// Dear ImGui: standalone example application for SDL3 + OpenGL
// (SDL is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan/Metal graphics context creation, etc.)
// Learn about Dear ImGui:
// - FAQ https://dearimgui.com/faq
// - Getting Started https://dearimgui.com/getting-started
// - Documentation https://dearimgui.com/docs (same as your local docs/ folder).
// - Introduction, links and more at the top of imgui.cpp
#include "imgui.h"
#include "imgui_impl_sdl3.h"
#include "imgui_impl_opengl3.h"
#include <stdio.h>
#include <SDL3/SDL.h>
#if defined(IMGUI_IMPL_OPENGL_ES2)
#include <SDL3/SDL_opengles2.h>
#else
#include <SDL3/SDL_opengl.h>
#endif
// This example doesn't compile with Emscripten yet! Awaiting SDL3 support.
#ifdef __EMSCRIPTEN__
#include "../libs/emscripten/emscripten_mainloop_stub.h"
#endif
// Main code
int main(int, char**)
{
// Setup SDL
if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER | SDL_INIT_GAMEPAD) != 0)
{
printf("Error: SDL_Init(): %s\n", SDL_GetError());
return -1;
}
// Decide GL+GLSL versions
#if defined(IMGUI_IMPL_OPENGL_ES2)
// GL ES 2.0 + GLSL 100
const char* glsl_version = "#version 100";
SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
#elif defined(__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
// Enable native IME.
SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");
// 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);
Uint32 window_flags = SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_HIDDEN;
SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL3+OpenGL3 example", 1280, 720, window_flags);
if (window == nullptr)
{
printf("Error: SDL_CreateWindow(): %s\n", SDL_GetError());
return -1;
}
SDL_SetWindowPosition(window, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED);
SDL_GLContext gl_context = SDL_GL_CreateContext(window);
SDL_GL_MakeCurrent(window, gl_context);
SDL_GL_SetSwapInterval(1); // Enable vsync
SDL_ShowWindow(window);
// Setup Dear ImGui context
IMGUI_CHECKVERSION();
ImGui::CreateContext();
ImGuiIO& io = ImGui::GetIO(); (void)io;
io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard; // Enable Keyboard Controls
io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad; // Enable Gamepad Controls
// Setup Dear ImGui style
ImGui::StyleColorsDark();
//ImGui::StyleColorsLight();
// Setup Platform/Renderer backends
ImGui_ImplSDL3_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 a nullptr. 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.
// - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
// - Read 'docs/FONTS.md' 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 \\ !
// - Our Emscripten build process allows embedding fonts to be accessible at runtime from the "fonts/" folder. See Makefile.emscripten for details.
//io.Fonts->AddFontDefault();
//io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
//io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
//io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
//io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
//ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
//IM_ASSERT(font != nullptr);
// 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;
#ifdef __EMSCRIPTEN__
// For an Emscripten build we are disabling file-system access, so let's not attempt to do a fopen() of the imgui.ini file.
// You may manually call LoadIniSettingsFromMemory() to load settings from your own storage.
io.IniFilename = nullptr;
EMSCRIPTEN_MAINLOOP_BEGIN
#else
while (!done)
#endif
{
// 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, 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.
SDL_Event event;
while (SDL_PollEvent(&event))
{
ImGui_ImplSDL3_ProcessEvent(&event);
if (event.type == SDL_EVENT_QUIT)
done = true;
if (event.type == SDL_EVENT_WINDOW_CLOSE_REQUESTED && event.window.windowID == SDL_GetWindowID(window))
done = true;
}
// Start the Dear ImGui frame
ImGui_ImplOpenGL3_NewFrame();
ImGui_ImplSDL3_NewFrame();
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 create 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 / 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();
glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
glClearColor(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
glClear(GL_COLOR_BUFFER_BIT);
ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
SDL_GL_SwapWindow(window);
}
#ifdef __EMSCRIPTEN__
EMSCRIPTEN_MAINLOOP_END;
#endif
// Cleanup
ImGui_ImplOpenGL3_Shutdown();
ImGui_ImplSDL3_Shutdown();
ImGui::DestroyContext();
SDL_GL_DeleteContext(gl_context);
SDL_DestroyWindow(window);
SDL_Quit();
return 0;
}
