Step 1: Create Project Directory Шаг 1: Создание директории проекта

Create a workspace folder and a new directory for your ImGui + SDL3 test project: Создайте рабочую папку для проектов и новую директорию для вашего тестового проекта ImGui + SDL3:

Windows (Command Prompt / PowerShell)

mkdir C:\projects\imgui-sdl3-opengl-test
cd C:\projects\imgui-sdl3-opengl-test

Ubuntu (Terminal)

mkdir -p ~/projects/imgui-sdl3-opengl-test
cd ~/projects/imgui-sdl3-opengl-test

Step 2: Create Source Files (main.cpp & CMakeLists.txt) Шаг 2: Создание исходных файлов (main.cpp и CMakeLists.txt)

You can create these files using Notepad / Sublime Text on Windows, or nano in the Ubuntu terminal: Вы можете создать эти файлы через Notepad / Sublime Text в Windows или с помощью nano в терминале Ubuntu:

Windows (Terminal / Notepad)

notepad main.cpp
notepad CMakeLists.txt

Ubuntu (Terminal / Nano)

nano main.cpp
nano CMakeLists.txt

1A. File Contents for main.cpp (Classic Loop) 1A. Содержимое файла main.cpp (Классический цикл)

#include <iostream>
#include <glad/glad.h>
#include <SDL3/SDL.h>
#include <SDL3/SDL_main.h>

#include "imgui.h"
#include "imgui_impl_sdl3.h"
#include "imgui_impl_opengl3.h"

int main(int argc, char* argv[]) {
    // 1. Initialize SDL3
    if (!SDL_Init(SDL_INIT_VIDEO)) {
        std::cerr << "SDL Initialization failed: " << SDL_GetError() << std::endl;
        return -1;
    }

    // 2. Set OpenGL 3.3 Core Profile attributes
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);

    // 3. Create SDL3 Window
    SDL_Window* window = SDL_CreateWindow("Dear ImGui + SDL3 (OpenGL 3.3) - Classic", 1280, 720, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);
    if (!window) {
        std::cerr << "Window creation failed: " << SDL_GetError() << std::endl;
        SDL_Quit();
        return -1;
    }

    // 4. Create OpenGL Context
    SDL_GLContext glContext = SDL_GL_CreateContext(window);
    if (!glContext) {
        std::cerr << "OpenGL context creation failed: " << SDL_GetError() << std::endl;
        SDL_DestroyWindow(window);
        SDL_Quit();
        return -1;
    }

    SDL_GL_MakeCurrent(window, glContext);
    SDL_GL_SetSwapInterval(1); // Enable VSync

    // 5. Initialize GLAD loader
    if (!gladLoadGLLoader((GLADloadproc)SDL_GL_GetProcAddress)) {
        std::cerr << "Failed to initialize GLAD!" << std::endl;
        SDL_GL_DestroyContext(glContext);
        SDL_DestroyWindow(window);
        SDL_Quit();
        return -1;
    }

    // 6. Setup Dear ImGui context
    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    ImGuiIO& io = ImGui::GetIO(); (void)io;
    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;

    ImGui::StyleColorsDark();

    // 7. Setup Platform/Renderer backends
    ImGui_ImplSDL3_InitForOpenGL(window, glContext);
    ImGui_ImplOpenGL3_Init("#version 330");

    bool running = true;
    bool showDemoWindow = true;

    // 8. Main Event Loop
    while (running) {
        SDL_Event event;
        while (SDL_PollEvent(&event)) {
            // Forward events to Dear ImGui
            ImGui_ImplSDL3_ProcessEvent(&event);

            if (event.type == SDL_EVENT_QUIT) {
                running = false;
            }
        }

        // Start Dear ImGui frame
        ImGui_ImplOpenGL3_NewFrame();
        ImGui_ImplSDL3_NewFrame();
        ImGui::NewFrame();

        // UI Definition
        {
            ImGui::Begin("ImGui + SDL3 Integration");
            ImGui::Text("Dear ImGui version: %s", IMGUI_VERSION);
            ImGui::Text("Application average: %.3f ms/frame (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate);
            ImGui::Checkbox("Show Demo Window", &showDemoWindow);
            ImGui::End();
        }

        if (showDemoWindow) {
            ImGui::ShowDemoWindow(&showDemoWindow);
        }

        // Rendering
        ImGui::Render();
        glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
        glClearColor(0.25f, 0.35f, 0.45f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);
        ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());

        SDL_GL_SwapWindow(window);
    }

    // 9. Cleanup
    ImGui_ImplOpenGL3_Shutdown();
    ImGui_ImplSDL3_Shutdown();
    ImGui::DestroyContext();

