Viewport: Renamed RenderPlatformWindows() to RenderPlatformWindowsDefault(), tweaked examples and emphasis optional Viewport code path. (#1542)

examples/directx10_example/main.cpp

@@ -208,9 +208,12 @@ int main(int, char**)
         ImGui::Render();
         ImGui_ImplDX10_RenderDrawData(ImGui::GetDrawData());
 
-        // Update and Render additional Platform Windows (when ImGuiConfigFlags_EnableViewports is enabled)
-        ImGui::UpdatePlatformWindows();
-        ImGui::RenderPlatformWindows(NULL, NULL);
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_EnableViewports)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
 
         g_pSwapChain->Present(1, 0); // Present with vsync
         //g_pSwapChain->Present(0, 0); // Present without vsync

examples/directx11_example/main.cpp

@@ -226,9 +226,12 @@ int main(int, char**)
         ImGui::Render();
         ImGui_ImplDX11_RenderDrawData(ImGui::GetDrawData());
 
-        // Update and Render additional Platform Windows (when ImGuiConfigFlags_EnableViewports is enabled)
-        ImGui::UpdatePlatformWindows();
-        ImGui::RenderPlatformWindows(NULL, NULL);
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_EnableViewports)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
 
         g_pSwapChain->Present(1, 0); // Present with vsync
         //g_pSwapChain->Present(0, 0); // Present without vsync

examples/directx12_example/main.cpp

@@ -401,9 +401,12 @@ int main(int, char**)
 
         g_pd3dCommandQueue->ExecuteCommandLists(1, (ID3D12CommandList* const*)&g_pd3dCommandList);
 
-        // Update and Render additional Platform Windows (when ImGuiConfigFlags_EnableViewports is enabled)
-        ImGui::UpdatePlatformWindows();
-        ImGui::RenderPlatformWindows(NULL, NULL);
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_EnableViewports)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
 
         g_pSwapChain->Present(1, 0); // Present with vsync
         //g_pSwapChain->Present(0, 0); // Present without vsync

examples/opengl2_example/main.cpp

@@ -117,9 +117,12 @@ int main(int, char**)
         //glUseProgram(0); // You may want this if using this code in an OpenGL 3+ context where shaders may be bound, but prefer using the GL3+ code.
         ImGui_ImplOpenGL2_RenderDrawData(ImGui::GetDrawData());
 
-        // Update and Render additional Platform Windows (when ImGuiConfigFlags_EnableViewports is enabled)
-        ImGui::UpdatePlatformWindows();
-        ImGui::RenderPlatformWindows(NULL, NULL);
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_EnableViewports)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
 
         glfwMakeContextCurrent(window);
         glfwSwapBuffers(window);

examples/opengl3_example/main.cpp

@@ -124,9 +124,12 @@ int main(int, char**)
         glClear(GL_COLOR_BUFFER_BIT);
         ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
     	
-        // Update and Render additional Platform Windows (when ImGuiConfigFlags_EnableViewports is enabled)
-        ImGui::UpdatePlatformWindows();
-        ImGui::RenderPlatformWindows(NULL, NULL);
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_EnableViewports)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
 
         glfwMakeContextCurrent(window);
         glfwSwapBuffers(window);

examples/sdl_opengl3_example/main.cpp

@@ -132,9 +132,12 @@ int main(int, char**)
         glClear(GL_COLOR_BUFFER_BIT);
         ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
 
-        // Update and Render additional Platform Windows (when ImGuiConfigFlags_EnableViewports is enabled)
-        ImGui::UpdatePlatformWindows();
-        ImGui::RenderPlatformWindows(NULL, NULL);
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_EnableViewports)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
 
         SDL_GL_MakeCurrent(window, gl_context);
         SDL_GL_SwapWindow(window);

examples/sdl_vulkan_example/main.cpp

@@ -469,9 +469,12 @@ int main(int, char**)
         memcpy(&wd->ClearValue.color.float32[0], &clear_color, 4 * sizeof(float));
 		FrameRender(wd);
         
