Examples: SDL3: Added comments to clarify setup for users of the unfortunate SDL_MAIN_USE_CALLBACKS feature. (#8455)

examples/example_sdl3_opengl3/main.cpp

@@ -26,6 +26,7 @@
 int main(int, char**)
 {
     // Setup SDL
+    // [If using SDL_MAIN_USE_CALLBACKS: all code below until the main loop starts would likely be your SDL_AppInit() function]
     if (!SDL_Init(SDL_INIT_VIDEO | SDL_INIT_GAMEPAD))
     {
         printf("Error: SDL_Init(): %s\n", SDL_GetError());
@@ -139,6 +140,7 @@ int main(int, char**)
         // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application, or clear/overwrite your copy of the mouse data.
         // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application, or clear/overwrite your copy of the keyboard data.
         // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
+        // [If using SDL_MAIN_USE_CALLBACKS: call ImGui_ImplSDL3_ProcessEvent() from your SDL_AppEvent() function]
         SDL_Event event;
         while (SDL_PollEvent(&event))
         {
@@ -148,6 +150,8 @@ int main(int, char**)
             if (event.type == SDL_EVENT_WINDOW_CLOSE_REQUESTED && event.window.windowID == SDL_GetWindowID(window))
                 done = true;
         }
+
+        // [If using SDL_MAIN_USE_CALLBACKS: all code below would likely be your SDL_AppIterate() function]
         if (SDL_GetWindowFlags(window) & SDL_WINDOW_MINIMIZED)
         {
             SDL_Delay(10);
@@ -209,6 +213,7 @@ int main(int, char**)
 #endif
 
     // Cleanup
+    // [If using SDL_MAIN_USE_CALLBACKS: all code below would likely be your SDL_AppQuit() function]
     ImGui_ImplOpenGL3_Shutdown();
     ImGui_ImplSDL3_Shutdown();
     ImGui::DestroyContext();