    SDL_GL_DestroyContext(glContext);
    SDL_DestroyWindow(window);
    SDL_Quit();

    return 0;
}

1B. File Contents for main.cpp (SDL3 Callbacks API) 1B. Содержимое файла main.cpp (SDL3 Callbacks API)

#define SDL_MAIN_USE_CALLBACKS 1
#include <iostream>
#include <glad/glad.h>
#include <SDL3/SDL.h>
#include <SDL3/SDL_main.h>

#include "imgui.h"
#include "imgui_impl_sdl3.h"
#include "imgui_impl_opengl3.h"

struct AppState {
    SDL_Window* window = nullptr;
    SDL_GLContext glContext = nullptr;
    bool showDemoWindow = true;
};

SDL_AppResult SDL_AppInit(void** appstate, int argc, char* argv[]) {
    if (!SDL_SetHint(SDL_HINT_MAIN_CALLBACK_RATE, "60")) {
        return SDL_APP_FAILURE;
    }

    if (!SDL_Init(SDL_INIT_VIDEO)) {
        std::cerr << "SDL Initialization failed: " << SDL_GetError() << std::endl;
        return SDL_APP_FAILURE;
    }

    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);

    AppState* state = new AppState();
    *appstate = state;

    state->window = SDL_CreateWindow("Dear ImGui + SDL3 (OpenGL 3.3) - Callbacks", 1280, 720, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);
    if (!state->window) {
        return SDL_APP_FAILURE;
    }

    state->glContext = SDL_GL_CreateContext(state->window);
    if (!state->glContext) {
        return SDL_APP_FAILURE;
    }

    SDL_GL_MakeCurrent(state->window, state->glContext);

    if (!gladLoadGLLoader((GLADloadproc)SDL_GL_GetProcAddress)) {
        std::cerr << "Failed to initialize GLAD!" << std::endl;
        return SDL_APP_FAILURE;
    }

    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    ImGuiIO& io = ImGui::GetIO(); (void)io;
    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
    ImGui::StyleColorsDark();

    ImGui_ImplSDL3_InitForOpenGL(state->window, state->glContext);
    ImGui_ImplOpenGL3_Init("#version 330");

    return SDL_APP_CONTINUE;
}

SDL_AppResult SDL_AppEvent(void* appstate, SDL_Event* event) {
    ImGui_ImplSDL3_ProcessEvent(event);

    if (event->type == SDL_EVENT_QUIT) {
        return SDL_APP_SUCCESS;
    }
    return SDL_APP_CONTINUE;
}

SDL_AppResult SDL_AppIterate(void* appstate) {
    auto* state = static_cast<AppState*>(appstate);
    ImGuiIO& io = ImGui::GetIO();

    ImGui_ImplOpenGL3_NewFrame();
    ImGui_ImplSDL3_NewFrame();
    ImGui::NewFrame();

    {
        ImGui::Begin("ImGui + SDL3 Callbacks API");
        ImGui::Text("Dear ImGui version: %s", IMGUI_VERSION);
        ImGui::Text("Application average: %.3f ms/frame (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate);
        ImGui::Checkbox("Show Demo Window", &state->showDemoWindow);
        ImGui::End();
    }

    if (state->showDemoWindow) {
        ImGui::ShowDemoWindow(&state->showDemoWindow);
    }

    ImGui::Render();
    glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
    glClearColor(0.25f, 0.35f, 0.45f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);
    ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());

    SDL_GL_SwapWindow(state->window);

    return SDL_APP_CONTINUE;
}

void SDL_AppQuit(void* appstate, SDL_AppResult result) {
    if (appstate) {
        auto* state = static_cast<AppState*>(appstate);

        ImGui_ImplOpenGL3_Shutdown();
        ImGui_ImplSDL3_Shutdown();
        ImGui::DestroyContext();

        if (state->glContext) {
            SDL_GL_DestroyContext(state->glContext);
        }
        if (state->window) {
            SDL_DestroyWindow(state->window);
        }
        delete state;
    }
    SDL_Quit();
}

2. File Contents for CMakeLists.txt 2. Содержимое файла CMakeLists.txt

cmake_minimum_required(VERSION 3.21)

if(NOT CMAKE_BUILD_TYPE)
    set(CMAKE_BUILD_TYPE "Debug")
endif()

project(imgui_sdl3_opengl_test CXX C)

set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

# -----------------------------------------------------------------------------
# Paths
# -----------------------------------------------------------------------------
if(WIN32)
    set(IMGUI_DIR "C:/libs/imgui-1.93.0")
    set(GLAD_DIR  "C:/libs/glad-0.1.36/opengl-3.3")
    set(SDL3_DIR  "C:/libs/sdl3-3.4.18-mingw/lib/cmake/SDL3")
else()
    set(IMGUI_DIR "$ENV{HOME}/libs/imgui-1.93.0")
    set(GLAD_DIR  "$ENV{HOME}/libs/glad-0.1.36/opengl-3.3")
    set(SDL3_DIR  "$ENV{HOME}/libs/sdl3-3.4.18-ubuntu/lib/cmake/SDL3")
endif()

