ocornut · PathogenDavid · Jul 21, 2021 · Jul 22, 2021
diff --git a/backends/imgui_impl_dx10.cpp b/backends/imgui_impl_dx10.cpp
@@ -624,6 +624,7 @@ static void ImGui_ImplDX10_CreateWindow(ImGuiViewport* viewport)
 
     IM_ASSERT(vd->SwapChain == NULL && vd->RTView == NULL);
     bd->pFactory->CreateSwapChain(bd->pd3dDevice, &sd, &vd->SwapChain);
+    bd->pFactory->MakeWindowAssociation(hwnd, DXGI_MWA_NO_ALT_ENTER | DXGI_MWA_NO_PRINT_SCREEN | DXGI_MWA_NO_WINDOW_CHANGES);
 
     // Create the render target
     if (vd->SwapChain)

diff --git a/backends/imgui_impl_dx11.cpp b/backends/imgui_impl_dx11.cpp
@@ -641,6 +641,7 @@ static void ImGui_ImplDX11_CreateWindow(ImGuiViewport* viewport)
 
     IM_ASSERT(vd->SwapChain == NULL && vd->RTView == NULL);
     bd->pFactory->CreateSwapChain(bd->pd3dDevice, &sd, &vd->SwapChain);
+    bd->pFactory->MakeWindowAssociation(hwnd, DXGI_MWA_NO_ALT_ENTER | DXGI_MWA_NO_PRINT_SCREEN | DXGI_MWA_NO_WINDOW_CHANGES);
 
     // Create the render target
     if (vd->SwapChain)

diff --git a/backends/imgui_impl_dx12.cpp b/backends/imgui_impl_dx12.cpp
@@ -898,6 +898,8 @@ static void ImGui_ImplDX12_CreateWindow(ImGuiViewport* viewport)
     IDXGISwapChain1* swap_chain = NULL;
     res = dxgi_factory->CreateSwapChainForHwnd(vd->CommandQueue, hwnd, &sd1, NULL, NULL, &swap_chain);
     IM_ASSERT(res == S_OK);
+    res = dxgi_factory->MakeWindowAssociation(hwnd, DXGI_MWA_NO_ALT_ENTER | DXGI_MWA_NO_PRINT_SCREEN | DXGI_MWA_NO_WINDOW_CHANGES);
+    IM_ASSERT(res == S_OK);
 
     dxgi_factory->Release();
 

diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
@@ -181,6 +181,8 @@ Docking+Viewports Branch:
 - Viewports: Fix popup/tooltip created without a parent window from being given a ParentViewportId value
   from the implicit/fallback window. (#4236, #2409)
 - Backends: Vulkan: Fix the use of the incorrect fence for secondary viewports. (#4208) [@FunMiles]
+- Examples: Disabled DXGI's automatic alt+enter fullscreen for DirectX 10/11 samples. Applications are free to
+  leave this enabled, but it does not work properly with multiple viewports. (#4350) [@PathogenDavid]
 
 
 -----------------------------------------------------------------------

diff --git a/examples/example_sdl_directx11/main.cpp b/examples/example_sdl_directx11/main.cpp
@@ -223,6 +223,13 @@ bool CreateDeviceD3D(HWND hWnd)
     if (D3D11CreateDeviceAndSwapChain(NULL, D3D_DRIVER_TYPE_HARDWARE, NULL, createDeviceFlags, featureLevelArray, 2, D3D11_SDK_VERSION, &sd, &g_pSwapChain, &g_pd3dDevice, &featureLevel, &g_pd3dDeviceContext) != S_OK)
         return false;
 
+    // Disable DXGI's automatic alt+enter fullscreen
+    // You are free to leave this enabled, but it will not work properly with multiple viewports
+    // For DirectX 11, this must be done for all windows associated with the device
+    IDXGIFactory* pSwapChainFactory;
+    if (SUCCEEDED(g_pSwapChain->GetParent(IID_PPV_ARGS(&pSwapChainFactory))))
+        pSwapChainFactory->MakeWindowAssociation(hWnd, DXGI_MWA_NO_ALT_ENTER);
+
     CreateRenderTarget();
     return true;
 }

diff --git a/examples/example_win32_directx10/main.cpp b/examples/example_win32_directx10/main.cpp
@@ -206,6 +206,13 @@ bool CreateDeviceD3D(HWND hWnd)
     if (D3D10CreateDeviceAndSwapChain(NULL, D3D10_DRIVER_TYPE_HARDWARE, NULL, createDeviceFlags, D3D10_SDK_VERSION, &sd, &g_pSwapChain, &g_pd3dDevice) != S_OK)
         return false;
 
+    // Disable DXGI's window management features (namely automatic alt+enter fullscreen)
+    // You are free to leave this enabled, but it will not work properly with multiple viewports
+    // For DirectX 10, this must be done for all windows associated with the device
+    IDXGIFactory* pSwapChainFactory;
+    if (SUCCEEDED(g_pSwapChain->GetParent(IID_PPV_ARGS(&pSwapChainFactory))))
+        pSwapChainFactory->MakeWindowAssociation(hWnd, DXGI_MWA_NO_ALT_ENTER | DXGI_MWA_NO_WINDOW_CHANGES);
+
     CreateRenderTarget();
     return true;
 }

diff --git a/examples/example_win32_directx11/main.cpp b/examples/example_win32_directx11/main.cpp
@@ -214,6 +214,13 @@ bool CreateDeviceD3D(HWND hWnd)
     if (D3D11CreateDeviceAndSwapChain(NULL, D3D_DRIVER_TYPE_HARDWARE, NULL, createDeviceFlags, featureLevelArray, 2, D3D11_SDK_VERSION, &sd, &g_pSwapChain, &g_pd3dDevice, &featureLevel, &g_pd3dDeviceContext) != S_OK)
         return false;
 
+    // Disable DXGI's automatic alt+enter fullscreen
+    // You are free to leave this enabled, but it will not work properly with multiple viewports
+    // For DirectX 11, this must be done for all windows associated with the device
+    IDXGIFactory* pSwapChainFactory;
+    if (SUCCEEDED(g_pSwapChain->GetParent(IID_PPV_ARGS(&pSwapChainFactory))))
+        pSwapChainFactory->MakeWindowAssociation(hWnd, DXGI_MWA_NO_ALT_ENTER);
+
     CreateRenderTarget();
     return true;
 }