SFML/imgui-sfml: Dear ImGui Integration for SFML 3

What ImGui-SFML solves for SFML applications

ImGui-SFML is a backend that allows an SFML application to use Dear ImGui, a C++ immediate-mode GUI library, alongside SFML rendering and window management. SFML handles graphics, input windows, events, and the main loop. Dear ImGui builds interface elements during each frame. This project supplies the bridge between those two models, so an application does not need to translate every Dear ImGui input and drawing operation into SFML code itself.

The intended users are developers building C++ applications with SFML 3 who need debug panels, editors, settings dialogs, or other interface elements during development. The repository is not a standalone game framework. It depends on SFML and Dear ImGui, and its integration instructions assume that the surrounding project already has a working SFML window and event loop.

The current `master` branch focuses on version 3, and the README says that no more features are planned for the 2.x release series. Its stated dependency range is SFML `>= 3.0.0` and Dear ImGui `>= 1.91.1, < 1.92.0`. That range is an important adoption constraint. An application using a newer Dear ImGui release will not match the documented requirements without resolving the compatibility issue.

FetchContent integration and the C++17 build boundary

The README recommends obtaining SFML and Dear ImGui with `FetchContent` or git submodules rather than installing loose copies. It links to a CMake dependency example and describes linking the resulting project through the `ImGui-SFML::ImGui-SFML` target. The project itself is written in C++17 because SFML 3 requires C++17. It also provides `.clang-format` and `.clang-tidy`, and contributing code should be formatted with ClangFormat.

The documented CMake integration point is a link operation against the backend target. The README gives the following example, which belongs in the application's CMake configuration after its dependencies have been defined:

target_link_libraries(game
  PUBLIC
    ImGui-SFML::ImGui-SFML
)

This snippet links the library but does not by itself fetch SFML, Dear ImGui, or ImGui-SFML. The README points to a separate dependency file and FetchContent tutorial for those setup steps. A project using another generator or dependency system should not assume that this target name is available automatically.

The source layout supports both this CMake route and manual integration. Files such as `imgui-SFML.cpp`, `imgui-SFML.h`, and `imconfig-SFML.h` are at the repository root. The `examples` directory contains build configuration and examples, including a minimal application and a multiple-window example.

A first SFML window with event forwarding and rendering

A minimal application creates an SFML `RenderWindow`, initializes ImGui-SFML, polls events, updates the backend, creates ImGui widgets, and renders the interface. The following example is taken from the README. It opens a 640 by 480 window, displays a green circle, shows Dear ImGui's demo window, and displays a custom button.

The event loop forwards each event to `ImGui::SFML::ProcessEvent`. The update call passes the elapsed `sf::Time` from `sf::Clock`. The application calls `window.clear()`, draws the SFML shape, then calls `ImGui::SFML::Render(window)` before displaying the frame. This sequence makes the backend's role visible: SFML owns the window and ordinary scene rendering, while the backend translates the ImGui frame into the target.

The example closes the SFML window when it receives `sf::Event::Closed`. After the loop ends, it calls `ImGui::SFML::Shutdown()`. The README specifies that shutdown should occur after `window.close()` has been called.

Manual integration when FetchContent is not used

The README provides a manual path for projects that cannot use FetchContent or submodules. The developer downloads Dear ImGui, adds its include directory, and adds the documented Dear ImGui translation units: `imgui.cpp`, `imgui_widgets.cpp`, `imgui_draw.cpp`, and `imgui_tables.cpp`. The project also requires copying the contents of `imconfig-SFML.h` into the application's `imconfig.h` file so `ImVec2` and `sf::Vector2f` can be cast in both directions.

The ImGui-SFML header and source files must also be added to the include and build configuration. The README says to link OpenGL if linking errors occur. This manual process has more integration points than the documented CMake target path, and it places responsibility for matching include paths, source files, library targets, and graphics libraries on the adopting project.

The repository also lists Conan, vcpkg, and Bazel options, but labels them as not officially maintained and likely to lag behind. That distinction matters when selecting a package manager. The source repository's own CMake guidance is the documented path with the clearest stated support.

Frame timing, custom fonts, and OpenGL state

ImGui-SFML needs several calls during each application frame. `ProcessEvent` receives polled SFML events. `Update` receives the `sf::Window` and an `sf::Time` delta, or can receive mouse position and display size explicitly. After Dear ImGui widgets are created, `Render` draws the ImGui interface through the SFML target. If the application updates more than once before rendering, the README says to call `ImGui::EndFrame` after the last `ImGui::End` in the update function.

Fonts have an additional data flow. If the default font is loaded, Dear ImGui uses it automatically. Calling `ImGui::SFML::Init(window, false)` prevents default font loading. Custom fonts are added through Dear ImGui's font API, and `ImGui::SFML::UpdateFontTexture()` updates the texture used for rendering them. The first loaded font is the default font and does not need to be pushed with `ImGui::PushFont`.

The README also describes OpenGL state handling. An application that draws only ImGui widgets without other SFML drawing may need to call `window.resetGLStates()` before rendering, but it only needs to do this once. This is a rendering-state compatibility note, not a general rendering replacement.

Multiple windows and current-window selection

The repository includes `examples/multiple_windows` for projects that create multiple SFML windows and run different ImGui contexts in them. The README says to initialize every window with the SFML window argument and shut down each registered window. Event processing must also use the overload that receives both `sf::Window` and `sf::Event`.

The current window is part of the backend's state. `ImGui::SFML::SetCurrentWindow` must be called before Dear ImGui functions such as `ImGui::Begin` or `ImGui::Button`, because those calls use the selected context and window state. The documented example is important for applications that render interface elements into different windows during one frame or update different contexts independently.

This feature adds state management to the application. A project with one window can follow the minimal example. A project with several windows must preserve window registration, select the current window before calling Dear ImGui, and use the corresponding shutdown overload. The README does not document a higher-level scene or workspace abstraction for this process.

Version limits, maintenance, and upgrade work

The main limitation is version compatibility. The documented Dear ImGui range stops before 1.92.0, while the repository lists recent releases `v3.0`, `v2.6.1`, and `v2.6`. The README also distinguishes the 3.x development line from the 2.x line, which it says will receive no further features. An upgrade can therefore involve more than changing a tag. It may require aligning SFML, Dear ImGui, source integration, and the backend version.

The repository is not archived, and the last push was on 2026-08-21. That is the available maintenance signal; the README does not publish a support policy or a compatibility matrix for every Dear ImGui and SFML combination. Maintenance and upgrade effort should be judged from the actual dependency changes and the project's version-specific instructions.

The repository is licensed under MIT. The license permits use, modification, distribution, and other actions subject to its terms, but the application owner remains responsible for reviewing license notices and dependencies. ImGui-SFML is also not a general SFML GUI system. It is a Dear ImGui backend, so projects requiring a retained-mode UI framework or a different GUI architecture should keep that distinction in view.

Editorial conclusion

Adopt ImGui-SFML when your project already targets SFML 3 and Dear ImGui >= 1.91.1 and < 1.92.0. Do not choose it without checking the version boundary, especially if your application depends on Dear ImGui 1.92 or later. Verify the CMake integration or manually configured source files first, then confirm window initialization, event forwarding, and shutdown order in your own application structure.

Frequently asked questions

Official sources

1. Issues
2. License: MIT
3. README
4. Releases
5. SFML/imgui-sfml on GitHub