff476425(v=vs.85).aspx#Defer_Issues_with_Flip
+                pImmediateCtxD3D11->Flush();
+
                 auto *pd3d11Device = ValidatedCast<RenderDeviceD3D11Impl>(m_pRenderDevice.RawPtr())->GetD3D11Device();
                 CreateDXGISwapChain(pd3d11Device);
             }
diff --git a/Graphics/GraphicsEngineD3DBase/include/SwapChainD3DBase.h b/Graphics/GraphicsEngineD3DBase/include/SwapChainD3DBase.h
index 0dc8bb0d..e61a3842 100644
--- a/Graphics/GraphicsEngineD3DBase/include/SwapChainD3DBase.h
+++ b/Graphics/GraphicsEngineD3DBase/include/SwapChainD3DBase.h
@@ -102,9 +102,18 @@ namespace Diligent
             swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
             swapChainDesc.BufferCount = m_SwapChainDesc.BufferCount;
             swapChainDesc.Scaling = DXGI_SCALING_NONE;
+
+            // DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL is the flip presentation model, where the contents of the back 
+            // buffer is preserved after the call to Present. This flag cannot be used with multisampling.
+            // The only swap effect that supports multisampling is DXGI_SWAP_EFFECT_DISCARD.
             // Windows Store apps must use DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL or DXGI_SWAP_EFFECT_FLIP_DISCARD.
             swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL;
-            swapChainDesc.AlphaMode = DXGI_ALPHA_MODE_UNSPECIFIED; // Not used
+
+            swapChainDesc.AlphaMode = DXGI_ALPHA_MODE_UNSPECIFIED; //  Transparency behavior is not specified
+
+            // DXGI_SWAP_CHAIN_FLAG_ALLOW_MODE_SWITCH enables an application to switch modes by calling 
+            // IDXGISwapChain::ResizeTarget(). When switching from windowed to fullscreen mode, the display 
+            // mode (or monitor resolution) will be changed to match the dimensions of the application window.
             swapChainDesc.Flags = DXGI_SWAP_CHAIN_FLAG_ALLOW_MODE_SWITCH;
 
             CComPtr<IDXGISwapChain1> pSwapChain1;
@@ -154,7 +163,7 @@ namespace Diligent
             if (m_pSwapChain)
             {
                 // If we are already in fullscreen mode, we need to switch to windowed mode first,
-                // otherwise swap chain creation will fail
+                // because a swap chain must be in windowed mode when it is released.
                 if (m_FSDesc.Fullscreen)
                     m_pSwapChain->SetFullscreenState(FALSE, nullptr);
                 m_FSDesc.Fullscreen = True;