From d92ad93fddbe367611ab4c38894a86ff0a42f8d7 Mon Sep 17 00:00:00 2001 From: moonpower Date: Fri, 26 Dec 2025 03:00:50 +0100 Subject: [PATCH] Backends: Enhance SDL_Surface example to match the renderer example --- examples/example_sdl2_surface/main.cpp | 110 ++++++++++++++++++++++--- 1 file changed, 100 insertions(+), 10 deletions(-) diff --git a/examples/example_sdl2_surface/main.cpp b/examples/example_sdl2_surface/main.cpp index 966660f59..85a086ced 100644 --- a/examples/example_sdl2_surface/main.cpp +++ b/examples/example_sdl2_surface/main.cpp @@ -9,15 +9,24 @@ int main(int, char**) { - if (SDL_Init(SDL_INIT_VIDEO) != 0) + // Setup SDL + if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER | SDL_INIT_GAMECONTROLLER) != 0) { printf("Error: %s\n", SDL_GetError()); return -1; } + // From 2.0.18: Enable native IME. +#ifdef SDL_HINT_IME_SHOW_UI + SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1"); +#endif + + // Create window + float main_scale = ImGui_ImplSDL2_GetContentScaleForDisplay(0); + SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI | SDL_WINDOW_SHOWN); SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+Surface Example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, - 1280, 720, SDL_WINDOW_SHOWN); + (int)(1280 * main_scale), (int)(720 * main_scale), window_flags); if (!window) { printf("Error creating window: %s\n", SDL_GetError()); @@ -31,53 +40,134 @@ int main(int, char**) return -1; } - SDL_Surface* framebuffer = SDL_CreateRGBSurfaceWithFormat(0, 1280, 720, 32, SDL_PIXELFORMAT_RGBA32); + int win_w = window_surface->w; + int win_h = window_surface->h; + SDL_Surface* framebuffer = SDL_CreateRGBSurfaceWithFormat(0, win_w, win_h, 32, SDL_PIXELFORMAT_RGBA32); if (!framebuffer) { printf("Error creating framebuffer: %s\n", SDL_GetError()); return -1; } + // Setup Dear ImGui context IMGUI_CHECKVERSION(); ImGui::CreateContext(); ImGuiIO& io = ImGui::GetIO(); (void)io; - io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard; - io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad; + io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard; // Enable Keyboard Controls + io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad; // Enable Gamepad Controls + // Setup Dear ImGui style ImGui::StyleColorsDark(); - ImGui_ImplSDL2_InitForSDLRenderer(window, nullptr); + + // Setup scaling + ImGuiStyle& style = ImGui::GetStyle(); + style.ScaleAllSizes(main_scale); // Bake a fixed style scale. + style.FontScaleDpi = main_scale; + + // Setup Platform/Renderer backends + ImGui_ImplSDL2_InitForOther(window); ImGui_ImplSDL2_SetGamepadMode(ImGui_ImplSDL2_GamepadMode_AutoFirst, nullptr, 0); ImGui_ImplSDLSurface2_Init(framebuffer); + // Our state bool show_demo_window = true; + bool show_another_window = false; ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f); + // Main loop bool done = false; while (!done) { + // Poll and handle events (inputs, window resize, etc.) SDL_Event event; while (SDL_PollEvent(&event)) { ImGui_ImplSDL2_ProcessEvent(&event); if (event.type == SDL_QUIT) done = true; - if (event.type == SDL_WINDOWEVENT && event.window.event == SDL_WINDOWEVENT_CLOSE && event.window.windowID == SDL_GetWindowID(window)) - done = true; + + if (event.type == SDL_WINDOWEVENT) + { + if (event.window.event == SDL_WINDOWEVENT_CLOSE && event.window.windowID == SDL_GetWindowID(window)) + done = true; + + if (event.window.event == SDL_WINDOWEVENT_SIZE_CHANGED || event.window.event == SDL_WINDOWEVENT_RESIZED) + { + // Recreate framebuffer at new size + window_surface = SDL_GetWindowSurface(window); + int new_w = window_surface->w; + int new_h = window_surface->h; + if (new_w != win_w || new_h != win_h) + { + SDL_FreeSurface(framebuffer); + framebuffer = SDL_CreateRGBSurfaceWithFormat(0, new_w, new_h, 32, SDL_PIXELFORMAT_RGBA32); + if (!framebuffer) { printf("Error creating framebuffer after resize: %s\n", SDL_GetError()); return -1; } + win_w = new_w; win_h = new_h; + // Re-init the backend with the new framebuffer + ImGui_ImplSDLSurface2_Shutdown(); + ImGui_ImplSDLSurface2_Init(framebuffer); + } + } + } } + // Skip rendering when minimized to avoid busy-looping + if (SDL_GetWindowFlags(window) & SDL_WINDOW_MINIMIZED) + { + SDL_Delay(10); + continue; + } + + // Start the Dear ImGui frame ImGui_ImplSDLSurface2_NewFrame(); ImGui_ImplSDL2_NewFrame(); ImGui::NewFrame(); + // 1. Show the big demo window if (show_demo_window) ImGui::ShowDemoWindow(&show_demo_window); + // 2. Show a simple window that we create ourselves. Mirror the SDL_Renderer example. + { + static float f = 0.0f; + static int counter = 0; + + ImGui::Begin("Hello, world!"); // Create a window called "Hello, world!" and append into it. + + ImGui::Text("This is some useful text."); // Display some text + ImGui::Checkbox("Demo Window", &show_demo_window); // Edit bools storing our window open/close state + ImGui::Checkbox("Another Window", &show_another_window); + + ImGui::SliderFloat("float", &f, 0.0f, 1.0f); // Edit 1 float using a slider from 0.0f to 1.0f + ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color + + if (ImGui::Button("Button")) // Buttons return true when clicked + counter++; + ImGui::SameLine(); + ImGui::Text("counter = %d", counter); + + ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate); + ImGui::End(); + } + + // 3. Show another simple window. + if (show_another_window) + { + ImGui::Begin("Another Window", &show_another_window); // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when clicked) + ImGui::Text("Hello from another window!"); + if (ImGui::Button("Close Me")) + show_another_window = false; + ImGui::End(); + } + + // Rendering ImGui::Render(); - SDL_FillRect(framebuffer, nullptr, SDL_MapRGB(framebuffer->format, + SDL_FillRect(framebuffer, nullptr, SDL_MapRGBA(framebuffer->format, (Uint8)(clear_color.x * 255), (Uint8)(clear_color.y * 255), - (Uint8)(clear_color.z * 255))); + (Uint8)(clear_color.z * 255), + (Uint8)(clear_color.w * 255))); ImGui_ImplSDLSurface2_RenderDrawData(ImGui::GetDrawData());