Viewport: Added PlatformHandleRaw. Update SDL+DX11 example. (#1542, #2635)

examples/imgui_impl_dx11.cpp

@@ -564,7 +564,13 @@ static void ImGui_ImplDX11_CreateWindow(ImGuiViewport* viewport)
     ImGuiViewportDataDx11* data = IM_NEW(ImGuiViewportDataDx11)();
     viewport->RendererUserData = data;
 
-    HWND hwnd = (HWND)viewport->PlatformHandle;
+    // When using SDL, PlatformHandleRaw will be the HWND (because PlatformHandle would be the SDL_Window)
+    // If not using SDL, PlatformHandleRaw will be null and PlatformHandle will contain the HWND
+    HWND hwnd = (HWND)viewport->PlatformHandleRaw;
+    if (hwnd == 0)
+    {
+        hwnd = (HWND)viewport->PlatformHandle;
+    }
     IM_ASSERT(hwnd != 0);
 
     // Create swap chain

examples/imgui_impl_sdl.cpp

@@ -456,6 +456,16 @@ static void ImGui_ImplSDL2_CreateWindow(ImGuiViewport* viewport)
     if (use_opengl && backup_context)
         SDL_GL_MakeCurrent(data->Window, backup_context);
     viewport->PlatformHandle = (void*)data->Window;
+
+#if defined(_WIN32)
+    // save the window handle for render that needs it (directX)
+    SDL_SysWMinfo info;
+    SDL_VERSION(&info.version);
+    if (SDL_GetWindowWMInfo(data->Window, &info))
+    {
+        viewport->PlatformHandleRaw = info.info.win.window;
+    }
+#endif
 }
 
 static void ImGui_ImplSDL2_DestroyWindow(ImGuiViewport* viewport)

imgui.h

@@ -2399,11 +2399,12 @@ struct ImGuiViewport
     void*               RendererUserData;       // void* to hold custom data structure for the renderer (e.g. swap chain, frame-buffers etc.)
     void*               PlatformUserData;       // void* to hold custom data structure for the OS / platform (e.g. windowing info, render context)
     void*               PlatformHandle;         // void* for FindViewportByPlatformHandle(). (e.g. suggested to use natural platform handle such as HWND, GlfwWindow*, SDL_Window*)
+    void*               PlatformHandleRaw;      // void* to hold the platfor-native windows handle (e.g. the HWND) when using an abstraction layer like SDL (where PlatformHandle would be a SDL_Window*)
     bool                PlatformRequestClose;   // Platform window requested closure (e.g. window was moved by the OS / host window manager, e.g. pressing ALT-F4)
     bool                PlatformRequestMove;    // Platform window requested move (e.g. window was moved by the OS / host window manager, authoritative position will be OS window position)
     bool                PlatformRequestResize;  // Platform window requested resize (e.g. window was resized by the OS / host window manager, authoritative size will be OS window size)
 
-    ImGuiViewport()     { ID = 0; Flags = 0; DpiScale = 0.0f; DrawData = NULL; ParentViewportId = 0; RendererUserData = PlatformUserData = PlatformHandle = NULL; PlatformRequestClose = PlatformRequestMove = PlatformRequestResize = false; }
+    ImGuiViewport()     { ID = 0; Flags = 0; DpiScale = 0.0f; DrawData = NULL; ParentViewportId = 0; RendererUserData = PlatformUserData = PlatformHandle = PlatformHandleRaw = NULL; PlatformRequestClose = PlatformRequestMove = PlatformRequestResize = false; }
     ~ImGuiViewport()    { IM_ASSERT(PlatformUserData == NULL && RendererUserData == NULL); }
 };