// dear imgui: standalone example application for SDL2 + OpenGL // If you are new to dear imgui, see examples/README.txt and documentation at the top of imgui.cpp. // (SDL is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan graphics context creation, etc.) // (GL3W is a helper library to access OpenGL functions since there is no standard header to access modern OpenGL functions easily. Alternatives are GLEW, Glad, etc.) #include "imgui.h" #include "imgui_impl_sdl.h" #include "imgui_impl_opengl3.h" #include <stdio.h> #include <SDL.h> // About OpenGL function loaders: modern OpenGL doesn't have a standard header file and requires individual function pointers to be loaded manually. // Helper libraries are often used for this purpose! Here we are supporting a few common ones: gl3w, glew, glad. // You may use another loader/header of your choice (glext, glLoadGen, etc.), or chose to manually implement your own. #if defined(IMGUI_IMPL_OPENGL_LOADER_GL3W) #include <GL/gl3w.h> // Initialize with gl3wInit() #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLEW) #include <GL/glew.h> // Initialize with glewInit() #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD) #include <glad/glad.h> // Initialize with gladLoadGL() #else #include IMGUI_IMPL_OPENGL_LOADER_CUSTOM #endif int main(int, char**) { // Setup SDL if (SDL_Init(SDL_INIT_VIDEO|SDL_INIT_TIMER) != 0) { printf("Error: %s\n", SDL_GetError()); return -1; } // Decide GL+GLSL versions #if __APPLE__ // GL 3.2 Core + GLSL 150 const char* glsl_version = "#version 150"; SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG); // Always required on Mac SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE); SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3); SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2); #else // GL 3.0 + GLSL 130 const char* glsl_version = "#version 130"; SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0); SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE); SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3); SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0); #endif // Create window with graphics context SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1); SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24); SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8); SDL_DisplayMode current; SDL_GetCurrentDisplayMode(0, ¤t); SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI); SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+OpenGL3 example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, window_flags); SDL_GLContext gl_context = SDL_GL_CreateContext(window); SDL_GL_MakeCurrent(window, gl_context); SDL_GL_SetSwapInterval(1); // Enable vsync // Initialize OpenGL loader #if defined(IMGUI_IMPL_OPENGL_LOADER_GL3W) bool err = gl3wInit() != 0; #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLEW) bool err = glewInit() != GLEW_OK; #elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD) bool err = gladLoadGL() == 0; #else bool err = false; // If you use IMGUI_IMPL_OPENGL_LOADER_CUSTOM, your loader is likely to requires some form of initialization. #endif if (err) { fprintf(stderr, "Failed to initialize OpenGL loader!\n"); return 1; } // Setup Dear ImGui context IMGUI_CHECKVERSION(); ImGui::CreateContext(); ImGuiIO& io = ImGui::GetIO(); (void)io; io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard; // Enable Keyboard Controls io.ConfigFlags |= ImGuiConfigFlags_DockingEnable; // Enable Docking io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable; // Enable Multi-Viewport / Platform Windows //io.ConfigViewportsNoAutoMerge = true; //io.ConfigViewportsNoTaskBarIcon = true; // Setup Dear ImGui style ImGui::StyleColorsDark(); //ImGui::StyleColorsClassic(); // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones. ImGuiStyle& style = ImGui::GetStyle(); if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable) { style.WindowRounding = 0.0f; style.Colors[ImGuiCol_WindowBg].w = 1.0f; } // Setup Platform/Renderer bindings ImGui_ImplSDL2_InitForOpenGL(window, gl_context); ImGui_ImplOpenGL3_Init(glsl_version); // Load Fonts // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them. // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple. // - If the file cannot be loaded, the function will return NULL. Please handle those errors in your application (e.g. use an assertion, or display an error and quit). // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call. // - Read 'misc/fonts/README.txt' for more instructions and details. // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ ! //io.Fonts->AddFontDefault(); //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f); //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f); //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f); //io.Fonts->AddFontFromFileTTF("../../misc/fonts/ProggyTiny.ttf", 10.0f); //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, NULL, io.Fonts->GetGlyphRangesJapanese()); //IM_ASSERT(font != NULL); 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.) // You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs. // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application. // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application. // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags. 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; } // Start the Dear ImGui frame ImGui_ImplOpenGL3_NewFrame(); ImGui_ImplSDL2_NewFrame(window); ImGui::NewFrame(); // 1. Show the big demo window (Most of the sample code is in ImGui::ShowDemoWindow()! You can browse its code to learn more about Dear ImGui!). if (show_demo_window) ImGui::ShowDemoWindow(&show_demo_window); // 2. Show a simple window that we create ourselves. We use a Begin/End pair to created a named window. { 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 (you can use a format strings too) 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 (most widgets return true when edited/activated) counter++; ImGui::SameLine(); ImGui::Text("counter = %d", counter); ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().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(); glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y); glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w); glClear(GL_COLOR_BUFFER_BIT); ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData()); // Update and Render additional Platform Windows // (Platform functions may change the current OpenGL context, so we save/restore it to make it easier to paste this code elsewhere. // For this specific demo app we could also call SDL_GL_MakeCurrent(window, gl_context) directly) if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable) { SDL_Window* backup_current_window = SDL_GL_GetCurrentWindow(); SDL_GLContext backup_current_context = SDL_GL_GetCurrentContext(); ImGui::UpdatePlatformWindows(); ImGui::RenderPlatformWindowsDefault(); SDL_GL_MakeCurrent(backup_current_window, backup_current_context); } SDL_GL_SwapWindow(window); } // Cleanup ImGui_ImplOpenGL3_Shutdown(); ImGui_ImplSDL2_Shutdown(); ImGui::DestroyContext(); SDL_GL_DeleteContext(gl_context); SDL_DestroyWindow(window); SDL_Quit(); return 0; }