# -----------------------------------------------------------------------------
# Locate Official SDL3 CMake Package
# -----------------------------------------------------------------------------
find_package(SDL3 REQUIRED CONFIG)

# -----------------------------------------------------------------------------
# ImGui Sources (including Demo Window and SDL3/OpenGL3 Backends)
# -----------------------------------------------------------------------------
set(IMGUI_SOURCES
    ${IMGUI_DIR}/imgui.cpp
    ${IMGUI_DIR}/imgui_demo.cpp
    ${IMGUI_DIR}/imgui_draw.cpp
    ${IMGUI_DIR}/imgui_tables.cpp
    ${IMGUI_DIR}/imgui_widgets.cpp
    ${IMGUI_DIR}/backends/imgui_impl_sdl3.cpp
    ${IMGUI_DIR}/backends/imgui_impl_opengl3.cpp
)

# -----------------------------------------------------------------------------
# Executable Target
# -----------------------------------------------------------------------------
add_executable(app
    main.cpp
    ${IMGUI_SOURCES}
    ${GLAD_DIR}/src/glad.c
)

# -----------------------------------------------------------------------------
# Include Directories
# -----------------------------------------------------------------------------
target_include_directories(app PRIVATE
    ${IMGUI_DIR}
    ${IMGUI_DIR}/backends
    ${GLAD_DIR}/include
)

# -----------------------------------------------------------------------------
# Backend Selection Definition
# -----------------------------------------------------------------------------
target_compile_definitions(app PRIVATE
    IMGUI_IMPL_OPENGL_LOADER_GLAD
)

# -----------------------------------------------------------------------------
# Static C++ Runtime (Applied to BOTH Windows & Ubuntu)
# -----------------------------------------------------------------------------
target_link_options(app PRIVATE -static-libgcc -static-libstdc++)

# -----------------------------------------------------------------------------
# Optimization & Symbol Stripping (Release Builds Only)
# -----------------------------------------------------------------------------
if(CMAKE_BUILD_TYPE STREQUAL "Release" OR CMAKE_BUILD_TYPE STREQUAL "MinSizeRel")
    target_compile_options(app PRIVATE -Os)
    target_link_options(app PRIVATE -s)
endif()

# -----------------------------------------------------------------------------
# Platform Linking & Dependencies
# -----------------------------------------------------------------------------
if(WIN32)
    target_link_libraries(app PRIVATE
        SDL3::SDL3-static
        opengl32
    )

    # Windows static linking & subsystem selection
    target_link_options(app PRIVATE -static)

    if(CMAKE_BUILD_TYPE STREQUAL "Debug")
        target_link_options(app PRIVATE -mconsole)
    else()
        target_link_options(app PRIVATE -mwindows)
    endif()
else()
    target_link_libraries(app PRIVATE
        SDL3::SDL3-static
        GL
        dl
        pthread
        m
    )
endif()

Step 3: Create Build & Execution Scripts Шаг 3: Создание скриптов сборки и запуска

Windows (MinGW / Batch Scripts)

config-win.bat

cmake -G Ninja -S . -B dist/win

build-win.bat

cmake --build dist/win

run-win.bat

@echo off
.\dist\win\app.exe

Run the scripts sequentially in Command Prompt or PowerShell: Последовательно запустите скрипты в командной строке или PowerShell:

config-win.bat
build-win.bat
run-win.bat

Ubuntu (Bash Scripts)

config-linux.sh

#!/usr/bin/env bash
set -e
cmake -G Ninja -S . -B dist/linux

build-linux.sh

#!/usr/bin/env bash
set -e
cmake --build dist/linux

run-linux.sh

#!/usr/bin/env bash
set -e
./dist/linux/app

Grant execute permissions on Ubuntu before running: Предоставьте права на выполнение в Ubuntu перед запуском:

chmod +x config-linux.sh build-linux.sh run-linux.sh
./config-linux.sh
./build-linux.sh
./run-linux.sh

Step 4: Expected Output Шаг 4: Ожидаемый результат

After running the build and execution scripts, a native desktop window will appear displaying Dear ImGui with the dark style, responsive widgets, and the interactive demo window: После запуска скриптов сборки и выполнения откроется нативное окно приложения с интерфейсом Dear ImGui в темной теме, интерактивными элементами управления и окном Demo:

Dear ImGui + SDL3 (OpenGL 3.3) - Classic

or (if using the Callbacks API version): или (если используется версия с Callbacks API):

Dear ImGui + SDL3 (OpenGL 3.3) - Callbacks