-        // Update and Render additional Platform Windows (when ImGuiConfigFlags_EnableViewports is enabled)
-        ImGui::UpdatePlatformWindows();
-        ImGui::RenderPlatformWindows(NULL, NULL);
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_EnableViewports)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
 
         FramePresent(wd);
     }

examples/vulkan_example/main.cpp

@@ -479,9 +479,12 @@ int main(int, char**)
         memcpy(&wd->ClearValue.color.float32[0], &clear_color, 4 * sizeof(float));
 		FrameRender(wd);
 
-        // Update and Render additional Platform Windows (when ImGuiConfigFlags_EnableViewports is enabled)
-        ImGui::UpdatePlatformWindows();
-        ImGui::RenderPlatformWindows(NULL, NULL);
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_EnableViewports)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
 
         FramePresent(wd);
     }

imgui.cpp

@@ -3602,7 +3602,7 @@ void ImGui::UpdatePlatformWindows()
 //        MySwapBufferFunction(data->Viewports[i], my_args);
 //
 // Note how we intentionally skip the main viewport (index 0) which is generally rendered as part of our main application.
-void ImGui::RenderPlatformWindows(void* platform_render_arg, void* renderer_render_arg)
+void ImGui::RenderPlatformWindowsDefault(void* platform_render_arg, void* renderer_render_arg)
 {
     if (!(ImGui::GetIO().ConfigFlags & ImGuiConfigFlags_EnableViewports))
         return;

imgui.h

@@ -551,7 +551,7 @@ namespace ImGui
     IMGUI_API ImGuiPlatformData* GetPlatformData();                 // List of viewports. Viewport 0 is always the main viewport, followed by the secondary viewports.
     IMGUI_API ImGuiViewport*     GetMainViewport();                 // GetPlatformData()->MainViewport
     IMGUI_API void               UpdatePlatformWindows();           // Call in main loop. Create/Destroy/Resize platform windows so there's one for each viewport
-    IMGUI_API void               RenderPlatformWindows(void* platform_render_arg, void* renderer_render_arg); // Call in main loop. Call RenderWindow/SwapBuffers from the ImGuiPlatformIO structure. May be reimplemented by user.
+    IMGUI_API void               RenderPlatformWindowsDefault(void* platform_render_arg = NULL, void* renderer_render_arg = NULL); // Call in main loop. Call RenderWindow/SwapBuffers from the ImGuiPlatformIO structure. May be reimplemented by user.
     IMGUI_API void               DestroyPlatformWindows();          // (Optional) Call in back-end shutdown if you need to close Platform Windows before imgui shutdown.
     IMGUI_API ImGuiViewport*     FindViewportByPlatformHandle(void* platform_handle);
 
@@ -1878,8 +1878,8 @@ struct ImFont
 // This is designed so we can mix and match two imgui_impl_xxxx files, one for the Platform (~ Windowing), one for Renderer.
 // Custom engine back-ends will often provide both Platform and Renderer interfaces and thus may not need to use all functions.
 // Platform functions are typically called before their Renderer counterpart, apart from Destroy which are called the other way.
-// RenderPlatformWindows() basically iterate secondary viewports and call Platform+Renderer's RenderWindow then Platform+Renderer's SwapBuffers,
-// You may skip using RenderPlatformWindows() and call your functions yourself if you need specific behavior for your multi-window rendering.
+// RenderPlatformWindowsDefault() basically iterate secondary viewports and call Platform+Renderer's RenderWindow then Platform+Renderer's SwapBuffers,
+// You may skip using RenderPlatformWindowsDefault() and call your draw/swap functions yourself if you need specific behavior for your multi-window rendering.
 struct ImGuiPlatformIO
 {
     // Platform (e.g. Win32, GLFW, SDL2)